9th High Power Targetry Workshop (HPTW2026)

16 Nov 2026, 08:00 → 21 Nov 2026, 13:30 Europe/Zurich

503/1-001 - Council Chamber (CERN)

Ana-Paula Bernardes (CERN), Charlotte Duchemin (CERN SY/STI/RBS), Marco Calviani (CERN), Thierry Stora (CERN)

The High Power Targetry Workshop convenes scientists and engineers from the international particle accelerator targetry community. Its scope encompasses applications in neutrino, neutron, radioactive ion beam and material & medical R&D irradiation facilities, including accelerator-driven systems and intensity frontier experiments.

Themes of the workshop include, but are not limited to:

• R&D activities to support design concepts
• Beam intercepting devices design, analysis and validation of concepts
• Radiation damage effects to materials - simulations and experimental studies
• Post-irradiation examination of systems and components removed from service
• Target facility challenges & opportunities
• Fabrication, assembly, inspection and quality assurance
• Operational experience
• Sustainability, dismantling and repurposing in target systems

 

If you are interested in staying up to date, please subscribe to the HPTW mailing list:

• With a CERN account

If you have a CERN account then please use it to login and then click "Add me as member".

• Without a CERN account

If you don't have a CERN Account then please follow this Knowledge Base article to create one: https://cern.service-now.com/service-portal?id=kb_article&n=KB0007539. And then click on "Add me as member".

CERN Hostel Booking Form - High Power Targetry Workshop.docx

Hotel Discount Reservation Codes.pdf

Monday 16 November

Registration

Intro & Keynote

Intro & Keynote: Welcome address by the CERN Director General

10:10 Coffee break

Session A - Target facility challenges & opportunities

1 The LBNF Neutrino Beamline Design – Progress and Future Plans

The Long-Baseline Neutrino Facility (LBNF) provides the infrastructure required to generate a high-intensity neutrino beam and transmit it approximately 800 miles (1,300 km) through the Earth to the DUNE (Deep Underground Neutrino Experiment) far detectors located deep underground at the Sanford Underground Research Facility in South Dakota. The LBNF Nu Beamline is designed to accept 1.2 MW of 120 GeV pulsed proton beam and be upgradable to 2.4 MW after 5 years of operation with an overall facility lifetime of at least 20 years. Major beam intercepting systems include the target, the focusing horns, the decay pipe, the hadron beam absorber, beam windows, and beam instrumentation. Supporting infrastructure includes multiple cooling systems, shielding, remote handling and radiation protection systems. Currently the LBNF Beamline project is completing final design, preparing for baseline and construction approvals, and aiming for the start of the world’s highest power neutrino beam to DUNE in 2031. This presentation will describe the LBNF Neutrino Beamline critical systems and provide an update on recent progress and future plans.

Speaker: Patrick Goodwin Hurh (Fermi National Accelerator Lab. (US))

2 ISIS Target Station 1: Remote repair of target trolley

During the shutdown following the 2025/1 user cycle, the Target trolley in TS1 developed a fault whilst transitioning between the operational and maintenance positions. Investigative work was carried out to establish the cause of the issue and it was diagnosed as a wheel bearing failure. Whilst challenging, a method of resolution was implemented, however this did not appear to solve the mobility issue.
Further investigation highlighted a mechanical issue between the forward portion of the trolley and the tunnel walls. The location of the fault is within a highly radioactive and contaminated area, inaccessible to perform hands-on repairs, and barely accessible by remote manipulator arms.
A mock-up of the tunnel dimensions and trolley rails was constructed in the prototyping area in order to establish a method of resolution. Following a number of suggestions, a final decision was made to construct a ‘cutting robot’ to utilise the existing rails and move on 3 axis’, using rotating abrasive wheels to remove the defective material.
The process was tested and refined in the prototyping area until the team were confident in their ability to complete the task, before the equipment was disassembled and transported into the radioactive handling cell for the cutting to commence.

Speaker: Henry Russell

3 Technical Design of the Second Target Station at the Oak Ridge National Lab Spallation Neutron Source

With the completion of the Proton Power Upgrade (PPU) Project of the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL), the preparations are complete to provide power to the Second Target Station (STS). STS will comprise of a rotating solid Tungsten target with two supercritical Hydrogen moderators feeding 20 instrument end stations. The STS is close to completion of final design and procurement is about to initiate upon pending approval of CD-2/3 by Department of Energy. Groundwork for the construction has commenced.
STS will complete the ORNL three source strategy, the HFIR, SNS and STS. Compared to other two currently operating neutron sources, STS will deliver high brightness cold neutron beams. The innovations in design of Target, Moderators, Beam extraction with today’s modern development tools, promise a significantly improved brightness that should allow for cutting edge science and engineering research using neutron scattering.
This talk will provide an overview of the technical solutions chosen for the STS Target Systems and current project status to achieve these objectives.

Speaker: Daniel Lyngh (Oak Ridge National Laboratory)

4 ESS Target Station Update: Progress Toward Beam on Target

The European Spallation Source (ESS) target station is a central component of the world’s most powerful neutron source, integrating the rotating tungsten target, helium cooling systems, moderators, reflector assemblies, shielding, and remote handling infrastructure into a highly demanding operational environment. This presentation will provide an update on the current status of the ESS target station, highlighting recent progress in installation, commissioning preparations, system integration, and operational readiness activities. The talk will present updates on cold commission phase, the experiences that were gained and lessons learned. In addition, the presentation will outline upcoming milestones toward first beam operations and discuss the role of the target station in enabling the ESS scientific program.

Speaker: Rikard Linander

CERN visits: Information Visits on Saturday

Convener: Claudia Ahdida

12:10 Lunch break

Session A - Target facility challenges & opportunities

5 The S3 target station and the GANIL Targets Laboratory

GANIL facility was upgraded with a superconducting linear accelerator, which delivers highly intense stable beams ranging from protons to uranium ions. Light ions are used at the Neutron for Science (NFS) experimental hall [1] and heavier ions are essential to produce exotic nuclei, like heavy neutron-deficient isotopes and super heavy nuclei, in the Super Separator Spectrometer (S3) [2, 3].
By combining the intense heavy ion beams with the fully instrumented target station, the various electromagnetic components, the fixed and movable beam dumps, S3 is a powerful tool to purify the elements of interest produced in the target from the primary intense ion beam, and retrieving them up to the focal plane with a high transmission [4, 5].
Furthermore, the increasing number of experiments at GANIL has driven a tenfold rise in target demand—from roughly 50 units per year to a projected 500+. In parallel, the materials used for these targets have become more sophisticated, now encompassing rare earth elements and natural uranium. This evolution not only requires a larger production volume but also demands higher quality standards, with strict criteria for homogeneity and purity. To address these requirements, cutting-edge equipment, controlled production environments, and stringent validation protocols are critical to ensuring reproducibility and precision
In response to these evolving needs, GANIL has established PALAIS (Plateforme cibles pour GANIL/SPIRAL2), a dedicated target fabrication platform designed to serve an international user community. This platform, PALAIS specializes in producing a diverse range of high-quality targets in large quantities.
We propose to present advancements on rotating targets’ stations including their instrumentation to control the integrity of targets within the S3 project and to provide an update on the GANIL Target Laboratory, which has recently undergone extensive renovation and modernization, including the acquisition of state-of-the-art equipment.

Speaker: Christelle STODEL

6 Design and R&D efforts for Accelerator Interfacing Systems for the Second Target Station’s Target Systems at Spallation Neutron Source

The Second Target Station’s (STS) Target Systems is comprised of systems necessary for converting oncoming pulses of protons into neutrons that can be used for novel neutron experiments. A 700kW proton beam will be delivered to a rotating tungsten target at a repetition rate of 15Hz. Several beamline interface and diagnostic components support safe, reliable operation. The proton beam window will provide a barrier between the high-vacuum accelerator atmosphere and the core vessel atmosphere while minimizing scattering of the beam to the target. The target viewing periscope (TVP) will provide an optical view of the front face of the rotating target, made visible by a luminescent coating. This device will enable a diagnostic measurement of the proton beam profile as it hits the target. Plans and R&D are in place to measure the front face of the target in IR range as well. The Target Systems scope also includes beam diagnostics - the halo monitor and harp. To reduce technical and schedule risk, R&D activities were performed to confirm material properties and execute design in collaboration with established vendors.

Speaker: Neelam Pradhan (Oak Ridge National Laboratory)

7 Design and Integration of the Beam Dump Facility Target Complex

The Search for Hidden Particles (SHiP) is a new high-intensity fixed-target experiment that will be installed in CERN’s Experimental Cavern North 3 (ECN3) within the North Area. The experiment will make use of the 400 GeV proton beam provided by the Super Proton Synchrotron (SPS). To enable its operation, a dedicated Beam Dump Facility (BDF) target complex will be built. The target complex consists of an underground target station within Tunnel Target Cave 8 (TCC8), a service building, and the access pathway from the surface to the underground. The target station comprises of the BDF tungsten target, vacuum vessel, trolley extraction system and a collection of shielding, giving an overall weight and size of the target station to be around 2000 Tonnes and 12m x 8.9m x 4.8m. A service building containing all infrastructure to cool and operate the target station, an installation shaft, and an underground area for maintenance and storage of spent components before disposal. This contribution details the main systems required to support the operation of the BDF target, including the radiation protection considerations, remote handling strategies, utilities requirements, cooling and ventilation aspects, installation and operation procedures, maintenance and decommissioning plans, and sustainability aspects.

Speaker: Gemma Stacey Humphreys (CERN)

8 CERN-ISOLDE targets for radioactive ion beam production

For more than 50 years CERN-ISOLDE has been producing a wide range of radioactive ion beams (RIBs) using the isotope separation on-line (ISOL) method. Central to ISOLDE’s beam portfolio is its diverse selection of thick target materials and the high energy proton beam (>= 1.4 GeV, 2 µA) both driving the radionuclide production. Isotopes are generated via spallation, fission and fragmentation reactions and released by heating the target material to ultra-high temperatures (> 2000 °C) in vacuum. Via a transfer line isotopes effuse to the ion source, where they are ionised, formed into an ion beam and send to experimental stations. More than 1000 isotopes with half-lives down to milliseconds of more than 75 elements are available for a broad range of physics research.
Ever increasing user demands in terms of yield and beam purity drive the development of target and structural materials. With this contribution, we will give an overview of ISOLDE’s “targetry” capabilities, highlight recent developments, tailored to provide diverse, high-intensity, high-purity RIBs.

Speaker: Simon Thomas Stegemann (CERN)

14:50 Coffee break

Session A - Target facility challenges & opportunities

9 Target Developments Towards the High-Power ISOL@MYRRHA Facility

ISOL@MYRRHA is being developed at SCK CEN as a next-generation isotope separation on-line facility for the production of radioactive ion beams. The facility will use a fraction of the 100 MeV MYRRHA proton beam to drive a dedicated ISOL target station, combining high beam intensity, up to 500 µA, with irradiation periods of up to 4 weeks. These conditions place ISOL@MYRRHA within the high-power targetry domain, with challenges related to power deposition in the target (10 kW) and the directly surrounding components.

This contribution will focus on the development of the ISOL@MYRRHA high-power target and its associated vacuum vessel. This vessel houses the target and ion source and integrates key interfaces such as the beam window, vacuum/gas/water seals, and the electrical and cooling services required for operation. Given the demanding beam power and operational requirements, a phased implementation approach will be followed allowing progressive validation of critical components and technologies. Several prototypes have already been developed, including lower-power target containers, ion sources, an additively manufactured target vessel, a reduced-power beam window, and porous target materials for the first years of operation (e.g. SiC and ThO₂ irradiated and tested at CERN). This contribution will also describe the current laboratory infrastructure at SCK CEN, used for the assembly, conditioning, and testing of these prototypes, and will highlight the main results and how they support the design of the ISOL@MYRRHA facility.

Speaker: Dr Joao Pedro Ramos (Belgian Nuclear Research Center (BE))

10 CERN-MEDICIS: Production of high-purity medical radionuclides for research and clinical translation

CERN-MEDICIS (Medical Isotopes Collected from ISOLDE) is a unique research facility located on the Meyrin site, next to the ISOLDE target area, dedicated to the production, purification, and offline mass separation of non-conventional medical radionuclides for research and development in nuclear medicine. Its mission is to provide high-purity radionuclides for developing novel radiopharmaceuticals for diagnostic imaging and targeted radionuclide therapy, supporting advances in precision medicine.
The facility has played a key role in establishing the European medical radionuclide infrastructure through the PRISMAP and PRISMAP+ projects, providing access to innovative radionuclides and fostering international collaboration. CERN-MEDICIS operates an isotope mass separator and a radiochemistry laboratory included within a Type A work sector. It exploits a target irradiation station supplied by 1.4 GeV proton beams from the CERN Proton Synchrotron Booster (PSB). In addition to irradiating targets on-site, it processes activated targets from external institutes, particularly during CERN Long Shutdown periods. After mass separation, radioactive ion beams are implanted into metallic foils and distributed to collaborating research centres for radiochemical processing and biomedical research.
To date, CERN-MEDICIS has supplied high-purity radionuclides to research institutes across Europe, Pakistan, and the United States, including K-43, Sc-43, Sc-44, Sc-47, Eu-145, Tb-149/Gd-149, Sm-153, Tb-155, Tm-165/Er-165, Tm-167, Er-169, Yb-175, Ra-223, Ra-224, Ra-225, Ac-225, and, for the first time in 2025, Cu-67 and Ac-226. Following CERN Council approval for clinical use of MEDICIS-produced radionuclides, high-specific-activity Sm-153 has been selected as the first isotope to advance toward clinical applications.
Continuous improvements in target preparation, isotope release, ion-source performance, molecular ion beam production, online implantation monitoring, and radiochemical processing have increased production yields, separation efficiencies, and delivered activities. This presentation will focus on these aspects.

Speaker: Patricija Kalnina (University of Latvia (LV))

11 The future TATTOOS radionuclides facility at PSI

TATTOOS (Targeted Alpha Tumour Therapy and Other Oncological Solutions) is a future ISOL (Isotope Separation On-Line) facility under development at the Paul Scherrer Institute in collaboration with the University of Zurich and the University Hospital Zurich. The facility will produce sufficient quantities of radionuclides for the diagnosis and therapy of cancer for use in clinical studies. TATTOOS will be housed in a new building and driven by a high-power (up to 59 kW) 590 MeV proton beam split off the main HIPA (High Intensity Proton Accelerator) beam. Initially, the target will consist of a tantalum cylinder with an equivalent length of up to 10 cm, but other materials, such as thorium and uranium carbides, are also under consideration. This contribution will provide an update on the project's progress and examine the milestones set on the road to achieving the ambitious goal of beam on target by 2032.

Speaker: Dr Davide Reggiani (Paul Scherrer Institute)

12 Project IMPACT at PSI with focus on HIMB: an upgrade of the meson target station at HIPA

The IMPACT project at the Paul Scherrer Institute (PSI) aims to significantly enhance the utilization of the 590 MeV proton beam from the high-intensity proton accelerator HIPA. The objective is to upgrade the existing Target Station M and its two beamlines into the HIMB (High Intensity Muon Beam) facility, and the installation of a new target facility, TATTOOS (Targeted Alpha Tumour Therapy and Other Oncological Solutions) for producing medical isotopes in large quantities and with high potential for cancer treatment and diagnostics. The following talk will focus on HIMB.

With HIMB muon production rates two orders of magnitude higher than current ones are feasible as shown in beam line simulations taking realistic magnetic fields into account. The installation of HIMB requires first the dismantling of the existing facility M—partly through remote handling—as well as a substantial reconfiguration of the experimental hall, impacting several beamlines. Many new components have been designed in-house including radiation hard magnets, complex large vacuum chambers and a new shielded remote controlled exchange flask for the highly activated components. The shielding of HIMB including beamlines and experimental stations and respecting all media supply lines regarding cooling, electrical power, signal cables, ventilation is under design as well. All beam intercepting devices like collimators, beamstoppers, profile monitors and the target station (except for the graphite target wheel) are manufactured in-house.

An overview of the HIMB technical and conceptional design and the implementation plan scheduled for 2028–2029 will be given.

Speaker: Daniela Kiselev

Tuesday 17 November

Session B - Operational experience

13 Operation and Maintenance Updates for the Mercury Target System at J-PARC Pulsed Spallation Neutron Source

Liquid mercury target system is used in Pulsed spallation neutron source at the Materials and Life Science Experimental Facility (MLF) of J-PARC. Mercury is contained in a stainless steel vessel, referred to as the target vessel, and is circulated in the mercury circulation system during beam operation to remove heat generated by proton beam injection at 3 GeV and 25 Hz, with a beam power of up to1 MW.
In April 2024, stable operation nearly 1 MW was successfully achieved for two months, representing a major milestone of the MLF. During the subsequent maintenance period, the beam entrance portion of the target vessel was cut to extract specimens for inspection of cavitation erosion on the interior surface after 1 MW operation. In addition, the mercury pump was replaced due to degradation of insulation resistance. After replacement, a small leakage of radioactive gas was detected from the replaced pump flange. Furthermore, in May 2025, approximately one month after resoling the gas leakage issue, a water leak from the water shroud of the target vessel was experienced.
In the workshop, the current operation status of the mercury target system and recent maintenance experiences, including the cutting of a proton beam window planned for the 2026 maintenance period, will be presented.

Speaker: Dr Takashi Naoe (Japan Atomic Energy Agency)

14 Performance overview of the new spallation target at LANSCE as viewed by the DICER instrument

A new moderated neutron spallation target assembly has been operational at the Los Alamos Neutron Science CEnter (LANSCE) since 2022. This new target, termed Mark-IV, improves on the neutron flux and energy resolution of the previous iteration, termed Mark-III. The performance of Mark-IV has been studied, implementing the recently developed Device for Indirect Capture Experiments on Radionuclides (DICER), located at LANSCE. DICER is an innovative neutron transmission instrument, designed to tightly constrain nuclear data on radionuclides. Substantial work is currently ongoing to benchmark the performance of this new neutron production target, and the first findings will be presented.

Speaker: Thanos Stamatopoulos

15 Remote Replacement of SNS Inner Reflector Plug-2

The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) uses an Inner Reflector Plug (IRP) to shield, reflect, moderate, and guide neutrons produced from the liquid mercury target. Since the first neutron production in 2006, the roughly 14.5’ tall, 34-ton IRP has been successfully replaced twice: IRP-1 in early 2018 and IRP-2 in late 2025. While general design guidelines to enable remote replacement of the IRP have maintained a three-segment disassembly and removal strategy, details specific to each IRP design have caused unique replacement challenges. Examples include changes in routing for the water cooling and hydrogen Cryogenic Moderator System (CMS) process piping, and modified shielding geometries. Additionally, seized segment tie rods complicated disassembly and removal operations. Comprehensive remote handling mock-up testing was employed to address the known design changes to IRP-2 and to mitigate radiological concerns. The goal of this presentation is to share the results, conclusions, and key lessons learned from the 2025 IRP-2 replacement operation.

Speaker: Luke Meyer

16 The SNS Mercury Target at 2 MW

The Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory was built with a mercury target system designed to be operated at up to 1.4 MW and upgraded in the future to 2 MW. The target system has now been upgraded and operated at 2 MW. This talk will discuss the challenges seen with the mercury target system, with an emphasis on lessons learned that would benefit future liquid metal target stations.
Specific topics include experience with the disposable target modules, the retrofit and operation of gas injection systems needed for pulsed beam operation, experience with component failures, and unexpected issues seen in operation. A large challenge with the SNS system involves the 2-phase flow of mercury and helium throughout the system that was not originally designed to operate in this way. Additionally, the added beam power and beam energy have caused challenges throughout the target building.

Speaker: Drew Winder

10:00 Coffee break

Session B - Operational experience

17 Present status and future of BigRIPS beam dump at RIKEN RIBF

At RIKEN RI Beam Factory (RIBF), various short-lived nuclei are produced via the reaction of primary heavy-ion beams at 345 MeV/nucleon with a beryllium target. The BigRIPS separator is utilized to separate and identify specific isotopes from the resulting reaction products. The unreacted primary heavy-ion beam is intercepted by water-cooled, high-power beam dump located inside or downstream of the first BigRIPS dipole magnet. These dumps safely dissipates an extreme heat flux exceeding 400 MW/m² (corresponding to a volumetric heat load of 50 GW/m³). While a V-shaped copper-alloy beam dump is currently employed, a rotating beam dump is planned for future implementation to accommodate higher beam intensities.

This presentation provides an overview of the current BigRIPS beam dump, shares operational experiences, and outlines the development plan for the new beam dump to support future RIBF upgrades.

Speaker: Yasuhiro Togano (RIKEN Nishina Center)

18 Production Target at J-PARC Hadron Experimental Facility

At the J-PARC Hadron Experimental Facility, a wide variety of nuclear and particle physics experiments have been conducted using secondary particles such as kaons and pions, produced in a dense metal target irradiated by a slowly extracted 30-GeV proton beam. The current target is a fixed-type gold block bonded to a water-cooled copper block. The target can accept up to 115-kW proton beam power for a 4.24-s repetition cycle. The target has been in service since 2020 and achieved stable 101 kW operation in 2026. To increase the acceptable beam power to 150 kW, development of a new target is underway. This report presents the operational status of the current target and the progress of the new target development.

Speaker: Dr Hiroaki Watanabe (KEK)

19 Innovations in High-Power Targetry for Medical Radionuclides: Overview and Developments within PRISMAP and PRISMAP+

The increasing demand for innovative medical radionuclides has strengthened the need for target systems capable of operating reliably under increasingly demanding irradiation conditions. High-power target development is therefore becoming a key enabling technology, requiring the integration of advanced materials, efficient cooling technologies, accurate thermo-mechanical design and innovative manufacturing techniques.
Within the European PRISMAP and PRISMAP+ initiatives, a coordinated research programme has been established to improve target technologies related to both direct irradiation facilities and Isotope Separation On-Line (ISOL) infrastructures. Bringing together complementary expertise from several European laboratories, these projects aim to address common challenges associated with high-power target operation while fostering the production of emerging medical radionuclides.
This contribution provides an overview of the target-related activities carried out within PRISMAP and PRISMAP+, highlighting the evolution from material optimisation and conventional target architectures towards innovative fabrication methods and advanced concepts. In PRISMAP, significant efforts have been devoted to the optimisation of target materials, thermal management strategies and high-temperature target assemblies, together with the characterisation of thermophysical and microstructural properties required for reliable target design.
Building upon these achievements, PRISMAP+ expands the research towards advanced manufacturing technologies, including spark plasma sintering, molecular plating and additive manufacturing. Particular emphasis is placed on engineered lattice structures featuring interconnected porosity, designed to improve heat removal, mechanical robustness and radionuclide release efficiency under high-intensity irradiation. All these developments support the production of several emerging medical radionuclides, including Sc-44, Sc-47, Cu-67, Tb-152 and Tb-155.
Beyond presenting individual technological developments, this contribution illustrates how PRISMAP and PRISMAP+ establish a collaborative European framework for advancing high-power target science, creating synergies between direct irradiation and ISOL communities while promoting innovative solutions for the production of medical radionuclides.

Speaker: Michele Ballan

Poster - flash presentation

12:00 Workshop Group Picture

12:15 Lunch break

Session C - Sustainability, dismantling and repurposing in target systems

20 Radiological characterization of the TCC8 / ECN3 dismantling

This work presents a comprehensive radiological characterization in view of the dismantling of the TCC8/ECN3 caverns, hosting the primary target area and secondary beamline of the NA62 experiment, in operation since 2009.
The 255 m-long beamline equipment, located in the underground caverns will be removed during the Long Shutdown 3 in preparation for the BDF facility.
The NA62 experiment operates with a mixed hadron beam at 75 GeV/c of momentum, produced by a 400 GeV/c proton beam of average intensity of 2.3x10^12 protons per spill on a beryllium target. The latter consists of a 400 mm-long rod of 2 mm diameter, suspended between thin foils and enclosed in an aluminium box, and cooled by forced air convection. Downstream, a water-cooled Cu-Cr-Zr collimator with an aperture of 1.5 cm in diameter is installed. These beam-intercepting devices, together with the surrounding cast iron shielding blocks of the target station, becomes highly activated during operation.
The analysis combines FLUKA MC simulations with ActiWiz and SESAME assessments to evaluate residual radiation fields, material activation, radioactive waste classification and prepare radioactive transport and storage. Detailed assessments of residual dose rates are provided for the beamline components located in TCC8, such as target, collimators, magnets and dump, at contact and distance-dependent dose rates relevant for dismantling, transport, and disposal operations. Estimated dose rate rates of the TCC8 equipment range from 1 mSv/h up to 60 mSv/h at 10 cm, after 2 years of cooling.
The simulation framework is benchmarked against survey measurements performed in March 2023, ensuring reliable predictions of radiological conditions. The study further addresses the activation and potential re-use of concrete shielding materials, supported by material composition analyses derived from gamma spectroscopy and XRF measurements.
Finally, the radiological classification of the TCC8 tunnel post-dismantling is discussed, providing key input for a radiological area classification.

Speaker: Elzbieta Nowak (CERN)

21 T2K Target Helium Cooling Trouble

The T2K neutrino target is graphite rod target, cooled using a closed loop helium circuit. Targets have been in operation with increasing beam power since 2009. The 3rd target was installed in late 2022.
In March 2025, a drop in Helium supply pressure indicated a system leak and caused operations to stop. Investigations were undertaken to establish the cause.
Remote leak detection methods, employed within the target station helium vessel, indicated the source of the leak to be a commercial chain clamp loosening likely due to combined thermal cycling and vibration. This was confirmed with further inspections in the target station remote maintenance area. The joint was tightened remotely to stop the leak, and a retrofit locking device was deployed to reduce the likelihood of recurrence.
This presentation summarises the work undertaken to diagnose and fix the helium cooling leak. This was completed successfully without costly replacement of target and/or horn systems, allowing T2K operations to resume in November 2025 with minimal disruption.

Speaker: Eric John Harvey-Fishenden (Science and Technology Facilities Council STFC (GB))

22 BDF Target Design Driven by Final Disposal Requirements: Outcome of the Service Cell Study

As part of the HI-ECN3 project, the final disposal of the Beam Dump Facility (BDF) targets for the new SHiP experiment must be addressed. These targets are expected to be among the most highly activated components ever built at CERN. With no elimination pathway existing at CERN for the preliminary target design, a study to define a processing route for the target using a Service Cell was carried out in synergy with the treatment of other legacy activated equipment awaiting disposal. Fitting the target into a certified disposal container required slicing it into four parts, a costly and complex operation for the Service Cell. This finding drove a revision of the target's design: reducing its longitudinal dimension by ~2 interaction lengths, with negligible impact on physics performance, allowing it to fit within the container without major cutting. This contribution details the resulting service cell processes, layout, associated tooling, and failure scenarios with their mitigation measures, along with the packaging strategy adapted to the target's revised size.

Speaker: Jean-Louis Grenard (CERN)

14:00 Coffee break

Session C - Sustainability, dismantling and repurposing in target systems

23 Twelve Years of Robotic Operations in Radioactive Accelerator Environments: Towards a Code of Practice for Remote Maintainability

Over the past twelve years, CERN has deployed robotic and remotely operated systems to inspect, maintain, recover and dismantle activated equipment in radiation-controlled accelerator facilities. These interventions have demonstrated that the success of remote operations depends as much on the design of the equipment and facility as on the capabilities of the robotic system itself.
This contribution presents operational experience gained from remote interventions on highly activated beamline and target-related equipment, highlighting recurring challenges encountered during maintenance and recovery activities. Common issues include inaccessible handling features, interfaces incompatible with remote tooling, limited visibility and manoeuvring space, incomplete configuration information, and insufficient consideration of recovery scenarios during the design phase. These limitations often increase intervention complexity, radiation exposure risk and equipment downtime.
Drawing on this experience, the presentation advocates a systematic design-for-remote-intervention approach, where remote maintainability is considered from the earliest stages of equipment and facility design. Key elements include intervention scenario definition, maintainability reviews, verification of robot-compatible interfaces, digital validation using CAD models and virtual mock-ups, representative testing where required, and quality-assurance criteria covering handling, tooling and recovery provisions.
Rather than promoting robotics as the default solution, this approach provides a structured framework for selecting the most appropriate intervention strategy, manual, remote or hybrid, according to operational and radiological constraints. The presentation concludes by outlining the foundations of a common Code of Practice for remote intervention and maintainability, aimed at translating operational experience into verifiable design requirements that improve maintainability, radiation protection, facility availability and end-of-life dismantling for future high-power target systems.

Speaker: Sergio Di Giovannantonio (CERN)

24 Dismantling and component replacement in highly radioactive areas at CERN: Operational Feedback and engineering challenges.

High-power beam facilities inherently generate highly activated equipment, posing significant challenges for radioactive waste management, facility upgrades, and decommissioning. This presentation provides comprehensive operational feedback on recent large-scale decommissioning operations conducted at CERN; three major projects will be discussed.

First, the complex dismantling of the CNGS (CERN Neutrinos to Gran Sasso) target area highlights the logistics, coordination and strategies deployed to safely evacuate historical components subjected to years of beam irradiation. Second, the ongoing ISOLDE beam dump replacement underscores the constraints of dismantling highly radioactive shielding blocks in a difficult environment with only very little and often unreliable information for the preparation of the operation. Finally, the decommissioning of the TCC8 target area for the future BDF (Beam Dump Facility) project illustrates the upgrade from legacy physics infrastructure to next-generation facilities, involving large-scale material characterization, shielding removal, and radioactive waste stream optimization.

Across these case studies, emphasis is placed on dismantling processes, contamination control, and the development of custom-built lifting and remote-handling tooling. By sharing key lessons learned regarding dose optimization (ALARA principles), mechanical handling tolerances, and waste management strategy, this contribution aims to deliver valuable insights for the international community. Ultimately, this feedback highlights the critical importance of incorporating "Design for Decommissioning" principles into the early conceptual phases of future high-power target systems.

Speaker: Nicolas Quinquis

25 Design and progress of beam Line from linac to reactor for CiADS proejct

CiADS (China initiative Accelerator Driven sub-critical System) is to demonstrate the nuclear waste transmutation with 500 MeV proton beam hitting the LBE (Liquid Lead-bismuth Eutectic) target, generating high-flux neutrons to boost the transmutation of nuclear waste in the reactor. BLR (Beam Line to Reactor) undertakes the task of 2.5 MW proton beam in CW (Continuous Wave) mode transportion with low level beam loss and beam homogenization on the beam window. With periodic beam collimation in phase space, beam power loss is limited within 10 W/m under the reactor top cover. By appling multi-order Fourier harmonic superposition scan, beam PCD (Peak Current Density) on the beam window is limited within 35 μA/cm^2 for 5 mA beam in φ250 mm beam tube. Given the particularity of the reactor, the beam tube above the reactor top cover is specially designed with maintenance consideration to meet the requirements for periodic replacement of the target and nuclear fuel. The design, key technology developement and project progress will be presented in the talk.

Speaker: Huan Jia (Institute of Modern Physics, Chinese Academy of Sciences)

26 Numerical modelling for targetry (FLUKA and MAP2X dedicated event)

Special satellite event dedicated to numerical modelling for targetry. The session will include a short demonstration of the capabilities of the FLUKA Monte Carlo code, including radiation damage features and unstructured mesh implementation, coupled with the MAP2X tool to support engineering calculations and modelling.

Science Gateway Visit: Welcome Drink Practical Information

Convener: Ana-Paula Bernardes (CERN)

Science Gateway Visit

Welcome reception & poster session

27 Benchmarking FLUKA-Based Predictions of Radiation Damage and Thermal-Conductivity Degradation in the ISIS TS1 Spallation Target

This study presents FLUKA predictions of radiation damage and gas production in the upgraded ISIS Target Station 1 spallation target under proton irradiation and proposes an approach for their experimental validation.
Displacement damage and gas production are evaluated on a plate-by-plate basis in both the tungsten cores and tantalum claddings. Displacement damage is quantified using the NRT-DPA and ARC-DPA models implemented in FLUKA, with particular attention paid to their physical interpretation and to the procedures adopted to calculate and normalise average and peak values. The resulting spatial distributions identify the regions of the target subjected to the highest levels of displacement damage and transmutation gas accumulation.
The effect of irradiation damage on the thermal conductivity of tungsten is investigated by coupling the FLUKA-predicted ARC-DPA distributions with two independent Molecular-Dynamics-based correlations describing thermal conductivity as a function of accumulated damage, k(dpa). The two correlations are compared, and the resulting predictions of thermal-conductivity degradation are benchmarked against direct measurements from a dedicated experimental campaign at ISIS and, where applicable, against values derived from thermal-diffusivity measurements of tungsten specimens irradiated with 500 MeV protons at PSI.
The predicted degradation of thermal conductivity is in good agreement within the uncertainties with the experimental observations over a broad range of irradiation conditions. Overall, the results support an integrated modelling methodology that links high-energy particle transport and displacement-damage calculations to the evolution of macroscopic thermophysical properties through molecular-dynamics-based k(dpa) correlations. This approach provides a valuable framework for assessing the performance and operational lifetime of irradiated materials in spallation neutron-source targets.

Speaker: Lina Quintieri (STFC- Rutherford Appleton Laboratory)

28 From As-Built Models to Next-Generation Targets: Modernizing WNR and the Lujan Center

This contribution presents the current status of the Target 4 (T4) spallation target at the Weapons Neutron Research Facility (WNR) and the Mark-IV target at the Lujan Neutron Scattering Center at LANSCE. It also introduces preparations for two major future efforts: the transformative WNR 2.0 target redesign and the future Lujan Mark V target. To support these projects, we are developing an integrated pipeline that incorporates accurate as-built geometries—obtained through complementary 3D-scanning and metrology techniques—into high-fidelity MCNP particle-transport models.
The pipeline is being developed and tested on Lujan flight paths using hybrid models that combine constructive solid geometry with unstructured meshes. Demonstrated applications include as-built reconstruction of the 100 μm-scale FP13–DICER collimator and metrology-driven, high-fidelity modeling of the FP14–DANCE beamline-axis alignment. These studies validate the integration of facility-scale metrology, detailed component scans, and particle-transport models in preparation for WNR 2.0 and Mark V. Locally deployed agentic AI tools based on the Gemma 4 31B model support MCNP input development, troubleshooting, verification, documentation, and traceable model updates, while machine-learning optimizers explore constrained target-design spaces. Together, these capabilities form a demonstrated, scalable framework for designing the next generation of LANSCE spallation targets.

Speaker: Josef Svoboda

29 The design of a high-performance target holder for the South African Isotope Facility for use in commercial radioisotope production

The iThemba Laboratory for Accelerator-Based Science (LABS) is a facility in Cape Town, South Africa, where fundamental nuclear physics research is conducted and where a variety of radioisotopes are made for theranostic purposes for the international market. Within iThemba LABS is the K = 200 Separated-Sector Cyclotron (SSC), which has historically been able to produce stable, light-ion beams up to 200 MeV. Routine production of a variety of radioisotopes using the SSC beam has been in operation since 1987. Consequently, a new C70 IBA accelerator was purchased, which is the 70 MeV H$^-$ cyclotron of the newly-established South African Isotope Facility (SAIF). It is capable of running tandem proton beams with an intensity up to 375 $\mu$A per port. In contrast, the SSC typically delivers beam currents up to 200 $\mu$A. As such, the bombardment station and target holder designs that were used for the SSC end station were re-evaluated for SAIF to accommodate this significant increase in maximum beam current. This talk will discuss the design considerations, simulations, fabrication, and testing of the improved target holders for SAIF before the facility was commissioned and started routine production in 2024.

Speaker: Johann Wiggert Brummer (iThemba LABS)

30 The (OLT) Off-line Tattoos test facility at PSI

The Off-Line TATTOOS (OLT) test facility is being developed to provide a dedicated infrastructure for the preparation, characterization, testing, and qualification of TATTOOS target components and ION beamline technologies. The purpose of the facility is to push the development of ion source target systems under controlled laboratory conditions, allowing for critical systems to be tested thoroughly prior to Online installation.
The OLT will provide the necessary equipment and controlled working environment to reproduce, as far as practicable, the relevant fabrication, assembly, handling, thermal, mechanical, vacuum, and diagnostic conditions encountered by TATTOOS targets during operation. It will support the development of new target designs, the qualification of materials and manufacturing processes, the verification of interfaces and procedures, and the investigation of failure modes.
The laboratory will therefore serve as an essential development and qualification platform within the TATTOOS infrastructure, bridging the gap between component and system development and their final implementation under beam conditions.

Speaker: James Cruikshank (Paul Scherrer Institute)

31 Inventory calculations of ESS target cooling system in support of personal dosimetry

The European Spallation Source (ESS) uses a helium cooling system to move heat from its rotating tungsten target. It is expected that part of the radioactive inventory produced in the spallation process will be transferred to the helium through diffusion, ejection and erosion. Part of this inventory will accumulate and decay in the helium, whereas part will be removed by different systems introduced in the loop to capture particulates and gases.

In this work we will present the modeling done at ESS to simulate the inventory that is expected in the helium coolant, and releases product of normal leakage and accidental scenarios.

Speaker: Jose Ignacio Marquez Damian (European Spallation Source ERIC)

32 Design and thermomechanical studies of the HIMB collimator system

Muons are essential tools in probing particle physics theories and for applied and fundamental solid state physics research. As part of the IMPACT project (Isotope and Muon Production using Advanced Cyclotron and Target technology), an upgraded muon target station and two new High Intensity Muon Beamlines (HIMB) will be installed at PSI’s High Intensity Proton Accelerator (HIPA). This upgrade will deliver unprecedented muon fluxes, enabling next generation lepton flavour violation experiments.

The graphite target wheel delivering the secondary muons has a fourfold increased length. Therefore, to prepare the 590 MeV proton beam for the subsequent targets, the downstream collimator system needs to be replaced. A new three stage collimator system has been designed for a potential 3 mA current using Monte-Carlo BDSIM simulations. ANSYS® simulations are performed to check the thermo-mechanical integrity of the engineering design.

Speaker: Jochem Snuverink (PSI)

33 Simulating Beam-Induced Shock and Jet Fragmentation in Liquid Lead Targets for High-Power Applications

A free-flowing liquid lead jet is under investigation as a beam-intercepting device candidate for a multi-MW class production target for a future Muon Collider. Pulsed beam deposition at 5 Hz, with a 2 ns pulse duration and a peak volumetric heating rate of 80 kW/cm³, drives severe pressure waves, with overpressures on the order of 40 GPa. The target geometry is a 50.9 cm long, 1 cm diameter liquid lead jet immersed in an argon-filled vessel. Multiphase compressible simulations were performed with the open-source ECOGEN solver, using the Noble-Abel Stiffened Gas and Ideal Gas equations of state for the lead and argon phases, respectively, and a Mie-Grüneisen equation of state to predict the liquid lead overpressure after the beam deposition. Results provide wall pressure distributions, characteristic shock time scales, and clear evidence of jet fragmentation. The shock is shown to attenuate from GPa- to MPa-level pressures in under milliseconds, with the low-density argon environment (100 Pa) damping the initial pressure by roughly five orders of magnitude; the resulting pressure loading on the nozzle wall settles to the order of a few MPa. These findings offer key insight into shock attenuation dynamics and structural loading, supporting the design, analysis, and validation of liquid lead targets under extreme pulsed loading conditions.

Speaker: Luca Tricarico (University of Bologna - ENEA)

34 Release tests of porous Titanium Carbide samples: comparison between additive manufacturing and powder-based feedstock materials

With the aim of improving radionuclide release in ISOL systems, titanium carbide targets based on non-stochastic cellular architectures with open and interconnected porosity are being developed. These structures significantly increase the surface-to-volume ratio compared to conventional disk geometries, enhancing thermal performance and heat dissipation.
A comparison is performed through simulations between three configurations: a monolithic target, a multi-disk target, and a 3D-printed gyroid lattice target. The improvement on thermal dissipation is quantified by the maximum driving proton beam current delivered to the target.
Nanostructured titanium carbide is developed following a sol-gel route using titanium isopropoxide and saccharose as precursors; the sol incorporates photoreactive moieties and can be shaped through vat photopolymerization additive manufacturing [1,2]. The resulting components are compared with standard titanium carbide disks produced from powder-based feedstock consisting of titania and graphite [3]. To isolate material effects, a first comparison focuses on simple disk geometries, comparing their release efficiency. A second investigation examines the production of gyroid lattice structures with varying wall thickness to improve the release.
Irradiation tests were performed at Paul Scherrer Institute using Injector II Cyclotron. Different target materials were irradiated with 62 MeV proton beam. Monte Carlo simulations were used to estimate production yields of selected radioisotopes. The activities are then compared to those obtained through gamma-ray spectroscopy measurements while microstructure SEM investigation will be used to understand damage due irradiation. Release tests are conducted using an induction heating furnace. Gamma-ray spectrometry measurements were used to evaluate the release behaviors at certain temperatures. In parallel, high-temperature tests to assess mass loss and material stability at high temperature will be performed at INFN-LNL, providing additional understanding of material behavior.
This comprehensive work aims to prove the potential of targets obtained through additive manufacturing for the ISOL technique.

[1] https://doi.org/10.1021/acsami.4c17707
[2] https://doi.org/10.1002/adfm.202406916
[3] https://doi.org/10.3390/ma15238358

Speaker: Mr Luca Avanzi (Università degli studi di Padova)

35 Design And Development of the new Isolde Beam Dumps at CERN

New beam dumps have been developed for the Isotope mass Separator On-Line facility (ISOLDE) at CERN, as part of the ISOLDE Beam Dump Replacement and Sustainability (IBDRS) project. The new design is engineered to ensure an operational lifetime of 30 years and to accommodate the planned quadrupling of beam power. The dump assembly consists of a series of cladded CuCr1Zr plates and a cladded Cu-HCP block, enclosed in a 316LN stainless steel vessel, with active water cooling. The cladding consists of 316LN stainless steel sheets which are diffusion bonded to the Cu-alloys by means of Hot Isostatic Pressing (HIP). The cladding was implemented to avoid direct contact between the cuprous materials and water, which would generate corrosion products that would gradually activate the cooling circuit. Extensive beam-matter and thermo-mechanical studies were conducted to evaluate temperature and stress levels under nominal and accidental beam conditions, as well as quantify cooling requirements and expected fatigue lifetime. Prototyping of the cladded blocks has been carried out successfully and series production has been initiated. This contribution presents the final design and validation, as well as the advanced manufacturing methods employed to provide a robust solution for the future ISOLDE beam dumps.

Speaker: Panagiotis Romanos Menachilis

36 Irradiation, Thermal, and Safety Studies for the CSNS Target Station

The China Spallation Neutron Source (CSNS) produced its first neutrons in August 2017 and currently operates at an average beam power of 185 kW. Given the successful operation of the CSNS-I and the growing demand from the user community, the Phase II project (CSNS-II), was initiated in January 2024 and is scheduled for completion in 2029. This paper presents the irradiation damage calculations and lifetime estimation of the TMR (target-moderator-reflector) key components, the thermal deposition characteristics and heat-transfer structure analysis of the spallation target, and the results of both simulation and experimental studies on the target under abnormal conditions, including Loss-Of-Coolant Accidents and unexpected power outages. In addition, a project is underway to investigate material irradiation effects based on the spallation target; accordingly, this paper also reports on the irradiation conditions, the radiation environment, the DPA (displacements per atom) rate, and hydrogen/helium yields for various samples.

Speaker: BIN ZHOU (Spallation Neutron Source Science Center, Institute of High Energy Physics, Chinese Academy of Sciences)

37 Irradiation induced degradation analysis in the welded joints of ESS Moderator & Reflector Plug components

The European Spallation Source (ESS), under construction in Lund, Sweden, is set to operate at a full proton beam power of 5 MW and peak power of 125 MW, making it the most powerful neutron source in the world. An integral part of ESS is the Moderator & Reflector Plug (MRP), designed to slow down high-energy neutrons and release them towards instruments. MRP is subjected to high pressure, intense radiation environment where it must sustain high particle fluxes in combination with thermal and mechanical loads. MRP is fabricated from aluminium alloys as they exhibit near transparency to cold and thermal neutrons, with Al 5000 & Al 6000 series preferred for their favorable thermal and mechanical properties. The increasing geometric complexity of MRP together with stringent requirements for dimensional stability and reproducibility, necessitates automated welding process. Therefore, electron beam welding (EBW) is utilized due to high precision, narrow heat affected zone and is effective for joining Al 6000 series, which are susceptible to welding induced strength degradation and solidification cracking, necessitating Al 4000 series filler metals to reduce hot cracking susceptibility. At high radiation doses, the microstructure and mechanical properties of MRP components are substantially altered, resulting in loss of ductility and fracture toughness, thereby limiting the service life of component. To date, irradiation studies have been predominantly focused on base materials, while the irradiation behaviour of welded joints incorporating dissimilar filler metals remains insufficiently understood. Current estimates indicate that radiation damage in aluminium at full proton beam power restricts MRP component lifetime to approximately one year, requiring annual replacement and resulting in substantial manufacturing, disposal and operational costs. This work investigates the irradiation behaviour of EBW Al 5000 and Al 6000 alloys incorporating Al 4000 series filler metals to optimize MRP joint design in terms of weldability and radiation resistance.

Speaker: Shabdali G. Ashwit

38 Conceptual design of the Beamstrahlung Windows for FCC-ee

In the FCC-ee Interaction Points (IPs), the crossing of $e^-$ and $e^+$ beams will lead to the emission of high-power beamstrahlung photons, which have to be absorbed by dedicated dumps. Separating the regions of the beam vacuum around the IPs and the Beamstrahlung Dumps, there will be Beamstrahlung Windows (BSW).

This contribution aims at presenting the current BSW conceptual design, highlighting challenges including material constraints (balancing transparency and strength); thermal stresses (around ~12 kW from the partial absorption of high energy photons); structural stresses (from the pressure differential between machine vacuum at room temperature and the beam dump side with ~1.2 bar Argon at 670 K); large diameter of 700 mm; and integration constraints with adjacent accelerator systems.

To achieve the conceptual design for this system, the design team employed Systems Engineering practices, spanning from stakeholder interviews, requirements gathering, functional analysis to the evaluation of candidate system architectures and design solutions. The preferred concept is presented, which will serve as the reference design for future technical developments for FCC-ee.

Speaker: Ivan Keiti Umezu

39 First-Principles Investigation of Mechanical Stability in Irradiated Pyrochlore Ceramics

The development of advanced nuclear energy technologies requires structural materials capable of maintaining their integrity under intense irradiation. Pyrochlore ceramics (A₂B₂O₇), particularly zirconate-, titanate- and hafnate-based compounds, have emerged as promising candidates owing to their exceptional resistance to radiation-induced amorphization, high chemical stability and favorable thermo-mechanical properties. Understanding the atomistic response of these materials to irradiation-induced defects is therefore essential for the rational design of next-generation nuclear waste forms and radiation-tolerant ceramics. In this work, first-principles density functional theory (DFT) calculations are employed to investigate the influence of radiation-induced point defects, including oxygen vacancies and anti-site defects, on the structural and mechanical properties of representative pyrochlore ceramics. Defect formation energies, local structural distortions, elastic constants, bulk shear and Young's moduli are systematically evaluated to quantify the effects of point defects on mechanical performance and structural stability. The calculations reveal that vacancy defects generally reduce elastic stiffness and mechanical robustness, whereas selected anti-site disorder configurations exhibit improved resistance to structural degradation. This study extends our previous combined experimental and computational investigations of depth-resolved elastic performance of irradiated spinel ceramics [1] and provides a computational framework for the future design and multiscale modeling of radiation-resistant pyrochlore ceramics for advanced nuclear applications.

This work is supported by AP32317389 grant from the Ministry of Science and Higher Education of Kazakhstan
Keywords: Density Functional Theory (DFT), radiation tolerance, elastic, strain, ceramics, mechanical stability, point defects.
References:
[1] Vladimir Bessonov, Jacques O'Connell, Toreniyaz Shomenov, Azat Abdullaev, Artem Kozlovskiy, Vladimir Skuratov, Yanwei Wang and Zhandos Utegulov "Controlling subsurface radiation tolerance in swift heavy ion irradiated ceramics", Applied Surface Science, 725, 165730 (2026)

Speaker: Toreniyaz Shomenov (Nazarbayev University)

40 Thermal Design Optimization of an ISOL Target Assembly with Multi-Layer Thermal Shielding

Efficient operation of ISOL radioactive ion beam (RIB) facilities requires target materials to be maintained at elevated temperatures to maximize isotope diffusion and effusion rates. In this work, we investigate a multi-shield thermal configuration designed to improve heat containment in the Ucx based target assembly. The proposed design enables higher operating temperatures to be achieved with lower input power, thereby enhancing thermal efficiency while maintaining reliable operation.

A set of simulations were performed to optimize the Target Ion Source System (TISS) being developed for the upcoming Stable and Unstable Isotopic Beam for Heavy Ion Research (SUBHIR) facility at BARC, India. The production target consists of porous UCx disks housed within a graphite container and indirectly heated through Joule heating of a surrounding tantalum tube. A coupled thermal–electrical finite-element model was developed using COMSOL Multiphysics to evaluate temperature distributions, radiative heat-transfer mechanisms, and thermal efficiency under high-temperature operating conditions.

For the unshielded configuration, a heating current of 1100 A produces peak target temperatures of approximately 1450°C while driving the tantalum heater close to its practical operating limit. To improve thermal efficiency, concentric tantalum radiation shields were introduced and systematically optimized with respect to diameter, thickness, and number of layers. The study demonstrates that shield geometry strongly influences heat retention, whereas shield thickness has a comparatively minor effect. An optimized two-shield configuration achieves target temperatures comparable to the unshielded 1100 A case while requiring only 650 A of heating current, corresponding to a reduction in current requirement of approximately 40%.

The results provide practical design guidance for high-temperature ISOL targets and demonstrate that optimized thermal shielding can substantially reduce power requirements while extending operational margins below tantalum thermal limits.

Speaker: Mohammad Asif Azad (Bhabha Atomic Research Centre)

41 Replacement of SNS Service Bay Bridge Systems

The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) utilizes a heavily shielded service bay to house the highly activated mercury process system. The service bay uses two independent bridge systems to support fully remote operations: an overhead gantry with 7.5-ton crane and a separate overhead gantry supporting a telescoping mast containing a specialized, dual-arm servo-manipulator. Together, these systems enable critical service bay activities, including target changeouts, equipment installations, mercury loop troubleshooting, waste activities, and other maintenance operations.
Technical obsolescence of the servomanipulator and both of the bridge control systems represents significant operational vulnerabilities. Procurement of a replacement servomanipulator has been completed and a subcontract for modernized bridge control systems is currently underway. This presentation will highlight the unique challenges of these two service bay operations: (1) replacement of the servo-manipulator and (2) implementation of the bridge controls upgrade, which requires replacement of cabling, gearboxes, motors, and other components while minimizing exposure to the extreme service bay environment. Details of the systems, a replacement plan, mock-up testing plans, and projected timelines will be shown.

Speaker: Luke Meyer

42 The beam destinations for the commissioning of the ESS proton accelerator

The commissioning of the high-power proton accelerator of the European Spallation Source (ESS) started in 2018 and it is ongoing in Lund (Sweden). The ultimate goal of the ESS proton accelerator is delivering 2.86 ms long pulses at 14 Hz and the nominal current of 62.5 mA on the ESS spallation target.
During the linac commissioning phases between September-2018 and June-2026, a variety of beam destinations have been used:
- Four compact and distinct Faraday cups in the Normal Conducting Linac, for measuring the proton beam intensity and pulse length,
- Two distinct types of Insertable Beam Stops in the superconducting linac, for dumping up to either 700 W and 1140 W (time-averaged beam power),
- One tuning beam dump for dumping protons in the [90, 2000] MeV range and up to 12.5 kW (time-averaged beam power), at the end of the superconducting linac.
The design, manufacturing, testing, installation and operation with beam will be summarized.

This work was performed in collaboration with ESS colleagues in Sweden, ESS Bilbao in Spain and companies from all around the world, including: Allectra Ltd. (UK), MEWASA (Switzerland), Pantechnik (France), Proactive R&D (Spain), RadiaBeam Technologies (USA), Reuter Technologie GmbH (Germany), and TWI Ltd. (UK). Multiple furnace runs were performed for heat treatment purposes at the MAX-IV in Sweden.
Radiation transport calculations were performed with the MCNP® code (distributed by the RSICC of the Oak Ridge National Laboratory), and Attila4MC® (distributed by Silver Fir Software).

Speaker: Dr Elena Donegani (European Spallation Source)

43 SFRS Target Installation

During 2026 the preinstallation and installation of the SFRS target area is remarable progressed. We will show the actual status as well as impressions for the main components of the Super-FRS - the target chamber, pillow seals, quadrupoles and beam catchers.

Speakers: Helmut Weick (GSI Helmholtzzentrum für Schwerionenforschung), Klaus Knie, Maximilian Schuett (GSI)

44 Machine Learning Based Anomaly Detection for Target System Operation

The Spallation Neutron Source has built and deployed an anomaly detection system for its target systems. These include the mercury loop, five cooling loops, and the cryogenic moderator helium and hydrogen systems. The system uses a machine learning approach to review operational data and identify potential anomalies. These anomalies are presented to human experts for evaluation. The humans provide feedback that will be vital to future improvements in the system, while also determining any needed actions. This sort of anomaly detection provides the humans involved with more information about strange system reactions. The system does not replace standard alarm at parameter values, but does provide the potential to identify problems and unexpected behavior before they cause alarms or beam stoppages. The system will be shown with the intent of sharing this approach with others and learning from what others are doing in this area.

Speaker: Drew Winder

45 Simulation study of the curtain-type liquid lithium jet as a muon source target

With the development of the China Initiative Accelerator Driven System (CiADS) and its Muon Science and Technology application platform (MuST), a curtain-type liquid lithium jet target has been proposed as a promising solution for high-power muon production. Monte Carlo and ANSYS Fluent simulations were combined to evaluate the muon yield, hydrodynamic stability, thermal response, and radiological characteristics of the free-surface liquid lithium jet target. For a fixed effective thickness of 3 cm, a 7-mm jet thickness is identified as the more preferable configuration. At this thickness, the surface muon production rate from the target is 3.29×10−6 μ+/p, and the muon capture efficiency reaches 36%. Considering the expected overall transmission efficiency of approximately 10% from the target region to the experimental area, a surface-muon beam rate on the order of 1010 μ+/s could be delivered to the experimental area at a proton beam current of 5 mA. Hydrodynamic simulations confirm that the jet maintains a continuous and stable free-surface morphology without obvious breakup or large-scale deformation. Transient thermal analysis shows that, under a 600 MeV, 5 mA proton beam and a jet velocity of 4 m/s, the maximum temperature rise is only ~35 ℃, demonstrating excellent heat-removal performance. Radiological analysis further shows that the dominant long-lived radionuclides in the lithium target are mainly 3H and 7Be. After one month of irradiation, the total activity of the lithium target is 2.2×1013 Bq, approximately 17.3 times lower than that of the graphite target. After 72 h of cooling, the maximum residual dose rate of the lithium target is 6.23×108 μSv/h, compared with 5.90×109 μSv/h for the graphite target, corresponding to a reduction factor of approximately 9.5. These results indicate that the curtain-type liquid lithium jet is a feasible and advantageous target solution for the high-intensity muon source driven by a high-current superconducting linac.

Speaker: jianwei Niu (Institute of Modern Physics, Chinese Academy of Sciences)

46 Development of Capacitance Sensor and Ceramic-Braided Cable for High-Temperature and High-Radiation Environments near High Power Target

We are developing a capacitance sensor composed only of metal electrodes and ceramic insulators for high-temperature (HT) and high-radiation (HR) environments near high-power targets. This capacitance sensor is designed to tolerate temperatures up to 300℃ and radiation levels in the order of MGy, and is planned to be used for monitoring the secondary particle production target at J-PARC. The sensor detects small capacitance changes in the order of pF and can potentially be applied to various measurements, such as displacement, liquid level, pressure, and rotation. For such small-capacitance measurements under HT/HR conditions, the environmental tolerance of the read-out cable is also essential. Radiation-induced current in the cable and degradation of insulation resistance at HT can cause measurement errors and noise. Therefore, the electrical characteristics of a ceramic-braided coaxial cable for the capacitance sensors were evaluated under HT conditions up to 300℃ and under gamma-ray irradiation up to 1.5 kGy/h. We also confirmed that an appropriate bias voltage on the shield line of the coaxial cable can suppress the effects caused by insulation degradation at HT and radiation-induced currents.
This presentation reports the operating principle and fabrication method of the capacitance sensor, as well as the results of gamma-ray irradiation tests and electrical characterization of the ceramic braided coaxial cable under HT conditions.

Speaker: Fumimasa MUTO (KEK)

47 Unstructured Mesh Neutronics Analysis for the SNS Second Target Station Final Design

The Second Target Station (STS) at the Oak Ridge National Laboratory’s (ORNL) Spallation Neutron Source (SNS) is designed to become the highest peak brightness source of cold neutrons in the world. The STS will generate neutrons via spallation of a rotating tungsten target with a short-pulsed 1.3 GeV, 700 kW proton beam from the upgraded SNS linac. Spallation neutrons will slow down to cold energies with a maximum at 3 Å in a pair of cryogenic para-hydrogen moderators surrounded with water premoderator and a beryllium reflector.
A wide range of MCNP radiation transport (neutronics) calculations was carried out to develop the final design of the STS. These calculations include an advanced automated optimization of the neutronics performance. Next, they include energy deposition in the target, moderators, and surrounding shielding to provide input for the subsequent structural stress and thermal hydraulic engineering analyses. They also include radiation damage in all components to determine their service lifetime, to mention a few.
The calculations employed the unstructured mesh (UM) geometry capability of MCNP6.2 and highly efficient mesh generators and variance reduction implemented in Attila4MC. This paper demonstrates the application of UM in several representative simulations and emphasizes the advantage of UM over the traditional constructive solid geometry (CSG) modeling.

Speaker: Lukas Zavorka (Oak Ridge National Laboratory)

48 Leveraging the Ability to Indirectly Couple Monte Carlo N-Particle Transport Code to Finite Element and Computation Fluid Dynamics for High Power Target Design.

The Los Alamos National Laboratory’s (LANL) Monte Carlo N-Particle (MCNP)1 transport code is used to perform neutronics calculations in support of the physics and engineering design process of high-power targets, beam windows, beam stops and other accelerator beam line components. From these calculations, MCNP data can be formatted and imported into Finite Element Analysis (FEA) and Computation Fluid Dynamic (CFD) software. The importing sequence involves transferring structured (voxels) or unstructured mesh (UM) tallies (power density or neutron flux) to serve as thermal and mechanical loads. Commercial FEA and CFD software do not natively process raw MCNP tallies; therefore, users often must format the data to import the spatial matrices. We will be describing various techniques of importing MCNP spatial matrices into the ANSYS simulation product tools, such as conjugate heat transfer (CHT) in Fluent and CFX; in addition to steady state and transient thermal simulation in ANSYS Mechanical. These techniques are extremely important for one-way and two-way coupling between MCNP and FEA and CFD solvers for multi-physics approach numerical simulations.

LA-UR-26-25496

Speaker: Eric Olivas (Los Alamos National Laboratory)

49 Design and Prototyping of the FCCee Positron Target

The positron-producing target is a critical component in the FCCee injection chain. A 6 GeV, 4 kW electron beam deposits a peak power density of up to 10 kW/cm3 in a dense metal target. The current design consists of a tungsten target cooled with embedded tantalum pipes, removing 1.2kW of heat using water at up to 20 bar. This contribution describes the prototype manufacturing processes used to achieve this complex design, including the use of novel glass-capsule Hot Isostatic Pressing (HIP) technology which removes the requirement for conventional HIP capsules. Design-for-manufacture improvements and proposed novel designs using heat pipes are also shown.

Speaker: Richard Cowan

50 Diagnostics and operational challenges of the J-PARC MLF muon target under 1MW beam operation

This abstract reviews the minor technical challenges encountered during the 1MW high-power beam operation of the Materials and Life Science Experimental Facility (MLF) muon target at J-PARC, focusing on beam monitor anomalies and the recent progress in developing monitor systems.
Achieving stable 1-MW operation is a major milestone, but the high beam power introduces severe thermal and mechanical loads on components near by target.
During recent 1MW operation, an anormaly was observed in the beam profile monitor, we found that the analysis suggesting it was induced by localized thermal effects from the intense proton beam. This presentation details the investigation into cause of this monitor anomaly.
Furthermore, we report on the recent development and progress of deveroping monitoring system utilizing infrared (IR) camera. This system is designed to provide real-time, non-contact thermal imaging of target body, allowing for the early detection of abnormal temperature rises and verification of thermal behavior under 1MW loads.The image data obtained from this IR camera offers the potential to estimate thermal diffusivity. In the future, we aim to develop a non-destructive monitoring system that can evaluate the radiation damage of target materials in-situ, without requiring the removal of the target from the beamline.

Speaker: Hikaru Sunagawa

51 Multi-order Fourier Harmonic Superposition Scan for CiADS Target

To meet the requirement of CiADS liquid lead-bismuth eutectic (LBE) target, 5 mA continous wave (CW) proton beam should be homogenized in the round area of Φ250 mm beam tube. A multi-order Fourier harmonic superposition scan method is proposed and implemented for the CiADS target beam delivery system. The scanning technique synthesizes multiple Fourier harmonic components with independently adjustable amplitudes, frequencies, and phase offsets to generate a controlled beam sweeping pattern across the target window. The effectiveness of this scanning strategy has been demonstrated through detailed beam optics design and simulation. By applying the multi-order Fourier harmonic superposition scan, the peak current density (PCD) on the beam window is controlled within 35 μA/cm² for 5 mA beam.

Speaker: Yuanshuai Qin (Institute of Modern Physics, Chinese Academy of Sciences)

52 Development of a Neutron Producing Lithium Target for the Moderator Test Station at Oak Ridge National Laboratory

The Moderator Test Station (MTS) is a facility under development at the Spallation Neutron Source (SNS). This facility will serve as a platform to efficiently test novel neutron moderator designs; it is currently not feasible to test conceptual moderators at the SNS first target station, as the moderators are integrated as part of the larger Inner Reflector Plug (IRP) assembly. The MTS will utilize an existing 2.5 MeV hydrogen ion beam located at the Beam Test Facility (BTF) to irradiate a target coated with enriched lithium-7 to generate neutrons using the 7Li(p,n)7Be reaction. The concept target for MTS consists of a thermally conductive metal substrate plate with a thin 50-100 µm layer of enriched lithium-7 metal deposited on the beam-facing surface. Sample targets were produced by depositing lithium metal via thermal evaporation on a variety of substrates to evaluate lithium adhesion and layer uniformity. Various protective layers were applied over the lithium layers and observed in ambient air to evaluate the effects on target handling time. Sets of test targets were produced and tested in an experiment at the beam test facility to evaluate the effects of incident beam angle and titanium overcoat on neutron production. Successful neutron production was demonstrated and the measured flux correlated closely with the calculated values. This poster will present the outcomes and preliminary data of these development tests

Speaker: Josh Watkins (Oak Ridge National Laboratory)

53 Development of a New-Generation Adjustable Aperture for High-Precision Power Control of CiADS Sub-critical Reactor

To achieve high-precision continuous regulation of beam current ranging from 0 to 10 mA for the CiADS superconducting linear accelerator and realize precise matching of sub-critical reactor power, a new-generation online continuous beam intensity adjustment device is developed in this paper. Targeting the inherent defect of tailing in the beam time-space distribution of conventional similar equipment, the proposed device enables stable high-precision control of beam intensity, and fully accommodates the subsequent power upgrading and iteration of the accelerator.

Speaker: Haihua Niu (Institute of Modern Physics, CAS)

54 Advances in the LBNF target system and their implications for future High-Power Target Facilities

The Long-Baseline Neutrino Facility (LBNF) target system represents a major milestone toward the realization of reliable multi-megawatt target technologies for accelerator-based neutrino experiments. Significant progress has been achieved in the design and validation of critical target station components, including target materials and geometries, helium-cooled target assemblies, radiation-tolerant diagnostics, and integrated target-horn systems. These advances have substantially improved our understanding of the production and collection of intense secondary particle beams under high-power proton beam conditions. The lessons learned from LBNF have broader implications for future accelerator-based physics programs, which will increasingly rely on efficient production and collection of pions, kaons, muons, and neutrons. As beam powers increase and scientific objectives diversify, future target facilities will require innovative approaches to maximize secondary particle yields while maintaining operational robustness and flexibility. This presentation will review recent advances in the LBNF target system, with particular emphasis on optimizing secondary particle production and collection. Building on these developments, we discuss conceptual multi-purpose target systems designed to enhance secondary beam performance. In particular, we introduce modified magnetic horn configurations that generate a dipole field component through either a tilted horn geometry or asymmetric currents in the horn inner conductor. Such configurations could spatially separate selected pion and kaon beams from the residual primary proton beam, potentially improving secondary particle capture and enabling more flexible beam delivery for future intensity-frontier experiments.

Speaker: Katsuya Yonehara

55 Dynamic Characterization of the LBNF Horn A Assembly Using Experimental Modal Analysis

The Long-Baseline Neutrino Facility (LBNF) provides the infrastructure required to generate a high-intensity neutrino beam and to transmit it approximately 800 miles (1,300 km) through the Earth to detectors located deep underground at the Sanford Underground Research Facility in South Dakota. The neutrino production target is integrated with the first electromagnetic focusing element (Horn A) and supported by a single-module assembly. The 1.5 m long graphite-core target is cantilever-mounted to the upstream face of Horn A. The target and horn system is designed for an initial beam power of 1.2 MW (upgradeable to 2.4 MW) and a pulsed electrical current of 300 kA. The combined Horn A and target assembly weighs approximately 5,000 lb (2,273 kg).
For the fully assembled Horn A system, Experimental Modal Analysis (EMA) was employed to characterize its dynamic behavior and determine its natural frequency response. The investigation considered multiple assembly configurations, including the horn with the cooling system, target mounting plate, electrical stripline, and target when it is installed. The correlation of their dynamic behavior may be revealed with the EMA study, which not only provides insight into the structural response at 625 Hz and 1250 Hz—frequencies at which the electrical current skin depth is fully developed through the inner conductor thickness—but also identifies natural frequencies associated with wobbling of the target support structure, a potential source of fatigue damage. Damping ratio from EMA may further help benchmark for future FEA study of the system. This report presents the methodology, results, and key findings of the modal analysis.

Speaker: Zunping Liu

56 Manufacturing and properties of high-strength tungsten for the BDF/SHiP target

The Beam Dump Facility (BDF), notably developed for the Search for Hidden Particles (SHiP) experiment, will host a pure tungsten, helium-cooled target, capable of fully absorbing the high-intensity 400 GeV/c proton beam delivered by the Super Proton Synchrotron (SPS). The 300 kW of average thermal power deposited in the target tungsten core requires an optimized design and high- strength pure tungsten blocks to ensure reliable operation over several years without failure.
To achieve the highest possible density and strength, the target core blocks will be made by stacking hot-rolled tungsten disks, joined together by Hot Isostatic Pressing (HIP). Preserving and enhancing the properties of the hot-rolled tungsten after the HIP process is essential. This requires careful preparation of the hot-rolled tungsten before HIP, as well as strict control of the HIP parameters, to avoid recrystallisation and embrittlement.
This contribution focuses on the manufacturing steps carried out at CERN and by its partner companies to produce the tungsten core blocks for the target. It also presents results from the tests performed on samples extracted from prototype blocks manufactured by the joining of hot-rolled tungsten disks via HIP. The impact of HIP temperature on recrystallisation and residual stress relaxation in tungsten is also discussed based on experimental results.
Improving the surface quality in the beam impact region and reducing residual stresses are expected to enhance the strength and fatigue lifetime of the tungsten core blocks. These improvements are expected to increase the operational reliability of the BDF target, extend its operational reliability, and postpone the need for target replacement.

Speakers: Patrick Michael Curran, Tristan Francois Calvet

57 Introduction of the Beam Technology Development Section at J-PARC

J-PARC has three proton accelerators and three research facilities with using MW-class high power proton beams. Each experimental facility is equipped with beam-intercepting devices, such as targets and beam
windows, to generate secondary particles; the survivability of beam-intercepting devices under intense beam irradiation is a key factor limiting the achievement of higher beam power.
In April 2026, the Beam Technology Development Section was established to address the development of common technologies across all facilities. This presentation reports on the activities of the newly established
Beam Technology Development Section.

Speaker: Shunsuke Makimura

58 Development of Innovative Additively Manufactured ISOL Targets Concepts for High-Power Applications

The increasing demand for beam quality and intensity at next-generation ISOL facilities poses significant challenges for target materials and geometries, requiring enhanced thermal management and potentially improved isotope-release performance. In this context, additive manufacturing (AM) offers unprecedented opportunities to engineer porous carbide-based target structures with tailored geometric and thermophysical properties.
This contribution presents recent developments high-power ISOL carbide targets produced by AM techniques within the INFN HISOL_NEXT project. The aim is to develop and test novel high-performance ISOL Target-Ion Source systems for the SPES facility at Legnaro National Laboratories.
To enhance heat dissipation under intense proton irradiation, target geometries based on Triply Periodic Minimal Surface (TPMS) structures, with particular emphasis on gyroid lattices, were investigated due to their favorable combination of mechanical stiffness and high surface-to-volume ratio. A comprehensive simulation workflow was established to support target optimization. The digital model of the TPMS-based geometries is converted into mesh models for Monte Carlo simulations to obtain spatial power-deposition distributions and isotope-production yields. The resulting power maps are subsequently used for coupled thermal–structural finite element analyses to evaluate temperature fields and thermally induced stresses. This iterative workflow enables progressive refinement of the target design to improve temperature uniformity, reduce thermal stresses, and increase operational reliability under high-power beam conditions.
Also, multiple design variants of the target are under investigation, including alternative structure topologies, with the intent of optimizing thermal management while preserving mechanical integrity and favorable isotope-release characteristics. Indeed, by exploiting the design freedom provided by AM technologies, novel target concepts can be explored to achieve a more homogeneous power distribution within the target volume. These efforts are guiding the exploration of the feasible design space for future target concepts and supporting the development of next-generation ISOL targets capable of operating under increasingly demanding beam power conditions.

Speaker: Michele Ballan

59 Development of In-Target Material Irradiation Capability at the CSNS Target

Beyond conventional pulsed neutron generation for scientific research, the China Spallation Neutron Source (CSNS) target has been optimized to develop an in-target material irradiation function. This capability aims to meet the irradiation evaluation demands of key components for high-power spallation facilities and fusion systems.
This study systematically explored the irradiation space, energy spectra and flux distribution of the target region. Sample thermal responses under beam irradiation were numerically simulated and experimentally verified. Comprehensive thermal-hydraulic and structural safety assessments confirm that the newly integrated irradiation function imposes no adverse effects on the target station’s operational stability and structural integrity. So far, the in-target irradiation function has been successfully implemented on the T7 target, undergoing nearly one-year stable operation with a maximum beam power of 185 kW. A new T8 target with higher operational power, elevated irradiation flux and adjustable sample temperature will be put into service in the second half of this year. This work enables CSNS to serve as a multi-functional high-flux platform for advanced nuclear material qualification.

Speaker: Mr Ruiqiang Zhang (IHEP, CAS)

60 HiRadMat: a high-power beam facility at CERN

HiRadMat is a unique facility at CERN, providing a high-energy, high-intensity, LHC-type beam to study beam–matter interactions under extreme conditions. Since its commissioning on 2011, the facility has hosted more than 50 experiments, ranging from material R&D for accelerator components to beam diagnostics and experimental astrophysics. Today, HiRadMat serves as CERN's reference test-beam facility for high-intensity studies where many components now deployed at CERN and other accelerator laboratories worldwide were first validated. The talk (or poster) will introduce the beam parameters, the available infrastructure and user support of the HiRadMat facility and present the highlights of the experimental campaigns over the years and their impact on detector & high power targetry R&D. The talk will conclude with an outlook on upcoming experiments and the future scientific programme of the facility.

Speaker: Paraskevi Alexaki (University of Liverpool (GB))

61 The TATTOOS ISOL target thermal transient behaviour

The TATTOOS facility at PSI, part of the IMPACT project, will produce medically relevant radionuclides by 590 MeV proton-induced spallation in a tantalum target operating at 2000–2400 °C for several weeks. The target is heated simultaneously by the proton beam from the High Intensity Proton Accelerator (HIPA) and by resistive (Joule) heating and is cooled almost entirely by radiation. No temperature diagnostic is accessible during operation, so maintaining the operating temperature window through beam trips and beam sharing with the Ultra Cold Neutron source (UCN) is a reliability challenge.
This contribution presents the thermal development of the target along two axes. First, we describe numerical simulations of the alternating beam/resistive heating operation, combining FLUKA energy deposition with homogenized target properties to predict the transient temperature evolution during beam trips and beam sharing phases for a static and rotating beam. Second, we present a concept to compensate for the loss of proton-beam heating: a model-based feedforward loop in which an analytical thermal model, fed by beam-intensity and profile-monitor data, regulates the resistive heating power to hold the target temperature without temperature feedback. We discuss the spatial mismatch between beam and resistive heating profiles, the resulting requirement on the allowable response time, and the implications for offline target conditioning and characterization.

Speaker: Rémi Martinie

62 Design and manufacturing of the next generation of CERN’s North Area Splitter Collimators (TCSC)

CERN’s Transfer Tunnel 20 (TT20) connects the Super Proton Synchrotron (SPS) to three primary targets in the North Area which provide secondary particles to experiments further downstream. Two splitter collimators (TCSC) are installed along this line, each protecting their respective downstream Lambertson septum magnets, which distribute the slow-extracted 400 GeV/c proton beams among the targets. During Long Shutdown 3 (LS3, 2026–2029), two redesigned TCSCs will be installed to improve cooling efficiency, mechanical robustness, and maintainability in the context of the North Area Consolidation (NACONS)project. The new design also incorporates additional radiation shielding to reduce dose rates in the surrounding area and minimise personnel exposure during tunnel interventions. This contribution presents the main design improvements, thermomechanical analyses, and manufacturing developments implemented to enhance the reliability, radiation safety, and thermal performance of the TT20 splitter collimators.

Speaker: Jules Braken (CERN)

Wednesday 18 November

Session D - Radiation damage effects to materials - simulations and experimental studies

63 Dynamic Fracture Response of Beam intercepting materials under Pulsed Proton-Beam Loading

High-power accelerator targets and beam windows experience highly localized heating during microsecond-scale proton pulses, producing stress-wave loading, high strain rates, and repeated transient tensile stresses. Target design and material qualification generally emphasize peak stress, fatigue, radiation damage, swelling, and thermal shock performance. However, the influence of pre-existing manufacturing defects on stress-wave-driven crack initiation is not routinely quantified. Because the crack-tip loading is transient and inertia-controlled, static fracture toughness cannot alone describe the relevant failure condition. This work develops an in-beam methodology to relate beam parameters and flaw geometry to crack initiation and catastrophic failure under representative proton-beam thermal shock.
Tungsten and Ti-6Al-4V disks, 20 mm in diameter and 8 mm thick, were fabricated with radial slits positioned at different offsets from a Gaussian proton beam with a nominal sigma of approximately 1 mm. Specimens were exposed to controlled pulses ranging from 12 to 288 bunches and to single or repeated exposures. Higher-intensity exposures caused complete separation of several tungsten specimens. Ti-6Al-4V did not exhibit comparable catastrophic separation, although preliminary observations indicate possible fine cracking that requires SEM confirmation. Two orthogonally oriented laser Doppler vibrometers recorded transient surface-velocity and displacement responses. Changes in the LDV time histories, frequency spectra, and scalograms relative to the reference response were then examined for signatures associated with crack initiation and propagation. Coupled transient thermal and dynamic finite-element analyses were used to resolve the evolving stress-wave field and crack-driving response, while frequency domain analyses were applied to identify vibration changes associated with crack extension. Post-test optical microscopy provided an initial correlation with physical damage.
The current work establishes a proof of concept for combining pulsed-beam loading, LDV diagnostics, transient simulation, and microscopy to investigate dynamic fracture under accelerator-relevant conditions.

Speaker: Patrick Goodwin Hurh (Fermi National Accelerator Lab. (US))

64 Radiation Damage Studies for High-Power Accelerator Applications at TRIUMF

High-power accelerator facilities require beam-intercepting materials that retain adequate mechanical and thermal performance under prolonged irradiation. However, representative experimental data remain scarce because relevant exposures may require years of operation, irradiation conditions are difficult to control, and activated materials are challenging to recover and characterize. At TRIUMF, two complementary approaches contribute accelerator-relevant data to the broader understanding of radiation damage: secondary irradiation of material samples during routine operation at the ISAC facility and the recovery of components following extended operational exposure.
Secondary irradiation studies have been used to investigate both established and emerging material systems, including compositionally complex and additively manufactured alloys. Complementing these controlled experiments, aluminum beam windows recovered from ISAC provide access to materials exposed to a high-power proton beam for several years, accumulating several dpa and helium concentrations near or above the commonly cited benchmark of approximately 2,000 appm. Across both secondary irradiations and service-exposed components, small punch testing is used to evaluate retained mechanical performance, while transmission electron microscopy characterizes irradiation-induced microstructural evolution. Ongoing developments aim to improve control of irradiation temperature, with the first temperature-controlled in-beam experiment targeted for 2027. Looking ahead, additional irradiation locations and planned recovery of operational components at TRIUMF’s new ARIEL facility could increase both the quantity and range of accelerator-relevant materials data generated through these approaches, supporting a sustained materials research program for future high-power accelerator facilities.

Speaker: Ferran Boix Pamies (TRIUMF)

65 Target Materials Research and Development for Future High-Power Accelerator Facilities

Accelerator beam-intercepting devices, including beam windows and secondary particle-production targets, operate under extreme thermomechanical loading and radiation damage. Their reliable performance and ability to withstand increasing beam powers are essential for maintaining particle-production efficiency and operational availability of future high-energy physics experimental programs. At Fermilab, and within the framework of the RaDIATE collaboration, target-materials research and development efforts are focused on improving the understanding of material behavior under accelerator-relevant irradiation and operating conditions. This talk will provide an overview of recent studies of conventional and emerging candidate target materials, including experimental characterization and post-irradiation investigations aimed at quantifying changes in microstructure and mechanical performance. The objectives of these studies are to inform material selection, component design, and operating limits for future multi-MW neutrino and muon facilities, while identifying key research directions needed to enable the next generation of accelerator target systems.

Speaker: Kavin Ammigan

66 Development of Radiation-Damage-Resistant Proton Accelerator Beam Windows Using Ti-15-3 Alloy

High-power proton accelerator facilities require beam window materials with excellent resistance to radiation damage while maintaining sufficient mechanical strength and ductility. Although Ti-6Al-4V alloy has been widely used for proton beam windows, irradiation-induced hardening and embrittlement remain significant concerns for future multi-megawatt beam operation. To address this issue, the β titanium alloy Ti-15V-3Cr-3Sn-3Al (Ti-15-3) has been investigated as a candidate material for the Hyper-Kamiokande neutrino beamline.

Systematic heavy-ion irradiation experiments, combined with nanoindentation, micro-tensile testing, and transmission electron microscopy, have demonstrated that solution-treated Ti-15-3 exhibits remarkably high radiation tolerance at room temperature. The experimental results suggest that efficient point-defect recombination is associated with sub-nanometer lattice disorder in the β (BCC) phase. Based on these findings, a new radiation-damage mitigation mechanism, Anomalous Point Defect Recombination (APDR), has been proposed.

Microstructural optimization of Ti-15-3 is currently underway through thermo-mechanical processing and two-step aging treatments to further improve radiation tolerance while maintaining the mechanical properties required for practical beam window applications. Preliminary ion-irradiation results indicate that the two-step-aged material exhibits only limited irradiation hardening at temperatures up to 300°C, suggesting further improvement in radiation tolerance through optimized microstructural control. Prototype beam window fabrication has also been successfully demonstrated as part of the Hyper-Kamiokande beam window development program.

This presentation summarizes recent progress from fundamental radiation-damage studies to prototype beam window development, highlighting the potential of Ti-15-3 as a next-generation beam window material for high-power proton accelerator facilities.

Speaker: Taku Ishida (KEK High Energy Accelerator Research Organization (JP))

10:20 Coffee break

Session D - Radiation damage effects to materials - simulations and experimental studies

67 Novel materials development to enable multimegawatt target systems

Operating target stations at Fermilab in the LBNF/DUNE era will require new techniques and technologies to overcome the challenges associated with the greatly increased beam power. The increase to 2+ MW will result in unprecedented levels of radiation damage and thermal shock in beam intercepting devices (BIDs). As two primary accelerator BIDs particle production targets and beam windows will face large hurdles to continuous operation in such environments. Novel high-entropy alloys (HEAs) and nanofibers are being developed at Fermilab for use as beam windows and particle production targets respectively to potentially mitigate these effects. HEAs as a material class potentially offer intrinsic radiation damage tolerance due to a distorted crystal lattice decreasing diffusion during the thermal spike portion of the radiation damage process and increasing recombination effects. Several low density HEAs with 4 – 6 component elements from the AlCoCrMnTiV system have been developed that are predicted by CALPHAD simulation to have single-phase BCC structures with ordered nanoscale precipitates present in several compositions. Nanofiber materials as a target structure offer intrinsic resistance to thermal shock as the 1D nature of the fibers results in discretized thermal transport and freedom for fibers to deform individually. This talk will describe the results of several irradiation studies of these materials, including low-energy heavy ion irradiations to high damage levels and a high-intensity, pulsed proton irradiation at CERN’s HiRadMat facility to study thermal shock effects. The results of a heat treatment study of several HEA compositions to increase precipitate concentrations and explore the interplay between precipitate dissolution and void swelling behavior will also be presented along with results from push-to-pull tests to determine the mechanical properties of single nanofibers. Finally, plans for alloy down-selection and next steps in the development process for both materials will be discussed.

Speaker: Abe Burleigh (Fermilab)

68 PHITS-Based Reconstruction of Heavy Ion Damage and Irradiation Conditions in Glidcop AL-15

The Facility for Rare Isotope Beams (FRIB) superconducting heavy-ion linear accelerator is designed to accelerate ions up to uranium to a maximum beam power of 400 kW. Beam-intercepting devices, such as targets and beam dumps, are essential to high-power beam facility operation. The FRIB linac also includes a low power charge selector (LPCS) dedicated to selecting charge states from stripped 20 MeV/u heavy-ion beams. The LPCS has two movable jaws made of Glidcop AL-15, a copper alloy containing 0.15 wt.% precipitated aluminum oxide. Significant beam-induced damage, including swelling, blistering, and cracking, has been observed on a recently removed LPCS after several years of service, motivating a simulation-guided reconstruction of the operational exposure and resulting damage.
In this work, the Particle and Heavy Ion Transport code System (PHITS) was used to reconstruct the beam distribution and displacement damage in the LPCS jaws. Lateral charge-state distributions were modeled to estimate the spatial distribution of intercepted beam on the Glidcop surface, while depth-dependent damage calculations were performed using the athermal recombination correction to dpa. Representative FRIB beam species, including 28Si, 36Ar, 48Ca, 64Zn, 82Se, 124Xe, and 238U, were simulated to evaluate ion range, damage localization, and peak accumulated displacement damage. These calculations provide a quantitative basis for relating observed macroscopic damage features to the underlying operational conditions. The reconstructed damage profiles were then used to guide a controlled Glidcop AL-15 irradiation campaign at the Michigan Ion Beam Laboratory using 6 MeV Ni ions at 200 °C. A dose ladder of 1, 10, 50, and 100 arc-dpa was selected for subsequent nanoindentation and microscopy studies of damage-dependent mechanical and microstructural evolution. This approach provides a case study in using Monte Carlo methods to connect accelerator operation, component damage reconstruction, and controlled irradiation experiment planning for high-power targetry applications.

Speaker: Ethan Fletcher (Michigan State University- Facility for Rare Isotope Beams)

69 Radiation effects on organic materials used in target subsystems: overview, challenges, and operation-oriented design of irradiation studies

A wide range of components within target subsystems are made of organic materials, such as lubricated moving elements, elastomeric seals, insulating materials, paints and coatings. These components are typically installed in areas with radiation levels in the order of 0.1-5 MGy/ year, where maintenance access is highly restricted.
These radiation levels are above the usability thresholds of generic organic materials; unfortunately, technical requirements do not always permit their replacement by more resistant inorganic alternatives. The most resistant organic materials are therefore needed; unfortunately, very few material studies explored dose levels encountered in operation, and the few studies available are often not usable. Dedicated irradiation studies are required to compare candidate materials for target systems under irradiation, assess the expected radiation damage, define usability thresholds and plan preventive maintenance.
Examples of recent material studies for target systems are presented, including elastomers for BDF/SHiP target vacuum vessel, and lubricating greases for alignment systems of particle dumps. The importance of designing irradiation studies based on operation conditions is highlighted, and the applicability of commonly adopted usability thresholds is questioned.

Speaker: Dominika Zemkova (CERN)

70 From Materials Verification to PIE activities at ESS

The European Spallation Source (ESS) is transitioning from construction to commissioning, with many components delivered through in-kind contributions. This introduces challenges in verifying material compliance and ensuring suitability for radiation environments. To address this, the Spallation Physics group has established a centralised materials engineering and characterisation function. This work integrates analytical testing, materials expertise, and cross-disciplinary collaboration to verify supplied materials, support material selection, and investigate failures across ESS systems.
Support is further provided for material selection, with emphasis on performance under irradiation, thermal loading, and mechanical stress. Failure analysis during installation and commissioning forms another key activity. In parallel, activities are expanding towards irradiation campaigns and post-irradiation examination (PIE) to better understand material degradation and to explore lifetime extension of critical components.
This contribution demonstrates how an integrated materials engineering approach supports risk reduction and enables reliable commissioning and operation of ESS systems. Selected case studies from recent years will be presented, illustrating how complementary analytical techniques have been applied to address specific materials-related challenges across ESS systems.

Speaker: Hossein Sina

12:10 Lunch break

71 Transport from Building 39 to Prevessin Training Center

72 Self-rescue mask training - Session 1 & 2

73 Transport from Prevessin Training Center to Building 39

Session E - R&D activities to support design concepts

74 Surrogate Modeling for Shielding and Muon Monitor Response Studies in High-Power Neutrino Beamlines

Muon monitor response in high-power neutrino beamlines depends on shielding configuration, proton beam conditions, and horn focusing. Studying these effects with high-statistics Geant4 simulations can become computationally expensive for large multidimensional parameter scans relevant to beam diagnostics and beamline optimization.

We present a Gaussian Process surrogate framework for Geant4-based studies of muon monitor response in the LBNF beamline configuration. The emulator was trained on simulations spanning proton beam offsets and horn-current variations and was used to study nonlinear beamline response across different operating conditions relevant to target and horn system performance.

These studies demonstrate that surrogate approaches can efficiently capture complex beamline response behavior while significantly reducing the computational cost of beamline sensitivity, optimization, and systematic studies in future high-power neutrino facilities.

Speaker: Michael Hedges

75 Engineering Design Calculations and Beam-Tests Benchmarking of the SPS Beam Dump Facility (BDF) Helium-Cooled Tungsten Target

At CERNs north area, the Hi-ECN3 (High Intensity Experimental Cavern North 3) project will host a Beam Dump Facility (BDF) production target for the Search for Hidden Particles (SHiP) experiment, to study physics beyond the standard model. Commissioning with beam on target is expected in the early 2030’s.
The solid, high-z target will fully absorb a 400GeV/p beam, dissipating an average of 305kW of beam-induced thermal power. Cooling is provided by 400-g/s of ambient temperature helium.
Engineering design studies were performed for nominal, commissioning and accidental conditions, using energy deposition, radiation damage and decay heat inputs. Emphasis was placed on managing thermal stresses, limiting peak temperatures and optimising helium flow distribution.
To validate the design approach, dedicated beam tests were performed on prototype assemblies during 2025 and 2026 in a dedicated slow-extraction testbench at CERN, using representative beam conditions. Cooling and beam parameters were monitored, while measured temperature responses were benchmarked against simulation predictions.
Initial analysis shows consistent behavior of the measurements with reasonable agreement between predictions and measurements, despite some discrepancies. The prototype campaigns allow benchmarking of the FEM models and confirm the feasibility of the helium-cooled tungsten concept for the BDF. These results contribute to the final target design and to the development of a new generation of helium-cooled high-power target technologies.

Speaker: Mike Parkin (CERN)

76 Fluidized Granular Targets- Development Work for the Muon Collider

To achieve higher power densities on target, flowing media provide a straightforward solution to reduce temperatures. However, obtaining flowing target material as dense as tungsten poses a complex set of engineering challenges, namely erosion, multi-phase fluid dynamics and manufacturing difficulties. For the Muon Collider a fluidized tungsten target is proposed, building upon the previous feasibility study by the Rutherford Appleton Laboratory. RAL, the University of Warwick, the University of Sheffield and the Royce Institute have developed the concept further, and carried out an experimental programme to boost confidence in reliability and plant design.

First-of-a-kind erosion testing has been conducted to identify candidate materials for the target container, and wear rates quantified which can be extrapolated to predict component lifetimes. Powder characterisation work has uncovered key engineering parameters for target media and allowed selection of suitable grades of tungsten powder.

Physicists at the University of Warwick are confident that a high yield target is feasible within engineering limits and the tight packaging requirements of the application, on par with solid target designs which may reach thermal limits.

These two prongs of the project are being used to propose an out-of-beam prototype target, which is planned to be constructed and operated in the next few years.

Speaker: Ben Suitters (STFC RAL)

77 Integrated material and architecture design of porous carbide ISOL targets for enhanced thermal stability and release efficiency

Research on ISOL targets has traditionally focused on material composition, while its combination with target architecture has remained largely unexplored. This integrated approach is increasingly relevant for next-generation targets, where material properties, geometry and manufacturing strategy must be jointly optimized to withstand beam-induced thermal loads while maximizing isotope release.
Carbides are particularly attractive target materials owing to their high-temperature stability, structural integrity under high-vacuum conditions and high thermal emissivity. Conventional carbide targets are typically produced by carbothermal reduction of pressed powder compacts consisting of metal oxides and a carbon source. However, this approach is limited by chemical heterogeneity and restricted geometrical complexity. To overcome these limitations, we developed a versatile sol-gel synthesis route based on hybrid organic-inorganic precursors, replacing both oxide and carbon powders. Molecular-scale mixing promotes excellent chemical homogeneity while enabling precise control of the resulting microstructure. Following conversion, the materials exhibit a combination of nanocrystalline carbide and overstoichiometric carbon phases in the shape of an open and interconnected micro- and mesoporous network, a feature expected to enhance isotope release kinetics while preserving thermal stability.
Moreover, the liquid precursor system can be functionalized with photocurable groups, enabling shaping through vat photopolymerization additive manufacturing. This approach provides unprecedented freedom in target design, allowing the fabrication of complex geometries with controlled porosity, including triply periodic minimal surface (TPMS) architectures characterized by high surface-to-volume ratio, favorable stress distribution and heat-transfer characteristics.
We will present the complete workflow, from material design and synthesis to additive manufacturing, post-processing and characterization, and demonstrate its application to titanium, uranium and silicon carbide systems. Additively manufactured carbide-based structures were successfully produced for all three materials and characterized in terms of phase composition, morphology, porosity and specific surface area. Preliminary tests on titanium carbide under conditions relevant to ISOL operation further support the potential of this material-by-design approach.

Speaker: Giorgia Franchin (Department of Industrial Engineering, University of Padova)

78 Liquid lithium film jet technology for high power beams

Liquid lithium film jet is a key enabling beam intercepting technology for high power accelerators. It overcomes inherent limitations with the high-intensity beams associated with extreme thermal loads and radiation damage, while leveraging the physical advantages of a low atomic number. A windowless free-surface film jet offers an ideal system for beamline applications. At Facility for Rare Isotope Beams (FRIB), such technology is employed for charge stripping in the linac, featuring the world’s most powerful heavy ion beams up to 30 kW. The liquid lithium film jet with 20 μm thickness flowing at 50 m/s is produced by impinging a round jet onto a deflector. As of June 2026, total circulation hours of liquid lithium in a high-temperature loop and ultra-high vacuum (10$^{-7}$ Pa) has exceeded 16,700 hours and broken the previous record [1].
In this talk, the technology of FRIB’s charge stripper is presented. Operation experience with high power heavy ion beams are reported including recent observation of free-surface flow instabilities. In the later part of the talk, various research activities are presented. The primary focus is on developing a new scheme to form the film jet to improve the performance of FRIB’s charge stripper and enhance the versatility. As a new application, concept for high-intensity pion and muon sources for the next generation multi-MW meson factories is also introduced.
This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics and used resources of the Facility for Rare Isotope Beams (FRIB) Operations, which is a DOE Office of Science User Facility under Award Number DE-SC0023633.

[1] R. Kolowith, J. D. Berg, and W. C. Miller, “Experimental lithium system. Final report,” Hanford Engineering Development Lab., Richland, WA (USA), HEDL-TME-84-29, Apr. 1985. doi: 10.2172/5580485.

Speaker: Ryoto Iwai (Facility for Rare Isotope Beams)

15:10 Coffee break

Session E - R&D activities to support design concepts

79 Target Materials R&D for the Second Target Station of the Spallation Neutron Source

The target systems at the Second Target Station (STS) of the Spallation Neutron Source (SNS) receive 1.3 GeV protons at 700 kW beam power to produce high-brightness cold neutron beams. Tungsten is used as target material which provides higher neutron yield per unit beam power. To handle a high intensity proton flux in a compact beam footprint, the target consists of 20 independent segments that rotate with the angular speed synchronized with 15 Hz proton beam pulses. The target rotation distributes beam power and radiation damage evenly to each segment, and it helps passively manage decay heat driven loss-of-cooling-accident (LOCA) events thanks to its relatively high surface to volume ratio. The significantly reduced time-averaged beam power per segment allows the target design team to develop an integrated monolithic target in which the spallation volume, cladding, and structural vessel are metallurgically diffusion-bonded. The spallation volume is edge-cooled with the coolant water flowing through channels in the vessel made of Inconel 718, which minimizes the risk of exposing tungsten to direct water contact preventing excessive tungsten corrosion while keeping brittle tungsten within the structural boundary. The STS Target Materials R&D program has focused on developing manufacturing routes of the target of a novel concept, studying properties of target materials of commercial grades and characterizing radiation damage behavior of spallation materials. This talk will present a status of the STS Target Materials R&D program with preliminary results obtained.

Speaker: Aaron Jacques

80 Development of production targets for a high-intensity muon source at CiADS

The production target of a muon source prefers a small beam spot and the beam intensity is usually high, especially for a MW-level beam. The R&D of the targets is critical for the MuST project, which was proposed to utilize the 5-mA proton beam of the superconducting linac of CiADS to support a high-intensity muon source. Both rotation graphite target and liquid lithium waterfall target are under development. The former can be used for a proton beam of 0.5 mA ~ 2 mA while the latter can be used under the 5 mA beam. The design of the target station, the develop progress of the rotation target prototype and the feasibility study of the waterfall-like lithium target will be introduced.

Speaker: Dr Han-Jie Cai (Institute of Modern Physics, Chinese Academy of Sciences)

81 An Evolving Design Framework for the Mu2e Production Target

The Mu2e experiment will search for the neutrinoless conversion of a muon into an electron in the field of an aluminum nucleus, improving the sensitivity to this charged-lepton-flavor-violating process by four orders of magnitude. This will require producing the world's most intense muon beam from a pulsed proton beam onto a compact, radiatively cooled production target inside of a high-field superconducting solenoid.

Rather than treating the production target as a fixed design, we have developed a modular target geometry and a flexible simulation framework that enable rapid incorporation and evaluation of new ideas emerging from both Mu2e and the broader high-power targetry community. This approach makes it possible to iterate quickly and explore a broad range of design alternatives without restarting the historically complicated and cumbersome design and simulation process. The framework has already led to a significant evolution of the production target and provides a path for continued improvement throughout the lifetime of the experiment. This presentation will describe the modular simulation workflow, the recent studies that motivated the new baseline Inconel-718 target design, and how the same framework is being used to evaluate future target concepts for Mu2e.

Speaker: Michael Hedges

82 Low-Density Materials and Nanomaterials for Accelerator Technologies

Low-density and nanostructured materials, notably carbon nanotube (CNT) assemblies and graphene-based materials, offer an attractive combination of low mass density, high specific strength, tailored electrical and thermal properties, and resilience to extreme operating environments. Recent advances in synthesis, processing, characterisation, and industrial-scale production have significantly improved material quality, reproducibility, and availability, enabling consideration of these materials for demanding accelerator applications. Potential use cases include high-power targets, beam intercepting devices, vacuum components, beam diagnostics, thermal management systems, and multifunctional structural materials.
The 2nd International Workshop on Low-Density Materials for Particle Accelerator Technologies was held at the University of Bath in June 2026, bringing together researchers from accelerator laboratories, universities, and industrial partners to assess the state of the art and identify future opportunities. Presentations covered the production and characterisation of CNT-based fibres, sheets, and composites; the behaviour of low-density materials under mechanical, thermal, and irradiation loading; and emerging applications in accelerator and target technologies. Particular attention was given to high-power target systems for radioisotope production, beam instrumentation, and advanced vacuum engineering. Contributions also highlighted recent developments in graphene and related low-dimensional materials, and their potential integration into next-generation accelerator components.
This presentation will summarise the principal findings and outcomes of the workshop, including the development of a first community position paper and the establishment of future collaborative research directions. The workshop highlighted both the growing maturity of low-density nanostructured materials and the key challenges that must be addressed before their wider deployment in accelerator facilities and other high-power scientific infrastructures.
[1] 2nd International Workshop on Low-Density Materials for Particle Accelerator Technologies, University of Bath, June 2026 https://indico.cern.ch/event/1660653/

Speakers: Chiara Pasquino (CERN), Raymond Veness (CERN), Thierry Stora (CERN)

83 Detailed Design and Production of the HL-LHC External Beam Dumps

The High-Luminosity Large Hadron Collider (HL-LHC) will increase the stored beam energy from 539 MJ to 710 MJ, requiring a new generation of external beam dumps capable of absorbing the beam within 86 μs. This contribution presents the detailed design of the HL-LHC Target Dump External (TDE) and the transition from development to the start of series production. The design combines a segmented core of carbon-fibre-reinforced carbon and isotropic graphite housed inside a thin-walled and electron-beam welded Ti-6Al-4V vessel. Particular attention is given to the dynamic response generated by beam-induced energy deposition, including vessel heating, longitudinal vibration, cyclic stresses and high accelerations at the end windows. The design process integrated particle-shower calculations, thermo-mechanical simulations, manufacturing feasibility studies, full-scale prototyping and material irradiation tests at CERN’s HiRadMat facility. These activities supported the selection of the vessel and core materials, the definition of the shrink-fitting and welding processes, and the validation of structural margins under nominal and accidental dilution scenarios. The contribution will also report on the start of series production, highlighting initial manufacturing activities, implementation of the defined processes, and early lessons.

Speaker: Nicola Solieri (CERN)

84 High-Power Target Developments at CEA Saclay for Neutron Sources

Neutron beams are required for a variety of scientific, industrial and medical applications. Nuclear research reactors, which until now have been the main sources of neutrons for these purposes, are reaching the end of their lifespans and are gradually being decommissioned around the world. High-intensity Compact Accelerator-based Neutron Sources (HiCANS) are smaller-scale facilities capable of providing local neutron sources for those specific purposes. They rely on a high-intensity, low-energy (< 40 MeV/u), light beam (protons, deuterons) striking a target to produce neutrons. However, high beam power (> 10 kW) is required to achieve high neutron fluxes, and the target must be able to withstand such power. Using the IPHI (High-Intensity Proton Injector) accelerator at CEA-Saclay (France), capable of delivering a proton beam of 3 MeV at up to 100 mA, the IRFU team studied two different types of target. The first was a water-cooled solid beryllium target [1], which was exposed to a 30 kW beam for more than 100 hours. The second was a liquid lithium target [2], which withstood a 10 kW beam for 80 hours. The behaviour of the targets, as well as their neutron production performance, were analysed in detail and compared with simulations. We will present the results of these tests.

[1] Schwindling J., Annighöfer B., Thulliez L.. & al., Long term operation of a 30 kW Beryllium target at IPHI. Journal of Neutron Research, Volume 24, Issue 3-4, Pages 289-298 (2022). https://doi.org/10.3233/JNR-220024
[2] Thulliez, L., Berton, N., Boudouin, R. et al. Neutron production with a 10 kW HiCANS based on SATELIT, a CEA-Saclay target with liquid lithium. Eur. Phys. J. A 62, 79 (2026). https://doi.org/10.1140/epja/s10050-026-01852-1

Speakers: Antoine Drouart (CEA Saclay), Christian VEYSSIERE (CEA Saclay), Loïc Thulliez (CEA-Saclay), Romuald Duperrier (CEA Saclay), Dr Xavier Wohleber (CEA Saclay)

SPC meeting

Thursday 19 November

Session F - Post-irradiation examination of systems and components removed from service

85 Post Irradiation examination (PIE) on ISIS TS2 targets

The operational lifetime of the tantalum-clad tungsten target on Target Station 2 (TS2) [1] at ISIS remains below that originally specified, despite sustained development over the past two decades. Previous work [2–7] has documented efforts to understand the underlying causes, alongside design changes and operational strategies to improve robustness and extend service life.
To support next-generation target design, ISIS has initiated a structured programme of post-irradiation examination (PIE) on retired TS2 targets, despite the absence of a dedicated on-site facility. The programme seeks to identify in-service material degradation, damage mechanisms, and component performance under mixed proton/neutron irradiation, with findings feeding directly into simulation refinement, materials modelling, and future design development.
This contribution charts the PIE programme’s progress to date, including the summer 2026 campaign, highlights early findings, and sets out future plans to expand its scope and impact.

References:
[1] - An Overview of ISIS Neutron Spallation Targets (AHIPS 2024), L. Jones https://indico.ijclab.in2p3.fr/event/10644/contributions/35451/attachments/24312/35378/An Overview of ISIS Neutron Spallation Targets.pdf
[2] - ISIS Target Station 2 – Update on Target Evolution (HPTW 2023), L. Jones https://indico2.riken.jp/event/3102/contributions/21965/attachments/12307/18009/HPTW2023-ISIS Target Station 2 Update on Target Evolution V2.pptx
[3] - Application of LES to the Thermal–Hydraulics of Target Station 2 of the ISIS Muon and Neutron Source (DLES 2023 Conference Paper), G. Cartland-Glover et al. https://link.springer.com/chapter/10.1007/978-3-031-47028-8_10
[4] - Measurement of residual strain in tantalum-clad tungsten after hot isostatic pressing (Journal of Nuclear Materials Research, 2020), D. Wilcox et al. https://doi.org/10.3233/JNR-200181
[5] – Stress Levels and Failure Modes of Tantalum Clad Tungsten Targets at ISIS (Journal of Nuclear Materials, 2018), D.Wilcox et al. https://www.sciencedirect.com/science/article/abs/pii/S0022311516312041
[6] - Simulating Performance of Tantalum Clad Tungsten Targets (IWSMT-13, 2016), D. Wilcox
https://conference.sns.gov/event/20/images/2907-Simulating_Performance_of_Tantalum_Clad_Tungsten_Targets_-_Dan_Wilcox.pdf
[7] - Design Modification of ISIS TS2 Target in order to Improve Longevity amid Spallation Reactions (IWSMT, 2013), A. Dey, L. Jones https://conference.sns.gov/event/20/images/2878-Design_Modification_of_ISIS_TS2_Target_in_Order_to...-_Arghya_Dey.pdf

Speakers: Mr Daniel Coates (UKRI - STFC), Stephen Gallimore (UKRI - STFC)

86 Tensile properties and microstructure of irradiated Al-6061 and Inconel 718 from proton beam windows at the Spallation Neutron Source

Administrative dose limits are used at the Spallation Neutron Source (SNS) for proton beam windows to limit the risk of failure to the window material from radiation-induced changes to mechanical properties. The limits depend on the perceived vulnerability of the material; transmutation-produced helium concentration is used to limit the lifetime of aluminum windows, and displacement dose is used for the Inconel 718 window lifetimes. To evaluate the efficacy of these limits, the tensile properties and microstructures were characterized for samples removed from proton beam windows at the SNS with aluminum 6061 and Inconel 718 windows after reaching their administrative dose limits. Deformation behavior of the specimen gauge sections was characterized during testing using digital image correlation (DIC), and the tensile specimen fracture surfaces were examined using a scanning electron microscope. The radiation-induced stored energy and retained transmutation products were measured using differential scanning calorimetry (DSC) and thermal desorption spectrometry (TDS), and the microstructure was characterized using various transmission electron microscopy (TEM) techniques. The latest results from tensile testing and microstructure characterizations of irradiated 6061 and Inconel 718 specimens will be presented and the impact on the lifetime of the proton beam windows will be discussed.

Speaker: David McClintock (Oak Ridge National Laboratory)

87 Post-irradiation examination of n_TOF Target #2: radiation protection challenges and lessons for future target design

The end-of-life management of highly activated accelerator targets presents significant challenges for radiation protection and radioactive waste management, while providing valuable feedback for the design of future target systems.
At CERN’s n_TOF facility, the target #2, with a core made of pure lead and irradiated by a 20 GeV/c proton beam with an average power of ~5 kW for almost ten years, could not be directly packaged for disposal because its dimensions were incompatible with the approved radioactive waste container. Rather than treating the operation solely as a waste processing task, a post-irradiation examination during the size-reduction process took also place.
The intervention required dedicated radiation protection planning, including the creation of a work area to contain potential contamination, assessment of dose rate and contamination risks, and the use of remote handling techniques to minimise personnel exposure. CERN robots were deployed to perform cutting operations on the two-tonne activated target, reducing hands-on work and supporting the ALARA approach.
The discovery of a significant beam-induced cavity highlighted the need for tighter control of beam parameters and target cooling, with important implications for future target design and operation.
The project demonstrated that post-irradiation examination of accelerator components provides essential feedback for both engineering and radiation protection. The creation of an ad-hoc work area made possible to carry out the intervention under controlled conditions. Although this approach provided the flexibility required to manage a non-standard and highly radioactive object, it also highlighted the practical limitations of relying on temporary facilities and the potential benefit of a dedicated facility for post-irradiation examination, dismantling, and radioactive waste processing activities.
In addition, incorporating radioactive waste management and dismantling constraints at the design stage can reduce future intervention complexity, occupational exposure, contamination risk, and radioactive waste volumes.

Speaker: Fabio Pozzi (CERN)

88 Transmutation Products in the SS316 Target Vessel at the Spallation Neutron Source

The mercury target at Spallation Neutron Source (SNS) is contained in two double-walled SS316 structures. Its mechanical properties and dimensional stability are closely watched and measured after removal at the end of each irradiation cycle. A comprehensive investigation involving particle transport and transmutation inventory calculations was conducted for all significant transmutants of Target 12, focusing especially on gaseous products. It is thought that isotopes of H, He, Ne, Ar and Kr play important roles in determining mechanical and dimensional stability of SS316 under irradiation.
After receiving an irradiation energy of ~4500 MWhr by 940 MeV protons, the SS316 vessel of Target 12 was estimated to produce a maximum of 4730 appm of hydrogen isotopes and 1150 appm of helium isotopes, with D and T contributing ~30% to the total H production, and He-3 similarily contributing ~30% to the total He production. The levels of hydrogen and helium are significantly higher than those produced in fission or fusion environments. Furthermore, in spallation environments isotopes of higher mass noble gases are produced in Target 12 with Ar-38 (33 appm) being the highest. Isotopes of neon (Ne-20, 21, 22, at 26 appm total) and other argon isotopes (Ar-36, 39, 40 at 18 appm total) are also produced. The Mo content of SS316 leads to generation of krypton isotopes at much lower levels (K-78, 80, 81, 82, 83, 84 at 2.3 appm total). Within the proton beam footprint there is a strong secondary neutron field in the SNS target vessel, but this study finds that neutron imapct is insignificant in producing or removing the heavier noble gas istopes of Ne, Ar and Kr. Additionally, it finds that Ti-44 with a1.157 MeV gamma ray from its short-lived decay of Sc-44 is suitable for a non-destructive gamma spectroscopy measurement to determine the proton beam profile.

Speaker: Wei Lu (Oak Ridge National Laboratory)

10:00 Coffee break

Session G - Fabrication, assembly, inspection and quality assurance

89 Lessons Learned from SNS Inner Reflector Plug Fabrication

The fabrication process for the most recently Inner Reflector Plug (“IRP-3”) was plagued with fabrication issues from the beginning and took over 7 years to complete. Complex and critical welds, exotic and dangerous materials, and stringent acceptance criteria were just some of the challenges faced in this formidable project.

The IRP is a crucial component of the Spallation Neutron Source (SNS); it surrounds the mercury target to reflect neutrons towards the instruments and controls the shape of the neutron pulses for scientific experiments. It is a complex assembly containing beryllium reflectors, cryogenic and water moderators, neutron poisons, and decoupling material. Depletion of neutron-moderating materials negatively affects the neutron pulse characteristics over time; as such, the IRP must be replaced periodically. In 2025, the IRP was successfully replaced for the second time; this talk will present some of lessons learned from the fabrication and installation process. Future design changes to improve manufacturability, as well as investigation of new fabrication techniques and technologies will be discussed.

Speaker: Josh Watkins (Oak Ridge National Laboratory)

90 Progress in Solid Tungsten Target of China Spallation Neutron Source

The China Spallation Neutron Source (CSNS), a large-scale neutron scientific facility, was completed and commissioned in 2018. Currently, an accelerator power upgrade project is underway, with a designed target to raise the operational power of the CSNS to 500 kW.
The CSNS target system is composed of tungsten target plates, a target vessel and a vessel cover. For the 500kW upgraded target design, sixteen gradient-thickness zirconium-coated tungsten target blocks are installed in parallel within the target vessel. The thickness of the tungsten blocks varies from 10.5 mm (the thinnest) to 80 mm (the thickest). Cooling water channels are fabricated between adjacent target plates, with channel widths ranging from 0.8 mm to 1.0 mm. Specifically, the cooling water channels at the front end are designed with a larger width to accommodate a higher cooling water flow rate. Numerical simulation results show that the maximum temperature at the core region of the tungsten target reaches approximately 220 ℃ under a total inlet flow rate of 200 L/min.
Considering the effect of decay heat, zirconium alloy coating is adopted to replace the conventional tantalum coating for CSNS target components. The bonding between tungsten substrate and zirconium alloy coating is achieved via diffusion welding. Preliminary investigations have demonstrated that direct diffusion welding of tungsten and zirconium tends to generate brittle ZrW₂ phases at the bonding interface, which significantly reduces the interfacial bonding strength. To address this issue, tantalum or titanium intermediate layers are introduced between tungsten and zirconium, enabling the successful fabrication of zirconium-coated tungsten targets for CSNS. The fabricated target blocks have been validated in the CSNS T6 and T7 target stations, and no operational abnormalities have been identified throughout the testing process.

Speaker: Shaohong Wei (1.Institute of High Energy Physics, Chinese Academy of Sciences (CAS), Beijing 100049, China 2.Spallation Neutron Source Science Center, Dongguan 523803, China)

91 Characterisation of Hot-Rolled Tungsten Plates for the Beam Dump Facility Target

The Beam Dump Facility (BDF) at CERN will use hot-rolled tungsten plates as the core target material, operating under cyclic proton beam loading with beam-normal surface temperatures of 50–350 °C, maximum principal stresses up to 100 MPa, and high-speed helium cooling containing trace levels of oxygen. This work presents an integrated qualification programme covering material characterisation, oxidation behaviour, and mechanical performance, supporting the definition of specifications for the procurement of the target materials.

Speaker: Patrick Michael Curran

92 Quantifying Performance Drivers and Tolerance Limits in Multi-Volume Reflection Arrays for Crystal Collimation

CERN has been developing bent crystal technology for beam manipulation. This approach uses silicon single-crystal strips to steer charged particles by small angles, directing them away from regions of high beam losses. An application has been identified within the Super Proton Synchrotron (SPS) slow extraction process. The proposed solution is the Multi-Volume Reflection Array (MVRA), which houses multiple consecutive crystals, improving performance but increasing system complexity.

For compliance, the crystals must steer charged particles through a known angle determined by the crystal geometry itself. Therefore, any misalignment or imperfection within the assembly can lead to deviation. Assembly conformance is evaluated through each crystal’s anticlastic angle and resultant torsion. The introduction of multiple crystals also imposes additional alignment requirements between consecutive crystals.

Multiple MVRAs have been assembled and tested. In parallel, a successful procedure to measure and quantify the assembly’s compliance has been developed and validated against several on-beam testing campaigns. This demonstrates correlation between measured crystal functionality on and off beam, indicating that assembly performance can be assessed without the beam. However, assembled MVRAs remain suboptimal due to assembly and manufacturing imperfections.

Relating assembly and manufacturing imperfections directly to MVRA performance is therefore necessary. To address this, a sensitivity study was carried out in which imperfections were parameterised using FEA simulations and validated against the previously developed autocollimator and on-beam methodologies. Combined with metrology reports and assembly process improvements, these parameters were subsequently correlated with the performance of the final assembled crystals.

The study showed that several components would require unrealistically tight manufacturing tolerances to achieve the desired MVRA performance, including single-digit nanometre surface properties across multiple reference areas. As a result, an alternative design strategy is required to achieve the target performance and full MVRA compliance.

Speaker: Michael William Howes

93 Experience with manufacturing, testing and commissioning of the Super-FRS Shielding Flask

The Super Fragment Separator (Super-FRS) at the Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany, is currently installing beam line components in target area to achieve the commissioning goal in 2027. During operation, the target area beamline inserts become activated due interaction with the primary beam. To enable safe maintenance, these activated plugs must be remotely removed from the beamline, transported using shielding flask to the hot cell facility for repair or replacement, and reinstalled without exposing personnel to radiation.
The Super-FRS shielding flask is a key part of this remote handling concept. The 56-ton flask provides the required shielding and handling capabilities while transporting activated beamline components between the target area, hot cell and park cells. Along with the support platform, pillow seal park cell frame, and associated control system, it forms an integrated g system capable of transferring all plugs.
Following the design phase, the project progressed through manufacturing, assembly, Factory Acceptance Testing (FAT), and Site Acceptance Testing (SAT) to prepare the flask for commissioning. These activities included mechanical and dimensional inspections, load testing, verification of lifting and positioning functions, electrical and control system integration, safety interlock testing, and validation of interfaces with the surrounding Super-FRS infrastructure. Throughout this process, close collaboration between GSI and the industrial partners helped resolve technical issues, optimize assembly procedures, and verify compliance with functional and safety requirements.
This contribution summarizes the experience gained during the realization of the SFRS Flask system, from manufacturing to commissioning. It describes the testing strategy, highlights challenges encountered during fabrication, assembly, and system integration, and presents the engineering solutions adopted. The paper also provides an overview of the current commissioning status and the lessons learned to support the development and qualification of future remote handling systems for accelerator facilities operating in high-radiation environments.

Speaker: Faraz Amjad

94 Benefits of in-house quality assurance methods in Target Manufacture

ISIS is one of the few facilities in the world that manufactures both targets almost entirely in house. A recent addition of a Target Manufacture workshop has meant that the Target group has expanded its production capabilities increasing capacity to put more focus towards refining and perfecting the manufacture and build of each target.
This facility also allows for a more reactive style of work that enables design changes to be implemented on the next operational target. It houses a range of specialised equipment including electron beam welders, a 5-axis CNC mill, and Electro Discharge Machines all supporting the manufacture of both ISIS targets. On site Ultrasonic Non-Destructive Testing (NDT) and Hot Isostatic Pressing (HIP) are utilised for quality assurance purposes and are crucial to the success of each target.
After the finalisation of a new onsite Hot Isostatic Press facility for Target Manufacture, all ISIS target HIP-ing is now carried out completely in house. Both targets that are currently in manufacture are the first to go through this facility and have provided promising results. This facility has allowed for quality control and assurance over the whole process including gas purity, operating parameters, and time between final welding and HIP treatment.
The Ultrasonic NDT is used to scan components and assemblies to check for a sufficient HIP bond to ensure good thermal transfer during operation. Through continuous development the Ultrasonic NDT is now being used for other aspects of quality assurance such as void detection investigations and cladding thickness inspection post HIP. Both processes providing further assurance in the quality of the manufacture and build of each target.
From both these systems we can confidently produce quality assurance documentation supporting target lifespan and details of their procedures, benefits, and results will be expanded on during the presentation of work.

Speaker: Grace Fenemore

12:30 Lunch break

95 Transport from Building 39 to Prevessin Training Center

96 Self-rescue mask training - Session 3 & 4

97 Transport from Prevessin Training Center to Building 39

Excursion

Loading 14: 15 from bus stop at Building 39.
Departure 14: 45 from bus stop at Building 39.
Return: Departure from Chateau de Chillon at 22:15 (TBC)

Conference Dinner

Friday 20 November

Session H - Beam intercepting devices design, analysis and validation of concepts

98 Basic Design of the 500 µA Proton Beam Dump for the ISOL facility in MYRRHA

The beam dump for the Isotope Separation On-Line (ISOL) system of the ISOL@MYRRHA facility is being developed by ESS-Bilbao in collaboration with SCK-CEN. Its primary function is to fully stop a 100 MeV, up to 500 µA proton beam (50 kW deposited power) downstream of the ISOL target station, across a wide range of operational scenarios arising from variations in target thickness and material.

The design comprises two main sub-components: a V-shaped structure to stop low-scattered beams under no-target or thin-target conditions, and two frontal plates to absorb heavily scattered beams when a target is present. The geometry of both components was derived from Monte Carlo (MCNP) energy deposition maps. CuCrZr was selected as the beam intercepting material for its high thermal conductivity and mechanical strength under irradiation. A 5° tilt angle was adopted for the V-shaped structure to distribute the beam power over a larger surface area, thereby reducing both peak surface heat flux and volumetric energy deposition.

Heat removal is achieved by forced convection through water-cooling channels machined directly into the CuCrZr plates, with a critical heat flux safety margin of at least a factor of two.

Coupled thermo-mechanical finite element analyses were performed for a comprehensive set of load scenarios, including nominal beam stopping without a target and normal operation with bismuth targets of varying thickness. Under the worst-case condition (no target with maximum horizontal beam deviation) the estimated fatigue lifetime exceeds 2500 hours, accounting for creep-fatigue interaction, corresponding to a minimum of 9000 thermal cycles between room temperature and worst case steady-state operating conditions. The design is shown to meet all functional and structural requirements, providing a baseline for detailed engineering and manufacturing.

Speaker: Luis Angel Fernandez (ESS-Bilbao)

99 Thermomechanical studies for the IMPACT HIMB target wheel design

The demand for high intensity muon facilities has been continuously increasing since muons play a significant role in research for particle and solid-state physics. The installation of a refurbished muon target station and two new High-Intensity Muon Beam lines (HIMB) in the framework of the Isotope and Muon Production using Advanced Cyclotron and Target technology project (IMPACT) at the PSI High Intensity Proton Accelerator (HIPA) will pave the way to unprecedented muon intensities allowing, among others, next generation lepton flavour violation experiments.
One of the key components for the upgrade is the target wheel made of SIGRAFINE® R6510 graphite, which will produce the muon beam. A novel target wheel configuration oriented at a 10° angle designed to withstand a 3 mA proton beam was chosen after several iterations on six different designs to optimise the surface muon production rate. This contribution will focus on the ANSYS® simulations performed to check the thermo-mechanical integrity and to finalise the number of tiles required to reduce the thermal stress.

Speaker: Dr Raffaello Sobbia (Paul Scherrer Institute)

100 Mu2e Production Target Design Updates and Testing

The Mu2e production target design has been updated in advance of the first run to improve target lifetime and integrated muon yield to the experiment. Both the target structure and material have changed. Instead of using a monolithic piece of tungsten with machined segments and cooling fins, separate pieces of Inconel 718 are mounted on a mechanically-separate support frame, all using the same low-mass mounting details as the previous design to maintain compatibility with the target remote handling system. This talk will present the engineering design iteration that led to this point, alongside discussion of the physics design from an engineering perspective, prototyping, and validation efforts. Future design iterations under investigation will also be presented.

Speaker: Mr Jonathan Williams (Fermilab)

101 Updates of a Helium-cooled Tungsten target design and prototype campaigns at the SPS Beam Dump Facility (BDF) at CERN

The Search for Hidden Particles (SHiP) experiment at CERN requires a production target to fully absorb a 350kW beam. The Target will be located in North Area’s SPS Beam Dump Facility (BDF). It consists of a segmented core of Tungsten blocks, actively cooled with helium to ensure efficient heat removal, with a required lifetime of 5 years. The core blocks will be manufactured from hot-rolled tungsten (W) plates, to benefit from the high mechanical properties, with the largest blocks being joined by Hot Isostatic Pressing (HIP) using Tantalum interfoils.

This contribution provides an overview of the BDF Target developments, outlines updates to the target design and details two prototype testing campaigns performed in 2025 and 2026, together with ongoing PIE.

Speaker: Rui Franqueira Ximenes (CERN)

10:20 Coffee break

Session H - Beam intercepting devices design, analysis and validation of concepts

102 IFMIF-DONES Lithium Target diagnostics

The Target System of IFMIF-DONES comprises a high-velocity (15 m·s⁻¹), high-temperature (300 °C) liquid lithium jet that serves as the interaction point for a 40 MeV, 125 mA CW deuteron beam linear accelerator. This configuration results in a continuous power deposition of 5 MW, driving intense neutron production for fusion materials qualification. Although the use of a liquid metal target effectively accommodates this extreme thermal load, it concurrently generates a harsh environment, characterized by intense radiation fields (~ 25 dpa·year⁻¹), high vacuum, elevated operational temperatures, and lithium vapor, which imposes stringent constraints on the design and implementation of target diagnostics.

This contribution presents an overview of the diagnostics system currently under development for the Target. The instrumentation addresses different critical measurement domains: beam-footprint on the lithium jet; beam-target alignment to verify the relative positioning with respect to the lithium jet; free-surface quality monitoring to detect perturbations such as waves, or thickness fluctuations; and thermo-hydraulic surveillance, including temperature and flow rate measurements within the lithium loop. Emphasis is placed on radiation-hard material selection, in-vessel cabling strategies, and the inherent trade-offs between measurement accuracy, positioning and component lifetime. An analysis of current R&D activities and prototype testing is provided.

Speaker: Dr Jorge Maestre (IFMIF-DONES)

103 Design and Challenges for a Liquid-Lead Dump for the FCC-ee Beamstrahlung Photon Beam

The FCC-ee will require dedicated beamstrahlung photon dumps capable of absorbing up to approximately 370 kW per interaction point and per beam. This contribution presents ongoing design studies and R&D towards a circulating liquid-lead dump concept, focusing on the design, analysis and challenges relevant to high-power beam intercepting systems. Liquid lead is investigated as a compact and thermally efficient absorber due to its high density, short photon attenuation length and low melting point, with concepts based on free-surface flow allowing energy deposition to occur primarily in the liquid phase rather than in solid structures. Monte Carlo simulations (performed with FLUKA) are used to quantify photon absorption and estimate power deposition in the liquid metal and surrounding structures, while CFD analyzes free-surface stability, thermal-hydraulic performance, and operating margins. The study identifies key target-facility challenges, including Pb – stainless steel material compatibility at 400–500 °C, corrosion and erosion control, oxidation management, radiation shielding, material activation and beam-window integration.
The results support liquid lead as a promising option for high-power photon-beam absorption, while highlighting the need for representative prototyping to validate the free-surface hydrodynamics, thermal-hydraulic system and operational regimes.

Speaker: Dr Silvio Candido (CERN)

104 DESIGN AND ANALYSIS OF ROTATING GRAPHITE TARGET SYSTEM AT FRIB

The Facility for Rare Isotope Beams (FRIB) is a high-power heavy ion accelerator facility at Michigan State University completed in 2022. Its driver linac is designed to accelerate all stable ions to energies above 200 MeV/u with beam power of up to 400 kW. Currently, FRIB is operating up to 20kW, delivering multiple primary beam species. The target absorbs roughly 25% of the primary beam power and the rest is dissipated in the beam dump. Presented here is an overview of the mechanical design of the rotating single slice graphite target system, thermal-structural analysis and future development of a multi-slice target system.

Speaker: Mohit Patil (Facility for Rare Isotope Beams, Michigan State University)

11:50 Lunch break

105 Transport from Building 39 to Prevessin Training Center

106 Self-rescue mask training - Session 5

107 Transport from Prevessin Training Center to Building 39

Session H - Beam intercepting devices design, analysis and validation of concepts

108 Revalidation of the LCLS-II-HE electron beam dumps under combined energy and power upgrade

The Linac Coherent Light Source II High-Energy (LCLS-II-HE) upgrade raises the original LCLS-II beam energy envelope from 4 GeV to 9.2 GeV. Three dumps serve the facility: one terminates the Soft X-Ray (SXR) beamline, one the Hard X-Ray (HXR) beamline and the third is the Beam Switchyard (BSY) primary dump. Each dump is a cylindrical aluminum-alloy 6061-T6 inner core into which 80 longitudinal cooling fins are machined; low-conductivity water flows along the channels between the fins, carrying the deposited heat from the aluminum to the facility heat exchanger.
Previous analyses confirmed the dumps withstand 4 GeV at 120 kW. This work requalifies them for the HE regime, up to 9.2 GeV and beyond 120 kW, assessing whether they keep adequate structural and thermal margin at the higher energy and power.
We present a coupled FLUKA–ANSYS revalidation of the dumps. FLUKA (Monte Carlo radiation-transport code) produces three-dimensional energy-deposition maps for the operating scenarios; the resulting volumetric heat-generation field is then mapped onto an ANSYS (finite-element) model of the dump for steady-state thermal and structural analysis, including stress and fatigue assessment. The thermal and stress fields are cross-checked against an independent analysis with ACE3P, SLAC's parallel multi-physics finite-element code.
The methodology is intended to be transferable to other accelerator facilities planning combined energy and power upgrades of beam-intercepting devices.

Speaker: Giacomo Lavezzari

109 Strain measurement analysis and simulations of SNS 2 MW target with gas injections

The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL) produces neutrons for scientific research and industrial development. A new mercury target design operating at 2.0 MW at 1.3 GeV was developed to accommodate recent proton power upgrade from 1.4MW at 1GeV to 2.8MW at 1.3GeV, which is called 2 MW target. Helium gas injection into the flowing mercury-spallation target material, has been used since 2017 to mitigate fatigue and cavitation-induced erosion damage to the stainless-steel target vessel. This approach has generally worked well, but the central zone of the beam has continued to show significant erosion on the vessel. Recently, a new injector system was developed and installed in the SNS 2MW design target to further improve damage mitigation near the beam’s center. Strain measurements of the target vessel’s response to proton pulses were collected during initial operation with gas injected from the swirl bubblers, the new injector, and combinations of both gas injection systems. Strain data allowed us to study the gas injection effects from the bubbler and the new injector by analyzing and quantifying the strain reductions. Strain simulations with gas injections from bubblers and the new injector are validated with the strain measurement data. The analysis of strain measurements and strain simulations of SNS 2 MW mercury target with gas injections from swirl bubblers and/or the new injector will be presented in this talk.

Speaker: Hao Jiang (Oak Ridge National Laboratory)

110 ISIS Targets: Analysis and Operating Experience

This talk will present the latest developments in analysis and operating experience of ISIS spallation targets. There are two main parts, corresponding to TS1 and TS2 target stations:
Operating data for the recently redesigned TS1 Project target and reflector has been collected since November 2022 [1]. This data is a valuable resource for monitoring target status, identifying irradiation-induced material property changes, and validating FEA simulations. The status of ongoing condition monitoring efforts will be presented. This data offers the opportunity to measure radiation-induced changes in the thermal conductivity of tungsten in-situ on an operating spallation target.
TS2 targets consistently require replacement only ~1.5 years into their nominally 5-year design lifetime, due to increasing activation of the cooling water. The root cause of this issue has been a long-standing mystery. Recent irradiated property data combined with detailed FEA now predicts target lifetimes which are consistent with the observed failures. The design of a multi-plate TS2 target variant is now underway, which is intended to mitigate these issues. The approach to setting simulation processes and design limits for the redesigned TS2 target will be discussed.

[1] D. Wilcox et al., “Simulated and measured performance of the ISIS TS-1 Project target”, Journal of Neutron Research, vol 26, 2024.

Speaker: Dan Wilcox

14:30 Coffee break

Session H - Beam intercepting devices design, analysis and validation of concepts

111 Simulating Horn-Induced Vibration Response in the LBNF Target

The LBNF pion-production target consist of a long cantilever structure, closely coupled to a magnetic horn. The length of target and closeness of coupling are novel compared to other neutrino facilities. There is a potentially significant risk of damage to the target due to vibrations transmitted from the horn. This talk presents simulation work to assess the risk, including transient simulations of the horn during pulsing, and the response of the target to this applied time history. This was simulated using a Response Spectrum analysis, following best practice from other fields including earthquake assessment and satellite launch analysis. Methods to “decouple” the horn and target as far as possible were designed and have now been prototyped.
Such vibration analyses are complex, and there are limits to the applicability of a purely analysis-based approach. A detailed programme of physical experiments is proposed to validate these simulations and minimise the risk during commissioning and operation of the first LBNF prototype target. This programme is now underway, starting with instrumented hammer vibration tests of individual parts of the target system, which have shown good agreement with simulation predictions thus far.

Speaker: Dan Wilcox

112 Upgrade of the SPS Transfer Line Dump for high intensity operation in CERN’s North Area

As part of the consolidation of CERN’s North Experimental Area (NA-CONS project), a movable external dump located in the TT20 transfer line has been redesigned to comply with the higher beam intensities required for the future BDF/SHiP facility, and to improve its operational reliability. The Target External Dump (TED) must be capable of dissipating up to 45 kW of steady-state power generated by the slow extraction of 400 GeV/c protons from the SPS under various operational scenarios. In addition, it shall also be able to withstand short, high-intensity pulses during machine development phases. Building upon proven design concepts implemented in the previous generations of SPS dumps, this new dump core consists of graphite blocks clamped by actively cooled CuCr1Zr plates, and is enclosed by two shielding layers, steel and marble, for radiological protection. The design has been validated by performing beam-matter and thermo-mechanical simulations. A dedicated testbench was used to estimate the thermal contact conductance between materials and provide realistic values for the simulations. This contribution presents the main stages of this upgrade, from conceptual design and validation to construction and assembly of the new dumps.

Speaker: Panagiotis Romanos Menachilis

113 Thermo-mechanical analysis of slow-extracted beam interception in Super-FRS at FAIR

At FAIR, pulsed beams of a wide range of heavy ions are anticipated to be used for the projectile fragmentation/fission. The beam stoppers in the Super-FRS have been designed to intercept unwanted fragments and the primary beam, and safely absorb the deposited energy with continuous dissipation of the generated heat. Each of the three beam stopper contains copper and graphite absorbers for slow and fast extraction modes, respectively.
During normal slow extraction operation, the primary beam, consisting of approximately $5\times 10^{11}$ particles per spill of $^{238}$U at energies ranging from 0.4 to 1.5 GeV/nucleon, deposits up to 29 kJ within the copper absorber over a spill duration of 900 ms, with successive spills separated by an interval of 2.5 s. Further, three types of abnormal spikes in slow extraction are considered, most severe of which deposits 100% energy within 100 ms. The energy (particle flux) distribution across the beam cross-section is considered to be two-dimensional Gaussian. The steep gradients in the energy density in the absorbing medium, governed by Bragg’s peak in the axial deposition rate, is more pronounced for beams of 740 MeV/nucleon intensity. Hence, 1.5 GeV/u and 0.74 GeV/u cases are studied.
The transient coupled thermo-mechanical analysis of the deposition of the normal as well as the three abnormal cases of the primary beams is carried out using explicit finite element method to study the distribution of temperature and stress in the absorbers. The simulation results are then used to optimize the entry profiles of the absorbers for maximum heat removal through the embedded cooling channels. For the case of normal operation, the peak temperature in copper absorber reaches 735 K and it undergoes yielding with effective plastic strain (EPS) of 0.0022. Lastly, the results of coupled thermo-mechanical analysis of chamber cooling and pillowseal flange bending are presented.

Speaker: Amit Kumar (CSIR-Central Mechanical Engineering Research Institute)

114 Multi-Physics Modelling and Design Upgrade of CERN's Antiproton Decelerator Magnetic Horn

Antiprotons are generated by impinging a focussed 26 GeV/c proton beam onto a target upstream of the Antiproton Decelerator (AD) ring. The AD magnetic horn (AD horn) is a focussing magnet with the crucial function of increasing the number of antiprotons collected inside the phase-space acceptance of the AD ring.
The AD horn is pulsed with a current of up to 430 kA in about 120 μs to generate the toroidal magnetic field of up to 13 T between its conductors, which is required for an effective collection of the antiprotons. As a result, the aluminium alloy conductors are subjected to a fast and intense magnetic pressure and ohmic heating, as well as the energy deposition from the particle shower generated in the AD target placed upstream. The resulting vibrational loads have led to the loosening of bolted connections at the electrical interfaces, causing several flashover events. To address this, a consolidation project for the complete AD horn assembly was initiated to increase its reliability, thereby reducing machine downtime, dose to personnel, and replacement costs. 
This study summarises the project status with a focus on the multi-physics approach using finite element analysis to characterise the electromagnetic, thermal, and mechanical behaviour of the system. Material limits regarding yielding, buckling, fatigue, and overheating are assessed. Additionally, an in-depth study of the bolted connections, with experimental data from Junker tests, is included to understand previous failure modes and to deduce preventive measures.  
Finally, this paves the way for prototyping and validating a consolidated design of the AD horn for implementation during CERN’s Long Shutdown 3.

Speaker: Leonhard Gross

Discussion and closing remarks

Saturday 21 November

Group D - Visit LSS6 - LHC beam dumping systems (LBDS)

115 Group D - Transport from B39 to LSS6

116 Group D - Visit to LSS6

117 Group D - Transport from LSS6 to B39

ALICE experiment underground visit

The participants will be divided in-situ in 3 groups of 12.

118 Transport from B39 to ALICE

119 Visit to ALICE

120 Transport from ALICE to B39

ISOLDE Hall, nuclear laboratories and MEDICIS facility

121 Group A - Visit MEDICIS

122 Group A&B- Visit ISOLDE

123 Group C - Visit MEDICIS

124 Group B - Visit MEDICIS

125 Group C - Visit ISOLDE

Group E - Visit LSS6 - LHC beam dumping systems (LBDS)

126 Group E - Transport from B39 to LSS6

127 Group E - Visit to LSS6

128 Group E -Transport from LSS6 to B39