Forum on Tracking Detector Mechanics 2026

Jun 1, 2026, 3:00 PM → Jun 5, 2026, 1:20 PM Europe/Rome

Maria Luisa (Hotel Hermitage)

Fabrizio Palla (Universita & INFN Pisa (IT))

A meeting to discuss issues of engineering and integration for present and future tracking systems.

Like last year, the Forum on Tracking Detector Mechanics will be organized together with the DRD8 collaboration meeting. We will begin on Monday afternoon with the Forum part and switch on Wednesday afternoon to the DRD8 collaboration meeting part, which will go until Friday noon. 

Topics include

• Advanced cooling system technologies
• Qualification of novel materials, including mechanical, thermal, and radiation hardness characterization
• Engineering solutions for complex mechanical systems: vacuum compatibility, lightweight structural design, precision alignment, vibration mitigation, high-accuracy assembly, and failure analysis
• Environmental control systems: robotics, automation, and intelligent integrated control architectures
• Integration, operation, maintenance, and decommissioning of tracking systems
• Service and lifecycle management: low material budget optimization, high-performance components, and intelligent system integration
• Numerical simulations: finite element analysis (FEA) with experimental correlation, augmented reality applications, and advanced design and qualification tools.

 

POSTER

Mon, June 1

3:00 PM → 7:00 PM Forum Session 1

Conveners: Burkhard Schmidt (CERN), Fabrizio Palla (Universita & INFN Pisa (IT))

3:00 PM Welcome and Organizational Information

Speaker: Fabrizio Palla (Universita & INFN Pisa (IT))

Biodola DRD8.pdf

3:15 PM Integration of the low-mass, vacuum-operating CBM Micro Vertex Detector

The Micro Vertex Detector (MVD) is the first downstream detector of the fixed-target CBM experiment at the future Facility for Antiproton and Ion Research (FAIR). It enables high-precision tracking of low-momentum particles in direct proximity of the target with the first station being placed only 8 cm downstream the interaction point. The four planar stations operate in the target vacuum and are equipped with $\sim$300 MIMOSIS CMOS Monolithic Active Pixel Sensors (MAPS).
For integration in the MVD, the sensors are wire-bonded to dedicated thin flex cables and glued onto Thermal Pyrolytic Graphite (TPG; 380 µm thick) carriers, which provide stiff, low-$X_0$ support with a high in-plane thermal conduction ($\sim$1500 W/m/K) in the acceptance. Actively cooled aluminum heat sinks outside the acceptance extract the heat. Sensors are integrated on both sides of carrier to achieve 100% fill factor.
In this contribution, we present the detector concept and the integration of MIMOSIS into the CBM Micro Vertex Detector as we progress toward production of components, followed by station assembly and readiness for first beam with CBM in 2028. A focal point will be the challenges associated with the stringent material budget constraints (0.3-0.5% $X_0$ per station), double-sided integration, and vacuum operation. Results from the R&D on TPG carriers and the preparation for use in high-precision tracking devices will be highlighted.

Speaker: Franz Matejcek (Goethe-Universität Frankfurt, Institut für Kernphysik)

2026-06-01_MVD-Integration_FMatejcek.pdf

3:35 PM Production-phase assembly, integration and metrology of the CBM Silicon Tracking System

The Silicon Tracking System (STS) of the CBM heavy-ion experiment at the future FAIR facility is designed to operate at beam-target interaction rates of up to 10 MHz, while keeping the total material budget low at 2–8% X₀ over a silicon surface area of around 4 m². These constraints necessitate a highly optimised mechanical design and a tightly coupled integration strategy.

The detector comprises double-sided, double-metal silicon microstrip sensors mounted on lightweight carbon fibre (CF) ladders, with each ladder hosting up to ten 62 mm-wide sensors. These ladders are integrated into C-shaped aluminium support frames containing mass-reducing cut-outs. These frames form modular units arranged in eight tracking stations within a CF sandwich enclosure. The system is complemented by a vacuum-tight conical beam pipe that is manufactured entirely from composite materials.

With the integration of the first units underway, significant effort is devoted to defining assembly procedures, including mechanical integration, dense, low-mass cabling and system-level testing. The coexistence of multiple materials and scales gives rise to complex thermo-mechanical behaviour, necessitating precise control of tolerances and interfaces throughout the integration hierarchy.

A dedicated metrology strategy has been implemented that combines the use of an optical table to take precise measurements of sensor placement on ladders with higher-level alignment procedures. These measurements are used to propagate the built geometry into the detector description and to assess deformation effects under operational conditions.

Finally, potential detector upgrade is discussed, including developing even lighter composite support structures and two-dimensional filament-based architectures.

Speaker: Maksym Teklishyn

teklishyn_cbm_sts_integration_ftdm2026.pdf

3:55 PM CHeT: A Cylindrical Helical scintillating-fiber Tracker for MuEDM Experiment

The muEDM experiment is a precision effort to search for a permanent electric dipole moment (EDM) of the muon, which would provide direct evidence for CP violation beyond the Standard Model. The project is being carried out at the Paul Scherrer Institute (PSI) and aims to demonstrate, in a compact setup, the feasibility of the frozen-spin technique for a future high-sensitivity measurement.
In the experiment, low-momentum muons (≈ 28 MeV/c) are injected into a superconducting solenoid (with a uniform 2.7 T magnetic field) where they are stored on a well-defined circular orbit. Thanks to a radial electric field, it is possible to realize the frozen-spin condition, in which the magnetic dipole precession is canceled so that the muon spin remains aligned with its momentum. Under these conditions, any gradual development of a vertical spin component would signal a non-zero muon EDM.
The general apparatus combines beam diagnostics, magnetic-field shaping, fast trigger logic, a pulsed magnetic kicker for storage, and precision detectors for monitoring both injected muons and their decay products.
The central physics detector used to measure the spin evolution of stored muons by detecting and reconstructing their decay positrons is the Cylindrical Helical Tracker (CHeT), designed to operate inside the bore of the superconducting storage solenoid under high-vacuum conditions. Its mechanical concept is based on a compact, fully cylindrical geometry centered on the 30 mm muon storage orbit, ensuring azimuthal symmetry and minimal systematic bias.
CHeT consists of multiple concentric cylindrical layers made from plastic scintillating fibers arranged in a stereo (helical) configuration. The fibers are wound around lightweight cylindrical support structures at alternating stereo angles, enabling three-dimensional track reconstruction while maintaining mechanical rigidity, enhanced by a carbon-fiber composite shell cast directly on each layer. The modular cylinder design allows staged installation: inner layers provide baseline tracking close to the muon orbit, while additional outer cylinders increase the lever arm and improve momentum and angular resolution.
Mechanically, the tracker is integrated into a central internal support structure that also carries the magnetic-field correction coils, the kicker system, and the frozen-spin electrodes. Strict radial constraints (≤ 80 mm outer radius for inner components) dictate a low-mass construction with precise tolerances to ensure alignment within the solenoid bore. Materials are selected for vacuum compatibility and low outgassing, as the detector operates at pressures of approximately 10⁻⁶ mbar.
The scintillating fibers are routed axially toward a dedicated services vacuum chamber, where they are coupled, in groups of four, to silicon photomultipliers (SiPMs). The SiPM boards are connected to custom PCB feedthroughs, which allow connection to the CAEN FERS (A5202) digitizing boards located outside the vacuum volume. The external placement of the digitizing electronics facilitates efficient cooling and improves space management within the vacuum region.
Overall, CHeT combines lightweight cylindrical support architecture, stereo fiber winding, vacuum-compatible materials, and modular assembly to achieve a mechanically stable and symmetric tracking system suitable for precision measurements inside a compact superconducting solenoid.
In this presentation I will outline the mechanical design of the detector, covering its development stages, fabrication process, and the current construction status.

Speaker: Daniele Pasciuto (Sapienza Universita e INFN, Roma I (IT))

DP_FTDM2026.pdf

4:15 PM Mechanical Design of the muEDM TPC

The muEDM experiment is a precision effort to search for a permanent electric dipole moment (EDM) of the muon, which would provide direct evidence for CP violation beyond the Standard Model. The project is being carried out at the Paul Scherrer Institute (PSI) and aims to demonstrate, in a compact setup, the feasibility of the frozen-spin technique for a future high-sensitivity measurement.
In the experiment, low-momentum muons (≈ 28 MeV/c) are injected into a superconducting solenoid (with a uniform 2.7 T magnetic field) where they are stored on a well-defined circular orbit. Thanks to a radial electric field, it is possible to realize the frozen-spin condition, in which the magnetic dipole precession is canceled so that the muon spin remains aligned with its momentum. Under these conditions, any gradual development of a vertical spin component would signal a non-zero muon EDM.
The general apparatus combines beam diagnostics, magnetic-field shaping, fast trigger logic, a pulsed magnetic kicker for storage, and precision detectors for monitoring both injected muons and their decay products.
The muon Time Projection Chamber (TPC) of the muEDM experiment is a gaseous tracking detector designed to characterize the phase space of injected muons during beam commissioning. A precise control of the muon beam phase space after injection is essential to achieve high storage efficiency and to ensure symmetry between clockwise (CW) and counter-clockwise (CCW) injection, thereby minimizing systematic effects.
The detector is a low-mass gaseous TPC read out by GridPix sensors, enabling high-granularity tracking while minimizing multiple Coulomb scattering of low-momentum muons. Two sets of four GridPix sensors allow reconstruction of approximately half a turn of the muon trajectory inside the magnetic field. The active volume is defined by an anode and cathode plane and a flexible PCB-based field cage providing a precisely shaped electric drift field up to 400 V/cm. To minimize material budget, extremely thin entrance windows are centered on the nominal CW and CCW trajectories. Silicon nitride membranes (500 nm thickness) mounted on silicon frames and ultra-thin Mylar foils (20 µm down to 2.4 µm) have been selected as possible solutions, and currently under studying to optimize mechanical robustness versus tracking resolution.
The tight spatial constraints imposed by the 200 mm inner bore of the solenoid, together with the vacuum and magnetic-field requirements, significantly complicated the mechanical design and integration, particularly with respect to cabling and services routing.
In this presentation I will outline the mechanical design of the detector, covering its development stages, fabrication process, and the current construction status.

Speaker: Daniele Pasciuto (Sapienza Universita e INFN, Roma I (IT))

4:30 PM Next forum advertisement

next forum.pdf

4:35 PM Coffee Break

4:55 PM Mechanical Design and Stability Systems of the MUonE Tracking Detector

The MUonE experiment at CERN proposes a novel approach to determine the hadronic vacuum polarization contribution to the muon anomalous magnetic moment (muon g-2) through muon-electron elastic scattering. This measurement is important given the recent experimental observation of the muon anomaly at Fermilab, as it provides an independent cross-check to the dispersive and Lattice QCD methods currently at the center of the muon g-2 puzzle. The MUonE experimental apparatus comprises a beam momentum monitoring system, a high-precision silicon tracking system, an electromagnetic calorimeter, and a muon ID detector. To achieve the necessary precision, the MUonE tracking system relies on a mechanical support structure made of Invar, a low-expansion nickel-iron alloy chosen to minimize thermally-induced structural instability. This structure houses the silicon detector modules within frames integrated with an active water-cooling system, and this entire assembly is contained in a light-tight, humidity-controlled enclosure. To guarantee sub-micron alignment stability, an internal laser holographic system provides structural monitoring during data acquisition. This presentation focuses on the mechanical design of the tracking system and presents the preliminary performance results from the 2025 Phase I experimental run, demonstrating the system stability and the monitoring capabilities.

Speaker: Anna Driutti (Universita & INFN Pisa (IT))

MuonE_FTD26.pdf

5:20 PM Mu3e helium cooling – system performance, humidity control, and optimization for future operation

The Mu3e experiment operates a silicon pixel detector with an unprecedented material budget of only 0.1% X₀ per tracking layer, enabled by cooling with gaseous helium to avoid introducing additional material from liquids or mechanical structures.
The helium plant was fully commissioned prior to the start of the 2025 vertex detector operation and successfully provided stable, continuous cooling of the inner layers with a mass flow of 2 g/s.
In this period, the cooling gas entered the detector at an inlet temperature of +15 °C.
During the vertex campaign, humidity ingress required periodic purging to maintain an adequately low dew point and prevent condensation on cold detector surfaces.
A simple drying bypass filled with molecular-sieve desiccant was implemented to facilitate this process efficiently.

Looking ahead to the 2026/27 campaign, the helium system will also cool the central outer detector layers.
Preparations include added insulation for operation down to –20 °C and continued optimization of flow cross sections, as the pressure margin is close to the limit for delivering the nominal 16 g/s through the turbo-compressor chain.
This contribution summarizes operational experience, humidity-control measures, low-temperature readiness, and ongoing optimization of the helium system for the next phase of Mu3e detector operation.

Speaker: Dr Thomas Theodor Rudzki (Physikalisches Institut Heidelberg)

Mu3e Helium (Google Slides)

Mu3e Helium (Google Slides)

5:40 PM Ultra-Light Mechanical Support Structures for the Mu3e Outer Pixel Tracker

We present the development and characterisation of ultra-light mechanical support structures for the Mu3e outer pixel tracker. Minimising material budget is critical for the Mu3e experiment, which searches for the charged lepton flavour violating decay $\mu^+ \rightarrow e^+ e^- e^+$. Thermal and electrical performance results will be presented for pixel tracking “ladders” comprising 70 µm MuPix sensors and low-density HDIs, supported by 25 µm mechanical stiffeners, with a total estimated material budget of X/X$_0$ ≈ 0.1% per ladder. The mechanical support must provide sufficient structural rigidity for ladder assemblies of approximately 30 cm in length, whilst minimising material contribution and avoiding interference with the electrical performance of the ladder. Comparative studies of unidirectional carbon fibre, Kevlar, polyamide film, and glass fibre as candidate support materials are presented, with the benefits and limitations of each discussed in the context of low-mass detector construction.

Speaker: Ashley Ellen McDougall (The University of Oxford)

FTDM2026_AMcDougall.pdf

6:00 PM A Straw Tube Tracker (STT) for the DUNE Near Detector Complex

The Deep Underground Neutrino Experiment (DUNE) will exploit the world’s most intense accelerator-based neutrino beam, produced at Fermilab (USA), to address fundamental questions in neutrino physics, including the neutrino mixing, the neutrino mass ordering, and CP violation in the lepton sector.

The System for on-Axis Neutrino Detection (SAND) is one of the components of the DUNE near detector complex with the goals of reducing the systematic uncertainties arising from the neutrino fluxes and neutrino-nucleus interactions, as well as to perform a broad range of precision measurements of fundamental interactions and searches for New Physics. The detector will operate in a 0.6 T magnetic field and will include an electromagnetic calorimeter refurbished from the KLOE detector, an active liquid-argon target of about 1 ton, and a modular low-density tracker integrating multiple thin nuclear targets.

A Straw Tube Tracker (STT) is being developed as the main tracking detector. Straw tubes provide a very low material budget within their 20 $\mu$m of shell thickness, preserving momentum and vertex resolution while ensuring close to 4$\pi$ acceptance for final state particles produced in neutrino interactions. The detector modules consist of alternating vertical and horizontal straw layers (two staggered layers per direction), to enable three-dimensional track reconstruction. The support structure is made of carbon fiber (CF) to further minimize the amount of material crossed by particles.
The self-supporting STT modules cover a large area of up to 3.9 m x 3.3 m with a total thickness of only 28 mm including the supporting CF frame. Each module integrates the front-end electronics and the high-voltage distribution to the straws, while ensuring gas tightness for an Ar/CO₂ (70/30) mixture and reliable electrical grounding.

So far two reduced-scale prototype modules (1.2 m x 0.8 m) have been constructed at CERN and in Pisa. The second prototype, including wire self-centring spacers and custom end-plug pins, has been characterized with radioactive sources and exposed to the CERN Proton Synchrotron beam in November 2025.
The construction of a full-scale prototype (pre-production “Module 0”), with maximum dimensions of 3.9 m x 3.3 m, is currently ongoing.
The mechanical structure of the STT modules is presented together with an overview of the main construction and assembly phases, as well as the first performance results obtained from the characterization of prototype detectors and the ongoing activities on the full-scale module.

Speaker: Saverio Mameli (INFN Pisa (IT))

2026_06_01_A straw tube tracker for the DUNE near detector complex.pdf

6:30 PM Full-scale thermo-mechanical prototypes for the ePIC OB stave and studies of active vibration damping in airflow-cooled detector structures

The support structures for the outer barrel (OB) of the ePIC Silicon Vertex Tracker (SVT) consist of staves approximately 40 mm wide and about 50 cm long in Layer 3 (L3), and 90 cm long in Layer 4 (L4). Heat generated by the MAPS sensors and the electronics required for serial powering is removed by forced air flow through internal channels within the stave structure.
We will report on production of full-size mechanical prototypes for the staves of L4 and tests of their mechanical and thermal performance, incl. deformations introduced by temperature gradients and air flow, and the temperature profiles achieved for realistic thermal loads.
Using prototype structures for the ePIC OB staves we have also studied the feasibility of active control of airflow-induced vibrations by modulation of the air-pressure. We will report on results from these studies.

Speaker: Georg Viehhauser (University of Oxford (GB))

Forum 2026 ePIC OB.pdf

Forum 2026 ePIC OB.pptx

7:00 PM → 7:45 PM Welcome reception

Tue, June 2

8:30 AM → 12:30 PM Forum Session 2

Conveners: Eric Anderssen (Lawrence Berkeley National Lab (US)), Georg Viehhauser (University of Oxford (GB))

8:30 AM The iVTX for the Belle II VTX upgrade project

The Belle II detector at the SuperKEKB collider at KEK in Japan is the world’s intensity frontier flavour physics experiment at an e+e- collider. This experiment is collecting data at the forefront of accelerator and instrumentation capabilities. It is expected that the detector will need to be upgraded to handle increased data rates, and a silicon detector upgrade is proposed, which would be built around the Obelix CMOS MAPS sensor. The baseline design includes an inner and an outer vertex detector. Here, we present the progress on the thermomechanical design for the inner vertex detector upgrade, the iVTX. The iVTX contains two layers of thin silicon ladders, mounted in a pinwheel geometry around a beampipe less than 25mm in diameter. Removing the heat from these sensors in a small space, whilst maintaining an extremely low mass in the physics acceptance region, presents a challenging design problem.

Speakers: Mr Dominic Howgill (University of London (GB)), Julien BONIS

8:50 AM The outer vertex of the Belle II VTX upgrade project

In 2032 the SuperKEKB collider will undergo a major upgrade of the interaction region to reach the target luminosity of 6 × 10^35 cm⁻²s⁻¹. A new vertex detector (VTX) for the Belle II experiment will be required to match the new geometry of the machine components and will be based on Monolithic Active Pixel Sensors (MAPS) to provide improved robustness against the higher expected machine background and enhanced track-finding efficiency.
The VTX will consist of five layers, all instrumented with the new depleted MAPS chip called OBELIX, spanning a radial range from 14 to 140 mm. While the two innermost layers (iVTX) adopt a cooling solution based on a high thermal conductivity plate (TPG) optimized for an ultra-low material budget, the three outer layers (oVTX) employ a more conventional and robust structure designed to ensure mechanical stability and efficient liquid cooling for the longer ladders.
Each oVTX ladder is built on a lightweight carbon-fiber truss supporting a cold plate with an integrated Kapton pipe for coolant circulation, following the design approach developed for the ALICE ITS2. OBELIX sensors are glued directly on the cold plate. Aluminum flex circuits are used to minimize the material budget, providing power distribution and data readout.
The thermal characterization is performed using Kapton heater elements mounted on the cold plate, together with a negative-pressure coolant circuit that maintains a uniform temperature along the entire ladder with only a few degrees of gradient. The oVTX material budget for perpendicular tracks of the longest ladder (70 cm) can be kept below 0.8% X₀, meeting the stringent mechanical, thermal, and physics requirements of the Belle II upgrade and complementing the ultra-light inner iVTX system.

Speakers: Ms Margherita Rovini (INFN Pisa), Maurizio Massa (Universita & INFN Pisa (IT))

Belle II VTX upgrade project v1.pdf

9:10 AM Mechanics for the VELO Upgrade 2

The LHCb Vertex Locator (VELO) is the silicon tracking detector located closest to the interaction region of the LHCb experiment at CERN’s Large Hadron Collider. A further upgrade is foreseen around 2034 to be able to operate at extremely high collision rates, which require new mechanical solutions to minimize material, improve thermal management, and ensure stable detector positioning close to the beam.

A central topic is the development of an ultra-light RF enclosure based on carbon-fiber composite structures. The RF box must provide effective electromagnetic shielding between the detector and accelerator vacuum while maintaining minimal material thickness within the detector acceptance and ensuring mechanical stability under vacuum conditions.

Integrated cooling substrates are also being studied as multifunctional mechanical supports for detector modules based on co-fired ceramics. These structures aim to combine efficient heat removal with embedded electronics routing, allowing power distribution and signal transmission to be integrated directly within the cooling substrate. This approach can reduce material, simplify module integration, and be compatible with the LHC vacuum.

Alternative closing mechanisms are also under evaluation. In particular, an iris-like concept is being explored to symmetrically close the detector around the beam axis, providing a potential alternative to the traditional two-half retraction scheme and offering improved mechanical symmetry and positioning stability.

Finally, the compatibility of detector modules with ultra-high-vacuum operation is being assessed. The use of low-outgassing materials and processes could enable the installation of fully assembled detector modules directly within the primary accelerator vacuum, potentially simplifying the RF enclosure and overall mechanical integration.

9:30 AM Developments in 3D printed substrates for cooling of the LHCb VELO Upgrade II modules

The upgrade of the LHCb Vertex Locator (VELO), planned to be installed in 2033, presents a wide range of mechanical engineering challenges driven by the need for minimal material budget, high radiation tolerance, and mechanical stability under stringent operating conditions.
Additive manufacturing is being explored as a promising technology for developing cooling substrates due to its design flexibility and fast turn-around time. Availability of 3d printable high-performance materials as CP1 aluminum-alloy and ceramics (AlN) extend its potential beyond the capabilities of the more conventional 3d printed titanium.
Collaborations with industrial partners have led to several lightweight designs, based on varying design principles such as maximizing glue surface, or minimizing conductive distance. FEM and analytical calculations, verified by cooling experiments are used to identify and characterize the aspects influencing the thermal performance. Steps are taken to further improve the performance by shape optimization and research into adhesives. Finally, the potentials and limits of the technology are discussed.

Speaker: Yutaro Takahashi (Nikhef National institute for subatomic physics (NL))

FTDM2026 VELO Mechanics YTakahashi.pdf

9:50 AM The upgrade of the silicon tracking detector at AMS-02

The Alpha Magnetic Spectrometer-02 (AMS-02) experiment is currently the only magnetic spectrometer operating in space. It holds irreplaceable significance for addressing major scientific questions such as the existence of antimatter and the nature of dark matter. Based on its highly productive physics results and potential, the AMS is expected to operate until 2030 and undergo a detector upgrade. The upgrade of the AMS silicon tracker involves adding a new layer of detectors based on silicon micro-strip technology outside the existing tracking system. This upgrade project aims to provide ultra-long (96 cm), high-precision (≤10 μm alignment accuracy), and low-mass silicon micro-strip detectors for space applications. Utilizing a high-precision gantry system, this project has overcome key challenges in the assembly of large-scale, high-precision silicon micro-strip detectors. It has successfully developed space-borne silicon micro-strip detection modules that feature the longest individual units and the highest alignment accuracy. This report will present the latest progress and core technologies in the production and assembly of the silicon micro-strip modules for the AMS upgrade project.

Speaker: Mr Xuhao Yuan (Institute of High Energy Physics, Beijing, China)

20260602-XuhaoYuan.pdf

10:15 AM Coffee Break

10:35 AM ATLAS ITk Global Mechanics: Design Overview and Lessons Learned During Construction

Abstract— The ATLAS ITk Global Mechanics, which houses the silicon detector and provides a platform for detector integration is 2.2 meters in diameter and 6 meters long. The Strip Barrels are four 2.8 meter long support structures for the Strip Detector barrel staves. These cylinders are all eccentrically stiffened structures built from ultra-high modulus carbon fiber with cyanate ester matrix. All of these structures were designed in house, however, the largest cylinders required external contracts with the smaller 2 being built in house. The unusual nature, large scale, and significant precision required in the assembly of these structures generated a challenging manufacturing and assembly process. This led to a number of challenges and issues that were faced by the team. We present the main challenges faced, and the lessons learned during the construction, including market survey, contract negotiation and construction management. We expect this material to be useful for guiding design and construction of future detectors.

Keywords—Global Mechanics, Carbon Fiber, Composites, Ultra Stable Structures, High Energy Physics Detectors

Speaker: Todd Claybaugh (Lawrence Berkeley National Lab. (US))

ATLAS Global Mechanics Lessons Learned - FoTDM 2026.pdf

11:00 AM The electrical isolation challenges of the module-to-cell interface in the ATLAS ITk Pixel Outer Barrel.

As part of the ATLAS Phase II Upgrade, a new all-silicon tracker will replace the current Inner Detector to meet the demands of the High Luminosity Large Hadron Collider (HL-LHC). The future Inner Tracker (ITk) will include a five-layer pixel detector with extended rapidity coverage. In the central section of the three outer layers, the so-called Pixel Outer Barrel (OB) will adopt a layout featuring tilted modules, introducing a series of innovative solutions to meet the stringent detector performance requirements.
The design of the Outer Barrel local supports relies on two main elements, namely the module cells and the functional local supports, both conceived to facilitate the replacement of defective modules during construction. Within the cells, a thin layer of thermally conductive yet electrically insulating epoxy adhesive is used to attach the silicon modules to a pyrolytic graphite heat spreader. However, testing of the first pre-production units revealed issues at this interface, as the thin glue layer alone does not ensure the level of electrical isolation required for safe detector operation.
This contribution reviews the solutions developed by the Outer Barrel community to address this issue, focusing on partial coatings of the pyrolytic graphite tiles. The design of these coatings, the results of their qualification campaign, and their impact on the detector thermal performance are discussed in detail.

Speaker: Diego Alvarez Feito (CERN)

CellElectricalIsolation_FDTM2026_DAF_02062026.pdf

CellElectricalIsolation_FDTM2026_DAF_02062026.pptx

11:30 AM Joining and manufacturing processes for detector cooling applications

Over the past 5 years, new joining procedures have been developed by CERN MME group in the framework of detector upgrades for ATLAS and CMS, to be installed during the LHC third Long Shutdown (LS3). These improved detectors rely on high-pressure CO2 cooling circuits reaching their innermost parts. This means that metallic piping is required to withstand pressures of up to 160 bar and temperature down to -40°C, while being as transparent as possible for the detectors. To meet these requirements, stainless steel and titanium piping as thin as 0.15 mm have been successfully joined to Copper-nickel, Titanium and Stainless steel. Various joining processes have been qualified, including vacuum brazing, vacuum induction brazing, electron beam brazing and orbital TIG welding. The assembly of metallic and ceramic components manufactured using additive manufacturing such as titanium and aluminium-nitride has also been investigated. This presentation provides an overview of the processes and material combinations qualified at CERN and their integration into the new generation of high performance detectors developed for HL-LHC.

Speaker: Thomas Demaziere (CERN)

tracking detector mechanics presentation.pdf

tracking detector mechanics presentation.pptx

11:50 AM Quality Control of CO2 Detector Circuits for the CMS Phase II Upgrades at CERN

Abstract
CMS Phase-II tracker and calorimeter subassemblies are currently in production, including their complex, high-pressure CO$_2$ cooling circuits. It is mandatory to ensure that these circuits are leak-tight and safe for operation. Adhering to CERN HSE’s regulations, any pipe assembly of the CO$_2$ cooling system must undergo specific tests and certifications. Furthermore, the 10-year minimum lifetime requirement for the detector adds a significant time dimension and difficulty to the certification of materials and joining techniques, particularly with thin-walled, non-standard pipework of these detectors.
This talk will go into detail on the efforts made at CERN for testing and validating prototypes, such as welded and brazed connections, as well as proof-testing final detector subassemblies. A multi-step protocol was developed to ensure thorough testing including helium leak tests, temperature and pressure cycling, combined with high-resolution CT scanning of the parts before and after the tests.
Keywords
CERN, HL-LHC, CMS, Carbon Dioxide, Refrigeration, Quality Control, CT Scanning

Speaker: Derek Jan Langedijk (CERN)

CO2 Pipe Joining Methods – Quality Control.pdf

CO2 Pipe Joining Methods – Quality Control.pptx

12:10 PM Vascular networks embedded in carbon composites: material characterisation and compatibility studies

There is great interest in the High Energy Physics (HEP) community to replace the plastic and metallic pipes currently used in local supports/cold plates. The Vaporization of Sacrificial Components (VaSC) [1-2] enables the possibility to embed a network of channels directly into a composite laminate. After a poly(lactid acid) (PLA) preform with the desired network design is introduced within the composite layers during lamination, a postcure thermal cycle removes it, leaving the channels embedded in the laminate. Enhanced thermal performance due to the absence of pipe walls, as well as improved material budget and thermo-elastic stability properties, seem to be promising benefits from this technology.
Previous studies [3-4] have focused on demonstrating that this technology is suitable for HEP mechanics. Braided reinforcements around straight channels greatly improves the burst pressure of vascular networks within composite plates.
However, new challenges arise from the use of pipeless embedded structures. Post-curing thermal cycles may have an impact on material behaviour, in addition to undesired residual thermal strains/stresses. Additionally, the compatibility between the composite material and the coolant may cause chemical-related issues, potential ageing effects and thermo-mechanical behaviour degradation due to erosion or microcracking. These questions will be addressed through experimental testing to assess the technology long-term reliability.
This presentation will introduce the ongoing efforts at CERN in joint collaboration with the University of Seville on these subjects.

[1] Esser-Kahn AP, et al. Three-dimensional microvascular fiber-reinforced composites. Adv Mater 2011;23(32):3654–8. https://doi.org/10.1002/ adma.201100933.
[2] Dong H, et al. Chemical treatment of poly(lactic acid) fibers to enhance the rate of thermal depolymerization. ACS Appl Mater Interfaces Feb. 2012;4(2):503–9. https://doi.org/10.1021/am2010042.
[3] M. Dias. “ Matériaux à faible masse et leur refroidissement pour de futurs capteurs dédiés à la physique à haute énergie”. Presented 21 Jun 2024. PhD thesis. Toulouse, CERN-THESIS-2024-219: Toulouse III U., 2024. url: https://cds.cern.ch/record/2915966.
[4] M. Dias et al. “Pressure resistance characterisation of vascular networks embedded in carbon composites for high energy physics applications”. In: Composites Part B 282 (2024), p. 111535. doi: 10 . 1016 / j . compositesb . 2024 . 111535. url: https://cds.cern.ch/record/2905914.

Speaker: Roberto Prieto Garcia (CERN)

2026_05_29_Slides_for_Forum_on_Tracking_Detector_Mechanics_2026_V3.pdf

2026_05_29_Slides_for_Forum_on_Tracking_Detector_Mechanics_2026_V3.pptx

12:30 PM → 3:00 PM lunch

3:00 PM → 3:30 PM Forum Poster Session

The posters will be displayed thoughout the Forum and the DRD8 meeting on screens for discussion with the participants.

3:00 PM Phase 2 automatic commissioning using auto scan

The ATLAS and CMS Phase 2 upgrade presents multiple challenges, one of which is the need to test the 2PACL based CO2 detector cooling system’s performance of multiple units in a short time frame with a limited team.
To address this requirement, various solutions were explored in the development of 2PACL control systems, ultimately leading to the implementation of a feature called Autoscan. This approach enables the automatic operation of different actuators, allowing them to follow multiple predefined test scenarios within a set time frame. Test requests are queued to facilitate continuous, large-scale testing, and the system can initiate tests outside of standard working hours, thereby extending the overall available testing time.
The development process ensured that the Autoscan implementation remains independent of PLC development, making it easily adaptable to different subsystems without requiring tracking of multiple PLC code versions. In its current state, the feature fully leverages the UNICOS control framework, simulating manual operations from the SCADA interface to the PLC. The PLC retains its independent development strategy, unaffected by the Autoscan feature, and remains the primary system for interlocking in case of issues.
Each subsystem hosts its own Autoscan functionality, ensuring that systems operate independently during scans. This feature allows cooling experts to focus on data analysis and provides a streamlined process for performing all necessary tests before the start of Long Shutdown 3 (LS3).

Speaker: Loic Davoine (CERN)

CP_36.jpeg

PO_36.pdf

3:00 PM Thermal Performance and Radiation Tolerance of Adhesives for the CMS Phase-2 Pixel Barrel Mechanics

The cooling capacity of the CMS Phase-2 pixel barrel mechanics must be significantly higher than that of the first two generations of CMS pixel detectors due to the increased granularity of the pixel readout chip and the corresponding higher power dissipation, as well as much higher expected total irradiation dose. All barrel ladders undergo thorough quality control tests with respect to temperature uniformity and the temperature difference between the CO₂ coolant and the pixel module.
During prototype testing, numerous adhesives have been tested and evaluated, both on single portions of the structure, and complete layers. Temperature uniformity across all points of the structure and greater thermal efficiency were achieved with less known and proviously not used glues.
To verify the radiation tolerance of the selected glues, irradiations with a Co-60 source were performed at RBI Zagreb at doses of 2 MGy, 3 MGy, 6 MGy, and 10 MGy. These doses correspond to the total ionizing dose expected for barrel layers 4, 3, 2, and 1, respectively, after 10 years of HL-LHC operation.
The results of the mechanical and thermal characterization of the glues before and after irradiation will be presented, together with the thermal performance of barrel layers constructed using the selected adhesive.

Speaker: Andrei Starodumov (Rudjer Boskovic Institute (HR))

CP_42.jpeg

PO_42.pdf

3:05 PM CMS capillaries production for LHC High Luminosity upgrade

The focus of this work is the current CMS capillary production state in view of the upcoming upgrade. Capillaries play a key role in a cooling loop by ensuring proper flow distribution among parallel branches. For this purpose, it is important that they are sized such that a given flow rate through each capillary produces the desired pressure drop.

Due to their small dimensions large quantities, the production process is extremely time-consuming and requires careful handling, as well as coordination among different working groups - from the data purchase to connector brazing and connection quality control.

In this poster, we present the current production status and recent tests carried out to investigate the impact of capillary shape changes after production. The results obtained led us to prototype and test capillaries in their installation configuration. Finally, close collaboration with the CERN brazing team guided the selection of Stainless Steel 316L as the appropriate material for capillary vacuum brazing.

Speakers: Arianna Eugeni (Universita e INFN, Perugia (IT)), Konrad Wladyslaw Szczyrbak (Tadeusz Kosciuszko Cracow University of Technology (PL))

CP_67.jpeg

PO_67.pdf

3:05 PM Manufacturing of tool based interposers for the ATLAS Inner Tracker Modules

The upgrade of the ATLAS Inner Tracker for the High-Luminosity LHC faced a critical challenge: thermal cycling from +20°C to -35°C induced cracks in silicon sensor modules due to coefficient of thermal expansion (CTE) mismatches between sensor materials and hybrid components. Finite element analyses revealed that the combination of stiff (TrueBlue) and soft (SE4445) adhesives exacerbated stress concentrations at sensor edges, leading to structural failures.
To mitigate this, an interposer-based decoupling strategy was developed using a Kapton foil as a mechanical buffer between sensors and hybrid/power boards. The interposer, bonded with SE4445 adhesive (containing glass beads for controlled thickness), effectively reduced stress transmission while maintaining electrical insulation. Validation tests on production-scale petals demonstrated crack prevention in interposer-equipped modules across multiple temperature cycles (-55°C), compared to consistent failures in non-interposed samples.
The solution was scaled through a semi-automated production tool with workflows, enabling consistent quality and a throughput of 4 hybrid arrays in one go. Collaboration with industry partner further accelerated production. This approach not only resolved the immediate reliability issue but also established a reproducible manufacturing process.
The tool’s design prioritized scalability for industrial production, featuring:
• Modular stencil systems for controlled glue coverage and thickness.
• Vacuum plates for accurate component positioning, reducing manual errors.
• Optimized Kapton cutting via pattern cutter to streamline integration into existing workflows.
By outsourcing the production to an industry partner after developing the tool enabled a ramp-up of hybrid arrays significantly, meeting the project’s throughput requirements.

Speaker: Mr Sören Ahrens (Deutsches Elektronen-Synchrotron (DE))

CP_61.jpeg

PO_61.pdf

3:10 PM Thermal Quality Control of TB2S Ladders for the CMS Phase-2 Tracker Upgrade

The focus of this work consists of thermal quality control of the TB2S ladder structures for the future CMS tracker, currently in construction for use in the High-Luminosity Large Hadron Collider (HL-LHC). Efficient and reliable cooling is crucial to ensure proper functioning of the tracker in the HL-LHC conditions, throughout the detector lifetime.
Production and QC of the TB2S ladders is done in collaboration between CERN, Pakistan institutes (NEW-2 and NCP) and IPHC Strasbourg. At CERN, a testing campaign has been conducted to validate the thermal performance of the first production ladders. The tests were done with two-phase CO₂ coolant in final operating conditions of −35°C and 12 bar. The main purpose of this test campaign was to verify the thermal performance of the ladders under final operating conditions, and to identify potential anomalies. Furthermore, these tests provided key feedback to improve the production QC tests that shall be done on all produced ladders.
The presentation describes the methods and the test setup used at CERN to measure the thermal performance with CO₂, using dummy heaters in place of real detector modules, and to compare results with those obtained with water cooling at the ladder production site in Pakistan.
The study continued by cross-checking the dummy-heater results against tests done with real detector modules performed in collaboration with IPHC Strasbourg and KIT. These tests confirmed that this QC measurement method with dummy-heaters provides the needed information on the cooling quality of the produced ladders. Finally, using the overall dataset, a thermal quality control method and flowchart was established to identify potentially anomalous ladders before their integration into the new CMS tracker.

Speakers: Mr Lorenzo Bistoni (Universita e INFN, Perugia (IT)), Pier Filippo Cianchetta (CERN)

CP_Thermal Quality Control of TB2S Ladders for the CMS Phase-2 Tracker Upgrade.jpeg

PO_Thermal Quality Control of TB2S Ladders for the CMS Phase-2 Tracker Upgrade.pdf

3:15 PM Mighty-SciFi Cryo Demonstrator for LHCb Upgrade II

Authors: Mighty Tracker Collaboration

Corresponding authors: joanna.liberadzka-porret@epfl.ch, gauri.napoletano@epfl.ch

Abstract:

In view of LHCb Upgrade II, taking place during Long Shutdown 4, the detector is going to be modified to operate at a several times higher instantaneous luminosity compared to Upgrade I. The Mighty-Tracker, which replaces the present Scintillating Fibre (SciFi) Tracker, will be composed of an inner pixel detector, called Mighty-Pixel, and an outer one consisting of scintillating fibres, known as Mighty-SciFi. A major challenge for the Mighty-SciFi is the operation of the Silicon PhotoMultipliers (SiPMs) in the radiation environment. To mitigate the increased level of radiation due to higher luminosity in Run 5, the photo-detectors are cooled to approximately 100 K to guarantee low noise (dark-count rate).

Dedicated vacuum insulated coldboxes have been designed, that integrate into the support C-Frame and SciFi mat modules. They house the 2K SiPM readout channels that allow for a spatial hit resolution of 100 µm. The coldbox design is optimised to provide low thermal contact between the SiPMs and SciFi mats on one side and the readout electronics outside the vacuum boxes on the other. With the help of the vacuum insulation and the thermal design optimisation, a total of less than 10 W of cooling power is required for a full box.

Two full-scale demonstrator setups cooled with liquid nitrogen have been built and operated confirming the thermal simulations. The operation of the Mighty-SciFi demonstrators allowed to confirm the expected detector response using signal injection with an electron source. Details of the mechanical design along with the cooling strategy, obtained temperatures and photo-detector response are presented.

Speaker: Gauri Napoletano (EPFL - Ecole Polytechnique Federale Lausanne (CH))

CP_13 - Napoletano.JPG

PO_13 - Napoletano.pdf

3:15 PM Vibration mitigation: cantilever spring blades for vertical seismic attenuation in GW interferometers

Seismic attenuation is a crucial aspect for the mirrors used in Gravitational Wave (GW) interferometric experiments, as the RMS ground motion is many orders of magnitude higher than the signal to be detected. For this reason, technologies capable of efficiently attenuating vibrations in high mass systems have been extensively developed in this field.
In this talk, we introduce cantilever spring blades, a mechanical passive element effectively used for vertical seismic attenuation in the main mirrors of Virgo and its upgrades. Their attenuation capability relies on the low-pass filtering behavior of a harmonic oscillator: the lower the resonance frequency, the stronger the attenuation above the cutoff.
This approach is well-suited for high mass payloads, but the main technological challenge lies in achieving sufficiently low stiffness while still providing reliable mechanical support against gravity. Cantilever spring blades have been specifically developed to address this issue, with maraging steel emerging as an excellent material choice due to its high mechanical strength, low creep sensitivity, and suitability for cold forming and heat treatment.
For future third-generation GW interferometers such as the Einstein Telescope (ET), even more demanding performance requirements and stricter environmental constraint -especially those related to cryogenics- will apply. For these reasons, the development and characterization of alternative materials for this application will soon become essential.

Speaker: Leonardo Lucchesi (INFN Pisa)

3:25 PM CMS Phase 2 Tracker Service Channel: Thermal Performance and Simulation Results

During the CMS Phase-2 upgrade, the cooling system of the CMS Tracker will be enhanced to operate its subsystems at temperatures down to -35degC. The cooling medium - liquid CO2 - will be distributed via Detector Transfer Lines (DTLs), passing through PP1s (Patch Panel 1) and then through the Tracker Service Channels (TSCs) before reaching the detectors inside the Tracker.
As the space inside the TSC is very limited, its design must be carefully considered, as condensation of water on the outer surface of the service channel could cause damage to the system. During Phase-1, this issue was solved through on-site modifications, which provided system safety but in a non-optimized manner.
This poster presents the results of numerous thermal simulations of a new TSC design performed during Phase-2 preparations, as well as the results of thermal tests carried out on a 1:1 prototype. Different scenarios were evaluated to optimize the design and identify an effective method to maintain the outer surface temperature of the TSC above the dew point.

Speaker: Bartosz Grygiel (CERN)

CP_87_CMS Phase 2 Tracker Service Channel Thermal Performance.jpeg

PO_87_CMS Phase 2 Tracker Service Channel Thermal Performance.pdf

3:25 PM Conceiving an anti-vibration mechanical system on the experience of the Superattenuator for Gravitational Waves detectors: present and future performance

Seismic vibration and local disturbances of any origin represent a nodal problem of ground-based detectors for Gravitational Waves observations and studies. The INFN Pisa group has been involved for more than 25 years in this research field, and it has collected fundamental experience on the development of the Superattenuator (SA), the best mechanical system in the world conceived for filtering vibrations at the level of the optical elements. This has been done to extend the detection bandwidth of the Advanced VIRGO interferometer in the low frequency region down to 5 Hz or better.
The Superattenuator is a complex system based on the working principle of a multi-stage pendulum suspended from an Inverted Pendulum structure adopted as a pre-isolation stage and acting in the frequency region around 50 mHz. The filtering performance is centered on the passive action of the multistage pendulum combined with the active feedback strategy applied in different points along the mechanical structure and for different frequency bands.
In this talk, we present an overview of the passive performance of our seismic isolation system considering the possibility to use it in a similar experimental context conceiving an anti-vibrational mechanical system with less demanding requirements.
The upgrades in progress on the cantilever spring blades and magnetic anti-spring (MAS) will be also described in view of the project for the next generation Seismic Isolation System of the Einstein Telescope (ET) and its underground giant laboratory for Gravitational Waves observation.

Speaker: Dr Franco Frasconi (INFN Pisa)

3:30 PM → 7:30 PM Forum Session 3

Conveners: Andreas Werner Jung (Purdue University (US)), Antti Onnela (CERN)

3:30 PM All hands on deck at DESY - Building the ATLAS and CMS end-caps for the Phase-2 Upgrade

The Phase-2 upgrades for the ATLAS and CMS detectors are the next big upgrade projects imminent. To cope with the challenging conditions for High Luminosity LHC (HL-LHC), the current trackers for both experiments will be replaced by new sub-detectors: the ATLAS Inner Tracker (ITk) and the CMS Tracker. The all-silicon detectors are segmented in the inner regions by the ITk Pixel and the CMS Inner Tracker populated with pixel sensors and the outer regions by the ITk Strip and CMS Outer Tracker (OT) with strip sensors.
Two of the end-caps - covering the forward regions for the HL-LHC collisions - for the ITk Strip and the CMS OT are being prepared and constructed at DESY Hamburg before shipping for installation at CERN. For fulfilling this task, teams of motivated physicists, engineers and technicians are working in DESY's Detector Assembly Facility, which are two state-of-the-art cleanrooms specifically constructed for the needs of the upgrades. Even though working on different detectors following own design approaches and across the big ATLAS and CMS collaborations, locally exchanging on knowledge, technology and methods is a big plus for the teams.
This contribution gives an overview of the status quo of the two upgrade projects, shows some insights on the local challenges for performing our quest of delivering two end-caps to CERN and finally has also an outlook for the future after the phase-2 upgrade completion in view of the DRD collaborations.

Speaker: Jan-Hendrik Arling (Deutsches Elektronen-Synchrotron (DE))

FoTDM26_ATLAS&CMSUpgradesAtDESY_Arling.pdf

4:00 PM Carbon Composite Support Wheel for HL-LHC CMS Tracker TB2S Detector

The Tracker Barrel with 2S Modules (TB2S) detector of the HL-LHC CMS Tracker will consist of 4416 silicon strip modules, supported by 368 “Ladder” structures. A carbon composite “Wheel” of 2.4 m diameter and 2.4 m length supports the Ladders as well as smaller sub-detectors of the Tracker. This presentation summarizes the main design features of the TB2S Wheel and explains the various production phases that are currently culminating in the final assembly and load testing of the Wheel. Various production difficulties and lessons learned will be explained.

Speakers: Marc KRAUTH, Philippe Lenoir (CERN)

2026-05-29_CMS_TB2S_Wheel_Forum_2026.pdf

2026-05-29_CMS_TB2S_Wheel_Forum_2026.pptx

4:30 PM CMS Phase 2 Tracker Barrel Pixel: Mechanic Assembly and Integration, tools and QC

During the LHC Phase 2 upgrade, the CMS Tracker will be upgraded to meet the performance demands of High-Luminosity LHC (HL-LHC). This presentation focuses on the realisation and technical decisions of the Tracker Barrel Pixel (TBPX), which has recently reached production phase. To start, it will be presented the current status of the prototypes and first final layers produced, followed by an updated overview of the production workflow. Special emphasis is placed on the most time consuming and complex assembly operations.
We then detail the technical solutions and precision tooling developed to overcome these challenges, optimizing both assembly time and mechanical accuracy.
Furthermore, we discuss the integration strategy, explaining the layer-by-layer assembly process required to complete a full TBPX quarter. Finally, we present the Quality Control methods, ranging from individual component testing to full-assembly validation—ensuring the system is fully qualified for the next decade of operations.

Speaker: Daniele Benvenuti (Universita & INFN Pisa (IT))

CMS Phase 2 Tracker Barrel Pixel 02_06_2026 DB.pdf

CMS Phase 2 Tracker Barrel Pixel 02_06_2026 DB.pptx

5:00 PM HL-LHC CMS Outer Tracker Endcap Double Disks (TEDDs): The First Experience of Integration and Test of Silicon Modules on “Dee” Structures

For the High Luminosity LHC (HL-LHC), the CMS is going to operate at up to 200 interactions per 25 $ns$ beam crossing and reaching up to 4000 $fb^{−1}$ of integrated luminosity. The CMS Tracker Phase-2 upgrade for the HL-LHC requires designing new Inner and Outer Tracker (OT) systems to cope with the increased luminosity, to ensure excellent tracking performance in the presence of a high level of pileup, and to implement the L1 trigger functionality (only for entire OT).

The upgraded OT system will consist of a barrel region and two endcaps made of double disks (TEDDs).TEDDs are built from large "dee" structures grouping more than 100 modules of two kinds: 2S modules built with two strip sensors and PS modules with strip and macro-pixel sensors. Theses are the largest and most complex substructures in the CMS tracker upgrade project, so the module integration process and the subsequent tests are critical steps to ensure detector performance, stability, and reliability.

This contribution will present the first experience of the step by step integration procedure, the test procedure, and performance results of silicon modules operated jointly on the structures. This will include observations on integration procedures and workflows, the tools and software developed for that purpose, the measurements made during integration, and noise measurements after integration in conditions close to the final detector environment.

Speaker: Semra Turkcapar (Universite Catholique de Louvain (UCL) (BE))

SemraTurkcapar_ForumOnTrackingDetectorMechanics_2June2026.pdf

5:30 PM Coffee Break

5:50 PM Composite Design, Manufacturing and FEA modelling lessons from the Inner Tracker Support Tube for HL-CMS

The Phase II upgrade of the Compact Muon Solenoid (CMS) detector includes major advancements in composite structures and thermal interface design. Following successful prototyping and validation, production of the Inner Tracker Support Tube (ITST) has begun. This presentation highlights key lessons learned and milestones achieved during the production of the ITST composite structures, including the central section and two end sections. Particular emphasis is placed on the transition from prototype to full-length components, including the development and scaling of finite element models for tool shape compensation and their impact on manufacturing accuracy. Critical insights were also gained from the design and implementation of internal bond lines and external interfaces, such as rails for pixel detector support structures. Results from validation tests are presented and compared with metrology data from produced components, demonstrating the correlation between design predictions and as-built performance. These findings provide important guidance for large-scale composite production in high-precision detector systems.

Speaker: Sushrut Rajendra Karmarkar (Purdue University (US))

2026 06 01 FTDM ITST Talk .pdf

6:10 PM Repair Campaign of the CMS Barrel Timing Layer - Tracker Support Tube, the BTST

The Barrel Timing Layer and Tracker Support Tube (BTST) is a 2.4-meter diameter, 5.3-meter long composite sandwich structure designed to provide primary mechanical support for the Barrel Timing Layer, Outer Tracker, and Inner Tracker detectors of the CMS detector for the HL-LHC. This presentation provides updates on repair campaign at CERN, simulation learnings and repair validation testing conducted to address findings from manufacturing quality control and road accident. Key learnings from the development of accurate material models—reflecting as-manufactured properties and realistic boundary conditions necessary to simulate worst-case loading scenarios expected during installation into the calorimeter with the temporary support structure (Eiffel tower)—are discussed. The learnings from the on-site repair campaign and details of the methodology used for affecting the repairs at CERN are presented. The metrology techniques used for validation of the BTST, and results from the QA/QC of repairs and mechanical and thermal load testing to validate the structure for use in the HL-LHC are presented. This talk serves as a follow-up to previous presentations at FTDM 2024 and FTDM 2025, which covered the initial design, simulation, and manufacturing process of the BTST as well as the simulation and prototyping for the repair campaign at CERN.

Speaker: Pierre Rose (CERN)

2026-06-02 Repair Campaign of the CMS BTST.pdf

2026-06-02 Repair Campaign of the CMS BTST.pptx

6:30 PM Thermal studies of the CMS Endcap Timing Layer cooling system

As part of the CMS Phase-2 Upgrade project, a novel detector, the Endcap timing Layer (ETL), will be installed during LS3 with the goal of precisely measuring the production time of minimum ionizing particles (MIPs) during HL-LHC era which comes with increased number of collisions. To ensure optimal operating conditions, a two-phase CO2 cooling system is going to be used to extract the heat dissipated by detector’s electronics tiled on the 6.35 mm thick aluminium cooling plate. Sixteen cooling loops, in parallel connected to a single manifold and composed of a capillary and an evaporator, are responsible for distributing the coolant across the plate. A dedicated test stand has been designed and assembled at the CERN Tracker Integration Facility (TIF) to test the final prototype of the cooling plate and optimize the cooling system design. It is complemented by a SCADA system which provides both safety and environmental monitoring functions. The test stand is capable of generating up to 5 kW of power controlled by a programmable logic controller (PLC) with implemented interlock algorithm. Vital system parameters are monitored with a number of instrumentation such as absolute and differential pressure sensors, coriolis flow meter, in-flow temperature sensors, etc. Due to the specific design of the cooling system, obtaining accurate theoretical predictions of the evaporators’ pressure drop is difficult; therefore extensive tests have been performed in order to obtain these values experimentally. The crosstalk between the loops has been observed and temperature uniformity across the plate has also been investigated. Additionally, besides nominal operating conditions, the system has been tested under potential failure modes that could occur during detector operation. The system’s response has been evaluated in case of a single loop clogging or complete flow shut-off and margin to reaching dry-out conditions has been studied. In parallel to these studies, the behavior of the TIF CO2 plant has been evaluated since the CO2 parameters, such as vapor quality (VQ) and mass flow, are comparable with ones expected during final operation at P5. A significant pressure drop has been noticed on the return line to the plant’s accumulator, resulting in higher temperature at the setup’s outlet. These results emphasize once again the importance of proper sizing of detector transfer lines (DTLs) to ensure optimal CO2 conditions at the detector level. The presentation summarizes the results of thermal studies and shares lessons learned during the operation and testing process of the system.

Speaker: Mihailo Lukovic (CERN)

7:00 PM The CMS TEPX detector for the Phase-2 Inner Tracker Upgrade: Thermal Performance and Simulation Results

During Long Shutdown 3, the Large Hadron Collider (LHC) at CERN will undergo an upgrade program, marking the beginning of the High-Luminosity era. The High-Luminosity Large Hadron Collider (HL-LHC) is expected to collide protons at a centre-of-mass energy of 14 TeV and to reach the unprecedented peak instantaneous luminosity of 7 x 10^34 cm^-2 s^-1 with the average number of pileup events between 140 and 200. This will allow the ATLAS and CMS experiments to collect integrated luminosities up to 3000 fb^-1 over 10 years of data taking. To cope with this extreme scenario, the CMS detector will be substantially upgraded before the start of the HL-LHC, as part of the CMS Phase-2 Upgrade. The entire CMS tracking system will be replaced, in particular the Inner Tracker (IT). The new detector will feature increased radiation hardness, higher granularity, larger acceptance and capability to handle higher data rate and longer trigger latency. The upgraded IT will consist of a barrel part (TBPX) plus eight small disks (TFPX) and four large disks (TEPX) per side. The TEPX disks will host pixel modules arranged in five concentric rings and will extend the coverage up to |eta|=4.0. In this contribution the new TEPX detector is presented, with particular focus on its mechanical structure and thermal performance. Along with the other Inner Tracker sub-sections, TEPX features an effective CO2 cooling system integrated within a very light support mechanics, where power and data lines are also embedded. The cooling design implements titanium pipes to keep a low material budget while ensuring that the modules temperature remains well below the critical value to avoid thermal runaway. A pre-production prototype of the TEPX disk that will be installed in the final detector has been tested under operational conditions to assess its thermal behavior and several measurements have been carried out in different regions of the disk. A comparison between experimental results and thermal simulations performed using finite element analysis is presented, including parametric studies on the impact of enhanced thermal interface conductivity. Based on the agreement between measurements and simulations, an optimized prototype was designed to improve heat extraction. The upgraded prototype was thermally characterized, and the results are benchmarked against updated finite element simulations. Finally, the extrapolation to end-of-life thermal behavior is discussed, accounting for the expected increase in power density and sensor leakage current over time.

Speaker: Yann Herpin (University of Zurich (CH))

2026-06-02 TEPX Thermal Performance and Simulation Results.pdf

2026-06-02 TEPX Thermal Performance and Simulation Results.pptx

8:00 PM → 10:30 PM Social Dinner

Wed, June 3

8:25 AM → 12:35 PM Forum Session 4

Conveners: Bart Verlaat (CERN), Paolo Petagna (CERN)

8:30 AM Commissioning Status and Performance of 2PACL CO₂ Cooling Systems for the ATLAS and CMS Phase-2 Detector Upgrades

For the Phase-2 upgrade of the ATLAS and CMS experiments, new generation 2PACL cooling systems will be installed for the thermal regulation of the inner tracking and timing detectors. A commissioning campaign is currently ongoing to validate operational readiness and characterize system performance.

The ATLAS system has been the focus of initial system verification and final development efforts. Accumulator stand-alone tests have been performed to validate the vessel design, and circulation of carbon dioxide at nominal conditions has helped validate the transferline configuration and overall plant performance. Improvements to the start-up procedure, control strategies and safety features have also been made, which is directly applicable to all future installations.

At CMS, commissioning efforts have successfully enabled circulation of carbon dioxide at low saturation temperatures through the experimental cavern. Besides putting multiple systems into service, this has also allowed validation of the transferline installation and manifold box design.

This contribution presents the status of the operational systems and the key challenges encountered during the commissioning process, as well as performance estimations of the detector, and the path forward to the start of LS3.

Speaker: Youri Penders

2PACL Commissioning Status Forum 2026.pdf

2PACL Commissioning Status Forum 2026.pptx

8:50 AM Early results from the Surface Storage

The 'Surface Storage' module is one of the biggest (and most visible) changes to the Two-Phase Accumulator Controlled Loop principle, developed specially to deal with the requirements from CMS and ATLAS for the Hi-Lumi Phase-2 upgrade.

This 12 m3 surface storage vessel will store all the extra CO2 that cannot be stored in the cavern due to space constraints. Flow to/from the underground is done using a thermosiphon loop, relying on the buoyancy differences between the liquid CO2 going down and the two-phase CO2 coming up. The transfer piping on surface has been carefully sloped towards the underground to ensure an absence of vapour bubbles that can break the static liquid column and interrupt circulation.

In this talk, we present the commissioning status of the Surface Storage module for ATLAS. The different operating modes are discussed, along with the control philosophy and control system design for the module. Results from the early commissioning are shown and discussed.

Speaker: Viren Bhanot (CERN)

2026-06-03-ftdm-surfacestorage-FIXED.pdf

9:10 AM Lessons learned from ATLAS and CMS 2PACL CO2 cooling systems installation for both mechanics and controls.

Within the framework of CERN’s High Luminosity LHC program, the ATLAS and CMS experiments are progressing in the installation and hardware commissioning of their environmentally sustainable, low-temperature detector cooling systems. These two-phase accumulator-controlled loop (2PACL) systems are unprecedented in scale and complexity—both mechanically and in terms of control systems—than any previous installations developed by the Experimental Physics Detector Technology Group.
This presentation will outline the numerous challenges encountered during the installation process, including construction by the manufacturer, transportation and on-site assembly. For the control systems, we will detail the quality assurance processes implemented, the safety measures adopted and the issues faced before and during hardware commissioning at both experimental sites.
We will discuss the strategies employed to minimize deployment time, highlight what was successfully anticipated, and reflect on oversights that emerged. Finally, we will propose additional measures that could further optimize preparation for the second phase of installation in ATLAS during LS3.

Speakers: Jerome Daguin (CERN), Lukasz Zwalinski (CERN)

Lessons learned from ATLAS and CMS 2PACL CO2 cooling systems installation for both mechanics and controls_2026_06_03_v2.pdf

Lessons learned from ATLAS and CMS 2PACL CO2 cooling systems installation for both mechanics and controls_2026_06_03_v2.pptx

9:40 AM Thermal and Pressure Drop Testing Campaigns of CO₂ Detector Transfer Lines for the CMS experiment

Detector Transfer Lines (DTLs) are a key element of the CMS Tracker two-phase CO₂ cooling system. They are responsible for distributing liquid CO₂ from the instrumented manifolds at the detector periphery into the detector volume. Their coaxial design (either one or four inner process pipes inside an outer process pipe) allows heat exchange between the liquid supply and the two-phase return, enabling the liquid CO₂ to reach saturation before expansion in the capillaries and evaporators. An insulation chamber surrounds the outer process pipe to ensure that the surface temperature remains above the ambient dew point. The qualification of the DTL design involves several engineering aspects, including thermal insulation and hydraulic performance. An experimental campaign was conducted in the Tracker Integration Facility (TIF) at CERN on two rigid DTL prototypes. The first one, for the High Granularity Calorimeter (HGCAL), was a coaxial vacuum-insulated rigid pipe with a vacuum-insulated flexible section in series. The second one, for the Tracker, was a four-into-one aerogel-insulated rigid pipe developed by the Mechanical and Materials Engineering (MME) group at CERN. The campaign combines thermal insulation testing with a pressure-drop mapping study. The thermal qualification for insulation performance validation is based on distributed pipe surface temperature measurements using PT100 sensors under nominal conditions, with a focus on the most critical locations (i.e., bellows, elbows, and spacers). To evaluate the condensation risk under final operating conditions, calculations were performed to extrapolate the measured surface-to-ambient thermal behavior in the TIF to the expected cavern ambient temperature. In parallel, the two-phase pressure drop in the DTL outer process pipe section is evaluated over multiple representative operating setpoints using temperature, absolute pressure, differential pressure, and mass-flow measurements. The aim is to determine the total ΔP of the assembly and verify that it remains within the available operating margin. The results of the prototype tests helped identify design corrections, including improvements to the aerogel filling procedure developed by EN-MME, as well as a dimensional modification consisting of an increase in the insulation chamber diameter of the Barrel Timing Layer (BTL) DTL to ensure compliant insulation performance. For the vacuum-insulated lines, the outcome was the decision to install getter pumps for active pumping in the vacuum-insulated flexible sections. The ongoing pressure-drop mapping campaign aims to validate the simulated pressure-drop budgets for the system and to support the commissioning and parameter tuning of the 2PACL equipment, such as plants and manifolds. The first results show trends consistent with the simulations. Data taking will continue in the coming months and will be used to fully validate the system assumptions.

Speaker: Levent Kilinc (CERN)

CMS_CO2_DTL_Testing.pdf

CMS_CO2_DTL_Testing.pptx

10:05 AM Group Photo & Coffee Break

10:35 AM Experimental testing of a TBPX cooling manifold: validation of the capillary design methodology

This study presents experimental tests on a TBPX cooling manifold conducted at CERN.

The objective is to validate the design methodology for all CMS Tracker capillaries, which is based on the modelling and simulation of different cooling loops (grouped by their manifold) using the Multiline tool.

The tested manifold, which groups seven lines, is the most complex and unbalanced one in the entire Tracker, since the thermal power applied across different evaporators varies by up to a factor of four. This circumstance implies considerably different pressure drops and mass flow requirements between neighboring cooling loops. At the aim of addressing this complexity, the capillaries have been designed with four different inner diameters (ranging from 0.5 mm to 0.8 mm) and four different lengths (from 0.8 m to 1.4 m).

Moreover, modules failure is simulated by turning off the heat load on one or more evaporators, thereby addressing the flow distribution in the case of dead loops.

The agreement between experimental results and simulations will validate the Tracker capillary design methodology for all manifolds, the majority of which feature balanced loops and, therefore, identical capillaries.

Speakers: Mr Lorenzo Bistoni (Universita e INFN, Perugia (IT)), Pier Filippo Cianchetta (CERN)

030626_Experimental_testing_of_a_TBPX_cooling_manifold_validation_of_the_capillary_design_methodology_V5.pdf

030626_Experimental_testing_of_a_TBPX_cooling_manifold_validation_of_the_capillary_design_methodology_V5.pptx

11:00 AM A Predictive Model for Dryout Onset in Milli Scale CO₂ Two Phase Cooling Channels

Two phase CO₂ cooling is increasingly adopted in low temperature and high heat flux applications across detector and tracking system infrastructures, where its favourable thermophysical properties offer significant potential for compact, low mass thermal management solutions. However, the onset of dry-out remains a critical design concern: while partial boiling enhances heat transfer, transitioning to a vapour dominated regime risks thermal runaway and structural damage. As a result, current engineering approaches often rely on overly conservative operating margins, limiting the achievable thermal efficiency. Understanding and predicting dry-out behaviour in milli-scale channels in therefore remains essential for advanced detector cooling system design.
This work presents a new theoretical model developed at the University of Bath and validated at the LUCASZ facility to predict the onset of dry-out in 1 mm diameter stainless steel milli-channels under controlled two phase CO₂ flow conditions. Unlike established correlations, the proposed model is independent of saturation temperature and heat flux, enabling its generalisation across a wide range of operating conditions and test configurations. Experimental validation employed a 180 mm test section instrumented with highspeed T type thermocouples at 12 axial locations, supported by preconditioning of the inlet flow through an electric heater, pressure control, and a uniform flow orifice arrangement. The test section was housed within a vacuum chamber to ensure thermal isolation.
Analysis of the experimental data demonstrates that dry-out onset can be expressed through an exponential correlation with pipe diameter, providing a robust and transferable predictor of vapour quality thresholds. The results further identify liquid–vapour interface stability as the dominant physical mechanism governing dry-out in milli scale geometries. By enabling accurate prediction of this transition without restrictive assumptions on temperature or heat flux, the model offers a pathway to more optimised CO₂ based cooling architectures, supporting next generation detector mechanics and thermal management strategies.

Speaker: Dr Joe Dawe (University of Bath (GB))

Dawe_&_Sameh_Elba2026.pptx

11:20 AM Experimental investigation of saturation temperature and pipe roughness effects on CO2 microchannel flow boiling for detector cooling

Two-phase evaporative CO$_2$ cooling is a leading solution for the thermal management of silicon detectors, enabling high heat removal with limited material budget and nearly isothermal operation in compact geometries. Nevertheless, reliable prediction of flow boiling heat transfer coefficients (HTCs) and the interpretation of the observed trends remain challenging in micro-scale channels, where the strongly temperature-dependent properties of carbon dioxide and confinement effects can alter the dominant mechanisms and challenge the validity of standard correlations.

This work presents an experimental study of boiling CO$_2$ in a single 1 mm inner diameter test section designed for detector-cooling R&D, combining local HTC measurements with high-speed flow visualization through a dedicated transparent section. This allows identification of flow regimes and comparison with existing flow pattern maps.
To extend previous work performed in this experimental setup, inlet conditions are tuned to a wide range of vapour qualities up to dryout inception and, when feasible, beyond. A systematic test matrix is explored in order to quantify the role of saturation temperature ($T_{\mathrm{sat}}$) across detector-relevant conditions, spanning $+15^{\circ}\mathrm{C}$ to $-25^{\circ}\mathrm{C}$, including intermediate points at $+5^{\circ}\mathrm{C}$, $0^{\circ}\mathrm{C}$, $-5^{\circ}\mathrm{C}$ and $-15^{\circ}\mathrm{C}$. For each $T_{\mathrm{sat}}$, three mass fluxes ($G = 530,\ 800,\ 1200\ \mathrm{\frac{kg}{m^{2}s}}$) and six heat fluxes ($q'' = 0,\ 10,\ 20,\ 40,\ 60,\ 70\ \mathrm{\frac{kW}{m^{2}}}$) are investigated.
The present experimental campaign also considers the effect of surface roughness on heat transfer and pressure drop, which was investigated through a selected set of measurements performed in a titanium pipe.

The combined dataset provides temperature-resolved trends of HTC and their dependence on other operating parameters, as well as a visual key for interpreting regime transitions and intermittent behaviours that are difficult to infer from time-averaged signals alone. This study provides further understanding of the physics CO$_2$ flow boiling in a single channel in the millimetre scale, contributing to the development and validation of predictive models for next-generation detector cooling systems.

Speakers: Giacomo Antonini (Università degli Studi di Perugia and CERN), Gian Marco Cioffi (Universita e INFN, Perugia (IT) and CERN)

Visualization_of_the_effect_of_saturation_temperature_on_CO2_microchannel_flow_boiling_Cioffi_Antonini.pptx

12:35 PM → 3:00 PM lunch

3:00 PM → 3:30 PM Presentations from Companies

Hexagon-MI-Forum on TDM and DRD8 CM.pptx

Prusa - Tracking Detectors Mechanism (Elba 2026).pptx

3:30 PM → 8:00 PM DRD8 Session 1

Conveners: Burkhard Schmidt (CERN), Corrado Gargiulo (CERN), Fabrizio Palla (Universita & INFN Pisa (IT))

3:30 PM Introduction DRD8

Speaker: Burkhard Schmidt (CERN)

4th DRD Collaboration Meeting – Introduction.pdf

4th DRD Collaboration Meeting – Introduction.pptx

3:40 PM Introduction WP1

Speaker: Fabrizio Palla (Universita & INFN Pisa (IT))

Biodola wp1 intro.pdf

Biodola wp1 intro.pptx

3:50 PM Status of the FCC-ee MDI full-scale mockup

The FCC-ee interaction region incorporates the crab-waist collision scheme to achieve unprecedented luminosity. This approach combines nano-beam focusing at the interaction point with a large horizontal crossing angle, which in turn requires a compact and sophisticated machine–detector interface layout.

To assess the feasibility of this advanced design, INFN and CERN have jointly launched an R&D programme to construct a full-scale mockup that includes thin, lightweight, actively cooled beam pipes, a mockup of a compact low-mass vertex detector and a mockup of the luminosity monitor (LumiCal). All beampipe elements are supported via bellows on a composite carbon-fibre cylindrical structure, that also holds the vertex and the LumiCal. This mockup complements the existing 3D CAD models and finite-element simulations, enabling an experimental validation of key components—such as the beam pipes and vertex cooling systems—tested under realistic thermal loads.

The main objective of the mockup is to validate the integration and assembly procedures of all the elements, particularly the routing of the services.
We will discuss the status of the project, the main issues found and the future steps.

Speakers: Dr Andrea Moggi (Universita & INFN Pisa (IT)), Manuela Boscolo (INFN e Laboratori Nazionali di Frascati (IT))

Status of the FCC-ee MDI full-scale mockup -v2.pdf

4:10 PM Ultra-thin beam pipes for FCC-ee

The interaction region of the Future Circular Collider (FCC-ee) requires extremely thin vacuum chambers capable of withstanding thermal loads while minimising the material budget, thus requiring active cooling.
The chambers have been designed considering the baseline material AlBeMet162, selected to satisfy stringent requirements on stiffness‑to‑mass ratio while minimising material budget near the detector acceptance. Detailed thermal, structural, and vibrational analyses were performed to evaluate the system's cooling performance, mechanical stability, and proper frequencies.
A mockup of the chambers has been realised at LNF-Frascati. The mockup has been fabricated in aluminium, given the difficulty of AlBeMet procurement, but with similar mechanical dimensions.
The inner chamber, about 20 cm long, has a diameter of 2 cm, and is composed of a double layer structure with about 350 µm thick walls, separated by 0.9 mm cooling channel, where liquid paraffin flow extracts a nominal nearly 30 W power load from beam wakefields. Two lateral ~120 cm long ellipto-conical beampipes on either side complement the central IR complex, where water cooling ducts extract about 130 W each. A dedicated hydraulic test bench was developed to reproduce the expected thermal loads using ohmic heaters and to control cooling conditions through adjustable flow rate and inlet temperature.
This talk will cover the mechanical design, fabrication, and experimental validation of the vacuum chambers of the FCC-ee interaction region that have been realised.
This activity is part of a INFN-CERN co-funded project, and also part of the ECFA-DRD8.

Speaker: Francesco Fransesini (INFN e Laboratori Nazionali di Frascati (IT))

Ultra-thin beam pipes for FCC-ee_Fransesini (3).pdf

Ultra-thin beam pipes for FCC-ee_Fransesini (3).pptx

4:30 PM Structural Design and Thermal Performance Study of CEPC Beam Pipe Based on an Aluminum Tube Substitution Scheme

As one of the core components of CEPCr, the structural design and thermal management of the beam pipe directly impact beam quality and experimental safety. This study addresses the process validation requirements during the development of the beam pipe by proposing an experimental scheme that uses an aluminum pipe as a substitute for the conventional beryllium pipe. The beam pipe adopts a double-layer structure, with an inner tube wall thickness of 0.2 mm, an outer tube wall thickness of 0.15 mm, and a gap of 0.2 mm between the inner and outer tubes. To verify the feasibility of the substitution, the mechanical properties, thermal conductivity, and irradiation characteristics of aluminum and beryllium were first compared, clarifying the differences in their physical properties. Subsequently, a thermal-structural coupling model of the beam pipe was established using the finite element method, and the temperature field distribution and heat dissipation performance of the aluminum pipe and the beryllium pipe were compared under identical thermal load conditions. The results show that, although aluminum differs from beryllium in thermal conductivity, it can still meet the heat dissipation requirements of the experimental stage through structural optimization. Based on these findings, the structural design and process feasibility assessment for the aluminum pipe substitution scheme were completed. This study provides critical process validation and design references for subsequent practical engineering applications utilizing beryllium pipes.

Speaker: Xiaoyan Ma (Chinese Academy of Sciences (CN))

Structural Design and Thermal Performance Study of CEPC Beam Pipe-DRD8.pdf

Structural Design and Thermal Performance Study of CEPC Beam Pipe-DRD8.pptx

Structural Design and Thermal Performance Study of CEPC Beam Pipe.pdf

4:50 PM Large-Scale Curved Sensor Mechanics and Integration for Future Vertex Detectors

Next-generation vertex detectors for experiments such as ALICE ITS3, FCC-ee, and EIC demand a novel mechanical approach to achieve unprecedented tracking precision. This requires a radical reduction in material budget and positioning the first detection layer closer to the interaction point. Within the DRD8 collaboration (WP1), we have developed an ultra-light, wafer-scale curved silicon pixel architecture following the ALICE ITS3 baseline. This concept, developed by the ALICE collaboration, utilizes 65 nm TPSCo CMOS imaging technology and stitching to create large-scale sensors. The design integrates ultra-thin sensors (thickness ≤ 50 μm) onto carbon foam structures that provide extremely low mass with adequate structural rigidity. These structures serve as both mechanical supports and thermal radiators, ensuring superior heat dissipation for thermally critical regions and enabling a self-supporting geometry with a first-layer radius of 19 mm and a total length of 266 mm.

This study presents the results of a systematic campaign conducted through a series of iterative engineering prototypes to validate the full concept development: from the mechanical assembly of curved sensors, service routing, and delicate component interconnectivity through the patch panel, to thermal and vibrational performance characterisation. We report key performance parameters, including a material budget of the overall mechanics X/X₀ < 0.05%. Experimental data confirms sub-micron aeroelastic stability (displacement < 1 μm) and validates an innovative air-cooling solution, achieving a peak temperature rise of ΔT < 7°C at 8 m/s airflow, eliminating the need for liquid-cooling infrastructure. Finally, we present the status of the Qualification Model, assembled with final-grade components and real sensors, representing the final milestone for system-level deployment in future collider experiments.

Speaker: Bartlomiej Adam Markiel (CERN)

20260603_FTDM2026_DRD8_ALICE-ITS3.pdf

20260603_FTDM2026_DRD8_ALICE-ITS3.pptx

5:10 PM Experimental studies for an air cooling system for the FCC-ee inner vertex

The inner vertex detector of the IDEA detector concept is based on MAPS technology, and is expected to dissipate less than about 50 mW/cm2. With such low power density air-cooling solutions can be developed. Two main mechanical arrangements for the silicon sensors are envisaged at the moment: a ‘traditional’ flat version, in which MAPS are put on top of a carbon fibre stave, and a curved sensor version, inspired to the ALICE ITS3 vertex detector. Preliminary simulations of the former geometry show that air-cooling can be successfully employed to maintain temperature control along the full length of the stave, which in the case of the longest structures are of the order of 50 cm dimensions, although with a considerable air-flow, that in turn induces vibrations smaller than the single hit resolution of the MAPS (~3 µm). The mechanical layout of such a solution should guarantee sufficient air-cooling capabilities and keep the mechanical structure vibrations at the minimum.
To validate the effectiveness of this approach, a dedicated experimental setup has been implemented, enabling precise measurements of pressure, temperature, and flow rate within the test section for both single-layer and multi-layer configurations. The experimental system provides essential feedback to the parallel computational fluid dynamics (CFD) studies, ensuring accurate data interpretation and reliable modelling of the airflow behaviour around the vertex detector staves. The presentation will provide a description of the mechanical and thermal solutions adopted to establish a hermetically sealed volume within the test section, in which cable routing constraints, together with the requirement to ensure efficient assembly and disassembly procedures, have represented significant technical challenges.
Presentation of the results on air-cooling performance as a function of the air-flow obtained by experimental measurement will be presented, and critically discussed.

Speaker: Gherardo Ammirabile (Universita & INFN Pisa (IT))

Experimental studies for an air cooling system for the FCC-ee inner vertex, Elba.pdf

Experimental studies for an air cooling system for the FCC-ee inner vertex, Elba.pptx

5:30 PM Coffee Break

5:50 PM Mechanical and Integration aspects of the FCC-SEED vertex detector concept

FCC-SEED is an innovative vertex detector concept designed for next-generation electron-positron colliders, particularly the Future Circular Collider (FCC-ee). The design leverages ultra-thin MAPS sensors, precisely bent to small radii to position the innermost layer in close proximity to the interaction point while conforming to the beam pipe. This approach minimizes material budget and maximizes acceptance thanks to a slight overlap of the curved sensors.

This presentation will outline the FCC-SEED concept and its overall geometric design, with a focus on the technical mastery of sensor curving using MIMOSIS chips. Additionally, we will discuss the roadmap for upcoming mechanical and integration studies, highlighting the challenges and solutions in achieving optimal detector performance. The project status, together with first realisations, will be shown.

Speaker: Jeremy Andrea (Centre National de la Recherche Scientifique (FR))

FCCSEED_DRD8_Elba_2026.pdf

FCCSEED_DRD8_Elba_2026.pptx

6:10 PM Overview of the Mighty Tracker Challenges: Material Budget, Tight Envelopes, Installation

In preparation for the High-Luminosity LHC planned for Run 5, the LHCb detector will undergo its second major upgrade (Upgrade 2). The five-fold increase in instantaneous luminosity will, in particular, pose challenges for the tracking system due to the increased occupancy and radiation conditions. The Mighty-Tracker upgrade aims to therefore replace the current Scintillating Fibre (SciFi) downstream tracker with a hybrid system consisting of an upgraded SciFi (Mighty-SciFi) and monolithic silicon pixels, the Mighty-Pixel. The Mighty-Pixel provides the necessary granularity and radiation tolerance to handle the high track density in the central region, while the Mighty-SciFi covers the peripheral acceptance region. The Mighty-Tracker stations of pixels and fibres will be alternating along the beam pipe. In total there will be four fibre stations and four pixel stations housed in thermal enclosure boxes due to the operating temperature of the pixels close to 0°C. The two central pixel stations contain two active pixel detector layers, therefore also requiring a larger thermal enclosure box. The total area of silicon pixels implemented across the 6 layers is planned to be just under 8m². This talk will first and foremost provide an overview of the detector upgrade.

The hybrid system (combining Mighty-SciFi and Mighty-Pixel detectors) must fit within the spatial constraints of the current SciFi system, presenting significant integration challenges. Access to LHCb sub-detectors is achieved by moving stations perpendicularly away from the beam pipe in two halves - a complex but currently successful procedure that will be replicated for the Mighty-Tracker.

However, the addition of Mighty-Pixel layers complicates physical access to detector components. Each Mighty-SciFi station measures ~5m by 6m. The dimensions will be similar for the Mighty-Pixel stations, with only the central part ~1.3 m² instrumented and housed in thermal enclosure boxes. Station extraction is constrained by cavern limitations, potentially requiring unique configurations for each access point.

New challenges include managing the thermal enclosure seals, the mechanical sensitivity of pixel layers, and aligning stations without direct line-of-sight. Additionally, the material introduced by Mighty-Pixel must be minimised to reduce fake hit rates and maintain tracking efficiency. Services, cabling, and support structures for the central region must traverse the active tracker area, necessitating strict material requirements.
This talk explores these challenges and proposed solutions for the hybrid design.

Speaker: Ksenia Solovieva (University of Freiburg (DE))

Mighty-Tracker_KSolovieva_Forum_DRD8.pdf

6:30 PM Lightweight hardware alignment system requirements and prototyping

The ability to spatially align tracking detectors is imperative for fully exploiting their technological capabilities. A precise method to achieve this, proven by its use in many high energy physics experiments, is the use of tracks from particle decays and from cosmic rays traversing the detector [1-3]. However, the precision achievable with this method is dictated by the available data sample size and for certain cases, like inaccurate modelling of data taking conditions and internal symmetries of the alignment problem, systematic biases can occur [2]. Hardware alignment systems, on the other hand, can quickly provide direct measurements of the detector position, which can supplement track-based alignment in problematic areas and potentially reduce the time needed for its convergence. Any such system has to adhere to strict material budget constraints and performance requirements. In this talk, a study of the requirements on and a design of a prototype of such a system in the context of the LHCb Upgrade 2 downstream tracker is presented.

[1] S. Borghi (on behalf of the LHCb Collaboration), Nucl. Instrum. Methods Phys. Res., Sect. A, vol. 845, pp. 560–564, 2017
[2] CMS Collaboration, Nucl. Instrum. Methods Phys. Res., Sect. A, vol. 1037, p. 166795, 2022
[3] J. Jiménez Peña (on behalf of the ATLAS Collaboration), J. Phys.: Conf. Ser. 664 072025, 2015

Speaker: Todor Georgiev Todorov (University of Freiburg (DE))

drd8-2026-elba-final.pdf

6:50 PM The LHCb Mighty Tracker: Thermo-mechanical design and prototype testing.

The LHCb experiment at the Large Hadron Collider will undergo a major
high-luminosity upgrade during Long Shutdown 4 as part of Upgrade II, tar-
geting instantaneous luminosities of up to 1.5 × 1034 cm−2 s−1, corresponding to
an order-of-magnitude increase over previous operation. This will increase the
total integrated luminosity from approximately 50 fb−1 to about 300 fb−1, sig-
nificantly raising detector occupancy, radiation levels, and data throughput. To
meet these demands, the downstream tracking system will be replaced by the
Mighty-Tracker, a hybrid concept combining monolithic High-Voltage CMOS
(HV-CMOS) silicon pixel sensors in the inner region with scintillating fibres
in the outer region. The silicon pixel modules, based on advanced HV-CMOS
technologies under development for Upgrade II, with Mighty-Pix as a leading
candidate, provide efficient charge collection, nanosecond-level time resolution
(∼ 3 ns), and excellent radiation tolerance. Sensor thinning to 150 μm min-
imises inactive material while preserving mechanical robustness and ensuring a
low overall material budget, while the outer scintillating fibre region guarantees
coverage of the peripheral acceptance.
The silicon sensors are integrated onto lightweight composite mechanical
staves engineered to provide micron-level alignment precision, structural stabil-
ity, and efficient thermal coupling to the cooling system under extreme operating
conditions, including hit rates up to 18 MHz/cm2 and radiation fluences of ap-
proximately 6 × 1014 neq/cm2. This work presents the assembly, validation, and
quality-control procedures developed for the Mighty-Pixel mechanical staves,
including precision glueing of silicon sensors and flex circuits. High-accuracy
metrology was performed on small stave prototypes to verify thickness, pla-
narity, and dimensional tolerances, while thermal performance was characterised
under representative power loads. Finite Element Analysis (FEA) was employed
to model thermo-mechanical behaviour and guide design optimisation, and ad-
hesive systems were qualified through controlled bonding procedures. A com-
prehensive material budget analysis was conducted to minimise radiation length
while preserving stiffness and thermal efficiency. The results demonstrate that
the Mighty-Pixel staves satisfy the stringent mechanical, thermal, and material
requirements for operation in the LHCb Upgrade II high-luminosity environ-
ment. This contribution presents the ongoing R&D efforts and summarises the
performance results from thermo-mechanical design and prototype testing.

Speaker: Mr Bilal Ganie (University of Manchester)

Mighty_Pixel_Tracker_Bilal_Ganie_Forum_Italy.pdf

7:10 PM New construction techniques for a fully carbon fiber DCH prototype

In the scenario of a future construction of an ultra-light drift chamber for the Future Circular Collider (FCC-ee), 4 meters long with an internal diameter of 80 cm and an external diameter of 400 cm, with a drift cell smaller than 1.5 cm, arranged in a full stereo configuration ( 50-250 mrad ) and instrumented with the Counting/Timing cluster technique, we propose the construction of a prototype, entirely made of carbon fiber, with a real length of 4 meters, respecting the total material budget which must be approximately 0.016 Xo for the tracks in the barrel region and 0.05 Xo for forward tracks. The prototype will be a slice of the real chamber, 60°, and two sectors will be instrumented for a total number of 1000 ultra-thin wires, Al-50µm and W-20µm. The purpose of the prototype is to test the concept of wire tension recovery system, mechanical coupling tolerances, and the electrostatic stability of wires in the stereo angle configuration.

Speakers: Alessandro Miccoli (INFN Lecce e Universita del Salento (IT)), Salvatore Maggiore (INFN Lecce e Universita del Salento (IT))

TDM_Isola_d_Elba2026.pdf

Thu, June 4

8:30 AM → 12:30 PM DRD8 Session 2

Conveners: Cristiano Turrioni (INFN, Sezione di Perugia (IT)), Nicola Pacifico (CERN), Sushrut Rajendra Karmarkar (Purdue University (US))

8:30 AM Introduction WP2

Speakers: Cristiano Turrioni (INFN, Sezione di Perugia (IT)), Nicola Pacifico (CERN), Sushrut Rajendra Karmarkar (Purdue University (US))

2026 06 04 DRD8 WP2 FTDM Meeting.pdf

2026 06 04 DRD8 WP2 FTDM Meeting.pptx

8:40 AM Performance Targets for Multi-Functional Structures in Future Tracking Detectors

Future collider particle detectors are being conceptualized worldwide. Most of these concepts foresee tracking systems significantly targeting per-layer material budgets at the 0.25–0.5% X₀ level, and simultaneously sustaining higher data rates, increased radiation doses, and stringent requirements on mechanical stability and cooling. In this regime, structural supports, services, and sensing elements might no longer be designed independently. An integrated approach based on multifunctional structures, where electrical, thermal, and mechanical functions are co-designed within the same architecture, may be instead required to meet the overall performance targets. Here we explore some of the most promising concepts that could enable multifunctionality, defining preliminary quantitative performance requirements for real world applications. One solution is ultra-thin and bent sensors integrating detection and structural functions. This approach introduces strict constraints on strain control, motivating the integration of Structural Health Monitoring (SHM) and strain-sensing technologies to quantify mechanical and thermal loads, and to prevent local failures in service. While bent structures in silicon have been already applied, we will also consider alternative materials, such as silicon carbide, which have different mechanical properties but may provide advantages in performance. A second promising solution involves carbon data transmission lines, with the potential of merging service and structural mass budgets, an increasingly critical aspect as detector size and data throughput grows. For these conductors, a performance matrix is outlined, including DC resistance per unit length, temperature dependence, magnetoresistance, inductance, AC losses in the 10–100 MHz range, mechanical robustness, and radiation tolerance. The objective is to define measurable targets and validation strategies that could enable the use of multifunctional structures in next-generation tracking detectors, and to potentially engage the community in collaborative efforts.

Speaker: Giorgio Vallone (Lawrence Berkeley National Lab. (US))

2026-DRD8-GM Elba-Final.pdf

2026-DRD8-GM Elba-Final.pptx

9:00 AM Ultra-light mechanics for a large-area silicon tracker at FCC-ee

The FCC-ee detector concepts feature tracking systems with a much larger volume than those of the LHC experiments, with dimensions of about 4 m in diameter and 4 m in length.
To meet the demanding physics performance requirements of FCC-ee, a silicon tracker must have an extremely low material budget, far beyond what has been achieved by large silicon trackers built to date.

This contribution presents a novel mechanical concept designed to meet these requirements. Starting from the cold-plate design originally developed for the ALICE ITS2, a new stave concept has been developed that provides both mechanical support and cooling for two active layers of silicon MAPS. The way individual staves are assembled to form the barrel structure is discussed, together with initial ideas for extending the concept to the endcap regions.

Speaker: Giada Bonini (Universita e INFN, Perugia (IT))

Ultra-ligth_mechanics_for_a_large-area_silicon_tracker_at_FCC-ee.pdf

Ultra-ligth_mechanics_for_a_large-area_silicon_tracker_at_FCC-ee.pptx

9:20 AM Prototyping and qualification of ultra-light ladders for the CMS TBPX L1 upgrade in preparation for a future replacement

At the beginning of 2025, a collaboration at CERN started the development of an upgraded mechanical design for the CMS Inner Tracker TBPX L1 in preparation for its future replacement.
Building on concepts originally developed for the ALICE Inner Tracker, a new ladder design was developed to significantly reduce the material budget, achieving a reduction of about a factor of three at the mechanical level. After adapting the design to the strict geometry and integration constraints, a prototyping campaign was launched to validate the main design aspects. This included the development of new production procedures and high-precision assembly jigs to manufacture cold plates with 100 µm thickness titanium cooling pipes embedded in a high-thermal-conductivity carbon-fiber layup, combined with a carbon-filament space-frame structure to increase stiffness.
A qualification campaign was carried out on individual components, including pressure tests and CO₂ cooling tests at operating conditions (12 bar and −35 °C) to validate the pressure drop and flow parameters at different vapor quality levels. Thermal tests with dummy heaters showed agreement within 1 °C with simulations performed in Ansys Fluent, also validating the simulations for different configurations, such as TBPX L2 and TBPX L1 with planar sensors instead of 3D sensors.
Additional effort was devoted to the design of compact pipe interconnections using soft-soldering techniques derived from the CMS Outer Tracker.
Parallel studies using the tracker layout were also performed to evaluate the impact of the reduced material budget on track reconstruction precision.
The project is now approaching the end of the feasibility study, including thermal, mechanical, metrology and mass validation. The next steps include finalizing the support structure, integrating bare modules to obtain a fully equipped prototype, and evaluating the procurement of materials to be ready for the construction of a full TBPX Layer 1 structure for a potential future replacement.
This R&D activity has also been included in the DRD8 program within WP2 starting in January 2026.

Speaker: Pier Filippo Cianchetta (Universita e INFN, Perugia (IT))

040626_Prototyping_and_qualification_of_ultra-light_ladders_for_the_CMS_TBPX_L1_upgrade_in_preparation_for_a_future_replacement_v3.pptx

9:40 AM Innovative mechanical structures via Additive Manifacturing

dditive manufacturing (i.e.”3D printing”) is increasingly being used in a number of areas from aerospace to medicine. Recent advancements in technology are widening the applications in which the 3D printing includes carbon fibers, reinforcing the mechanical properties of the matrix. Continuous Fiber Reinforced Composites (CFRC) exhibits mechanical performances better than when short CF are injected during the fabrication process. While there are many different parameters relevant to the characteristics of the final sample, a number of studies are addressing this issue in a systematic way.
In Pisa we started an R&D program aimed at assessing whether present technology allows us to build mechanical components suited to present and future applications in high energy physics. This implies both understanding how to exploit the AM potentialities, and the properties of the products.
We are concentrating on using directional (i.e. non-isotropic) materials to build structures that can also embed services. To this aim we characterized several samples. We will discuss results and perspectives.

Speaker: Giorgio Chiarelli (INFN Sezione di Pisa,)

DRD-4 giugno.pptx

10:00 AM Design, Fabrication, and Testing of an Extremely Low Material Budget Carbon Fiber Triangular Truss

The content includes:
1. Design and simulation of the carbon fiber triangular truss;
2. Development of the triangular truss: introduction to mold design and manufacturing process;
3. Static load testing of the carbon fiber triangular truss.

Speaker: Dr Xiaohui Qian (IHEP.CAS)

Triangular carbon fiber beam for CEPC-ITK-xiaohui20260604-V2.pdf

10:20 AM Coffee Break

10:40 AM Development of a material knowledge base for High Energy Physics Experiments

High Energy Physics experiments make use of advanced materials that are often used within harsh environments, having to withstand radiation levels in the order of several MGy. Several data collections and databases have been compiled in the past, with the intent to provide the community with an entry point to material test data. We will report here on the efforts within the project 2 of Work Package 2, addressing the creation of a material knowledge base using the most recent technology, with the aim of helping the community in the choice of appropriate materials for their application as well as providing an entry point to quantitative data essential in future experiments designs.

Speaker: Nicola Pacifico (CERN)

20260604_DatabaseDevelopment.pdf

20260604_DatabaseDevelopment.pptx

11:00 AM Active vibration control of detector structures

Active vibration control has potential to reduce error contributed by detector vibrations without adding significant mass to support structures.

Prototype outer-barrel staves for ePIC were used as a test-bed for an active vibration control system based on the well-known Filtered-X LMS algorithm, implemented on an FPGA. Erroneous stave oscillations, caused by the air cooling system, were measured with capacitive sensors, and appropriate antivibrations induced in the stave by an external speaker coupled to the inlet coolant flow. This proof-of-concept system demonstrated significant attenuation of first-mode stave vibrations.

The practicality of active vibration control systems for future ultra-light detector structures will also be discussed. Vibration measurement systems and antivibration actuators (if not external) must be light, radiation hard, and not interfere with sensors or readout. A number of possible implementations will be proposed.

Speaker: Finn Barber (University of Oxford)

Active vibration control of detector structures.pdf

11:20 AM Mechanical Performance of Carbon Fibre Composites After Proton Irradiation: Tensile Testing of Unidirectional and Woven Laminates

Carbon fibre is a popular choice for high performance, demanding applications. It has exceptional and customisable stiffness to weight ratios, strength to weight ratios, thermal stability, and design flexibility. However, future detector upgrades will expose these materials to increasingly high levels of radiation, therefore requiring a better understanding of radiation induced changes in mechanical performance.

Whilst historical CERN yellow pages data is available, their application to modern composite materials and detector structures is limited due to outdated material systems, incomplete material definitions, different irradiation conditions, and the lack of structural mechanical testing for modern composite laminates.

This study investigates the effect of proton irradiation on the tensile properties of two lightweight carbon composite laminates which are under consideration for use in the LHCb VELO detector. The materials evaluated are a spread tow unidirectional, and 2x2 woven laminate. The samples were manufactured with varying fibre angles to establish off-axis behaviour and matrix dominated responses.

Samples were irradiated at the CERN IRRAD facility with 1.6e16 protons (neq = 1e16). Destructive mechanical testing was done on both irradiated and on-irradiated samples to quantify changes in elastic modulus and tensile strength. Results show that elastic modulus is largely unaffected after irradiation, and reductions in tensile strength is observed, particularly for off axis fibre orientations. This indicates long chain polymer scission and embrittlement of the material post irradiation. These findings provide valuable data for the design and modelling of composite support structures in future high luminosity tracking detectors, where long term mechanical stability under radiation exposure is critical.

Speaker: Todd Slater (University of Oxford (GB))

Composite Material Qualification for Detector Mechanics.pdf

Composite Material Qualification for Detector Mechanics.pptx

11:40 AM Measuring Electrical Resistivity of the CMS TFPX Carbon Fiber Support Structures

This talk will cover recent efforts to measure the electrical resistivity of the carbon fiber composite support structures of the CMS Phase-2 Tracker Forward Pixels (TFPX). The efforts comprise a custom system built at Florida Tech as well as the use of a Quantum Design Physical Property Measurement System at the University at Buffalo. In the near term, the results will help to inform the TFPX grounding scheme. In the longer term, the setups will be used for characterization of candidate materials for the DRD8 efforts.

Speaker: Christine Angela McLean (The State University of New York SUNY (US))

202606resistivityMcLean.pdf

202606resistivityMcLean.pptx

12:00 PM Low Mass Carbon Composites with Integrated Thermal Pathways

Thermal management of particle sensors and electronics on carbon composite support structures is a critical challenge in particle detectors. This work presents a composite laminate design incorporating graphene/graphite sheets and carbon nanotube yarn to enhance thermal transport while maintaining structural performance. Integration strategies, including surface treatment and co-curing methods, are developed for compatibility with typical composite manufacturing processes. A combined analytical and finite-element modeling framework is used to create a digital twin of the structures, incorporating thermal contact resistance and effective temperature dependent material properties. The results demonstrate a scalable approach for improving heat dissipation in advanced low mass support structures, enabling more efficient thermal management for future detector applications.

Speaker: Sushrut Rajendra Karmarkar (Purdue University (US))

2026 06 04 FTDM Low Mass Carbon Composites with Integrated Thermal Pathways.pdf

2026 06 04 FTDM Low Mass Carbon Composites with Integrated Thermal Pathways.pptx

12:30 PM → 2:45 PM lunch

2:45 PM → 3:15 PM DRD8 Poster Session

3:15 PM → 7:00 PM DRD8 Session 3

Conveners: Bart Verlaat (CERN), Oscar Augusto De Aguiar Francisco (The University of Manchester (GB)), Paolo Petagna (CERN)

3:15 PM Introduction WP 3

Speakers: Bart Verlaat (CERN), Oscar Augusto De Aguiar Francisco (The University of Manchester (GB))

260605_DRD8WP3_intro.pdf

260605_DRD8WP3_intro.pptx

3:25 PM Silicon Microchannel Cooling - From Performance Characterization to Detector Applications

Cooling via micro-channels (MCC) directly embedded in silicon as the sensitive detector material has many advantages and is as such interesting for future detector applications - including photon science detectors or large-scale high-energy physics experiments.
With the start of DRD8, the established collaboration between CNM and DESY has gained new drive. In the first step, the characterization test stand at DESY was re-commissioned to analyse MCC samples on their hydrodynamic and thermal properties. Measurements on the latest design of MCCs were taken and also compared to finite-element simulations. With the knowledge and expertise gained, the next goals along the R&D line for the short-, mid- and long-term development in view of applications in real-world detector challenges will be addressed.
As such, in this contribution, we will give a status update on the MCC characterization measurements and will give an outlook for our next steps and interests in the development.

Speaker: Jan-Hendrik Arling (Deutsches Elektronen-Synchrotron (DE))

FoTDM26_MCC_DESYCNM_Arling.pdf

3:40 PM Monolithic integration of cooling microchannels in all-silicon ladders for vertex detectors

New generation of vertex detectors must have excellent thermo-mechanical stability,
and all-silicon ladders are considered as promising solutions for future detectors, such as
the forthcoming upgrade of the Belle II vertex detector in Japan. However, power
consumption asymmetries between the active area (sensor) and periphery (readout
electronics) can induce large temperature gradients within the all-silicon ladder. Air cooling
can help to reduce the overall temperature of the ladder, but in some cases a combination
of air and microchannel cooling will be required to minimize the temperature gradient and
achieve homogeneous thermal profiles.
Microchannel cooling offers a very competitive alternative to traditional cooling systems. The
very short path between the heat load and heat sink gives an increased thermal evacuation
performance, this is combined with the reduced material needed for the integrated
microchannels and the reduced Coefficient of Thermal Expansion (CTE) mismatch between
the cooling material and the sensor material to obtain a very optimized cooling for radiation
detectors. The development of the technology needed for the full integration of the sensor
with the cooling microchannels in a single piece (monolithic integration) is an ambitious
challenge, as the conditions for the microchannel formation must be compatible with the
sensor itself, requiring the optimization of the fabrication techniques to ensure the
compatibility with CMOS processes.
As a demonstrator, all-silicon ladder prototypes with integrated cooling microchannels are
presented. Power consumptions for the active area and periphery of the ladders are
emulated using aluminum heaters, taking as reference values the expected in the Belle II
detector upgrade. The bulk in the active area is thinned to 50 microns, and the design of the
microchannels cooling circuit, integrated in the periphery of the ladder, is optimized using
finite-element simulation packages. Variations of prototype ladders with two different sizes,
three microchannel dimensions, and integrated using different wafer bonding techniques are
fabricated and evaluated in this contribution to the Forum on Tracking Detector Mechanics
2026.

Speaker: Javier Fernandez-Tejero (Institut de Microelectrònica de Barcelona (IMB-CNM, CSIC) (ES))

20260604_MonolithicIntegrationMicrochannelsLadders_JavierFernandez-Tejero.pdf

3:55 PM Studies on the structural resistance of Silicon microchannels

The cooling of some silicon vertex detector, like the LHCb VELO, is based on the technology of micro-channels, directly produced in the silicon underneath the read-out modules, that are the main heat sources. With CO2 boiling coolant the sensor can be operated at temperatures, i.e. -40°C, that take the detector safe from the thermal runaway point of view.
The silicon wafer becomes a real "pressure system", to be tested at high pressure levels, i.e. 186 bar for actual CO2 cooled detectors; the possibility to use Kripton cycles, undr study, will also increase the pressure levels.
A structural analysis of the silicon is presentedto be used as a driveline in the prodction process, that could be base both on "etching technology" or on the technology of "buried channels", that we are actually pursuing for the next VELO detector upgrade

Speaker: Simone Coelli (Università degli Studi e INFN Milano (IT))

2026-06-04-DRD8-microchannel-structural-SimoneCoelli.pdf

2026-06-04-DRD8-microchannel-structural-SimoneCoelli.pptx

4:10 PM Design Strategies to Improve CO₂ Boiling Heat Transfer in Silicon Microchannel Heat Sinks

The VErtex LOcator Upgrade II (VELO U2) detector, together with several other experiments at CERN, aims to advance our understanding of high-energy physics by employing advanced custom-made sensors integrated with an optimized electronic readout system (ASICs). These components require low operating temperatures and high cooling capacity in order to maintain high measurement precision and minimize electronic noise. The combined power dissipation of the sensors and readout electronics—and therefore the required cooling capacity—is projected to be approximately 1–2 W/cm², while the target operating temperature is −25 °C or lower. These demanding conditions make the system well suited for a two-phase CO₂ boiling heat-transfer heat sink.
Two-phase flow boiling CO₂ cooling offers several advantages: (i) the high heat-transfer coefficient (HTC) associated with boiling, (ii) the low temperature of CO₂ boiling at manageable operating pressures, (iii) the relatively high heat-transfer performance of boiling CO₂ compared with many alternative coolants, and (iv) the experimentally demonstrated feasibility of CO₂ boiling heat sinks in similar high-energy physics applications.
The present research aims to advance the state of the art by building on the results previously obtained in the VELO and VELO U1 detectors. The objective is to achieve significant improvements in the HTC, reduce the superheat required for the onset of boiling, and decrease the pressure drop during CO₂ flow through the heat sink. To achieve these goals, several design improvements are proposed: (i) increasing the density of microchannels to expand the available area for convective heat transfer by approximately 30%, (ii) incorporating nucleation cavities to reduce the superheat required to initiate boiling, (iii) introducing interconnected microchannels to facilitate the propagation of boiling throughout the available heat-transfer area, and (iv) implementing fluid diodes to mitigate vapor backflow.
The incorporation of fluid diodes replaces the conventional microchannel restrictors commonly used in such systems. While restrictors introduce significant pressure losses in both downstream and upstream directions, fluid diodes primarily generate resistance in the upstream direction. This directional pressure drop is beneficial because it suppresses vapor backflow—an effect frequently observed during flow boiling in microchannels—without significantly increasing downstream pressure losses.
The preliminary results are encouraging, as the extensive experimental database available for water boiling in microchannels can be partially extrapolated to CO₂ boiling conditions. According to nucleation criterion, the characteristic size of active nucleation cavities for water boiling in microchannels at 100 °C and 1 bar is comparable to that of nucleation sites activated during CO₂ flow boiling at −30 °C and 15 bar. This similarity suggests that design principles derived from water-based studies can provide useful guidance for CO₂ microchannel heat-sink design.
In addition, preliminary optimization studies of the fluid diodes have produced promising results. For single-phase liquid flow, the measured diodicity is approximately 3. During actual operation, an even higher diodicity is expected because vapor backflows typically exhibit significantly higher velocities. These higher velocities lead to increased pressure losses in the reverse-flow direction during flow boiling, which in turn enhances the effective diodicity of the device.

Speaker: Anze Sitar

260604 Sitar Microchannel cooling Elba v3.pdf

4:25 PM Recent Developments in Microchannel Cooling and Interconnection Technologies

Within the DRD8 framework, a French IN2P3 R&D program involving several institutes (LPSC, LEGI, CPPM and LPNHE) develops and studies advanced microchannel cooling technologies for silicon detectors.

The program includes the design and fabrication of micro-channel heat exchangers in Si-Si, Si-pyrex and other materials such as ceramics. In addition, alternative carbon micro-tube heat exchangers are being explored as lightweight cooling structures, together with interconnection systems based on additive technologies in peek and ceramics.

This work focuses on recent developments in exchangers fabrication, interconnection and device characterisation in the French institutes of the project, and on pressure tests of the cooling devices and the interconnection systems.

Speaker: Bianca Raciti (Centre National de la Recherche Scientifique (FR))

2026_06_04.pdf

4:40 PM Nanofibre-Enhanced Thin Heat Pipes for Thermal Management of Silicon Pixel Detectors (HENAPIX project): Concept, Fabrication Approach and Preliminary Numerical Results

Future high-energy physics experiments require silicon tracking detectors with unprecedented spatial and timing precision while maintaining an extremely low material budget. Concepts for next-generation colliders such as the Future Circular Collider impose stringent constraints on the thermal management of vertex detectors. Advanced pixel technologies, including Monolithic Active Pixel Sensors (MAPS) and Low Gain Avalanche Detectors (LGADs), feature high channel densities and demanding front-end electronics, leading to localized power densities approaching or exceeding 1 W/cm². These heat loads are highly non-uniform, with low power density in the pixel matrix and significantly higher dissipation in peripheral readout electronics.
The HENAPIX (HEat pipe NAno Fiber PIXel detectors) concept proposes a passive cooling solution based on an ultra-thin heat pipe integrated within the silicon detector structure. The device consists of a flattened vapor chamber, a few hundred micrometers thick, containing a working fluid and a nanostructured capillary wick made of electrospun fibers with diameters of 400–800 nm. The nanofiber structure combines fluid-philic and fluid-phobic regions to control evaporation and condensation processes. Heat generated by the electronics induces local evaporation of the working fluid; vapor spreads within the chamber and condenses in colder regions, releasing heat, while capillary forces return the liquid to the evaporator region. This mechanism enables efficient heat dissipation across the detector surface without external power or fluid flow. The proposed system aims to remove heat fluxes exceeding 1 W/cm² while maintaining a low material budget. The thin structure enables integration directly on the backside of silicon sensors or in compact optoelectronic devices, potentially enabling efficient cooling with lightweight external radiators or low-velocity airflow.
The design of the heat pipe relies on high-fidelity numerical simulations combining Computational Fluid Dynamics (CFD) with Conjugate Heat Transfer (CHT) modelling. These simulations incorporate the thermophysical properties of the working fluid, phase-change processes, and the capillary characteristics of the nanofiber structure. The numerical framework is used to explore the parameter space governing system performance, including temperature gradients, vapor-pressure distribution, capillary-pumping limits, and fluid flow within the porous wick. In parallel, the morphology and physical properties of the nanofiber tissues (such as fiber diameter, porosity, and wetting behavior) are experimentally characterized and incorporated into the numerical models to achieve predictive simulations of the thermofluidic behavior of the system. Structural aspects of the device are also investigated through finite element (FEM) analyses to evaluate the mechanical deformation of the thin silicon envelope and the stresses induced by thermal gradients and internal pressure.
The conference presentation will report the current progress of the HENAPIX project. It will present experimental results on the morphology and capillary properties of the electrospun nanofibers, together with preliminary results from the coupled CFD–CHT simulations used to model the thermofluidic behavior of the heat pipe. The contribution will also include results from structural studies aimed at evaluating the mechanical response of the thin silicon envelope and its stability under operational conditions. Finally, details of the fabrication processes will be discussed. These results represent the first step toward demonstrating a nanofiber-enhanced ultra-thin heat pipe as a passive cooling solution for next-generation silicon detector technologies.

Keywords: thin heat-pipe, cooling, pixel detectors, nanomaterials, thermal management, CFD+CHT

Speaker: Alessandro Mariotti (Università & INFN Pisa (IT))

DRD8_Henapix_Ammirabile_et_al.pdf

DRD8_Henapix_Ammirabile_et_al.pptx

4:55 PM Coffee Break

5:15 PM Liquid CO2 Jet Impingement Cooling

Jet impingement is an efficient cooling method that sprays coolant directly onto the heat source. This removes the heat transfer impact of the support structure materials – including TIM – by allowing heat to pass unimpeded into the coolant. In data center and turbine blade cooling applications, jet impingement has been demonstrated to remove heat fluxes more than 300W/cm2. There is lack of literature using CO2 jet impingement, especially in the two-phase regime, which benefits from natural disruption of the vapor layer and low pressure drops. This work develops an experimental setup for simulation validation and cooling performance characterization. The setup uses a 3D printed titanium cooling manifold which can be swapped out to explore various geometries. First results from this setup in the single- and two-phase regimes will be presented. This work aims to provide engineers predictive correlations with which to design future cooling devices.

Speaker: Benjamin Edward Pulver (Purdue University)

2026-06-04 CO2 Jet Impingement Cooling.pdf

2026-06-04 CO2 Jet Impingement Cooling.pptx

5:30 PM New Members to DRD8: An Overview of Experimental Capabilities and Infrastructure at the University of Bath

As new members of DRD8 and the CMS collaboration, the University of Bath offers a broad, collaboration ready platform that spans experiment, design and computation, enabling rapid support across detector mechanics, cooling, materials, electronics and operations. At the core is IAAPS, a purpose-built research environment with configurable thermal and fluid test cells, adjacent control rooms, safe high pressure gas handling and low temperature operation. This provides both the space and the services required to host new detector cooling equipment and related infrastructure. Bath’s wider facilities include microfocus CT for internal geometry and porosity mapping, nanoindentation and profilometry for local property measurements, SEM, EBSD, EDX and in situ XRD for microstructural and residual stress analysis, together with environmental mechanical testing and bespoke rigs for qualification of thin wall tubing, joints and additively manufactured components. These assets have already supported CMS related delivery in cooling joints, mechanical assurance and production quality assurance.
Across IAAPS and the wider university, Bath maintains a versatile suite of experimental platforms capable of supporting a broad spectrum of detector relevant studies. Configurable test cells, high pressure and low temperature infrastructure, and integrated data acquisition and control systems enable precise, instrumented experimentation across mechanical, thermal, electrical and multi-physics domains. Mature electrical and sensing capabilities, including power electronics benches, signal conditioning, embedded instrumentation and high-fidelity data acquisition, support the development and testing of diagnostics, control architectures and component level subsystems relevant to detector environments. These capabilities extend beyond fluid flow studies to include structural testing, thermal management, sensor integration, electromechanical behaviour and the wider challenges associated with detector design and qualification.
On computation, Bath and IAAPS provide access to institutional high performance computing resources and Isambard AI for computational fluid dynamics, reduced order modelling, uncertainty quantification, optimisation and data workflows. Taken together, the mechanical and micromechanics capability, additive manufacture and metrology, instrumentation and controls, modelling and computing, supported by a proven operations pipeline, position Bath to contribute immediately to detector design, qualification and integration tasks. These capabilities also provide a strong foundation for building a sustained programme of shared test campaigns and tool development with DRD8 and CMS.

Speaker: Prof. Carl Sangan (University of Bath (GB))

Lunt_&_Sangan_Elba2026.pptx

5:45 PM AM4CMS – Additive Manufacture for Cooling Manifold Structures: Project Initiation

This presentation will provide an introduction to the Additive Manufacture for Cooling Manifold Structures (AM4CMS) programme, outlining the objectives and early‑stage activities which will be completed by the team for the next two years. This initiation phase will establish the experimental and modelling foundations needed to enable the next generation of additively manufactured CO₂ cooling manifolds for high‑performance thermal management systems.
The project addresses major knowledge gaps in the behaviour of two‑phase CO₂ within milli‑scale geometries, where complex interactions between phase change, flow stability, and geometry impose significant constraints on manifold design. To generate the foundational dataset required, a bespoke experimental rig will be developed and commissioned at Bath. Testing will then be performed using the capabilities of CERN’s two‑phase LUCASZ test facility, to analyse CO2 response at the low temperature and high pressures required. The work will proceed through a structured sequence of benchmark tests involving straight channels, 90° elbow geometries, and T‑junctions, providing high‑fidelity measurements of pressure drop, vapour‑quality evolution, liquid–vapour interface stability, and early‑stage dry-out behaviour.
These geometries represent the essential building blocks of more complex manifold architectures, and their systematic characterisation will underpin the development and validation of low‑order and computational models central to AM4CMS. The methodologies, datasets, and rig capability established during this initiation phase will form the technical basis for subsequent project stages and will directly support an invited EPSRC resubmission. This will be submitted in mid‑2026 and will focus on an expanded three‑PDRA, three‑year programme aimed at extending the experimental parameter space, incorporating manifold‑scale testing, and delivering a complete design and optimisation framework for advanced CO₂ cooling networks.

Speaker: Alexander Lunt (University of Bath (GB))

Lunt_&_Sangan_Elba2026.pptx

6:00 PM Warm CO2 cooling in compact geometries: sub- and supercritical regimes

Supercritical carbon dioxide (sCO2) is characterised by low viscosity and a peak in specific heat capacity near the pseudo-critical point, making it a promising fluid for electronics cooling in the temperature range 31–50°C. However, systematic heat transfer data at the millimetre scale remain scarce, limiting the applicability of existing predictive correlations. The CO2-SASS experimental setup built at CERN enables the measurement of relevant data, expanding the knowledge regarding cooling with carbon dioxide at ambient temperature in compact geometries. Further, connections between supercritical and near-critical subcritical heat transfer (>25 °C) have been previously reported in literature, but are poorly characterised experimentally.

This study will present and discuss a systematic dataset of heat transfer coefficients and pressure drops for both sCO2 and warm subcritical CO2 in a 1 mm diameter pipe across conditions relevant to future detector cooling and electronics thermal management. The dataset provides physical insight into the similarities and differences between the two regimes. In addition, representative practical application cases illustrating the use of carbon dioxide in such conditions will be presented.

Speaker: Ms Camila Pedano-Medina (CERN)

2026_06_DRD8_collaboration_meeting_pedano_sco2.pdf

2026_06_DRD8_collaboration_meeting_pedano_sco2.pptx

6:20 PM A new compressor-ejector cycle concept for detector cooling for both Krypton and CO2.

A novel cycle has been developed using an ejector driven by a compressor. This cycle gives a low quality 2-phase flow similar as the traditional 2PACL system provides. The advantage of this ejector system is that it can go lower in temperature than the liquid pumped 2PACL since there is no limitation with respect to the needed subcooling anymore. Where a 2PACL with CO2 is limited to -45°C, an ejector cycle can go as low as -55°C, and able to work close to the triple point.
The ejector cycle can work with Krypton for the ultra low temperature range (-140°C -55°C) or with CO2 for the temperature range above. The design for a Krypton or CO2 filled system is rather similar so 1 system could be used for both Krypton or CO2. Initial warm operation could be done with CO2, where a refill with Krypton could be applicable for a cold use later.
The concept design was proven in a study carried out by CERN and NTNU. The challenge for the future is the development of a good oil free compressor, A controllable ejector and the qualification for cold temperature use of typical components designed for CO2 refrigeration.

Speaker: Bart Verlaat (CERN)

NewCycle30may26.pdf

NewCycle30may26.pptx

6:40 PM Research on Krypton cooling for applications between -55°C and -140°C

Krypton has been identified as a candidate cooling fluid for the temperature range below the usable range of CO2. Krypton has a critical point of -63.7°C @ 55.3 bar and a normal boiling point of -153°C. In between this range Krypton can be used as 2-phase evaporative cooling, and above the critical point as a super critical single phase cooling. The CERN EP-DT-DC cooling group together with NTNU in Trondheim (NO) have built a Krypton demonstrator system proving the concept of Krypton in both super critical and sub critical operation. The demonstrator was built with standard CO2 refrigeration components and has demonstrated cooling performance on a typical detector cooling tube (D=2mm x L=1m) down to -82°C at 450 Watt.
Krypton is gas at room temperature, and therefore a new cycle type was developed. The new cycle is a compressor driven cycle with an ejector to obtain low quality liquid conditions needed in the detector. Krypton pressures are similar to those of CO2, this means that typical CO2 components have the potential to be used.
The demonstrator was built with a single stage compressor and was therefore limited in low temperature. A 2-stage compressor system should have the potential to go as low as -140°C and can serve detectors like Silicon Photomultipliers giving a cheaper and more efficient alternative to cryogenic LN2 cooling.

Speaker: Bart Verlaat (CERN)

Krypton3jun26.pdf

Krypton3jun26.pptx

7:00 PM → 8:00 PM Farewell event: Wine tasting

Azienda Arrighi Isola d'Elba - https://www.arrighivigneolivi.it/vinomarino/

Fri, June 5

8:30 AM → 10:30 AM DRD8 Session 4

Conveners: Corrado Gargiulo (CERN), Diego Alvarez Feito (CERN)

8:30 AM Introduction to WP4 and WP1 Project 2

Speakers: Corrado Gargiulo (CERN), Diego Alvarez Feito (CERN)

DRD8_WP1&WP4_Intro_05062026_DAF_VR2.pdf

DRD8_WP1&WP4_Intro_05062026_DAF_VR2.pptx

8:40 AM Robotic Radiation Survey and Localization Technology for The Experimental Hall

Real-time, high-precision radiation dose monitoring and environmental parameter measurement of key components within the experimental halls of high-energy particle colliders are essential for ensuring equipment safety and experimental data integrity. Conventional manual measurement methods not only face significant personnel safety risks and operational inefficiencies in high-radiation areas but also suffer from limited measurement coverage. This study explores autonomous robotic measurement solutions suitable for the complex environments of particle colliders, with particular emphasis on precise localization technologies. The research team conducted feasibility assessments of various mobile robotic platforms, including quadruped robots and unmanned aerial vehicles (UAVs), and evaluated the performance characteristics and accuracy of diverse positioning approaches, such as visual SLAM, LiDAR, Ultra-Wideband (UWB), and multi-sensor fusion strategies. Currently, the project has progressed to the procurement and integration testing phase of key localization modules, aiming to establish a robotic measurement system capable of withstanding radiation environments while meeting stringent positional accuracy requirements. Subsequent efforts will focus on experimental validation and algorithmic optimization of the localization modules, laying the technical foundation for unmanned, high-precision autonomous radiation surveying within collider facilities.

We'd like to present in the DRD8 part of the meeting.

Speaker: Haoyu Shi (Chinese Academy of Sciences (CN))

Robits_DRD8_20260605.pptx

9:00 AM Mobile Mesh Networks

Remote inspection of underground infrastructure at CERN increasingly relies on mobile robotic systems to reduce human exposure to hazardous environments and improve operational efficiency. These environments, including detector caverns and accelerator tunnels, present significant challenges for wireless communication due to their complex geometry, confined spaces, and the presence of large metallic structures. Although the CERN Wi-Fi infrastructure provides widespread coverage, signal attenuation caused by distance, multipath effects, and physical obstructions can result in partial or complete communication loss.
Since the CERN Wi-Fi network constitutes the primary interface for teleoperation and data exchange with remote operators, maintaining connectivity is critical. However, robots operating beyond reliable coverage areas risk communication blackouts, potentially compromising mission success and system safety. To address this limitation, a mobile robotic mesh network is proposed. In this architecture, a designated “leader” robot functions as a communication gateway, maintaining a stable link to the CERN Wi-Fi network, while “follower” robots form an ad hoc multi-hop network that extends connectivity into otherwise unreachable regions.
This work presents the current development status of the proposed mobile mesh network, with particular emphasis on the communication protocols and network topology strategies adopted to ensure robustness and low-latency data exchange for real-time operation. Additionally, future developments are outlined, including the integration of network fail-safe mechanisms, autonomous navigation, obstacle avoidance, and distributed swarm intelligence to enhance network reliability and operational autonomy.

Speaker: Paolo Francesco Scaramuzzino

20260605_DRD8_CollaborationMeetingElba_Scaramuzzino.pptx

9:20 AM Adaptive Robotic Intelligence for the Sustainable Lifecycle and Automated Decommissioning of Future Tracking Systems

The development of next-generation tracking detectors comprises challenges in mechanical integration, high-density service routing, and long-term maintenance. As these systems become more complex and are deployed in constrained, high-radiation environments, traditional manual intervention reaches its limit.

di.monta introduces a novel approach to detector lifecycle management through robust, adaptive and AI-enhanced robotic automation. With our platform, we address the key objectives of DRD8 Work Package 1 (Global System Design and Integration), and specifically supporting Project 1.2 (Robotics in the HEP Experimental Caverns).

By utilizing our robot-agnostic orchestration di.core, we provide robotic units with our modular di.skills. Our di.skills range from high-precision detection of various components, over loosening complex mechanical connections like fasteners and connectors, to deriving adaptive task plans. Our solution is explicitly designed to handle the variable states we face in HEP experiments. For example, we enable automated decommissioning by safe, fast and precise dismantling of detectors to facilitate the circular economy through component reuse and high-purity recycling.

With the integration of our adaptive robotics, we propose a shift towards sustainable HEP engineering, where automated dismantling is considered from the initial design phase to ensure the efficient decommissioning of future collider experiments.

Speaker: Carolin Benjamins (RWTH Aachen)

2026-06-05_benjamins_1_dimonta_drd8.pdf

2026-06-05_benjamins_1_dimonta_drd8.pptx

9:40 AM Learning from Demonstration for Robotic Disassembly

The disassembly of complex technical systems is still predominantly performed manually, as the required process knowledge—such as action sequences, grasping positions, and handling strategies—is difficult to formalize and implement. Observing human workers during task execution offers a promising approach to automatically extract this knowledge. This is particularly relevant in domains such as the disassembly of patch panels on detector interfaces in the CMS experiment, where each sub-detector contains 20 to 30 panels and around ten sub-detectors must be handled. Learning from a limited number of human demonstrations can therefore enable the replication of such processes by robotic systems.

This work presents part of a Learning from Demonstration (LfD) framework which aims to transfer process knowledge from human workers to robotic systems, enabling non-experts to teach robots disassembly tasks. For this purpose, a markerless Optical Motion Capture (OMC) pipeline is developed to extract skeletal hand tracking data in real-time. This data is processed by a Recurrent Neural Network (RNN) to identify and parameterize the operations performed by the worker. It is shown that a virtual scene representation, including object poses, can be dynamically maintained solely based on hand motion. Furthermore, the results indicate that hand joint angles can be used to infer the type of object being grasped. Future work will leverage the extracted information to generate flexible task plans and enable robotic systems to autonomously replicate demonstrated disassembly processes.

Speaker: Carolin Benjamins (RWTH Aachen)

2026-06-05_benjamins_2_LfD_DRD8Forum.pdf

2026-06-05_benjamins_2_LfD_DRD8Forum.pptx

10:00 AM Looking ahead

Feedback from recent DRD Managers Forum Meetings

Speaker: Burkhard Schmidt (CERN)

4th DRD Collaboration Meeting – Looking ahead.pdf

4th DRD Collaboration Meeting – Looking ahead.pptx

10:20 AM Farewell

Speaker: Fabrizio Palla

farewell Elba.pptx

10:30 AM → 12:00 PM DRD8 Collaboration Board

Indico Link for CB meeting

10:30 AM Indico Link to the agenda

https://indico.cern.ch/event/1692244/

12:00 PM → 1:00 PM lunch

1:00 PM → 1:20 PM Bus departure to Roma FCO airport