Forum on Tracking Detector Mechanics 2015

15 Jun 2015, 08:00 → 17 Jun 2015, 18:00 Europe/Amsterdam

Z011 (Nikhef, Amsterdam)

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

Topics include

• Detector cooling
• Deflection, stability and precision of the structures, achieved and revisited requirements for the next generation
• Thermal expansion differences inside the detector
• Mass and therefore radiation length of mechanics, cables and pipes
• Humidity control, including gas flushing inside detector volume and along services
• Structural issues concerning humidity or outgassing
• Choices of construction materials
• Rails for support and guidance
• Alignment systems, requirements and "weak modes" of the system, in-situ adjustments, sensors including load sensors
• Pipe materials, pipe connection techniques and fittings
• Shock and vibration issues such as bond wire vibration during transport and in operation
• Effects on mechanics during fast discharge of magnet coils
• Tracker to beam-pipe interfaces and bakeout scenarios
• Failure management: What do we do to achieve a tracker with maximum duty cycle
• Service management: What strategies do we have to deal with services? How can we minimise installation and testing times?
• Radiation and mechanics: A discussion about the impacts of radiation on the design, materials and also issues like access constraints
• Maintenance scenarios and the required special tooling
• FEA and its comparison to real objects

Monday 15 June

1 Welcome by the organizers

2 Welcome at NIKHEF

Speaker: Frank Linde (NIKHEF (NL))

3 Requirements and Specifications for metal cooling tubes for evaporative CO2 cooling

As part of our R&D on cooling tubes for the barrel strip system of the ATLAS phase II tracker upgrade we have identified requirements and specifications for these tubes. One of the most important of these is the understanding of the pressure requirements. For this definitions and the subsequent calculations of required wall thickness by design by formula (DBF) we follow EN and ASME standards, as much as they are applicable. Because of the special constraints the cooling tube will be subjected to within the local support staves we have backed up these calculations by FEA studies of the stresses in the tubes (design by analysis - DBA). We have a preference for metallic tubes and our R&D has focused on stainless steel and titanium, and we will present the calculations for these materials, but the approach can easily be generalized. In this presentation we will list all requirements and their inputs under special consideration of the relevant parts of the EN and ASME standards.

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

Draft document Cooling_tube_report_-_requirements_and_specifications_v2.3.docx Cooling_tube_report_-_requirements_and_specifications_v2.3.pdf

Slides Cooling_tubes_–_Requirements_and_Specifications.pdf Cooling_tubes_–_Requirements_and_Specifications.pptx

4 Vacuum flex lines design, production, qualification and tests for the ATLAS IBL CO2 cooling system

The Insertable B-Layer (IBL) is the innermost layer of the ATLAS pixel detector; it has been installed on a new beam pipe with reduced diameter and successfully inserted in the Inner Detector (ID) volume. The IBL is a fundamental detector to improve the vertex reconstruction and to provide an additional tracking layer in case of failure or radiation damage in the other three layers of the Pixel Detector of ATLAS. To extract the 1.5 kW power dissipated by its on-detector electronics, the IBL is equipped with an evaporative CO2 cooling system based on a 2-PACL (2-Phase Accumulator Controlled Loop) cooling concept. The cooling plant is connected to the IBL thanks to a long vacuum transfer line of about 90 m that reaches the Muon sector 5 of ATLAS where a junction box, provided with a dummy load and a distribution manifold, are installed. From the manifold box the fluid is distributed to the detector thanks to 14 vacuum flex lines. Vacuum is a very effective thermal insulation system and in cryogenic installation vacuum is quite commonly used to reduce the heat transfer by convection. In our case this choice was fundamental in order to transfer the coolant through a volume in which the dew point is just a few degrees below the ambient temperature and the humidity level could become a serious problem. The 11 meter long stainless steel flex lines are constituted of 3 concentric pipes: starting from the smaller we find the inlet liquid capillary (ø 1.6x0.3 mm), the outlet gas pipe (ø 4x0.5mm) and the vacuum hose (ø 17.2mm). They are made of commercial and customized components. The flex lines concept was mechanically and thermally tested in the laboratory by bending the lines to check if and how this may affect the mechanical stability and thermal insulation. The design criteria were mainly driven by the results of these tests and on the assembly sequence of the parts. The construction of the flex lines was done according to a precise sequence of operations and quality checks; it took about 12 weeks starting from the orbital welding parameters optimization to the final flow tests. The quality criteria were very carefully defined to guarantee the reliability of the lines given that each one cools 7 % of the IBL. This paper is about the concept design, production and qualification of the 14 vacuum concentric flex lines that were successfully installed and are now fully operational. We will present the details of the mechanical assembly process, the solutions we adopted, the tooling preparation and the qualification tests that were carried out in order to guarantee the best performance and long term stability.

Speaker: Claudio Bortolin (CERN)

Slides ForumNikhef2015.pdf ForumNikhef2015.pptx

12:30 Lunch

5 Mass flow rate measurements for CO2 cooling systems: methods and results

In CO2 evaporative detector cooling systems, the measurement of the mass flow rate is not always trivial. Not many instruments can be used in magnetic field or radiation environment and few of them can measure CO2 in two phase. After a brief review of the existing measurement techniques reported in literature, the presentation highlights the experience gained so far at CERN with a few mass flow meter models available on the market or designed by the team. Three measuring principles are investigated: Coriolis, thermal and differential pressure. Data on the use of the three types are shown and compared in order to suggest the best possible instrument for the various application cases.

Speaker: Jerome Daguin (CERN)

Slides 150615_DJ_FLOW_MEASUREMENT.pdf

6 Micro-channel cooling for high precision vertex detectors: status and perspectives

For future Vertex detectors, where the requirements on material budget minimization and performance optimization will push at the limit the design and technology choices, thermal management solutions based on ultra-thin micro-channel heat exchangers are being envisaged. The NA62 GTK detector, launched in operation at the end of 2104 has demonstrated for the first time the practical feasibility of the direct cooling of a pixel detector module by a micro-fabricated silicon device circulating single-phase liquid refrigerant. The very advanced studies in preparation of the “phase-I” upgrade of the LHCb VELO detector (detailed in a separate presentation) suggest that the thermo-physical characteristics of CO2 are very favourable for its use in connection with evaporative flow in micro-channel devices. On the other hand, a recently presented study on a possible application of this technology to the upgrade of the ALICE ITS detector provided the first demonstration of two devices hydraulically interconnected through an integrated micro-fluidic distribution line, allowing for controlled evaporation of C4F10 in both micro-devices. Starting from these achievements, the presentation will review the latest technical progresses and the open issues to be addressed in view of the challenges posed by the next generation of detectors. Different lines of investigations will be discussed, in particular in view of the 4-years networking activity to be soon launched in the context of the recently approved AIDA-2020 programme; and different options will be examined from a detector engineering point of view. Finally, some preliminary ideas will be presented for long-term developments, requiring a level of technology not available today for operational implementation, yet ready for interesting early feasibility studies.

Speaker: Paolo Petagna (CERN)

Slides

• Boiling_9W_inlet_20150424_Reduced.wmv
• P.PetagnaFORUM_TK_MEC_2015-LIGHT.pdf
• P.PetagnaFORUM_TK_MEC_2015-LIGHT.pptx
• P.PetagnaFORUM_TK_MEC_2015.pdf
• P.PetagnaFORUM_TK_MEC_2015.pptx
• P.PetagnaFORUM_TK_MEC_2015.pptx

7 Progress on the LHCb VELO microchannel cooling

The LHCb Vertex Detector (VELO) will be upgraded in 2019 to a lightweight, pixel detector capable of 40 MHz readout and operation in very close proximity to the LHC beams. The thermal management of the vacuum-resident system will be provided by bi-phase CO2 circulating in micro channels embedded within thin silicon substrates onto which active elements are placed. This solution has been selected due to the excellent thermal efficiency, the absence of thermal expansion mismatch with silicon ASICs, the radiation hardness of CO2, and very low contribution to the material budget. The R&D effort for LHCb is focusing on the design and layout of the channels together with a fluidic connector and its attachment which must withstand pressures in excess of 200 bars. Even distribution of the coolant is ensured by means of the use of restrictions implemented before the entrance to a race-track layout of the main cooling channels. In this talk,a characterisation of a realistic microchannel prototype will be presented and compared to simulation. The design of a suitable fluidic connector, together with the vacuum soldering technique will be described.

Speaker: Pawel Jalocha (University of Oxford (GB))

Slides PawelJalocha_Nikhef_15jun2014.pptx

15:45 Coffee

8 Endcap mechanics and cooling for the CMS tracker upgrade

The extreme pile-up conditions expected in the CMS detector during operation in the High Luminosity LHC (HL-LHC) necessitate the replacement of the entire tracking system during long shutdown 3 (LS3). New silicon modules with higher radiation tolerance and enhanced functionality will be installed. To further improve radiation resistance, the tracker will be operated at a lower temperature (-20°C) with respect to the current detector. In addition, it is highly desirable that the overall mass of the tracker be reduced. Progress towards achieving these aims for the endcap region of the outer tracker will be presented. To reduce mass, the silicon modules will be attached directly to the endcap disks, rather than to intermediate structures (‘petals’) as in the current endcaps. Individual lightweight conductors will replace relatively heavy printed circuit boards. Furthermore, cooling of the modules will be achieved using two-phase CO2, a low-density fluid which allows the use of small diameter pipework. The status of the endcap mechanics, including disk design, module layout, services routing and cooling, will be presented, together with results from initial prototyping of the disk mechanics and cooling circuits.

Speaker: Nick Lumb (Universite Claude Bernard-Lyon I (FR))

Slides Lumb_Nikhef_mechanics_forum_150615.pdf Lumb_Nikhef_mechanics_forum_150615.pptx

9 The SLIM proposal for the ATLAS ITK pixel barrel

The Pixel ITK mechanics after having defined the engineering requirements is now considering new options for module and service local support for the barrel region. While targeting for a material budget as low as possible and a layout that ensures the perfect hermeticity, the module have to be able to safely operate with respect to the thermal run away effect in the silicon sensor whatever technology is considered. The SLIM (Stiff Longeron for ITK Modules) concept is a novel approach that tries to combine interesting features that was proposed so far. The SLIM concept is based on a layout that allows a silicon surface optimization using barrel sensor orientation combined with tilted modules with respect to eta. It is also proposed to combine a modular approach on a self-supported structures designed for thermo-mechanical performances. It will be showed that the material budget which is one of the key parameters can be optimized and scaled according to the thermal requirements while not degrading the tracking performances and the mechanical stability. This talk will presents and describes the engineering solutions chosen and the performances achieved.

Speaker: Sebastien Michal (Universite de Geneve (CH))

Slides 2015_06(JUNE)_15_SLIM_FORUM.pdf 2015_06(JUNE)_15_SLIM_FORUM.pptx

10 LHCb SciFi Detector and Read-out box

The upgrade of the complete LHCb detector will extend the physics reach of the experiment, by allowing it to run at higher luminosity with increased trigger efficiency. The tracking system behind the magnet will be replaced by a new Scintillating Fibre Tracker (SciFi), a modular array of 5 m long layers of scintillating fibers, consisting of six densely packed layers of round fibers with a diameter of 250 µm. The fibers will be read out by Silicon Photomultipliers (SiPMs) housed in the so-called “Read-out Boxes” at the top and bottom of each fiber module. We will present a summary of the main SciFi design choices, and discuss in detail the specific challenges posed by the design of the Read-out Boxes (where fiber modules, photon detectors and on-detector readout electronics are integrated) stemming from thermal expansion and contraction (different CTE’s in combination with ∆T’s of 90°C), condensation and frost prevention, and high positioning accuracies.

Speaker: Rob Walet (N)

Slides 2015-06_TFDM_SciFi_rev06.pdf

18:30 Reception

Tuesday 16 June

11 Advanced Materials and Tools Research at Berkeley

Over the past two years a variety of topics in advanced materials and tools for instrumentation have been under study at LBNL. This talk will present results on thermally enhanced polymers and laminates, low mass foams, air cooling, and precision metrology for inspection and defect location. A broad survey of filler materials has been conducted, a protocol for thermal measurement developed, and outstanding performance has been observed for certain additives. Practical application in laminates has been studied. Carbon foams with low density and high conductivity have been known for some time. A new hollow ligand foam has been studied and evaluated for an air flow cooling application. Precision microscopy using line scan cameras and confocal scanners has been applied to a variety of 2D and 3D inspection applications.

Speaker: Eric Anderssen (Lawrence Berkeley National Lab. (US))

Slides 2015-06-16_Mech_Forum_Anderssen_Haber.pdf 2015-06-16_Mech_Forum_Anderssen_Haber.pptx

12 Mechanics and Cooling for the LHCb Upstream Tracker Detector

The LHCb Detector will undergo an upgrade during the LHC shutdown in 2019. The UT (Upgrade Tracker) is a silicon strip tracking detector being designed and constructed as part of this upgrade. The UT will provide a fast momentum measurement for the trigger as well as function as part of the overall tracking system where it will severely reduce the presence of “ghost” tracks. The UT Tracker consists of ~10x10 cm2 silicon strip sensors, with custom ASIC readout chips (SALT) arranged as modules containing flex circuits and ceramic substrates. These modules are to be mounted on staves, lightweight CFRP and foam sandwich structure supports with integrated CO2 cooling. The cooling tube follows a snake-shaped routing which allows the tube to run under all the ASICs and provide efficient cooling. Construction is planned to start this year. The design details of the UT Tracker staves and modules will be presented, including prototype results, mechanical component tests, thermo-mechanical simulations, and other R&D activities.

Speaker: Burkhard Schmidt (CERN)

Slides LHCb_UT_UPSTREAM_TRACKER_-_Forum_2015v4.pdf LHCb_UT_UPSTREAM_TRACKER_-_Forum_2015v4.pptx

10:30 Coffee

13 The vacuum envelope of the upgraded LHCb VELO detector

The LHCb vertex detector (VELO) is shielded from the LHC beam by a thin envelope called the RF box. Tight constraints on maximum thickness, vacuum tightness, conductivity and rigidity make the construction of the RF box a challenge. We discuss progress in the construction of the RF box for the upgraded VELO detector, which is planned for installation in 2018.

Speaker: Wouter Hulsbergen (Nikhef National institute for subatomic physics (NL))

Slides FTDM2015_hulsbergen.pdf FTDM2015_hulsbergen.pptx

14 CMS FPIX Phase I Progress

A new forward pixel detector for the CMS experiment is currently under construction, for installation during the extended year end shutdown 2016/2017. I am reporting on the latest developments in mechanics and cryogenics, and progress with construction.

Speaker: Stefan Gruenendahl (Fermi National Accelerator Lab. (US))

Slides FPIX_Mechanics_June2015.pdf FPIX_Mechanics_June2015.pptx

12:30 Lunch

15 Tour

16 Advanced Engineering Plastics in High-Tech applications – material selection guidelines

High tech applications mostly demand high-tech materials. As engineering plastics have evolved over time, they have become a great alternative to traditional materials such as metals in many applications. However each polymer has its specific advantages & limitations, and the use of fillers can even more influence the specific properties. During this presentation, I would like to provide technical-oriented & straightforward steps in the material selection of Advanced Engineering Plastics. Topics covered are wear resistance, temperature effects, dimensional stability, X-ray radiation transparency, radiation resistance (UV & Gamma), radiation shielding (neutrons only), outgassing in high vacuum, ESD properties, bonding and machine-ability / possible tolerances.

Speaker: Mr Michiel de Schipper (Quadrant Engineering Plastics Products)

Slides Quadrant_Plastics_presentation_to_Nikhef_and_CERN_-_Advanced_Engineering_Plastics_in_high-tech_applications.pdf

17 Material Challenges for Metallic 3D-Printed Parts

Additive manufacturing of metals offers great opportunities for the aerospace and high-tech industry, however it also faces serious challenges. Some of these challenges lie in the field of material science and quality control. This presentation gives an overview of the state of the technique, current applications in aerospace and the challenges that are being tackled in the Netherlands.

Speaker: Mr Emiel Amsterdam (National Aerospace Laboratory (NLR))

Slides NLR-Forum-Tracking-Detector-Mech.pdf

16:00 Coffee

18 Module Designs and Assembly for CMS Tracker Phase 2 Upgrade

PS (Pixel-Strip) modules and 2S (Strip-Strip) modules will be the detection devices used for the future phase 2 upgrade of the CMS Tracker. 7084 PS modules and 8424 2S modules would be integrated on different parts of the detector (TBPS, TB2S, Endcap Double-Disc) for more than 218 m² of active silicon sensor surface. Both modules are designed to be as light as possible to ensure minimal impact on tracking from the material budget. However, the modules must also have sufficient strength, a high mechanical precision, and efficient heat removal to support/cooling structures and thus materials such as carbon-fibre/polymer and aluminium/carbon-fibre composites are being employed. The assembly of the modules must at the same time allow for high throughput as well as mechanical precision (especially the silicon sensors) and thus tooling and assembly procedures must be well conceived. The presentation summarizes the current status of the module designs and also describes some of the prototype jigs needed to build them.

Speaker: Pierre Rose (Ministere des affaires etrangeres et europeennes (FR))

Slides Status_of_the_Module_Designs_Forum_Amsterdam.pdf Status_of_the_Module_Designs_Forum_Amsterdam.pptx

19 Double-Sided Metrology of Strip-Modules for the CMS Phase2-Upgrade

For the Phase2-Upgrade of the CMS Silicon Tracker new double-sided modules are foreseen, providing track information to the first trigger stage of CMS. Hence two strip sensors, positioned on top of each other at a small distance (~3 mm), will be part of a single module, allowing for a combined readout using a single front-end-chip. From the correlation between hits in both layers within one front-end, tracks can be filtered on their transverse momentum for the first trigger stage (min. 2 GeV). In this schema, the relative sensor-to-sensor alignment within one module plays a crucial role, since for the first trigger stage it cannot be corrected using software alignment techniques. Therefore all modules will be required to fulfil rigorous quality criteria. To verify the assembly accuracy, especially the relative sensor placement, it is required to relate measurements from the opposite sides of the module with high accuracy to each other. In absence of a commercially available solution, a prototype for a double-sided metrology machine has been developed at RWTH Aachen University. Apart from the general measurement method, results on achieved accuracies will be presented, as well as the ongoing work on a full scale double-sided metrology set-up. Furthermore the potential usage during the module production will be discussed, in conjunction with possible module assembly strategies.

Speaker: Marius Preuten (Rheinisch-Westfaelische Tech. Hoch. (DE))

Slides 2015-06-16_mpreuten_double-sided-metrology.pdf

20 CMS Phase 2 silicon pixel-strip thermal mock-up module - building and testing

The talk will discuss the thermal tests of a CMS Phase 2 prototype pixel-strip module carried out at Fermilab. The prototype is based on the common design and assembled using the same raw materials as foreseen for the production module. A rod support structure was also built to carry the prototype and provide a realistic cooling scheme via the CO2 test stand at Fermilab. Data results at various heat loads will be discussed and compared with simulations.

Speaker: Andreas Jung (Fermi National Accelerator Lab. (US))

Slides Nikhef_TaM_CMS_ajung_2015.pdf

20:00 Meeting dinner

Wednesday 17 June

21 The MVD of the CBM experiment at FAIR: Selected Aspects of Mechanical Integration

The Compressed Baryonic Matter experiment (CBM) at the future FAIR facility at Darmstadt (Germany) explores the phase diagram of strongly interacting matter in the regime of highest net baryon densities with numerous probes, among them open charm. Open charm reconstruction requires a vacuum compatible Micro-Vertex Detector (MVD) with unprecedented properties, arranged in (up to) four planar detector stations in close vicinity of the (fixed) target. The CBM-MVD requires sensors featuring a spatial resolution of < 5 µm, a non-ionizing radiation tolerance of > $10^{13}$ n$_{\text{eq}}$/cm², an ionizing radiation tolerance of 3 Mrad, a readout speed of few 10 s/frame, and the integration in detector planes with several per mille X0 material budget only. In the pre-production phase we are constructing the precursor of the second MVD station. The project addresses a double-sided integration of 15 MIMOSA-26 sensors onto a 8x8 cm² CVD diamond carrier featuring a thickness of 150 µm. The sensors are arranged in ladders composed of 3 sensors each This contribution summarizes the activities undertaken to construct a precursor of a quadrant of the second MVD station, in particular: - Vacuum-compatible gluing procedures - Positioning of ultra-thin sensors using dedicated jigs - Development of low material budget, copper-based flex-print cables - Thermal management studies in vacuum - Sensor commissioning and bonding

Speaker: Tobias Hubertus Tischler

Slides Tischler_MVD_of_the_CBM_experiment_selected_aspects_of_mechanical_integration.pdf

22 Ultra-Light Weight Mechanics and Cooling of the Mu3e Experiment

The Mu3e collaboration is setting up an experiment to study the decay of a muon into three electrons μ+→e+e-e+ . Any observation of this decay with the Mu3e experiment would point to physical processes so far not described in the standard model, mediated by the exchange of very heavy particles. The Mu3e Experiment is a combination of three detector technologies. The main part is a High Voltage – Monolithic Active Pixel Sensor (HV-MAPS) Tracker combined with a Fiber Tracker and a Tile Detector. The Experiment is sub segmented into five stations. A main requirement is to reach a very low material budget (of 0.1% X/X0 per layer). Therefore the mechanics use an ultra-light weight support structure to fulfill this requirement. A folded 25 µm thick KaptonTM foil is used as a base support structure for the silicon chips. At the ends segmented support rings made out PEI give further stability to the system and serve in addition as a distribution for the gaseous Helium cooling. In this talk an overview of the extensive R&D concerning choice of materials and their mechanical properties as well as the development of the He-cooling will be presented. Summary

Speaker: Bernd Stefan Windelband (Ruprecht-Karls-Universitaet Heidelberg (DE))

Slides Ultra-lightweight_mechanics_and_cooling_of_the_Mu3e_Experiment.pdf

10:30 Coffee

23 The ultralight mechanics and cooling system of a DEPFET-based pixel detector for future colliders

The DEPFET Collaboration develops highly granular, ultra-thin active pixel detectors for high-performance vertex reconstruction at future e+e- collider experiments. A fully engineered vertex detector design, including all the necessary supports and services and a novel ladder design with excellent thermo-mechanical properties, is being developed for the Belle II experiment. The self-supporting all-silicon ladder combined with the low power density of the DEPFET array and a cooling strategy that relies on forced convection of cold air to cool the active area allow for a very thin detector (0.2% X0). In the contribution, a detailed description of the full engineering system will be explained, including the latest finite-element simulations as well as thermal mockup measurements. In addition, a novel cooling concept based on wafer integrated micro-mechanized channel cooling and a low mass petal solution for the forward region of the ILC detector concepts will be presented.

Speaker: Ignacio Garcia (IFIC)

Slides Forum_tracking_Amsterdam_IGG.pdf

24 Thermal mock-up studies for the Belle II vertex detector

The cooling system of the BelleII vertex detector is based on the 2-phase accumulator controlled loop method with CO2 as the coolant. The DESY group is in charge of building a thermal mock-up in order to study and optimize the cooling system. This talk shows the design for this thermal mock-up and some results for the preliminary measurements.

Speaker: Hua Ye

Slides ThermalMockup_Forum15_NIKHEF_201506_HY.pdf

12:30 Lunch

25 Understanding the deformation issue of the ATLAS IBL detector

The ATLAS cosmics run over the last month has revealed a stability issue in the mechanics of IBL detector. In particular a global and coherent rotation of the Z=0 detector cross section has been observed analyzing the alignment parameters of the muon tracks. Such instability affects the overall tracking performances. Understanding the causes of the deformation allows to set operation conditions meant to mitigate the deformation and reestablish the nominal detector performances. The talk collects the experimental evidences of the distortion and provides the mechanical explanation.

Speaker: Danilo Giugni (Università degli Studi e INFN Milano (IT))

Slides 2015-06-17_Understanding_the_deformation_issue_of_the_ATLAS_IBL_detector.pptx

26 Radiation tolerant fiber optic sensors for long-term humidity monitoring in the CMS experiment

Relative humidity (RH) monitoring has a significant impact in various application fields and many sensing schemes and solutions have been proposed according to the specific applications. Here we concentrate our attention on the use of RH fiber optic sensors (FOS) recently developed for application in the CMS experiment. Any humidity sensor to be introduced in the volume of a Tracking detector should comply with many requirements in terms of radiation resistance (required up to 1 MGy for regions close to the Interaction Point), insensitivity to strong magnetic field, small dimensions and low mass, operation at very low temperatures, reliable readings across long distances and reduced number of wires for operation. In this scenario, FOS-based thermo-hygrometers appear as a good alternative to the conventional instruments. Indeed, the fiber itself, if properly selected, can tolerate a very high level of radiation, optical fiber transmission is insensitive to magnetic field and electromagnetic noise and perfectly suited for read-out over very long distances. After a few years of development, 72 FOS thermo-hygrometers, based on polyimide-coated Fiber Bragg Gratings (FBG) organized in multi-sensors arrays, have been installed in CMS in December 2013 and are currently providing constant monitoring of temperature and RH. However, experience in operation has shown some limitations of the polyimide coated FBG sensors which will be thoroughly discussed An alternative to overcome the FBGs’ limitations, might come from an innovative class of RH-FOS, based on high-sensitivity titanium dioxide coated Long Period Grating (LPG). Preliminary results obtained on samples produced in-house are very encouraging. In this contribution we present results from the first application of FBG thermo-hygrometers in CMS and we discuss the status of the R&D on the new generation of LPG sensors.

Speaker: Gaia Maria Berruti (Universita del Sannio (IT))

Slides ForumOnTrackingDetector_nickef.pdf ForumOnTrackingDetector_nickef.pptx

27 X0 : CAD estimation material

Obtaining accurate and quick estimates of the amount of material represented by a detector is essential in the design phase, especially for tracking detectors. It allows the designers to have a quick feed-back of the effect of the design choices on important aspects of the physics performance. The best available information on the detector geometry is the 3D CAD mockup. We will show through several examples (IBL, ITK, ID services, and also LArg calorimeter) how the 3D CAD mockup can be used efficiently to produce this information under Catia , by using a Visual basic macro able to access the geometrical information inside Catia. The presentation will cover the internal logic of the macro, the preparation of the CAD mockup for adequate analysis. Results obtained will be shown and discussed, including limitations on amount of information that can be extracted.

Speaker: Didier Laporte (Centre National de la Recherche Scientifique (FR))

Slides 2015_06_17_CAD_X0_estimation.pdf

28 Developments for future tracking systems based on Medipix based read-out chips

The developments within the Medipix collaboration on hybrid pixel detectors for many applications outside the world of high energy physics over the last decade have led to interesting design features that are now being considered or even applied in tracking systems for ATLAS and LHCb. Especially, the development of chips with timing capabilities such as Timepix3 has triggered this return to high energy physics. The Timepix3 chip can be applied for gaseous tracking systems in e.g. ATLAS, while a descendent of the Timepix3 chip, the Velopix chip is being designed for the upgrade of the LHCb vertex detector. In this contribution, the next generation is contemplated. What are the requirements we want to aim for and how do we deal with the possibilities new technologies like 3D integration offer us and the implications of increasing complexity such as the increase of power density and the necessary cooling?

Speaker: Jan Visser (Nikhef National institute for subatomic physics (NL))

Slides Jan_Visser_Medipix.pdf

29 Closeout