CM Lei Simon Kwan. Fermilab. Simon Kwan - Fermilab CMS Tracker Upgrade Workshop Sept 2,

Transcription

1 FPIX Experience on TPG CM Lei Simon Kwan Fermilab Simon Kwan - Fermilab CMS Tracker Upgrade Workshop Sept 2,

2 Phase 1 FPIX Disk layout requirements 1. Fits within Phase 1 FPIX envelope definition 2. Modules oriented radially (requires only 2x8 modules, and slightly improves resolution compared to the layout of the current detector) 3. Locates all outer radius sensors as far forward and out in radius as possible (to minimize the gap in 4-hit coverage between the end of the 4th-barrel layer and the forward-most disk) 4. Maximize 4-hit coverage between end of 4th layer barrel up to eta = 2.5, for particles originating at the IP +/-5cm, using a minimum number of modules 5. Keep the same 20 degree tilt as the current detector 6. Individual modules and/or module-support substrates removable and replaceable without disassembling other modules on the disks 7. Identical substrates (blades are the same) 8. Minimizes the amount of material required for cooling and module support (assuming cooling using CO 2 ) 9. (Highly desirable) Delta T < 5C across a single module 10. (Desirable) Separate inner from outer rings for easier replacement of blades on the inner ring (with earlier radiation damaged modules). Simon Kwan - Fermilab CMS Tracker Upgrade Workshop Sept 2,

3 The Edge Cooling Concept -- capture the cooling tube inside the ring. CM Lei (Mech Eng) with input from SK, Arndt One piece ring made of CC Ss tubing Machined groove to house tubing Cooling tube: simple to fabricate and less temperature difference from inlet to outlet Cf skin to enclose the tubing Simon Kwan - Fermilab CMS Tracker Upgrade Workshop Sept 2,

4 Material Candidates for Substrate Material Density Modulus, E_ab Modulus, E_c Strength Thermal K_ab Thermal K_c cte_ab cte_c Rad L, X0 g/cc Gpa Gpa Mpa W/m-K W/m-K ppm/k ppm/k cm Porous Materials fuzzy C, 5% pr carbon foam, low density SiC foam, 8% packing ratio RVC foam (vitreous C) carbon foam, medium density carbon foam, high density poco-foam, 25% pr rohacell Solid Non-metalic Materials pyrolitic graphite, PGS peek CoolPoly E5101 (PPS) CFRP (M46J-epoxy) glassy C CFRP (K13C2U-epoxy) CFRP (K139-EX1515) Poco graphite ACF-10Q C-C composite (carbon fiber/carbon matrix) SiC G10 (glass fiber/epoxy) pyrolitic graphite, TPG * * Alumina Silicate Vespel SP1 Polyimide CVD Diamond DLC (diamond-like carbon) coating Solid Metalic Be AlBeMet BeO Aluminum Nitride (AIN) silicon aluminum 6061-T stainless steel copper Simon Kwan - Fermilab CMS Tracker Upgrade Workshop Sept 2,

5 Thermal Pyrolytic Graphite (TPG) A unique form of pyrolytic graphite Made by the decomposition of a hydrocarbon gas within vacuum furnace High thermal conductivity (in-plane k = up to 1700 W/m-K, out-of-plane k = 10W/m-K at room temperature) Low CTE (in-plane = -1 ppm/c, out-of-plane = 25 ppm/c) Low density = 2.26 g/cc X0 = 18.9 cm (X0*k = 321 W/K vs 51 W/K of Be) Friable, needs encapsulation; carbon fiber composite is chosen for needed rigidity within material budget constraint. Extensive studies performed by BTeV from Also used by ATLAS (strips) and LHCb. Vendors: Momentive Performance Materials ( Quote: TPG0044 TPG.38MM THKx90mmx150mm LG.38MM +/-.03mm 20-50pc's ea. MiNTEQ ( Simon Kwan - Fermilab CMS Tracker Upgrade Workshop Sept 2,

6 TPG Experience at FermiLab TPG was proposed to use for BTeV pixel detector at Fermilab in We got the idea from ATLAS SCT which used TPG in their barrel and end cap. TPG attached to LN2 cold block PGS flexible thermal coupling Modules TPG encapsulated with one ply of CFRP for the facing TPG CF Simon Kwan - Fermilab CMS Tracker Upgrade Workshop Sept 2,

7 TPG Material Studies at Fermilab BTeV work focused on Material properties, FEA, substrate design, and system issues Material studies include Thermal Conductivity at RT and low temperature Temperature profile (cold at one end and heat applied at the other end) Mechanical Tensile modulus measurement before and after irradiation Pull strength test (effect of encapsulation) Flexure modulus measurement CTE studies (dummy silicon and bump-bonded dummies) Simon Kwan - Fermilab CMS Tracker Upgrade Workshop Sept 2,

8 Encapsulation Material is mechanically weak (friable and delaminates easily) in out-of-plane direction To get to the robustness we want to allow easy handling during plane assembly, needs encapsulation on the TPG pieces Vendors do offer encapsulated TPG but these are too thick QMC/CERN have a patent on the use of encapsulated TPG for thermal management ( rter).pdf) Encapsulation: Drilled holes Encapsulate Evaluate the strength by Simple peel test using scotch tape Pull test Simon Kwan - Fermilab CMS Tracker Upgrade Workshop Sept 2,

9 TPG: Challenging Problems and Needs Need to stiffen TPG substrate (delamination) Parts got damaged easily Too much handling Prefer to do work in-house (avoid shipping) Need to do the strengthening without adding a lot of material while keeping a reasonable thermal performance. One ply of CFRP on TPG as facing sheet. Carbon fiber is thermally and electrically conductive Need to make sure insulating resin does not cover up the fibers and hurting thermal performance. Can be done at Fermilab (loads of experience and equipment) Simon Kwan - Fermilab CMS Tracker Upgrade Workshop Sept 2,

10 TPG Experience at Fermilab - continued (1) Perforated holes drilling on TPG was needed before encapsulation. It would improve the rigidity of the substrate. Tensile pulling test on encapsulated TPG samples were done, and the improved strength was verified. Thermal conductivity measurement of TPG were checked and its high thermal K characteristic at low temperatures was verified. Plasma cleaning on the CFRP encapsulated TPG was checked, the thermal performance could be slightly improved as a thin layer of the impregnated epoxy was removed. TPG might not be very flat due to the relief of internal stress when made at the factory. It could be flattened somewhat when CFRP was added. T P G K [ W /m K ] TPG Thermal Conductivity [W/mK] Temperature [C] This perforated hole was basically filled up completely with epoxy 500 Simon Kwan - Fermilab CMS Tracker Upgrade Workshop Sept 2,

11 TPG Experience at FermiLab continued (2) The BTeV prototype was made and thermal-cycle tests with heaters and cooling on and off were conducted. Objectives wereto verify the temperature difference across the substrate is within expected range during the thermal changes; To verify the displacement of the substrate is not excessive. Results were satisfactory, no alarming problem was found. Test was conducted within a dry box with small amount of nitrogen flowing Kapton heaters on dummy silicon were used to simulate module heat load Cooling contacts were provided at ends An optical camera was used to observe the target displacements RTDs were glued on substrate to record thermal data Pin & hole engagement at large end Pin & slot engagement at small end Simon Kwan - Fermilab CMS Tracker Upgrade Workshop Sept 2,

12 TPG Experience at FermiLab - continued (3) It was successfully used for Fermilab MTest Pixel Detector telescope TPG encapsulated with two plies of CFRP for the facing PEEK Cooling tube glued on the back of TPG Simon Kwan - Fermilab CMS Tracker Upgrade Workshop Sept 2,

13 TPG Experience at FermiLab - continued (4) It is used for the PHENIX pixel detector TPG encapsulated with two plies of CFRP for the facing PEEK Cooling tube glued on the back of TPG Simon Kwan - Fermilab CMS Tracker Upgrade Workshop Sept 2,

14 Upgrade Design for FPIX MODULE LAYOUT Outer Inner 12 identical half-disks only 2x8 modules One 2x8 module placed on each side of a substrate for all outer and inner radius blades Substrate uses Thermal Pyrolytic Graphite material with excellent in-plane thermal conductivity Simon Kwan - Fermilab CMS Tracker Upgrade Workshop Sept 2,

15 Basic Design of the Pixel Blade Solid TPG (0.88 mm thick) encapsulated with carbonfiber facing (0.06 mm thick). All blades are identical with one module on each side. (Only 2x8 module is used.) Cooling is arranged at one end of the blade in which good contact with the ring is kept. Extra tab is provided to facilitate in handling. provisions (threaded screw) allows the blade to be attached/removed from the ring so no need to remove neighbors for removal (repair). Simon Kwan - Fermilab CMS Tracker Upgrade Workshop Sept 2,

16 The Current Fabrication 1. Flatness inspection when received from vendor 2. Perforated holes drilling; 3. CFRP coating (Encapsulate TPG with one ply of CFRP (60 micron thick) with carbon fibers along the heat sink direction 4. Precision hole and profile machining Simon Kwan - Fermilab CMS Tracker Upgrade Workshop Sept 2,

17 FEA Check on Blade with Two 2x8 Modules Blade thickness: 0.06 mm cf mm TPG mm cf Multi-chip thickness (overall mm): Adhesive:.050 mm ROC:.200 mm Bump-Bond:.020 mm Sensor:.270 mm HDI:.200 mm Simplified model: ROC were a continuous layer instead of 16 tiny ones; Bump-bonds were modeled as a continuous isotropic layer; HDI was modeled as a continuous isotropic layer; Flexible silicone glue was used for all adhesion layers Temperature was set fixed at the end(s) of blade at -30C 150% heat load, 7.3 W on blade. Simon Kwan - Fermilab CMS Tracker Upgrade Workshop Sept 2,

18 0.06 cf TPG cf Blade 150% heat load, 7.3W per blade; sensor: 0.6 W; ROC: 6.7 W Configuration (1) Heat sink on outer edge only HDI being the outermost within module T = 5.2C across model Front Side Back Side Simon Kwan - Fermilab CMS Tracker Upgrade Workshop Sept 2,

19 0.06 cf TPG cf Blade 150% heat load, 7.3W per blade; sensor: 0.6 W; ROC: 6.7 W Configuration (1) Heat sink on outer edge only HDI being the outermost within module T = 4.6C Across CF T = 4.4C Across TPG Simon Kwan - Fermilab CMS Tracker Upgrade Workshop Sept 2,

20 0.06 cf TPG cf Blade 150% heat load, 7.3W per blade; sensor: 0.6 W; ROC: 6.7 W Configuration (1) Heat sink on outer edge only HDI being the outermost within module T = 3.5C Across ROC T = 3.4C Across sensor T = 3.4C Across HDI Simon Kwan - Fermilab CMS Tracker Upgrade Workshop Sept 2,

21 Summary Edge cooling simplifies the cooling tube bending and reduces the pressure drop and hence T Edge cooling exploits the excellent thermal conductivity of TPG We have quite a number of years of experience working on TPG Reasonably easy and relatively cheap to produce the TPG substrates Simon Kwan - Fermilab CMS Tracker Upgrade Workshop Sept 2,