Update on the Phase 1 FPIX Half Disk Design

1. Update on the Phase 1 FPIX Half Disk Design Simon Kwan Fermilab on behalf of the USCMS Pixel Mechanics R&D group CMS Tracker Upgrade Workshop – June 3, 2009

2. Current FPix Detector 192 panels are needed Experiment needs 672 plaquettes (7 types and 5 types of sensor module) assembled on 192 panels (4 types). Two panels placed back-to-back on Al cooling channel to form a blade CMS Tracker Upgrade Workshop – June 3, 2009

3. Current Phase 1 BPIX / FPIX envelope definition CMS Tracker Upgrade Workshop – June 3, 2009

4. Phase 1 FPIX Disk layout requirements • Fits within Phase 1 FPIX envelope definition • Modules oriented radially (requires only 2x8 modules, and slightly improves resolution compared to the layout of the current detector) • 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) • 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 • Keep the same 20 degree tilt as the current detector • Individual modules and/or module-support substrates removable and replaceable without disassembling other modules on the disks • Identical substrates (blades are the same) • Minimizes the amount of material required for cooling and module support (assuming cooling using CO2) • (Highly desirable) Delta T < 5C across a single module • (Desirable) Separate inner from outer rings for easier replacement of blades on the inner ring (with earlier radiation damaged modules). CMS Tracker Upgrade Workshop – June 3, 2009

5. FPix Phase 1 Upgrade Plans • Baseline: 3 disks in each endcap • Layout: • Current detector has 7 module types and panels placed between r=59.7mm to 144.6mm (total 84 modules per half disk or 540 ROCs) • Upgrade detector: arranged modules radially; one module type (2x8) placed between r=45mm to 161mm (total 56 to 60 modules per half disk or 896 to 960 ROCs) • Modules divided into an outer ring of 34-36 modules and inner ring of 22-24 modules • Both outer and inner assemblies contains identical blades with 2 plaquettes (1 plaquette placed on each side of a substrate). • C02 cooling ; use thin-walled SS tubing 316 L and the size is tentatively chosen (1.638 mm OD, 1.435 mm ID) based on getting a continuous loop providing enough cooling power for each blade assembly. • ultra light weight mechanical support and with cooling tube (aim at material reduction of about a factor of 2) CMS Tracker Upgrade Workshop – June 3, 2009

6. Upgrade Design for FPIX MODULE LAYOUT • 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 Outer Inner CMS Tracker Upgrade Workshop – June 3, 2009

7. All Identical disks (1st and 2nd disks in locations to maximize 4-hit eta coverage) 6 disks = (6x68) outer + (6x44) inner = 672 2x8 modules (10752 ROCs) Z loc. TBD suggest 491mm from IP 396 291 η = 1.3 η = 1.6 η = 2.1 64.8 161 η = 2.5 45 30 60 2x8s 2x8s 2x8s 2x8s 2x8s 2x8s Note: distance units in mm current FPIX 4 disks at (mean) Z: ±355 and ±485 mm CMS Tracker Upgrade Workshop – June 3, 2009

8. Solid TPG (0.88 mm thick) encapsulated with carbon-fiber 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). Basic Design of the Pixel Blade CMS Tracker Upgrade Workshop – June 3, 2009

9. Half disk consists of one inner blade assembly and one outer blade assembly and they are assembled next to each other. Inner blade assembly consists of 11 or 12 blades and is supported by the outer blade assembly. Outer blade assembly consists of 17 or 18 blades. All blades are supported by 2 rings; Cooling tube is embedded at least in one of the rings. Basic Design of the Half Disk CMS Tracker Upgrade Workshop – June 3, 2009

10. 11 blades with Z offset =4.0 mm, Blade separation = 5.0 mm Ring width = 45 mm Inner Blade Assembly 3.0 mm thick CC ring for cooling and support uses 0.7 mm thick carbon fiber ring for support use only Note: through holes on rings for fastening blades not shown) CMS Tracker Upgrade Workshop – June 3, 2009

11. 17 blades with Z offset = 2.2 mm, arranged in 2 rows Blade separation = 5.46 mm Ring width for inner ring = 34 mm Ring width for outer ring = 62 mm Outer Blade Assembly 3.0 mm thick CC ring for cooling and support uses 0.7 mm thick carbon fiber ring for support uses only Note: through holes on rings for fastening blades not shown) CMS Tracker Upgrade Workshop – June 3, 2009

12. The Edge Cooling Concept -- capture the cooling tube inside the ring. 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 CMS Tracker Upgrade Workshop – June 3, 2009

13. The Half Disk Cf supporting spokes CMS Tracker Upgrade Workshop – June 3, 2009

14. Current vs Proposed upgrade FPIX detector CMS Tracker Upgrade Workshop – June 3, 2009

15. Material Budget Seems feasible that we can achieve the goal of reducing the material by x2 CMS Tracker Upgrade Workshop – June 3, 2009

16. FEA Check on Blade with Two 2x8 Modules Blade thickness: 0.06 mm cf + 0.88 mm TPG + 0.06 mm cf Multi-chip thickness (overall 0.790 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. CMS Tracker Upgrade Workshop – June 3, 2009

17. Configuration (1) Heat sink on outer edge only HDI being the outermost within module 0.06 cf + 0.88 TPG + 0.06 cf Blade 150% heat load, 7.3W per blade; sensor: 0.6 W; ROC: 6.7 W ∆T = 5.2C across model Front Side Back Side CMS Tracker Upgrade Workshop – June 3, 2009

18. Configuration (1) Heat sink on outer edge only HDI being the outermost within module 0.06 cf + 0.88 TPG + 0.06 cf Blade 150% heat load, 7.3W per blade; sensor: 0.6 W; ROC: 6.7 W ∆T = 4.6C Across CF ∆T = 4.4C Across TPG CMS Tracker Upgrade Workshop – June 3, 2009

19. Configuration (1) Heat sink on outer edge only HDI being the outermost within module 0.06 cf + 0.88 TPG + 0.06 cf Blade 150% heat load, 7.3W per blade; sensor: 0.6 W; ROC: 6.7 W ∆T = 3.4C Across HDI ∆T = 3.5C Across ROC ∆T = 3.4C Across sensor CMS Tracker Upgrade Workshop – June 3, 2009

20. Configuration (1) Heat sink on outer edge only HDI being the outermost within module 0.06 cf + 0.88 TPG + 0.06 cf Blade 150% heat load, 7.3W per blade; sensor: 0.6 W; ROC: 6.7 W ∆T = 1.0C across the mid-cut section CMS Tracker Upgrade Workshop – June 3, 2009

21. OTHER OPTION BEING CONSIDERED Identical 1st and 2nd disks, different 3rd disk to reduce number of modules and material 6 disks = (4x72) outer + (4x48) inner + (2x56) middle = 592 2x8 modules (9472 ROCs) 461 396 291 η = 1.3 η = 1.6 η = 2.1 η = 2.5 2x8s 2x8s 2x8s 2x8s 2x8s CMS Tracker Upgrade Workshop – June 3, 2009

22. An alternative design is to have the pixel modules arranged in a cone We had studied this geometry (see Jan ’09 presentation) and found out that the resolution wasn’t that good Re-visited this geometry during the last couple of weeks With inner and outer assembly, it’s possible to optimize the layout of each separately to obtain excellent resolution in both the azimuthal and radial direction Latest (evolving) idea is to explore concept of inverting the cone (apex towards the I.P) and combining it with the 20 deg tilt for the inner assembly to get better radial resolution for large eta IP Cone-1 Cone-2 Cone-3 Inverse Cone Geometry CMS Tracker Upgrade Workshop – June 3, 2009

23. Summary • We are making good progress to have a conceptual design in the summer • Prototype work will follow • Design needs to be verified by simulation • Resolution vs eta • Material distribution • Acceptance • In good position to have a TDR by next March CMS Tracker Upgrade Workshop – June 3, 2009