1. LV-HV cable reuse for the Si Tracker Being worked out with S. Wenig

2. Cable reuse scenarios  Two possible reuse scenarios: –Scenario 1: Reuse of SCT Type-II/III and Type-IV cables Cut SCT type-II cables in chamfer region –Type-II/III splices not accessible –Chamfer region: next to cryostate bore, intermediate between splices and PP1 –Scenario 2: Reuse of TRT type-III cables Dismount all type-II cables up to PP2 Reuse type-III cables from PP2 to US/USA15

3. LV cables available  LV cables available: –Scenario 1: Reuse of SCT cables Currently 4088 SCT cables (Type-II/III and Type-IV) installed –2 LV lines (+ returns) per cable, i.e. 8176 LV lines available »Type-II: (19x) 0.2 mm conductor diameter: 0.597 mm2 »Type-III: (19x) 0.25 mm conductor diameter: 0.93 mm2 »Type IV: (19x) 0.3 mm conductor diameter: 3.958 mm2 –Scenario 2: Reuse of TRT cables Currently 1100 TRT Type-III LV cables –Solid copper lines with large cross section (35, 50 mm2) –550 LV lines available (+ returns)

4. LV cable needs  LV cable needs: –DC-DC powering: 1 power line per stave, ~ 5.3 A for barrel short strips, ~ 1.9 A for barrel long strips End of Stave (EoS) boards included in the power scheme –Serial powering: 1 power line per stave ~ 2.2 A for barrel short strips, ~ 1.5 A for barrel long strips EoS boards not included in the serial power chain  Additional power line ~ 0.8 A, 2.5 V?  Include it in the serial powering chain (step-up charge pumps 1.2 - 2.5 V at the EoS boards)?

5. LV: Feasibility of both scenarios  Scenario 1: 8176 LV cables available –Several lines have to be combined to reach a maximum voltage drop of 1 V until chamfer region DC-DC powering: –Type-IV: 3168 lines –Type-II/III: 6912 lines –1264 spare Type-II/III lines Serial powering: –Type-IV: 3168 lines –Type-II/III: 7920 lines »Number could be reduced significantly including EoS in the serial power chain –256 spare Type-II/III lines –Conclusion: there are enough LV lines (Type-II/III and Type-IV) available for both powering schemes (including returns) –Possibility to include EoS boards on SP chain: –Additional 1.2 V step in the chain (low effect on system efficiency, < 1% decrease) –Use of step-up charge pumps in the EoS boards from 1.2 V, ~ 2.14 A to 2.4 V, ~ 0.8 A –Some prototypes of step-up charge pumps designed and fabricated by CERN (Jan Kaplon, Michal Bochenek), with ~ 84% power efficiency

6. HV Cables Based on Fixed Length Barrel layout Assuming one HV line per module Number of lines (same number needed for returns) Current estimation Sigi Wenig 6

7. There are 4088 SCT cables (Type-II/III and Type-IV) installed Each cable comprises 1 HV line (and 1 returns), i.e. 4 088 HV lines are available Conclusion: Present SCT cables can make up for only 24% of necessary HV leads (lines+returns) 25 744 HV leads (lines+returns) to be installed !! Scenario 2 being worked out Match Requirements to Scenario-1 (Re-use SCT Cables) Sigi Wenig 7 S. Wenig, CERN