1 End-cap Module Electrical Specs. And Performance C. Lacasta + J. Pater, R. Bates, J. Bernabeu, P. Dervan, A. Greenall, C. Ketterer, J.E. Garcia, G. Moorhead, M. Vos, Z. Dolezal, M. Donega, M. D'Onofrio, M. Mangin-Brinet, R. Wallny + Many others

1 Specifications ❑ Performance goals At the operating threshold: ✔ Noise occupancy < 5  after full irradiation dose, 3  protons/cm 2. ✔ Tracking efficiency > 99% Capability to tag beam crossings

1 Noise Performance ❑ Limit on chip will depend on threshold settings for a given noise occupancy level. ❑ For 1fC threshold, ‹ 1900 e - ENC ❑ Effective noise is Electronics noise ⊕ Threshold spread E. noise ~ 1800 e - ENC ⇒ Thrs. Spread < 600 e - ENC ❑ Expected median charge: ~3.3 fC ❑ S/N ~ The efficiency will limit the threshold.

1 Comparator and Timing

1 Power Consumption Total power consumption: ~5.2 W

1 Performance ❑ 16 modules built: 2 middle + 9 outer + 5 inner 6 modules irradiated (data from 4 of them) 7 modules sent to the beam test 6 modules in the system test (up to now) ❑ Data handling: Cal. Pulse needs a correction factor. ✔ Obtained for each wafer from 5 test structures: ✔ Average: ✔ Error (std. Dev.): 0.01 Noise is normalized to ATLAS-SCT operating temperature: ✔ Noise slope:  Non-irradiated: 5.5 ± 2 e - ENC/°C  Irradiated: 15 ± 3 e - ENC/°C

1 Stability

1 Non-Irradiated Modules Average Gain ~50 mV/fC 2 °C: ● Outer: 1440 e - ENC ● Middle: 1345 e - ENC ● Inner: 920 e - ENC Noise occupancy ≤ Threshold spread: 160 e - ENC

1 Irradiated modules ❑ Difference in 2 irradiated periods Annealing ? ❑ For k5-310 and k5-312, specs are met if threshold increased slightly. ❑ Threshold spread within specs. ❑ More later....

1 Timing and PC ❑ Timewalk: Non-irradiated : 10ns -> peaking time: 22 ns Irradiated: 13 ns -> peaking time : 29 ns ❑ Power consumption: 5.5 W for both

1 System Test ❑ Sector of a disk As close to final as possible ❑ Can hold 33 modules: 13 outer, 10 inner, 10 middle ❑ Multi-module Runs (4O, 2M) No degradation in performance Correlated noise studies: compatible with zero Gaussian noise. ❑ Grounding & Shielding: Several options opened Noise injection (pipe and tapes) studies ongoing. No conclusive yet.

1 System test

1 Noise Injection

1 Beam Test ❑ 7 modules 3 outer unirradiated 2 outer irradiated 1 middle 1 inner ❑ Remarks Efficiency calculated on “selected” channels Noise taken from “in situ” calibrations. Normal incidence ✔ Not the best case for end-cap modules.

1 Beam Test ❑ Irrad. Modules. Detector voltage ~ 375 V.

1 Beam Test ❑ No plateau on charge collection ❑ Cluster width too high ❑ >>> Non depleted <<<< Is the noise from characterization “valid” ? Is the signal too slow and we loose charge ? Source measurements + August test beam on new irrad.

1 Summary ❑ Modules specify the specs: Efficiency and noise occupancy specs require a slightly higher than 1fC threshold Modules could be operated stable up to 600V Modules irradiated in June in better shape. Sent to the August TB. ❑ System test: Results encouraging: ✔ No performance degradation ✔ No significant correlated noise