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This report details the testing of 16 TOB modules at UCSB, revealing significant noise issues linked to bias voltage and micro-discharge effects. Notable defects were identified in multiple channels across several modules, including scratches and lithographic errors. The findings highlight concerns in channels 278, 279, 333, and 377, among others. The investigation suggests that 11 out of 16 modules demonstrate some level of micro-discharge, affecting the overall sensor performance.
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Noise in TOB modules and sensor quality Regina Demina University of Rochester
Module 876 • Of the 16 modules tested at UCSB, • Observed peculiarity in module testing : • Noise on some channels increases with bias voltage. • Micro discharge effect (also seen in D0 sensors delivered by Micron)
Module 876 • Defects in channels 278 and 279. Not found in sensor probing
Module 877 • Defect (scratch) in channel 333. Not found in sensor probing
Module 878 • Defect in channel 377. Not found in sensor probing
Module 880 • Strip 91 a known pinhole in the first sensor.
Module 868 • Mid-sensor opens in channels 69-71 in the 1st sensor
Module 883 • Defect in channel 166. Not found in sensor probing
Module 883 • Scratch in channel 316
Module 872 • Defect in channel 303. Not found in sensor probing
Module 872 • Scratch in channel 344. Not found in sensor probing
Summary • Module # Comments 875 Channel 384 has high noise, but no lithography error present. NOT SEEN IN SENSOR PROBING 874 Found High Istrip channel in 2nd sensor (294) causes noise. Remove 293-295 between sensors and module is good 873 Micro-discharge at channel 14 at 270 V (need to pluck 10-18 to remove cmn). No obvious sensor damage. NOT SEEN IN SENSOR PROBING 872 4 channels with noise increase with HV. 3 have obvious lithographic error. NONE SEEN IN SENSOR PROBING 871 Micro-discharge at channel 181 at 300 V (need to pluck 175-187 to remove cmn). No obvious sensor damage. NOT SEEN IN SENSOR PROBING 870 Good 883 Channel 166 has increasing noise with HV. Has lithographic error (see picture). NOT SEEN IN SENSOR PROBING 882 Good
Summary • Module # Comments 881 Micro-discharge at channels 438-440 (need to pull 434-444 to stop high cmn). Channels start discharging at 0V and get worse 869 Micro-discharge at channels 29-30 (need to pull 24-36 to stop high cmn) at 400 V 868 3 mid-sensor opens, lithographic error (see photo). NOT FOUND IN SENSOR PROBING 880 NO PROBLEMS 879 NO PROBLEMS • 878 Channel 377 has increasing noise vs bias. Lithographic error found in second sensor (see picture). • NOT SEEN IN SENSOR PROBING • 877 Channel 334 has slightly higher noise at 550 V. Lithographic error found in first sensor. (See picture.) • NOT FOUND IN SENSOR PROBING • 876 Channels 278-279 have increasing noise vs. bias voltage. Sensor lithographic error found on both channels (see picture) NOT FOUND IN SENSOR PROBING
Summary • Out of 16 modules built 11 show some signs of micro discharge. • Total number of noisy strips – 17 • Number of strips with high I strip – 1 • Number of strips with obvious lithographic error – 8 • Opens - 3
