Is Increased Bias Current and CMN Correlated? 22 sensors with a >1.5 mA increase in bias current at UCSB Probed both at UCSB/UR Ordered sensors by increase in current Built 8 modules with these sensors Used every other sensor in list starting with the lowest current change Sensor always placed in position furthest from hybrid 1 module built with 2 “bad” sensors 6 of 8 modules have common mode noise Of the two modules without common mode noise: One module had only 1.8 mA of increased current Increased noise seen around known unbonded pinhole The other module now has a current consistent with QTC measurement after construction From these modules, we assume ~11 of the 13 sensors left would cause CMN Could be used in study of cause of CMN

5104 Sensors 20275912 21738507 Channels 442 at 80V Increased bias current seen at 60V in sensor reprobing

5110 Sensors 31215014 14308304 Channels 203 at 70V Increased bias current seen at 30V in sensor reprobing 251 at 130V Increased bias current seen at 130V in sensor reprobing

5124 Sensors 24104717 31830607 Channels 160-162 at 150V Increased bias current seen at 250V in sensor reprobing

5160 Sensors 15061422 21174105 Channels 86-90 at 200V Increased bias current seen at 220V in sensor reprobing

5232 Sensors 14842724 14842701 Channels 505,506 at 350V Increased bias current seen at 400V in sensor reprobing

5294 Sensors 20825319 20833807 Channels 280, 281 at 250V Increased bias current seen at 250V in sensor reprobing

Conclusions 12 of 13 sensors with a current increase of >3000 mA caused common mode noise 2 of 9 modules with a current increase between 2-3 mA caused common mode noise