1. 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

2. 5104
Sensors
Channels
442 at 80V
Increased bias current seen at 60V in sensor reprobing

3. 5110
Sensors
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

4. 5124
Sensors
Channels
at 150V
Increased bias current seen at 250V in sensor reprobing

5. 5160
Sensors
Channels
86-90 at 200V
Increased bias current seen at 220V in sensor reprobing

6. 5232
Sensors
Channels
505,506 at 350V
Increased bias current seen at 400V in sensor reprobing

7. 5294
Sensors
Channels
280, 281 at 250V
Increased bias current seen at 250V in sensor reprobing

8. 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