To do:

1) Disconnect ribbon cables from p+n junction FEE64 adaptor PCBs of upstream DSSSD, apply c. 100V bias and check leakage current is zero i.e. eliminate shorts in PCBs

 - When the p+n ribbon cables were disconnected for both the upstream and downstream AIDA, the pins and ribbon cables did not appear to have any blemishes.

- Both sets of adaptor PCBs were biased to 100 V and only had an apparent fluctuation in current at c. 0.01 uA. At low voltages (~10V) the current cycled between 0 and 1 uA.

2) Check that all ribbon cables are properly seated in the adaptor PCBs

- When inspected all ribbon cables seemed to be properly seated. A decent press was applied to confirm the seating. The PCBs themselves were inspected and no noticeable damage was observed.

3) Check all adaptor PCB connector pins are OK: will need to remove ribbon cables

- Done for the p+n side, can decide if this is needed for the n+n side.

4) If/when you open check seating of all Kapton PCBs in the DSSSD connectors *and* carefully check that ribbon cable and Kapton PCB connectors are aligned and not out by 1 or 2 rows say.

-  Will have to decide further.

5) From email discussion: Check the SHV connector is grounded if one unplugs the cable from the back of the HV module. If yes: We are touching a ground somewhere. If no: it's via the HV (fine).

- When HV#0 was disconnected from the HV module, we used a multimeter on the SHV connecter and frame and read zero resistance 0L on the meter. While when completing the circuit for HV#1 (still) plugged into the HV module we read a resistance of > 1.7 Ohm.

- The HV is touching ground somewhere. This should not be a problem however as the snout is isolated, and this was observed by connecting the SHV to the snout and reading 0L.

6) Properly cover snout with black cloth and bias upstream.

- Snout was covered with black cloth and a black bag. The downstream detector p+n side was biased at 50V and charging/discharging was observed. This is probably due to a short connection somewhere.

Summary: from the p+n side test the voltage-current break down appears to come from inside the snout.