ELOG DESPEC

AIDA GELINA BRIKEN nToF CRIB ISOLDE CIRCE nTOFCapture DESPEC DTAS EDI_PSA 179Ta CARME StellarModelling DCF K40

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Entry time:

Fri Apr 8 08:59:42 2022

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09:59 Noticed that the right hand ribbon cable for aida07 was offset vertically by 1. i.e. Only 1 of the 2 rows of pins in. Unbiassed detectors and reconnected.
      Rebiassed detectors - leakage current on DSSD2 increased to 9.96uA - Attachment 1

Power cycling FEEs

Following restart the FEEs show some improvement in rates - attachment 2
      Rate spectra - attachment 3
      Still issues with aida11 in the rate spectra (Likely a misaligned ERNI connector)

Pulser on rate spectra - attachment 4
      Pulser off rate spectra - attachment 5
      We can see that with the pulser on there are events in the channels in aida01 and aida11
      With the pulser off these channels disappear.
      ERNI connector is then likely aligned the issue is more likely the DSSD ribbon cable is misaligned.

Taking bias off to investigate.

10:39 Could not observe anything out of alignement about either the connectors or the adaptor boards
      Note that after pushing on the connector AIDA01 had largely recovered

13:30 Top of snout taken off while mounted in S4. It was observed that one of the ribbon cables for aida11 was off by 1 row.
      This was corrected in situ and the snout was put back together and made light tight again.
      Oddly leakage current still the same - DSSD2 has come down though - attachment 6
      FEEs powercycled for new tests

Half the channels in aida11 had appeared again
      Took apart once more and found the other header also off by one row which has been corrected

FEEs powercycled for new test

All of aida11 now showing - attachment 7
      Statistics at 0xa shown in attachment 8
      All p+n for DSSD1 are good (aida01, 03, 09, 10, 11 and 12)
      p+n for DSSD2 are so so (aida05, 07, 13, 14, 15 and 16)
      All n+n 2, 4, 6 and 8 are poor still

14:50 p+n waveforms - attachment 9
      n+n waveforms - attachment 10

Current jumper configuration
      LK1 (Bias ground) on FEEs 6 and 8
      LK2&4 on all p+n
      LK3 on aida03 and aida07 (Bottom middle)

15:00 Investigated whether there was a light leak. Placed black material over snout.
      Leakage on DSSD2 dropped to 5.6 - attachment 11
      There was a light leak
      Stats have decreased slightly - attachment 12

16:00 Move raspberry pis atop 5mm alminimum plate to keep away from FEE64 PSUs
      No change

16:30 Remove pulser network from all FEEs 
      Rates get noticably worse in many FEEs... why?
      Stats - attachment 13

Possible ideas include braid touching things it shouldn't (Adapter PCBs?)

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Attachment 1: