ELOG DESPEC

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

DESPEC

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Entry time:

Mon Mar 7 12:20:26 2022

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Remove all DSSD ribbon cable braid ground from FEE64s to check n+n ground loops

Removing all on n+n side only and test resistance to ground: 4, 6 and 8 show continuity to ground, 2 shows no connection (braid ring terminal to copper bar)

Remove all p+n braids as wll and check:
- See no continuity to ground (good)
- Snout has no continuity to ground (good)
- n+n side fees 4 and 8 to seem to have continuity to snout though (bad) 
- p+n checked and don't seem to have continuity to gnd (except when braid was touching a LEMO barrel)
- n+n aida06 maybe has high resistance connection to ground (bad) or (about 0.7 V drop according to RS multimeter)

Bias+Power up and check noise
aida09 Peak width =    86.03+/-  1.721
aida02 Peak width =   509.48+/- 11.1812

Low frequency noise on wavesforms corresponds to ca 100 kHz - switching power supply?

Attachment 6 - ADC data item stats
               all p+n/n+n cable braids disconnected
               all FEE64 adaptor PCBS grounded to Copper busbar OK

Remove guard ring jumper on upper-middle p+n FEE (rear guard ring of middle DSSSD)
Attachment 7 - ADC data item states
No real change to rates

Remove field plate jumpers on all p+n FEEs
Attachment 8 - ADC data item states
No real change to rates

Remove bias LK1 jumpers on n+n FEES:
Generally worse across the p+n side, no real change to n+n side

Attachment 9 - Stats with LK1 removed:
aida09 Peak Width = 181.77. p+n see Attachment 10
aida02 Peak width =   505.23. n+n see Attachment 11

Attachment 12 - p+n waveforms
Attachment 13 - n+n waveforms

High frequency component reduced but 100 kHz low frequency component stronger

Remove LK3 from aida03,aida07 (no jumpers at all on any FEE) - DSSSDs floating
No significant change, see attachment 14 stats

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Attachment 1: