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AIDA
GELINA
BRIKEN
nToF
CRIB
ISOLDE
CIRCE
nTOFCapture
DESPEC
DTAS
EDI_PSA
179Ta
CARME
StellarModelling
DCF
K40
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Message ID: 404
Entry time: Mon Mar 7 12:20:26 2022
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| Author: |
NH, TD |
| Subject: |
AIDA Grounding Checks Mon 7 Mar |
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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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