AIDA
GELINA
BRIKEN
nToF
CRIB
ISOLDE
CIRCE
nTOFCapture
DESPEC
DTAS
EDI_PSA
179Ta
CARME
StellarModelling
DCF
K40
AIDA
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Entry time:
Fri Nov 20 16:29:49 2015
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<p>Powered system up from state it was left in last night. Biased to +200V with leakage current 3.9uA @ room temp 23.3oC.</p> <p>nnaida14 now performing as it was at the beginning of yesterday, with nnaida11 back to having noisy waveforms.</p> <p>Tried various combinations of grounding to ascertain minimum possible configuration to maintain (or improve) current performance.</p> <p> - detector ground jumper required, noise in waveforms increases significantly if removed</p> <p> - system seemingly has no preference of jumper combinations for the left-hand pairs of pins, other than all 4 at once increase noise. Any combination of 3 or fewer seems to have no effect</p> <p> - fitted additional small braids to kaptons and took them directly to the PCBs (like in the previous ELog entry) which made no difference</p> <p>Found LEMO connectors on both PCBs to show open circuit with the Cu adapter mount block (not mezzanine block). Wrapped thin braid round connectors and took attached directly to each respective Cu block.</p> <p>Resistance between any two points between the detector and Cu mezzanine blocks now < 0.5 Ohm.</p> <p> - when i left for lunch this had no effect on nnaida11, but nnaida14 showed improvement in fine noise on waveforms but none for the low frequency 'wave' (see attachment 1)</p> <p> - after returning from lunch, both were noisy again and I was unable to repeat original improvement over a few attempts at the same or similar grounding. Subsequently removed completely and performance returned to normal...</p> <p>When we arrived on Wednesday, detector box was floating and performance was OK. Box is now not floating, and attempts to make it so were unsuccessful, although nothing I did changed the noise situation.</p> <p>Removing the Al plates either side of the detector made had no impact on the noise.</p> <p> </p> <p>Didn't get chance to try swapping the PCBs over.</p>
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nnaida14_goodGNDbetweenAll.png
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