ELOG DESPEC

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

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Thu Aug 15 14:09:39 2019

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Noise seemed less strong today, unsure of cause. I had re-taped snout as tape was not sticking well.

Figures 1-4: Waves for all 4 FEEs connected to the DSSD 
Figures 5-8: Zoomed in on region 400-600 
Figures 9-10: Rates in DSSD

Note in particular fee09 has a clear noise pickup somewhere. Also appears when no DSSD voltage. 
Peak distance = 6 channels = 16.6 MHz.

Fee09 is connected to HV bias core (-160 V) 
However unplugging the HV cable from it shows no difference.

Must be related to something else.

Update 16:29 CEST: 
Distance is more like 5 channels (20 MHz) 
Fee09 picks it by far most strongly but all fees you can make it out 
Additionally can see a slower waveform especially on other fees... approximately 40 channels = 2.5 MHz

Checked with multimeter that low resistance path between FEE cooling plate and ground LEMO connector 
also low resistance between ribbon cable copper shield and ground LEMO connector.

Noise seems to appear even if pulser cable unplugged at pulser end or when attentuation is increased weaking pulse.

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