ELOG AIDA

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

AIDA

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Wed Nov 11 17:36:19 2015

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Upon starting system with nothing connected beyond adapter PCBs, observed pulser peak FWHM of ~12-15ch in nnaida13+14 and ~15-18ch in nnaida11+12
All newly shielded new kapton cables passed continuity tests between drain wire and Cu tape.
Throughout all tests, grounded cable has been connected to nnaida13. All other nnaida have ground isolated cables.
Initially, upon biasing, leakage current reached 50uA at ~2V HV and tripped.
After much searching, found one of the drain wires from the kaptons to be touching the core of the HV cable.
Tidied all drain wires and made sure none were touching anything they shouldn't.
Bias ramped up successfully to +200V with leakage current of 5.630uA @ room temp ~25.5oC.
Very noisy waveforms to begin with, notes Cu tape on kaptons was in contact with the Al housing for the detector.
Isolated kaptons from Al housing with black tape and the waveforms became much less noisy, but still not as calm as expected.
Connecting Cu covered kaptons with croc clips made this problem worse. However, grounding adapter PCBs together improved the waveform noise.
FWHM with new cables ~200-300ch, much worse than previous cables.
Reconnected system with old kaptons and they now see FWHM of ~200-300ch, as opposed to ~100ch observed earlier in the year.
What has changed?
Waveforms are smoother with old kaptons, but still not as flat as previously observed.
Had some issues with waveforms not being output by FEE cards and ASIC4 of nnaida12 has failed to Check/Load and is not outputting any data.
Standard ASIC parameters throughout, with shaping time of 0.5us.

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