ELOG AIDA

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

AIDA

Fields marked with * are required

Entry time:

Thu Nov 19 17:31:24 2015

Author*:

Subject*:

Powered system on from the state it was in last night. Biased to +200V with leakage current 3.9uA at room temp 22.8oC.
Performance of nnaida14 at shaping time of 8us slightly worse than last night - peak now non-Gaussian and double peaked. New source of noise?
Trying different permutations of grounding options initially led to no improvements.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; - tried various jumper combinations and taking the braids from the kaptons to various different points on the adapter PCBs - no appreciable changes.
However, connected the braids from the kaptons to the thick Cu braid with a crocodile clip and the noise in the back side FEEs significantly reduced.
Throughout, both sides of the detector saw improvements, but the front side performed much better than the back (rear waveforms were still just noise, just slightly reduced noise).
Soldered 4 drain wires to the&nbsp; thick Cu braid to improve connection and taped them to the Cu tape on the kaptons so as to give the shortest possible distance between kapton and thick braid (attachment 2).
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; - performance in nnaida11 improved dramatically, the waveforms looked sensible instead of just noise (see attachment 1)
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; - however, nnaida14 waveforms have now just gone to noise... We have swapped the performance of the front/rear strips.
In investigating this, we have found poor connections and high resistance between the Cu blocks and adapter PCBs, despite all screws connecting them -&gt; a good connection cannot always be assumed it seems.
However, taking a braid from the PCBs directly to the Cu blocks makes little difference to performance. Neither did putting an Al plate on the front of the detector.
The Al detector box was previously floating, but now is not - the effect of this will be investigated tomorrow.

Encoding: HTML ELCode plain
Suppress Email notification Resubmit as new entry

Attachment 1:

nnaida11_wav.png Original size: 1445x1029

Attachment 2:

IMG_20151119_162831.jpg Original size: 3200x2368

Attachment 3:

Drop attachments here...

ELOG V3.1.4-unknown