ELOG AIDA

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

AIDA

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Entry time:

Tue Feb 17 06:32:24 2015

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17/02/15
1515: Installed detector BB18 2977-7 with 3 modified kapton cables, one unmodified (in nnaida1) with 207Bi source.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Bias voltage @ -100V with leakage current -11.6uA @ ambient temp of ~20oC.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; nnaida1,3,6,8 connected to detector, all with shaping time of 2us and hold time 8us.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Slow comparator thresholds around 0x18 and fast comparators 0xf (see below images).
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Pulser at 50,000 with x5 attenuator @ 25Hz. Both polarities supplied via use of Ortec 433A dual sum and invert amp.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; nnaida1+6 p+n side, -ve bias. nnaida3+8 n+n side, ground.
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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; nnaida3 most well behaved, with low rate similar to that of pulser rate and no missing channels. Waveforms look good.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Pulser peak has smallest FWHM @ ~150ch, compared to 1000s of ch for the other nnaida.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; For comparison, nnaida7 (not connected to detector) has peak width of ~18ch FWHM.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; nnaida1,6,8 have typical pulser peak widths of the order 1000-3000ch FWHM. Peak too broad in nnaida6 to be distinguishable from noise peak.
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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Waveforms from nnaida3 stable and as expected. nnaida1+6 slightly more variable and noisy.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Waveforms from nnaida8 see much greater noise and variability, including rail-to-rail transitions.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Increasing the pre-amp reference from 0x30 to 0x60, removes rail-to-rail transitions, but waveforms remain just as noisy.
&nbsp;
1650: Successfully started Merge and Tape servers, writing data to disk.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Merge terminal window shows errors regarding Sync pulse timestamp sequence errors (see attachment #18).&nbsp;
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1900: Installed Caen N1419 floating HV bias supply.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Connected to detector via nnaida3, positively biasing n-side through core with p-side as low V reference through braid. Saw no leakage current =&gt; open circuit.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; After some problem solving found reversing the bias and negatively biasing p-side worked. Possible broken bond wires delivering bias on n-side.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Connected to nnaida8 (also positive bias to n-side) and found short circuit. Saw leakage current of 200uA (trip level) @ 5V.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Changed to negative polarity bias and connected to nnaida6 and saw sensible leakage current of -11.5uA @ -100V bias.
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Spectra for each module showed FWHM for the pulser peaks to be: nnaida1 ~800ch, nnaida3 ~150ch, nnaida6 ~3000ch, nnaida8 ~1200ch.
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; FWHM in nnaida1 reduced by ~1/3, nnaida6 shows little change, nnaida8 reduced by ~1/2. nnaida3 shows no change, but in line with what was seen at DL. (w.r.t peak widths seen last night using Selena bias supply)
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; nnaida3 performing much better than other three cards connected to detector, but in line with what was seen at DL. Other 3 cards very noisy.
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