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 Apr 4 22:28:14 2025
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<p>17/02/15</p> <p>1515: Installed detector BB18 2977-7 with 3 modified kapton cables, one unmodified (in nnaida1) with 207Bi source.</p> <p> Bias voltage @ -100V with leakage current -11.6uA @ ambient temp of ~20oC.</p> <p> nnaida1,3,6,8 connected to detector, all with shaping time of 2us and hold time 8us.</p> <p> Slow comparator thresholds around 0x18 and fast comparators 0xf (see below images).</p> <p> Pulser at 50,000 with x5 attenuator @ 25Hz. Both polarities supplied via use of Ortec 433A dual sum and invert amp.</p> <p> nnaida1+6 p+n side, -ve bias. nnaida3+8 n+n side, ground.</p> <p> </p> <p> nnaida3 most well behaved, with low rate similar to that of pulser rate and no missing channels. Waveforms look good.</p> <p> Pulser peak has smallest FWHM @ ~150ch, compared to 1000s of ch for the other nnaida.</p> <p> For comparison, nnaida7 (not connected to detector) has peak width of ~18ch FWHM.</p> <p> 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.</p> <p> </p> <p> Waveforms from nnaida3 stable and as expected. nnaida1+6 slightly more variable and noisy.</p> <p> Waveforms from nnaida8 see much greater noise and variability, including rail-to-rail transitions.</p> <p> Increasing the pre-amp reference from 0x30 to 0x60, removes rail-to-rail transitions, but waveforms remain just as noisy.</p> <p> </p> <p>1650: Successfully started Merge and Tape servers, writing data to disk.</p> <p> Merge terminal window shows errors regarding Sync pulse timestamp sequence errors (see attachment #18). </p> <p> </p> <p>1900: Installed Caen N1419 floating HV bias supply.</p> <p> Connected to detector via nnaida3, positively biasing n-side through core with p-side as low V reference through braid. Saw no leakage current => open circuit.</p> <p> After some problem solving found reversing the bias and negatively biasing p-side worked. Possible broken bond wires delivering bias on n-side.</p> <p> Connected to nnaida8 (also positive bias to n-side) and found short circuit. Saw leakage current of 200uA (trip level) @ 5V.</p> <p> Changed to negative polarity bias and connected to nnaida6 and saw sensible leakage current of -11.5uA @ -100V bias.</p> <p> Spectra for each module showed FWHM for the pulser peaks to be: nnaida1 ~800ch, nnaida3 ~150ch, nnaida6 ~3000ch, nnaida8 ~1200ch.</p> <p> 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)</p> <p> 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.</p> <p> </p>
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