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

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Entry time:	Sun Aug 22 18:40:08 2021
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> > > > 11:30 BNC PB-5 pulser polarity chnaged from positive to negative (using LOCAL control) > > Swap BNC cables (top + bottom & left + right) from BNC PB-5 and Cooknell SA1 Sum Amp outputs > > Switch Cooknell SA1 Sum Amp output from negative to positive > > > > Observe pulser peak of c. 15 ch FWHM for aida08 and c. 35 ch FWHM for aida14 > > > > This probably indicates > > - noisy Cooknell SA1 > > - problem with T and/or Lemo-00 cable between BNC PB-5 and Cooknell SA1 > > > > > Investigate noise situation of AIDA (no DSSSDs connected) > > > > > > Figs 1-6: Waves, Pulser Peaks + Widths before any changes > > > - aida16 very noisy ASICS 1&2, normal ASICS 3&4 > > > - back-side aidas (02,04,06,08) worse resolution than front-side > > > - high-frequency noise still noticeable in waveforms > > > > > > Figs 7-8: Remove pulser in (from NIM rack) only > > > - no noticable change > > > > > > Figs 9-10: Remove all pulser cables from adapter boards > > > - looks improved > > > > > > Figs 11-12: HV Braid->GND Jumpers removed > > > > > > Fig 13-14: All HV cables removed > > > - aida06, aida14 isn't updating > > > - very noticable improvement > > > > > > Fig 15-16: Intermediate HV cables re-added > > > - signal worse in FEE64s with HV cables > > > - aida09, aida01, aida10, aida13, aida05, aida14 don't have HV interconnect cables, look good > > > > > > Conclusion: We see noticeable improvements removing the interconnect cables between FEE64s. > > > > > > Pulser widths now: > > > - aida14 (-ve amplitude) = 13.5 channels > > > - aida08 (+ve amplitude) = 40 channels (?) > > Removed the T-piece between pulser and summing amplifier > pulser FWHM still ~30 channels - not the T-piece, probably summing amp > > Checked the noise of HV and LV on battery DSO > - LV - no noticeable noise on any channel (< 5 mV rms) > - HV - noticable periodic signal (~100 kHz, 100 mV Vpp) on both core and braid channels, common to both > independent of bias voltage > See figs 1-6 : 0V, 10V, 20V, 50V, 100V, 0V (high photo resolution) of bias voltage > AC coupled 1MOhm Ch1 = HV Core, Ch2= HV Braid, Math=Ch1-Ch2 > > Filtering on AIDA front end ~ 10 nF (gnd), 3 kOhm (series) - low pass ~ 33kHz rolloff > 100 kHz would be attenuated factor of 5 maybe - 20 mV signal - still quite high for ASICs > Try introducing additional inline filtering of maybe 3 kHz (1 nF gnd, 3 kOhm series) 1nF/3k => 333kHz low pass rolloff 10nF/1M => 100Hz low pass rolloff > Check on one DSSSD, if see improvement can migrate to adapter boards in new revision > > Things to do: > TD: > Inline filters > NH: > Check same behaviour other N1419ET HV supplies > Check line voltages from CAEN NIM bin Encoding: HTML ELCode plain Suppress Email notification Resubmit as new entry

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