ELOG DESPEC

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

DESPEC

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Entry time:	Fri Nov 7 16:11:46 2025
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> 19.06 Found HV OFF, DAQ GOing > > DAQ STOP > FEE64 power OFF > > > > 12:55 We are going to try the follow changes to the AIDA scheme of 241012025. > > > > - Fitting LK1 (aida01, aida14), removing LK1 (aida03, aida07, aida11, aida15) - only 1x LK1 needs to be fitted per Si wafer > > - Removing LK4 to see what (if anything) changes. > > > > Check that all of the screws securing the copper foil to ground are tight - snout install/removal tends to loosen screws. > > > > - Remove the bias line between aidas 12-3-15 and aidas 16-7-11 > > - Remove the test circuit > > (These two should eliminate any extra ground path on the front, except via the DSSD) > > > > - Use a multimeter to confirm 0 Ohm between all the copper foils (short the two probes to correct for resistance of the probe leads) > > > > - Try combinations of LK2/LK4 on the n+n fees > > > > 13:01 We check first the grounding with a multimeter and the different copper grounding components. They should all be grounded to the large iron frame, which is in > turn grounded to the platform. We also checked that the CAEN HV PSU was also grounded to the platform (it is). > > > > 13:22 We removed the LK on aida03, aida07, aida11, aida15 and added LK1 to aida01 and aida14. We try starting the DAQ and seeing the response from these changes. > > > > 13:25 We tried biasing with this configuration and the first DSSD on HV01 read a leakage current of 40 uA (too high). So we biased it down and reassessed. > > > > 13:30 It turns out we had LK1 fitted to aida04. We tried biasing again but this time DSSSD on HV01 tripped. They are fitted with LK4 so we biased down and removed > these link on aida06 and aida08. > > > > 13:35 Trying to bias now with LK4 removed from aida06 and aida08. We tried fitting and removing again. Now the setup appears to bias. This was probably due to a stray > piece of copper shielding touching the PCB. > > > > 14:22 We are checking the noise conditions now. TEMPS OK. FADC Align and whiterabbit timestamps OK. > > > > 14:30 With the changes above we have noticed an intense 5/2 ms pulsed signal in the wave forms. See attachment 2 > > > > 15:20 We decabled everything and the current scheme from 24102025, see prev. elog entry is in attachment 1. > > > > 15:34 We have unbiased AIDA1 and the wave forms improve for AIDA2 (?), 5/2 ms pulsed signal is still observed in AIDA1 Encoding: HTML ELCode plain Suppress Email notification

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