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:	Thu Apr 3 15:07:32 2025
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<p> With the system in T9 and a Keithley Source Meter supplying HV to the detector.</p> <p>The source meter supplies 200V and measures the current .... </p> <p>I noticed that the current value was not stable... varying by +/-0.5uA. In conversation with Marcello i learnt that normally much more stable than this. </p> <p>I have carried out the following changes.</p> <p>added a 22nF X7R capacitor at the detector end of the Kapton cable from the HV connector pin  ( G/R ) to the ground plane of the Kapton.</p> <p>added a 14k resistor in series with the HV supply +ve signal before it connects to the adaptor board.</p> <p>isolated the G/R connection on the second Kapton that would normally be connected to the HV on the detector.</p> <p>The HV now is a lot quieter +/-0.01uA.</p> <p>Next i disconnected the HV -ve input from ground at the adaptor board. This resulted in all the FEE64 being equally noisy!!</p> <p>Next I connected a 22nF X7R capacitor between the HV negative and ground at the adaptor. This resulted in all FEE64 becoming equally calm. </p> <p>The FWHM of the spectra is not good at 250 to 300 but the fact that all FEE64 are equal now is interesting.</p> <p>I will update this post with pictures.</p> <p> Update:- </p> <p>This change was not stable and repeatable. I changed back to the original connections and things haven't gone back. </p> <p>So power down and leave for today.... It doesn't make sense to me ... but then that's nothing new :-)</p> <p>It appears that something is heating/charging up during the day and the noise becomes swamped by this effect ????</p> Encoding: HTML ELCode plain Suppress Email notification

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