Thu 11/10/2022 2pm
- Detector status:
- Raw mode run:
- Lubomir found some problems with FDC preamps following the recent raw data run 111255 - the first for this run period. It looks like the gain of 3 preamps has dropped to half, and there are a handful of other isolated channels which look like their signal height readout is missing bits. See https://logbooks.jlab.org/entry/4081020
- He was worried about the number of blank channels for the CDC but in fact the CDC looks fine - there are many channels which are not connected to anode wires and report only cross-talk. There is a list of these here: https://github.com/JeffersonLab/halld_recon/blob/master/src/plugins/monitoring/CDC_roc_hits/JEventProcessor_CDC_roc_hits.cc#L390 At least one more CDC channel has become inoperative since the electronics loaned to CPP were returned.
- Tungsten shielding:
- We briefly discussed Sasha's inquiry about possibly removing the tungsten plate for beam systematics tests. This should not pose a problem to the drift chambers at 200nA beam current. However if this goes ahead we should make sure that RoboCDC is switched OFF, as the HVB currents in the CDC would double. The logbook entry from 19 April 2018 about the W plate insertion is at https://logbooks.jlab.org/entry/3563927 't w
- New year maintenance:
- We discussed plans for maintenance during the short break between PrimEx and GlueX. We do not propose to touch the CDC electronics at present. Since another set of channels developed the same kind of problem as I-1 and I-26, where they trip and have to be coaxed very gradually back up to full HV, and these were solved by switching to a different HV module, the leading theory is now that there is some problem with the HV module and probably not with accumulation of debris on the HV boards. Maybe it is overheating.
- Most of the parts needed for the assembly of the large-scale GEM-TRD arrived/were shipped to UVA. The procedure require testing the GEM foils under HV that is planned to be done in December. The final assembly will be done in December/January.