Meeting 2021 10 27
From Hall A Wiki
GMn GEM commissioning Meetings: WEDNESDAY 10:00am - 11:00am
Link to all previous meetings: GMn GEM Commissioning Meeting
Please use sbs_gems mailing list for plots/communications and HALOG entries relevant to GEMs!
Update on BB GEMs(Sean, Ezekiel, Holly, Anu)
- GEM Alignmnet - Sean
- UV replacement layer is in INFN test lab on nitrogen. HV has been tested. Unclear when we will install (depends on Jessie for support). Resistor replaced photo
- Current BB/SBS experiment status: https://logbooks.jlab.org/entry/3932961
- Resistor changed out on UV layer 0 https://logbooks.jlab.org/entry/3930452
- 10uA on deuterium in last SBS kinematics (highest currents/occupancies so far): https://logbooks.jlab.org/entry/3931870
- BB GEMs currently back on nitrogen while Hall A work is ongoing https://logbooks.jlab.org/entry/3932943
- GEM HV supplies disconnected yesterday for Hall A work https://logbooks.jlab.org/entry/3932945
- BB GEM gas switches ok now. Still plan to calibrate the mixing unit in the future with Jack, but probably lower priority than the Hall A issues.
- INFN trip limits https://logbooks.jlab.org/entry/3931889
- Currents and set voltages in the EPICS archiver as of Monday https://logbooks.jlab.org/entry/3932174. This was always reported as a snapshot in the HALOG with the BB EPICS start of run entries.
- Replay plots post to logbook automagically. Example here: https://logbooks.jlab.org/entry/3932008
- MPD 23 (INFN J2 bottom APV backplane) misbehaves with beam and crashes CODA after some number of events. Consistent problem since beam. Not a problem with cosmics.
- J0 commmon mode drifts sometimes and seems correlated with the LV cable not being held securely (vertically) in connector. Weight of cable over time pulls it down some.
- GEM Current Study with beam at SBS-1 and SBS-4 configurations- SBS-1 LH2 SBS-4 LH2 SBS-4 LD2