Meeting 2024 05 08

GMn GEM commissioning Meetings: WEDNESDAY 10:30am - 11:30am

Link to all previous meetings: GMn GEM Commissioning Meeting

Please use sbs_gems mailing list for plots/communications and HALOG entries relevant to GEMs!

Increased gas mix a bit last week [1][2][3][4]
Tweaked the G1 HV on the rear tracker [5][6][7][8]
rear GEMs at about 70% efficiency [9]
LV problem yesterday [10]
12uA on deuterium has about the same rates at 15uA on hydrogen [11][12]
Work tomorrow:
- Individual power supply channels for L6M1, L3M3, L4M0
- Armen will inspect and repair the LV cable connection
- repair APVs on L6M1, L7M2, L4M1, L4M0 (I think we need to slide out L5 and L7?)

L3M3L2M1 (G2 &G3) — L3 faces the analyzer, L2 is high..decoupled now and only running L2M1 (L3M3 off)
L4M0M1 (G2) — faces the analyzer, high ...decoupled now and only running L4M1 (L4M0 off)
L5M2M3 (G2) - this one is low and possibly accessible, but needs to be slid out
L6M0M1 (G3) (beamline side) – it’s high and likely hard to reach
L6M2M3 (G3) — this one is low and possibly accessible, but probably too tight a fit to check anything
L8M0M1 (G2 & G3) – might be easily checkable from the platform with a stepladder or the one with handrails. This is on the HCAL side. (currently kept off)
L6M0 gas issue? - not a gas issue, probably one of the electrodes are disconnected from the HV distribution. This is most likely to have happened right at the detector. Another possible cause could be one of the gem foils being at reverse polarity.
L9M2M3 - Transfer 2 HV channel does not ramp up beyond certain values. see https://logbooks.jlab.org/entry/4289553

Contents