Meeting 2022 02 02

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!

---

Discussion on personnel for supporting GEMs in upcoming SBS experiments (all)

• From UVa, Anu and Sean will still be involved till Fall 2022 or early 2023. John B. will be involved through GEN-RP. 2 new students from Nilanga's group will be getting involved near beginning of the summer.
• From Hampton, Manju and Saru will getting involved now and primarily focused on GEN-RP GEMs. Thir will also remained involved.
• Zeke will still be involved during GEN and GEN-RP.
• Holly will be present for all!
• Currently it seems for near future activities and commissioning of GEN-RP GEMs in the Hall experience folks like Anu, Sean, John, Zeke will be involved to provide teaching and transition for new people from both UVa and Hampton.
• New Hampton and UVa people have access to JLab, which is good.
• There are discussions of constructing 4 new layers at UVa, so workforce will have to be considered for that as well.
• Currently it is not clear what will run after GEn run period. Either SIDIS or GEP. Workforce should be reconsidered as that approaches.

Update on BB GEMs(Sean, Ezekiel, Holly, Anu)

• This morning the BBCal threshold was increased to about 500 mV. Currently the excess currents on LD2 at a beam current of about 4.5-5 uAmp are reasonable and stable.
• Anu and Sean recently replaced an entire new backplane and APVs for the 3rd UV layer and this returns that active area so there are no missing APVs.
• Currently there are no extra 3 and 4 slot backplanes. So production of more spares needs to be considered
• Analysis of negative pulse study (https://logbooks.jlab.org/entry/3979464) still underway
• Negative pulse analysis ideas
  • The occupancy of the negative signals
  • Timing distribution of the negative signals
  • Fraction of negative signals to positive signals
  • Fraction of negative signals to positive signals on the same event
  • Fraction of negative signals to positive signals on the same event in the same APV
  • Fraction of negative signals to positive signals on the same event in the same MPD
  • Use tracking to see if negative signals correlate to track position
  • Check if the hits turned a negative signal into a positive one

Update on UVa GEM layers for GEn-RP (Anu, John, Thir)

• APV inventory
• Updates on GEn-RP analyzer/replay