Meeting 2022 07 27

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!

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Near term work plan

• All the fibers are connected both in the MPDs and the VTPs. We routed one extra, long, fiber cable as we found that a single long fiber cable supports only 48 MPDs and we currently have 50 MPDs for all the inline layers. Two fiber path panels were also ordered for the new long fiber cable.
• Clock signal is available now in the SBS GEM bunker
• Power is supplied to the SBS GEM bunker via a transformer similar to BB GEMs - Jack
• Network cables were routed to all the network controlled devices in the SBS GEM bunker
• Alex is working on getting all the VME crates and power strips on to the network now. Once this step is completed, we will start the low level tests.

• See installation plan for SBS here: plan
  • [photos from the hall https://hallaweb.jlab.org/wiki/index.php/File:Installation_Update_22June2022.pdf]
• Installation of HV dividers on BB: work plan
  • BB APV Status
• Thoughts on special run requests during GEn:
  • Luminosity studies (Nilanga)
  • Full readout studies for negative pulse studies and etc (Sean)

Update on INFN GEM layers for GEn-RP

• Ran up a new divider on the front layer GEM of the inline stack. Verified temperature and V/I consistent with divider run-up with no GEM.
• Currently in Hall. Plan to install new dividers on upstream-most layer while we can easily access. Will need sliding platform to remove the layer to install the new dividers on the second layer.

Update on UVa GEM layers for GEn-RP

• Gas shut-off valve configuration for outputs were changed as per the advice from Nilanga and Huong. Now we have two shut-off valves for the two separate outputs instead of T-ing the outputs and putting a single shut-off valve. This work is only partially completed as we had to order more shut-off valves for this. In the meantime, we disconnected the unfinished GEMs from the T connectors.
• We successfully completed out very first HV test under Nitrogen in Hall! See the log entry: SBS Inline UVA GEM first HV test under nitrogen in the Hall

Update on BB GEMs

• Gas flowing fine now, https://logbooks.jlab.org/entry/4019525
  • Setting up automatic HV turn off if the gas ratio is incorrect.
• GEN BB production rates