[Sbs_gems] [New Logentry] Proposed GEM Work Plan

[mcjacob at jlab.org]

Logentry Text:
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After a lengthy discussion both during and right after the RC meeting, we have settled on a tentative work plan (subject to hall availability and other changes) for the GEMs including implementing the new gas mixture:

Since the gas lines to the hall are already being flushed, we don't need to worry about accessing the hall in the morning. Instead, whenever we are able to access the hall in the afternoon, we will first set our two primary test modules to flush:
L13 M1 - This module HV works but the 12-slot backplane is out. We can still read ADC and pedestal data from the 2 5-slot backplanes.
L15 M1 - This module has a history of sparking and is operated at a much lower HV

We also have the issue of L14 M0 and M1 to address. One of these modules has been discharging which causes CODA to crash. These two are coupled to the same HV channels and cannot be operated separately, so while we are suspicious of M1 (which has had shorted sectors in the past), we are unsure which one is causing the problem. We will attempt to determine which one is causing the tripping, if this can be done we will decouple the 2 modules and only operate the good one. If this cannot be done, then we will also put these two modules on the new isobutane gas mixture. In the latter case, we would leave the two modules off until we have determined safe operating voltages from our tests on the 2 primary modules.

The last piece of work in the hall is replacing the bad MPD that remained unresolved after the escorted access on Monday. All in all, we anticipate this work in the hall will take 2 hours to finish. The chambers need a total of ~3 hours to flush, we expect by the time we are done in the hall and prepared for stability tests upstairs sufficient time will have passed.

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This is a plain text email for clients that cannot display HTML.  The full logentry can be found online at https://logbooks.jlab.org/entry/4440758
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