[Sbs_gems] [New Logentry] GEM efficiencies look lower (especially layer 0) after HV trip/reset compared to previous 40-uA runs

[puckett at jlab.org]

Logentry Text:
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The reported efficiency of layer 0 of the BB GEMs has gone down very significantly compared to earlier 40-uA runs on Helium-3 after the two recent HV trip events. Also, the overall number of tracks found in 50k events also appears to have gone down quite a lot, although this could be partly due to beam being off during part of the first 50k events of run 3731. 

Compare: 

https://logbooks.jlab.org/entry/4115219 

with 

https://logbooks.jlab.org/entry/4114669

Are we sure that (a) the GEMs (layer 0 in particular) have the correct HV settings and (b) that nothing else has changed with the beam and/or target and/or detectors? 

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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/4115238
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