[Sbs_gems] [EXTERNAL] RE: [New Logentry] Follow-up Re: Question UVA UV GEM

[Gnanvo, Kondo (kg6cq)]

Hi Andrew,
I think this depends on how this ADC distribution compare with the other layers. If it is not a outlier, then I agree with you. But if it is larger than the other chambers, it will be safer to lower the HV a little bit (not too much) we can quickly see if it affects efficiency (which I would doubt).
It always safer to operate at the lowest HV that do not affect the performances considering that this is the first layer with the most exposure to high rate

Thanks
Kondo

From: Sbs_gems <sbs_gems-bounces at jlab.org> On Behalf Of Andrew Puckett
Sent: Sunday, December 5, 2021 11:07 AM
To: Kondo Gnanvo <kagnanvo at jlab.org>
Cc: Sbs_gems at jlab.org
Subject: Re: [Sbs_gems] [New Logentry] Follow-up Re: Question UVA UV GEM

I would not recommend changing the HV based on this plot alone without more care analysis. We inevitably see saturation in some small fraction of events. I don’t think it is anything to worry about.
puckett.physics.uconn.edu


On Dec 5, 2021, at 10:55 AM, kagnanvo at jlab.org<mailto:kagnanvo at jlab.org> wrote:

Follow-up Re: Question UVA UV GEM<https://logbooks.jlab.org/entry/3956838>

  *   Edit<https://logbooks.jlab.org/entry/3956838/edit?destination=email/send>
  *   Delete<https://logbooks.jlab.org/entry/3956838/delete?destination=email/send>

Lognumber 3956838<https://logbooks.jlab.org/entry/3956838>. Submitted by kagnanvo<https://logbooks.jlab.org/user/kagnanvo> on Sun, 12/05/2021 - 10:50<https://logbooks.jlab.org/entries?start_date=1638715842&end_date=1638723042&book=BIGBITE&book=HALOG&book=SUPERBIGBITE>.
Logbooks:
BIGBITE<https://logbooks.jlab.org/book/bigbite> HALOG<https://logbooks.jlab.org/book/halog> SUPERBIGBITE<https://logbooks.jlab.org/book/superbigbite>
References:
3956665 - Question UVA UV GEM<https://logbooks.jlab.org/entry/3956665>

It looks like APV25 saturation which might indicate that the gain is a bit too high.
GEM expert on call might want to consider lowering HV a little bit (~25 V). Should be safer and not affect efficiency.
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