[Sbs_gems] [EXTERNAL] RE: [New Logentry] Brief Voltage Spike on uva_xygem_2

[Gnanvo, Kondo (kg6cq)]

Hi all,
I think we should be clear on what we are discussing here!

  *   What I saw on the logbook looks like a spark from me and I don't really think it is something to worry about. We expect that with GEMs unless there is a specific pattern with that spike and in that case we should take ab look and try to understand. I would suggest that GEM expert look at the chart and come with a clear conclusion on that



  *   Reducing HV for 50 V because of APV saturation is a discussion that we had yesterday , so I will not repeat the argument here but let's try not to mix issues and solution we apply to try to address.


Best regards
Kondo

From: Sbs_gems <sbs_gems-bounces at jlab.org> On Behalf Of David Flay
Sent: Monday, December 6, 2021 3:46 PM
To: Liyanage, Nilanga K (nl8n) <nl8n at virginia.edu>; sbs_gems at jlab.org
Subject: Re: [Sbs_gems] [New Logentry] Brief Voltage Spike on uva_xygem_2

Thanks Nilanga,

Zeke and I will do that before we start the next run.

Best regards,
David

----------------------------------------------------------------
David Flay, Ph. D.
Hall A/C Staff Scientist
Thomas Jefferson National Accelerator Facility
Office: CEBAF Center, C119
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________________________________
From: Liyanage, Nilanga K (nl8n) <nl8n at virginia.edu<mailto:nl8n at virginia.edu>>
Sent: Monday, December 6, 2021 3:37 PM
To: David Flay <flay at jlab.org<mailto:flay at jlab.org>>; sbs_gems at jlab.org<mailto:sbs_gems at jlab.org> <sbs_gems at jlab.org<mailto:sbs_gems at jlab.org>>
Subject: [EXTERNAL] Re: [Sbs_gems] [New Logentry] Brief Voltage Spike on uva_xygem_2


Hmmm, that is a bit worrying.

I think, until we understand this a bit more, we should back down the HV on just this one module by 50 V.

I expect the reduction of efficiency to be very small because of this change. So I think we should do this soon.

Best

Nilanga

________________________________
From: Sbs_gems <sbs_gems-bounces at jlab.org<mailto:sbs_gems-bounces at jlab.org>> on behalf of flay at jlab.org<mailto:flay at jlab.org> <flay at jlab.org<mailto:flay at jlab.org>>
Sent: Monday, December 6, 2021 3:20 PM
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Subject: [Sbs_gems] [New Logentry] Brief Voltage Spike on uva_xygem_2

Brief Voltage Spike on uva_xygem_2 <https://logbooks.jlab.org/entry/3957495>

  *   Edit<https://logbooks.jlab.org/entry/3957495/edit?destination=email/send>
  *   Delete<https://logbooks.jlab.org/entry/3957495/delete?destination=email/send>

Lognumber 3957495<https://logbooks.jlab.org/entry/3957495>. Submitted by flay<https://logbooks.jlab.org/user/flay> on Mon, 12/06/2021 - 15:17<https://logbooks.jlab.org/entries?start_date=1638818252&end_date=1638825452&book=HALOG>.
Logbooks:
HALOG<https://logbooks.jlab.org/book/halog>
Entry Makers:
flay

Just catching up on this after the DAQ has settled back in and the HCAL HV was power cycled.

At around 13:50 we had a HV spike on uva_xygem_2, see attached.
[https://logbooks.jlab.org/files/styles/plentybig/public/2021/12/3957495/uva_xygem_2_spike_12-06-21.png]
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