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

[Xinzhan Bai]

Hi Nilanga,

This also happened on UV #0 in the past two days also, at least twice on
that chamber as I noticed. For the xy GEM chambers, I've only seen it once
(the one David posted). I am also concerned by this, since we already have
APV saturations in every layer, I agree that we should back down on the HV
by 50 V. I want to back down by 50 V for all GEM chambers, is that OK for
everyone?

Best,

XInzhan

On Mon, Dec 6, 2021 at 3:37 PM Liyanage, Nilanga K (nl8n) <nl8n at virginia.edu>
wrote:

>
> 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> on behalf of flay at jlab.org <
> flay at jlab.org>
> *Sent:* Monday, December 6, 2021 3:20 PM
> *To:* sbs_gems at jlab.org <sbs_gems at jlab.org>
> *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.
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