[Sbs_gems] [EXTERNAL] UV Latency Analysis Results

[Sean Jeffas]

Hi Andrew,

I am not sure if you meant to only reply to only me, but here are the plots
you asked for. I actually already had them but decided it was kind of
overkill.

Best,
Sean

On Thu, Jan 13, 2022 at 3:21 PM Andrew Puckett <puckett at jlab.org> wrote:

> Hi Sean,
>
>
>
> Interesting results. Another interesting way to visualize these results
> would be in terms of the strip mean times, which might (or might not) have
> somewhat better resolution than the time sample peaking distribution. I
> would also be curious to see a couple of alternative ways of visualizing
> the data. For example:
>
>
>
>    1. A more “binary” approach: 1D and 2D distributions vs. x and/or y
>    for hits peaking in sample 5 and for hits NOT peaking in sample 5
>    2. Same as 1, but perhaps broken out by hits peaking in samples 1, 2,
>    3, 4, 5, etc.
>
>
>
> Cheers,
>
> Andrew
>
>
>
>
>
>
>
> *From: *Sbs_gems <sbs_gems-bounces at jlab.org> on behalf of Sean Jeffas <
> sj9ry at virginia.edu>
> *Date: *Thursday, January 13, 2022 at 3:03 PM
> *To: *Sbs_gems at jlab.org <sbs_gems at jlab.org>
> *Subject: *[Sbs_gems] [EXTERNAL] UV Latency Analysis Results
>
> Hi All,
>
>
>
> I have finished analyzing the spatial distribution of the peak time
> samples. I have attached the results below for two runs.
>
>
>
> *Run 13240: *Taken January 11th with all four UV layers and 2 uA on LH2
> at the SBS-14 kinematic.
>
> *Run 12423:* Taken December 1st with J0 still in the layer 1 position but
> the UV layer was in layer 3 position. This was 2 uA on LD2 at SBS-11.
>
>
>
> In the recent run (13240) you can clearly see the peak time sample is
> uniform over the hit map for every layer except for layer 1 and layer 3.
> Similarly if you look at the December run (12423) the same issue was
> present in layer 3, but we never noticed it because we were always the
> first and last bin out of the analysis. John and I measured the resistors
> on the GEMs today and did not find a resistance that would suggest that the
> gas window has collapsed onto the cathode. Unfortunately the shielding
> blocks us from seeing the gas window, otherwise it would be very easy to
> tell.
>
>
>
> Therefore our current conclusion is that since the GEM layers 1 and 3 both
> have a non uniform gas flow, this is probably causing some bend in the
> readout board, which causes this issue. To fix this we can turn down the
> gas flow rate and see how everything is affected. Since the experiment is
> down for a few days it would be good to turn it down today and take some
> cosmic data, if possible.
>
>
>
> Best,
>
> Sean
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mailman.jlab.org/pipermail/sbs_gems/attachments/20220113/eb63de3f/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Latency_study_run13240.pdf
Type: application/pdf
Size: 424020 bytes
Desc: not available
URL: <https://mailman.jlab.org/pipermail/sbs_gems/attachments/20220113/eb63de3f/attachment-0002.pdf>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Latency_study_run12423.pdf
Type: application/pdf
Size: 629806 bytes
Desc: not available
URL: <https://mailman.jlab.org/pipermail/sbs_gems/attachments/20220113/eb63de3f/attachment-0003.pdf>