[Sbs_gems] [EXTERNAL] Re: Cosmic data on the GEn-RP setup in EEL125

[Brad Sawatzky]

Hi John,

I took a very cursory look at the trigger NIM bin last week and noted
that the airflow through the NIM bin had been cut off by the VME crate
installed above.  The NIM bin and its modules were pretty warm..  I
corrected that and the cooling is good now.

We should still go through the trigger with a scope to be sure, but
if the (potential) trigger weirdness coincides with the VME crate
installation, then the artifacts may go away with adequate airflow
through the electronics.

-- Brad

On Fri, 04 Mar 2022, John Boyd wrote:

> Here are the two largest sets of data in thus far from the eel 125 setup.
> Please forgive the confusing numbering/naming convention but after the new
> year the layers were reordered in the database to account for the tracking
> in the analyzer.
> December: Layers 1-6 -> inline stack. Layers 7&8 -> polarimeter
> 2 scintillators on the polarimeter side and 4 scintillators on the opposite
> inline side.
> February: layers 1&2 -> polarimeter. Layers 3-8 -> inline stack.
> The main thing to investigate here really is the cluster maps. You can see
> that on the higher numbered inline layers there are regions of poorer
> coverage or clusters. Since we can see this from the hitmaps produced by
> Xinzhan's GUI this is not an artifact of the tracking analysis. I also don't
> think these are GEM-related issues (though there is one gem [G3 in one of
> the inline layers]). I believe this to be symptoms of a less-than-perfectly
> calibrated triggering/daq setup. Perhaps the voltage setting on the
> scintillators is incorrect (though it was directly transferred over from the
> cleanroom). Or there is some light leakage on the some of the scintillators
> on the end with 4 of them. Or there could be connections issues at the
> PMTs.
> At 3 hz for cosmics on this setup it takes a while to gather this
> qualitative data so any fixes/changes/investigations will require their due
> time and should get fair pre-condiderations before any major actions are
> taken.
> I look forward to any and all input and discussion on this. With the
> schedule as it is we can work certain investigations into play and try out
> some things. The triggering system directly biases all off the data we
> collect so it is important to have it working properly and efficiently.
> Best regards,
> John

-- 
Brad Sawatzky (he/him), PhD <brads at jlab.org> -<>- Jefferson Lab/ Hall C/C111
Ph: 757-269-5947  -<>-  Fax: 757-269-5235  -<>- Pager: brads-page at jlab.org
The most exciting phrase to hear in science, the one that heralds new
  discoveries, is not "Eureka!" but "That's funny..."   -- Isaac Asimov