[Primexd] [Revised Logentry] Bad pi0 distributions from online monitoring over weekend

[Ilya Larin]

Hi Colin,


I think the reason of the bad looking pi0 spectra is simple:

the target was emptied on that run and we don't have tracking to get vertex position. Thus Vertex default assignment is wrong, which is disturbing invariant mass spectra.


 Ilya


________________________________
От: Primexd <primexd-bounces at jlab.org> от имени gleasonc at jlab.org <gleasonc at jlab.org>
Отправлено: 11 декабря 2018 г. 11:10:03
Кому: primexd at jlab.org
Тема: [Primexd] [Revised Logentry] Bad pi0 distributions from online monitoring over weekend

Bad pi0 distributions from online monitoring over weekend<https://logbooks.jlab.org/entry/3637502>

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Lognumber 3637502<https://logbooks.jlab.org/entry/3637502>. Submitted by gleasonc<https://logbooks.jlab.org/user/gleasonc> on Tue, 12/11/2018 - 11:05<https://logbooks.jlab.org/entries?start_date=1544540718&end_date=1544547918&book=HDFCAL>.

Last updated on Tue, 12/11/2018 - 11:08

Logbooks:       HDFCAL<https://logbooks.jlab.org/book/hdfcal>
Entry Makers:   gleasonc

I noticed there was a significant change in the pi0 mass distribution on Saturday afternoon (see plots below). Run 52429 looks normal. The next run, Run 52430 looks quite bad. There seems to be a lot fo events missing in the pi0 peak that are now shifted to a lower mass in addition to much more noise. Run 52430 was started at 15:38:05. Was this around when you changed to the new FCAL hv set points? I'm wondering if the increase in hv would have caused this noise to appear, or shift the pi0 peak to a lower value. Anyways, it might be worth good to have Ilya at this soon on a channel by channel basis.

[https://logbooks.jlab.org/files/styles/plentybig/public/2018/12/3637502/Run052429.png]
[https://logbooks.jlab.org/files/styles/plentybig/public/2018/12/3637502/Run052430.png]
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