[Halld-pid] Start Counter Meeting Minutes, January 10, 2019

[Mark Ito]

Folks,

Please find the minutes here 
<https://halldweb.jlab.org/wiki/index.php/GlueX_Start_Counter_Meeting,_January_10,_2019#Minutes> 
and below.

   -- Mark

________________________________________


    Minutes, GlueX Start Counter Meeting, January 10, 2019

Present:

  * *FIU: * Werner Boeglin, Mahmoud Kamel
  * *JLab: * Thomas Britton, Mark Ito (chair), Simon Taylor, Beni Zihlmann

There is a recording of this meeting <https://bluejeans.com/s/UEwUD> on 
the BlueJeans site <https://jlab.bluejeans.com/>. Use your JLab 
credentials to authenticate.


      Review minutes from the meeting on December 13

We went over the minutes 
<https://halldweb.jlab.org/wiki/index.php/GlueX_Start_Counter_Meeting,_December_13,_2018#Minutes> 
and noted that the plan is to do the DIRC commissioning with the liquid 
hydrogen target and start the PrimEx run with beryllium.


      Calibration and Efficiency

Sean recently implemented the use of Mahmoud's new z-dependent 
resolution parametrization in halld_recon 
<https://github.com/JeffersonLab/halld_recon/pull/76>] and halld_sim 
<https://github.com/JeffersonLab/halld_sim/pull/27>.


      SiPM bias currents

Beni has looked into using the SiPM bias-voltage-supply current as a 
method to monitor radiation damage. He found that these currents have 
been recorded in the EPICS Archiver. The current if very small, there is 
a noticeable increase year-to-year by a few percent, roughly consistent 
from channel-to-channel. He reminded us that each supply channel serves 
then four SiPM's that read-out one start counter paddle.

We should compare the observed behavior with the BCAL. We should also 
check with Carl Zorn that the absolute magnitude of the current seen in 
the Archiver is reasonable.

Werner mentioned that another way to monitor dark rate is to look at 
pedestal widths of the ADC's.


      NIM Paper

Mark reported that Eric Pooser has pushed the paper through the Lab 
approval process, submitted it the the arXiv, and submitted it to NIM. 
Just this morning Eric reported that the arXiv has assigned a temporary 
submission identifier, submit/2531925. He also reports that NIM has 
assigned a reviewer, Peter Krizan, and a manuscript number, 
NIMA-D-19-00031.


      Maintenance

We discussed ideas for insuring reliable operation of the start counter 
going forward.

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  * This page was last modified on 13 January 2019, at 16:13.

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