[Halld-pid] Start Counter Meeting Minutes, December 13, 2018

[Mark Ito]

Folks

Please find the minutes here 
<https://halldweb.jlab.org/wiki/index.php/GlueX_Start_Counter_Meeting,_December_13,_2018#Minutes> 
and below.

   -- Mark

____________________________________________


    GlueX Start Counter Meeting, December 13, 2018, Minutes

Present:

  * *JLab: * Mark Ito (chair), Simon Taylor, Beni Zihlmann

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


      Announcements

The target will not be changed from LH_2 to beryllium for the CompCal 
commissioning period. The start counter will not be disturbed in the 
near future.


      Review minutes from the meeting on November 29 (SiPM Monitoring)

We looked over the minutes from the previous meeting 
<https://halldweb.jlab.org/wiki/index.php/GlueX_Start_Counter_Meeting,_November_29,_2018#Minutes>. 


Since the last meeting Mark spoke to Carl Zorn about monitoring the 
health of the SiPMs. He remembers having concerns about the neutron dose 
so near the beamline. Carl pointed out two monitoring methods:

 1. Measuring the dark rate directly by measuring the rate of
    single-pixel events with the beam off. In the lab this is done by
    looking at ADC data and observing the the distribution of 1-,
    2-,..., n-pixel events. It is not clear if this can be done in situ
    in the Hall with the FADC-250s. The scalar rates with beam off might
    show something; this is not clear either. We need to see if the
    EPICS scalars were recorded in the Archiver.
 2. Measure the bias voltage supply current. This will be roughly
    proportional to the dark rate. These currents might be in the
    Archiver as well.

We need to do more research on these approaches.


      NIM Paper

The December 7th deadline for comments has come and gone. Eric has 
produced a new draft, incorporating comments from Simon, Beni, and Mark. 
It has been posted on the DocDB as Version 4 
<https://halldweb.jlab.org/doc-private/DocDB/ShowDocument?docid=3497&version=4>. 
Note there are some minor technical problems with references, but all 
text modifications are present.

After technical corrections, the plan is to announce this as a final 
draft to the PID email list and then:

 1. Submit it to the JLab approval process.
 2. Post it the the arXiv.
 3. Submit it to Elsevier.

Retrieved from 
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  * This page was last modified on 13 December 2018, at 11:50.

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