[Halld-pid] Start Counter Meeting Minutes, May 21, 2015

[Mark Ito]

Folks,

Please find the minutes of the last Start Counter meeting below and at

https://halldweb.jlab.org/wiki/index.php/GlueX_Start_Counter_Meeting,_May_21,_2015

   -- Mark
_________________________________________________________________

GlueX Start Counter Meeting
Minutes

Present: Mark Ito (chair), Eric Pooser, Simon Taylor, Beni Zihlmann

Review minutes from the April 28 meeting

We went over the minutesfrom 
<https://halldweb.jlab.org/wiki/index.php/GlueX_Start_Counter_Meeting,_April_28,_2015#Minutes> 
last time.

The bias scan was done during the Spring run. Results were reported 
<http://argus.phys.uregina.ca/cgi-bin/private/DocDB/ShowDocument?docid=2730> 
by Mahmoud Kamel at the Collaboration meeting last week.

Propagation Time Calibration

Eric presented slides 
<https://halldweb.jlab.org/talks/2015/ST_Propagation_Time_Update.pdf> on 
the status of the propagation time calibration. He has tried several 
methods for fitting the dependence of the time difference between two 
hit counters vs. the hit position difference, where hit position is 
measured along the counter and is determined by charged tracks. He sees 
a few percent variation i the light propagation velocity depending on 
the fit method. The values are also significantly slower that those 
measured on the bench at FIU. See his presentation for details.

We had two suggestions for things to try:

 1.

    a cut on minimum energy using the FADC data

 2.

    restricting the fit region to positions with high statistics

Next Meeting

We will meet again in two weeks, on June 4.

Retrieved from 
"https://halldweb.jlab.org/wiki/index.php?title=GlueX_Start_Counter_Meeting,_May_21,_2015&oldid=67372"

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