[Halld-pid] Start Counter Meeting Minutes, August 24, 2017

[Mark Ito]

Please find the minutes below and at

https://halldweb.jlab.org/wiki/index.php/GlueX_Start_Counter_Meeting,_August_24,_2017#Minutes

________________


    August 24, 2017, Minutes

Present:

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

There is a recording of this meeting <https://bluejeans.com/s/W23BR/> on 
the BlueJeans site <https://jlab.bluejeans.com/>. Use your JLab 
credentials to authenticate.


      Announcements

Thomas reported that the start counter hits are in HDvis. Hit counters 
are shown in orange; un-hit counters in faint white. The target has not 
been added yet. To see the current version, click here 
<https://halldweb.jlab.org/talks/2017/HDvis2/js/event.html>.


      Review of minutes from the last meeting

We went over the minutes from July 27 
<https://halldweb.jlab.org/wiki/index.php/GlueX_Start_Counter_Meeting,_July_27,_2017#Minutes>. 


  * Mahmoud overcame the problem he reported last time with modifying
    the PID library.
  * After putting the new attenuation constants into the CCDB, Mahmoud
    did not see a significant improvement in the dE/dx measurement. He
    is repeating the calibration with the new, self-consistent version
    of the software to see if that makes any difference.


      Start Counter Performance Studies

Mahmoud presented his latest results. For all of the details and his 
plots, see his slides 
<https://halldweb.jlab.org/talks/2017/SC_Meeting_8_24_2017.pdf>

  * *Propagation Time Corrections*. Using charged tracks he measures the
    light propagation time in the counters and fits that time vs. light
    propagation path length in the counters to a straight line,
    separately for each counter and separately for the three regions of
    the counters, straight, bend, and nose.
  * *Time Resolution*. In a similar procedure he measures the time
    difference between the start counter hit and the prediction from the
    charged track taking account of the propagation time as determined
    in the previous study. If he restricts the fit to a single Gaussian
    to a region of &plusm; one sigma, he gets an average time resolution
    of 214 ps. This tight restriction may give a slightly optimistic
    results. We discussed various ways of getting a more fair
    characteristic resolution number. We also noted that there is a
    contribution to the resolution from the charged track timing.


      NIM Paper

Mark reported status as told to him by Eric Pooser prior to the meeting.

  * Many plots had to be redone to get publication quality versions.
    There was some significant computer file archaeology involved, but
    this work is done. Eric should be done with his parts of the paper
    by this week.
  * Machmoud is working on the plots on the attenuation measurements
    with real data and the attendant text. Those should be ready by the
    end of next week.
  * All members of the start counter working group should have a look at
    the paper. It is in Eric's Github repo at
    https://github.com/pooser/st-nim-article.
      o At some point we should move it to the gluex-documents repository.
  * We agreed to circulate a draft among collaborations members for
    comments and author list corrections.

-- 
Mark Ito, marki at jlab.org, (757)269-5295

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