[Halld-pid] Time-of-Flight Meeting Minutes, October 10, 2018

[Mark Ito]

Folks,

Please find the minutes here 
<https://halldweb.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_October_10,_2018#Minutes> 
and below.

   -- Mark

______________________________


    Minutes, GlueX TOF Meeting, October 10, 2018

Present:

  * *JLab: * Thomas Britton, Ashley Ernst, Mark Ito (chair), Simon
    Taylor, Beni Zihlmann

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


      Announcement

Ashley will be taking on the role of FSU TOF person at JLab. To start, 
she is going to work on the calibration of the Fall 2018 data. She has 
been talking to Beni about this and reviewing the code. Great news!


      Review of minutes from the August 15 meeting

We glanced at the minutes 
<https://halldweb.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_August_15,_2018#Minutes>. 
No significant comments were offered.


      Calibration Status

  * Sean Dobbs has written the group: TOF calibration skims are ready.
  * Beni reports that the Spring 2018 TOF constants are not doing too
    badly with the Fall 2018 data as judged from monitoring plots.


      Upgrade Plan

We skimmed through the talk Paul Eugenio gave 
<https://halldweb.jlab.org/doc-private/DocDB/ShowDocument?docid=3777> at 
the collaboration meeting on re-configuring the inner portion of the 
TOF. In it, he showed an "Option #2" that is less different from the 
current configuration than Option #1 presented at a previous meeting. In 
particular, it simplifies the design of a new light guide arrangement by 
having fewer consecutive "half-width" paddles in the array. The cost is 
also much less.

Beni is continuing study of the amplified base, but he is not optimistic 
that it will solve our high-rate-on-inner-counters problem.

We all agreed that Option #2 has a lot to recommend it and should be 
pursued immediately. Mark will talk to Paul to get more details on how 
to proceed.


      Lucite Shield and Geometry

Thomas reported a visit he received from Jon Zarling asking about 
whether or not the Lucite shield was present in the Monte Carlo. Jon is 
doing an FCAL efficiency study for data and for Monte Carlo and the 
shield could affect things. At one point Thomas had put the shield into 
the geometry and run Monte Carlo with the revised geometry, but that 
study did not get completed.

Ashley was tasked with picking up where Thomas left of and finish 
putting the shield in the standard geometry.

Beni recalled that Brad Cannon had presented, at a Collaboration 
Meeting, results of rate studies 
<https://halldweb.jlab.org/doc-private/DocDB/ShowDocument?docid=3232> 
before and after installation of the shield in the Hall. Mark remembered 
that Paul had also presented results 
<https://halldweb.jlab.org/wiki/index.php/GlueX_TOF_Meeting,_January_10,_2017#Lucite_Shield_Results> 
at a TOF meeting.


      Working Group Re-Organization and Work Packages

We discussed the proposal from the Collaboration Board 
<https://halldweb.jlab.org/doc-private/DocDB/ShowDocument?docid=3757> on 
the re-organization of working groups and the associated set of work 
packages 
<https://halldweb.jlab.org/wiki-private/index.php/2018_Work_Packages>. 
 From the discussion:

  * As Mark mentioned at the collaboration meeting, there is still a
    role for the individual detector working groups on subjects from
    hardware to calibration.
  * Thomas pointed out that a lot of the people who might form the new
    PID working group are the same ones attending the current TOF, Start
    Counter, and DIRC working group meetings.
  * Beni suggested making a list of new grad students to work on the
    packages.
  * The proposed work packages are of two types: (1) detector-specific
    understanding of performance and (2) an overall PID system.
  * PID for GlueX needs a global philosophy for combining information
    from all detector elements. This is a common practice across many
    experiments (Beni described the Hermes scheme, Thomas the LHC-B scheme).
  * A new PID working group could design this system. It should be
    formed with folks who have experience with the idea. Until a design
    is in place, writing detailed work packages staffed with "workers"
    might be premature.
  * Thomas and Simon mentioned that there is already a form of this idea
    in the PID FOM. It makes a combined χ^2 from the TOF and tracking
    dE/dx information.
  * Error estimation is essential as input to any global scheme. Here
    the detector working groups might be the best place to host the work.

Retrieved from 
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  * This page was last modified on 10 October 2018, at 17:03.

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

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