[Lowq] Minutes of the eg6 meeting on May 4

[Hovanes Egiyan]

  Minutes of the May 4 meeting


       From Lowqwiki

Present: Stepan, Valeri, Hovanes

On the phone: Lamiaa, Raffaella, Raphael, Eric, Yohann

Notes by Hovanes


[edit 
<http://clasweb.jlab.org/rungroups/lowq/wiki/index.php?title=Minutes_of_the_May_4_meeting&action=edit&section=1>]


    Pass 0 preparation status

    * Lamiaa gave an update on the code and calibration status
    * There are differences in the time alignment in the monitoring
      histograms and the histograms that Lamiaa sees in the calibration
      code /p2p_delay_el/. While the /p2p_delay_el/ shows that the peaks
      are centered at zero, the monitoring histograms show a clear
      offset and some misalignment between paddles.
    * The group agreed that the left-right calibrations are sufficient
      and there is no need to work more on that. We only need to fix the
      paddle-to-paddle calibrations. Hovanes and Lamiaa will investigate
      the reason for the differences in the two procedure by the next
      meeting.
    * Raffaella got the scripts for building the C_SQL monitoring web
      pages from Mauri.
    * The eg6 monitoring web page
      <http://www.jlab.org/Hall-B/secure/eg6/cooking/online_sql/monitor.html>
      is ready. Some of the variables are showing no entries on these
      histograms. Possible reasons are absence of the numbers in the
      database, or just a simple problem with the histogram scale.
      Raffaella will look into this.

[edit 
<http://clasweb.jlab.org/rungroups/lowq/wiki/index.php?title=Minutes_of_the_May_4_meeting&action=edit&section=2>]


    RTPC calibrations with elastic events

    * Eric is studying the elastic events on the hydrogen target. He
      observes shifts in the missing mass of protons by ~4MeV. Posssible
      reasons are:

       1. wrongly reconstructed electron momentum in CLAS
       2. wrongly reconstructed electron angle in CLAS
       3. wrong beam energy

    * Stepan suggested checking if Hall A has beam energy measurements
      which would also allow determination of Hall B beam energy.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: https://mailman.jlab.org/pipermail/lowq/attachments/20100506/98536e92/attachment.html