[Lowq] Minutes of the eg6 meeting on August 17

[Hovanes Egiyan]

  Minutes of the August 17 meeting


       From Lowqwiki

Present: Stepan, Bayram, Dave, Carlos, Hovanes

On the phone: Eric, Yohann, Raphael, Lamiaa

Notes by Hovanes.


    Contents

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    * 1 TOF status
      <http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Minutes_of_the_August_17_meeting#TOF_status>
    * 2 EC timing
      <http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Minutes_of_the_August_17_meeting#EC_timing>
    * 3 Hodoscope status
      <http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Minutes_of_the_August_17_meeting#Hodoscope_status>
    * 4 Solenoid current
      <http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Minutes_of_the_August_17_meeting#Solenoid_current>
    * 5 Other
      <http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Minutes_of_the_August_17_meeting#Other>

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    TOF status

    * Lamiaa is doing second the third iteration, and it is nearly
      complete.
    * She keep track of the calibrations at JLab TOF page.
      <http://www.jlab.org/%7Eelfassi/eg6/calib/tof/check/>
    * She was not able to finish it this week because of the power
      outage in Cebaf Center last weekend.
    * Stepan noticed some inconsistencies in the resolutions for run
      61107. The &sigmas; for electrons from the "scres_ch7el61107.eps"
      of the widths and the RF-offset plot did not agree well. Lamiaa
      thinks it is because when fitting slices there is not enough
      statistics and it yields larger values for the widths from the fit.
    * Lamiaa thinks she will finish this week. But she will need help
      identifying the run ranges to which the p2p constants need to apply.

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    EC timing

    * Lamiaa cooked run 61107 with the new TOF constants for Bayram. (EC
      timing for 61195 has already been done).
    * Bayram calibrated 61107 as well. The comparison plots
      <http://clasweb.jlab.org/rungroups/lowq/wiki/images/e/e0/EC_TIMING_61107.pdf>
      looked good.
    * Stepan suggested to make summary tables with the relevant numbers,
      like resolutions for layers, peak positions, beta position and
      widths.
    * Hovanes suggested to make the plots wider to fill the page more
      efficiently. It would make it easier to see.

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    Hodoscope status

    * Will was not present because his classes started, but Carlos said
      that he got the code from M. Yurov and he already extracted the
      pedestals from the pedestal runs using Mikhail's package.
    * Carlos was not sure how to extract the gains. He did not show
      plots bu he described the eg6 ADC to be much "cleaner" than what
      e1dvcs/eg1dvcs had not exhibiting single or double photoelectron
      peaks.
    * Will will probably be here next week and show some of the plots.


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    Solenoid current

    * Hovanes looked into the issue of solenoid current for eg6
      <http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Problems_with_solenoid_current_in_Pass0v0_cooking>.


        Pass0 v0 cooking was done with essentially solenoid current set
        to zero for DC tracking. 
        DC currently tracking uses RUN_CONTROL->currents->ptm CALDB item
        which was not set correctly and was not used either. 
        RTPC uses RUN_CONTROL->currents->solenoid , although currently
        it is hardcoded in /gem/gem_init_c.c/. 

    * We decided to use RUN_CONTROL->currents->solenoid for both DC and
      RTPC tracking. Hovanes will do that.
    * Hovanes will also correct the current units in the CALDB for
      solenoid to mA.
    * It was also suggested that we need to use the same magnetic field
      file for both DC and RTPC tracking.
    * The normalization issue is still not fully understood. Hovanes
      will look into the code more.
    * We may need to check the sign of the current by cooking the same
      set of files with positive and negative fields and check for
      instance that the elastic scattering events have back-to-back
      tracks (??=180^o ). At this point we believe that the positive
      sign is the correct one.

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    Other

    * Yohann showed a plot which he got by cooking a 1.2 GeV run, but on
      the electron momentum spectrum he got the quasielastic peak at 1.3
      GeV .
    * One of the possibilities was that he used 2100 Amps for the torus
      current instead of 1900 Amps. Yohann will check the Tcl file to
      check the setting he used when cooking this run.

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