[Lowq] Minutes of the eg6 meeting on May 11

[Hovanes Egiyan]

  Minutes of the May 11 meeting


       From Lowqwiki

Present: Hovanes, Stepan

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

Notes by Hovanes.


    Contents

[hide <javascript:toggleToc()>]

    * 1 TOF status
      <http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Minutes_of_the_May_11_meeting#TOF_status>
    * 2 IC related issues
      <http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Minutes_of_the_May_11_meeting#IC_related_issues>
    * 3 Elastic calibrations with H2
      <http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Minutes_of_the_May_11_meeting#Elastic_calibrations_with_H2>
    * 4 RTPC calibrations
      <http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Minutes_of_the_May_11_meeting#RTPC_calibrations>

[edit 
<http://clasweb.jlab.org/rungroups/lowq/wiki/index.php?title=Minutes_of_the_May_11_meeting&action=edit&section=1>]


    TOF status

    Lamiaa and Hovanes gave an update on the TOF system calibrations
    <http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Status_of_TOF_on_May_11_2010>.


        * Lamiaa set the RF offset to zero for 61695 and the run was
          recooked.
        * She recalibrated the paddle-to-paddle offset for this run with
          modified /p2p_delay_el/ program with RF-time taken from *HEVT*
          bank.
        * After updating the CALDB and recooking the same run the TOF
          overall resolution is on the order of 160ps.
        * Some paddles are still off and they will need to be taken care
          of manually.
        * Since there were beam tune changes during eg6 run the
          RF-offset may need to be calibrated for a few runs.
        * On unrelated note, Stepan pointed out that EC time information
          is not available.

[edit 
<http://clasweb.jlab.org/rungroups/lowq/wiki/index.php?title=Minutes_of_the_May_11_meeting&action=edit&section=2>]


    IC related issues

    * There were no updates on IC calibrations.
    * Dave Jenkins is looking for ?^0 s and ?s in the data.

        He could see ?^0 s in EC. He would like to also satrt looking
        into ?^0 s in IC. 
        Dave wants an event generator to simulate ?^0 s and ?s to check
        his programs. Stepan suggested /fsgen/ phase space generator. It
        is easy to use, but an input file needs to be modified for
        desired channel and kinematics. 


[edit 
<http://clasweb.jlab.org/rungroups/lowq/wiki/index.php?title=Minutes_of_the_May_11_meeting&action=edit&section=3>]


    Elastic calibrations with H_2

    Eric continues studying elastic scattering kinematics on hydrogen
    target
    <http://clasweb.jlab.org/rungroups/lowq/wiki/images/1/1e/Eric_05112010.pdf>
    using the nominal beam energy of /E/_/e/ = 1.2067GeV and detected
    electron parameters.

        * He sees sector dependence on the position of the missing mass
          and excitation energy versus sector.
        * Five sectors are shifted to one side, except sector 2 for
          which the peaks are at the right location.
        * Stepan will check if /E/_/e/ = 1.2067GeV matches the
          "Tiefenback number" in the BOS files.
        * Stepan suggested to also look at ?-dependence of the peak
          positions.
        * Eric also wanted to know if the magnetic field map we are
          using in the reconstruction is consistent with Saclay field map.

[edit 
<http://clasweb.jlab.org/rungroups/lowq/wiki/index.php?title=Minutes_of_the_May_11_meeting&action=edit&section=4>]


    RTPC calibrations

    Raphael studied the drift paths in eg6 RTPC
    <http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/First_drift_path_observations>
    using single pass events on helium target.

        * He compared the the z- and &\phi; position from the pads to
          the positions from the tracks he swam starting from the point
          given by electrons.
        * At this point he assumes a linear dependence between the
          radial position of the hit positions and the TDC values.
        * He sees a constant 5mm shift in the z-coordinate.
        * There is also nonlinearity in the ? vs TDC dependence which
          Raphael interprets as the nonlinearity between R and TDC.
        * He will try to fit this dependence and see what happens in the
          next iterations.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: https://mailman.jlab.org/pipermail/lowq/attachments/20100511/53f27cc1/attachment.html