[Lowq] Minutes of the eg6 meeting on August 31

Tue Aug 31 17:17:03 EDT 2010

Dear All,

I would like to thank Hovanes for his leadership throughout the eg6 period
and even before when developing the proposal. I would like to congratulate
him on his new position. Hall D is lucky to have him on its staff.

My best wishes to Hovanes for more success in his new job. Fortunately he
will be close and I am sure we can always count on him for help.

Thanks Stepan for taking this task in hand. I will do my best to help more.

All the best,

Kawtar

Kawtar Hafidi
Argonne National Lab
Physics Division
PHY 203 Room B-273
Argonne, IL 60439
Ph: 1-630-252-4012
Fax:1-630-252-3903
www.phy.anl.gov/mep/staff/Hafidi_K.html

On Tue, Aug 31, 2010 at 11:02, Stepan Stepanyan <stepanya at jlab.org> wrote:

>  Dear all,
>
> On behalf of eg6 group I want to thank Hovanes for his valuable
> contribution to the setup and running of the eg6 experiment and
> for his leadership in the data calibration till now. Lets wish him a
> good luck and success in his new position as Hall D staff.
> I hope he will find time to contribute to the eg6 in the future.
>
> Stepan
>
> On 8/31/10 11:44 AM, Hovanes Egiyan wrote:
>
> Minutes of the August 31 meeting From Lowqwiki
>
> Present: Bayram, Dave, Stepan, Hovanes
>
> On the phone: Raphael, Raffaella, Will
>
> Notes by Hovanes.
>    Contents [hide]
>
>    - 1 Announcements<http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Minutes_of_the_August_31_meeting#Announcements>
>    - 2 EC timing<http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Minutes_of_the_August_31_meeting#EC_timing>
>    - 3 Solenoid<http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Minutes_of_the_August_31_meeting#Solenoid>
>    - 4 Hodoscope<http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Minutes_of_the_August_31_meeting#Hodoscope>
>
>    [edit<http://clasweb.jlab.org/rungroups/lowq/wiki/index.php?title=Minutes_of_the_August_31_meeting&action=edit&section=1>
> ]
> Announcements
>
>    - Hovanes will start working for Hall D this fall and will not be able
>    to continue performing the dutie of the analysis coordinator. Stepan agreed
>    to be the eg6 analysis coordinator.
>
>
>  [edit<http://clasweb.jlab.org/rungroups/lowq/wiki/index.php?title=Minutes_of_the_August_31_meeting&action=edit&section=2>
> ]
>  EC timing
>
>    - Bayram looked at 6 GeV cooked data and he came to concluion that they
>    do not need more calibrations, at least for the next cooking pass.
>    - There was a small issue with 1.2 GeV timing when he looked at run
>    61441<http://clasweb.jlab.org/rungroups/lowq/wiki/images/9/93/EC_TIMING_61441.pdf>.
>    There was ~100ps offset for EC time with respect to SC time although the
>    start times from both EC and SC were at zero.
>    - An attempt to calibrate EC timing with 1.2 GeV data itself was not
>    successful because because there were no hits in large areas of EC because
>    of the CLAS configuration for low energy runs.
>    - It was decided to keep only two calibration points for EC timing.
>
>
>
>  [edit<http://clasweb.jlab.org/rungroups/lowq/wiki/index.php?title=Minutes_of_the_August_31_meeting&action=edit&section=3>
> ]
> Solenoid
>
>    - Hovanes compared the 3 solenoid field maps<http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Solenoid_update_31Aug2010>:
>
>
>
>    1. The DC tracking FPACK map
>    2. Solenoid field map currently being used in *gem* package
>    3. Field map sent by Eric
>
>
>    - His conclusion is that there is a bug in the tracking code when
>    reading the field map. It creates 0.5cm offset in Z and R-directions.
>    - This needs to be checked by cooking data. It would be good to check
>    e1dvcs data on proton with and without "fixing" the bug and see if there is
>    improvement in the elastic event angle and vertex matching.
>    - We need a map with known current at the power supply and clearly
>    identified format (preferably FPACK file similar to what is being used in DC
>    tracking now).
>
> [edit<http://clasweb.jlab.org/rungroups/lowq/wiki/index.php?title=Minutes_of_the_August_31_meeting&action=edit&section=4>
> ]
>  Hodoscope
>
>    - Wiil studied the ADC spectra for pedestals and production runs<http://clasweb.jlab.org/rungroups/lowq/wiki/index.php/Aug31_hodo>.
>
>    - The ADC spectrum for the eg6 pedestal runs is drastically different
>    from what Mikhail Yurov had from previous CLAS periods.
>    - It seems like the HV were off during the pedestal runs. Therefore
>    this particular run is useless even for pedestals extractions.
>    - Stepan suggested to look at the plot of energy (ADC) vs timing (TDC)
>    and use cuts on these plane to select out-of-time hits to get the pedestal
>    and the single photoelectron peak.
>    - Dave performed studies to identify π0 in IC/SH<http://www.jlab.org/%7Ejenkins/eg6/31aug10/31aug10.html>.
>
>    - Dave looked at the time difference between hits in IC and CLAS. He
>    sees two peaks, and he interprets the peak at -2ns as the events with
>    correct timing and places cut around it.
>    - He also uses energy corrections provided by F.-X. and looks at 2-γ
>    pairs.
>    - Looking at the occupancy of the hodoscope he also see the missing
>    segment due to HV channel being off.
>    - Dave also uses cuts on the energy versus time plots to select in-time
>    events in hodoscope. When he does it he sees that ~8% of pions produce hits
>    in the hodoscope, which is more or less consistent with what Mikhail Yurov
>    found (~5%).
>
>
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