[G12] Minutes from 02/24/10 meeting

[Craig Bookwalter]

Hi folks,
  Minutes from today's meeting are found at the following link:

  http://clasweb.jlab.org/rungroups/g12/wiki/index.php/24Feb10

  and pasted below:

Agenda

    * Diane/Sasha: Update on gflux
    * Gagik: Missing tracks
    * Heghine: Momentum correction status
    * g12 status talk
    * Wiremaps
    * Analyses status:
          o eta pi- Delta++ Diane
          o pi+ pi+ pi- Craig
          o Cascades Johann
          o Kaons Will/Mike
          o K+ K- Mukesh
          o KKpi Miles
    * Other business

[edit]
Minutes

    * Attending: Craig, Dennis, Robin, Eugene, Will, Carlos, Paolone,
Diane, Johann, Ben, Mike P., Sasha O., Mukesh
    * Eugene explained to us how gflux works -- it basically watches
average interval b/t events and when the interval fluctuates, a flag
is set until another scaler comes along and says the beam is OK. g12
had about 10-15 trips an hour, and at 30 seconds recovery a pop, we
have 5 minutes/hour of bad or no beam, according to gflux. The event
loss during this period is less than the 1/12 intoned by the times
because the beam is off or at low flux after a trip. Dennis wants to
neglect this for now because none of the analyses are looking for a
precise cross-section.
    * Ben is concerned about some strange fluctuations he's seeing in the
cascade yields--he is concerned that the yield from counter to counter
in the tagger is not uniform.
    * g12 only has one good normalization run, most likely due to
bleedthrough from Hall-A running
    * Sasha O. says his preliminary number for total flux from 10% of the
data over all energies in g12 is 5.5e17 photons/s, 6.7e16 photon/s
    * Craig's using the CMU kinematic fitter to do momentum corrections
    * Discussion of who's giving the g12 update talk at the collaboration
mtg is postponed so we can include Paul
    * Maurizio has completed the wiremaps and the results are available at
the above link. They should be uploaded by tomorrow morning.
    * Johann is currently working on monte carlo for the cascades -- the
values are coming out high for both the sigma and the cascade
    * Diane calculated the vertex that her photons are being calculated
from -- 99% of the time it's from the event vertex, as one would want.
    * Miles showed some results from his analysis of K-K+pi+
    * Johann says the majority of jobs that are left (200 files worth
excluding the single-sector runs, which all fail) are failing on
matching event counts b/t the raw file and the outputs from the skim
program.