Minutes for Small Angle GDH Target Meeting, click here.
    Minutes for A1n Analysis Meeting, click here.
    Minutes for g2n Analysis Meeting, click here.
    Minutes for GDH Meeting, click here.
 

    Tentative Date of next Collaboration Meeting:  December 6-7 2002
 
 

    Kees de Jager opened the meeting by discussing the schedule:
         As long as the first septum magnet arrives by November 11th, there is no change
    in the short term schedule.  When the first septum arrives only basic inspections will
    be made to insure that the magnet was not damaged during delivery.

         A contingency plan has been developed for different possible scenarios in
    case the septum isn't ready for the December commissioning period.

    Paul Brindza discussed the status of the septum magnets:
        If no major problems develop, the first septum should be ready to ship by
    October 29th and should be at Jlab the first week of November.   The voltage tap
    resistors were moved out of the magnet due to the unexplained failure of G0's
    resistors.  Also the relieve values were checked due to the problem with G0's
    burst disk.

        The coil fitting for the second magnet is well underway, but the magnet probably
    will not be ready in under 4 months and may take as long as 6 months.

   Al Gavalya discussed the design Status:
        Design work for saGDH is being finished.  The design for the correction coil mounts
    will be finished in the next week by Joyce.  Susan is finishing the collimator design,
    and Al has been working on the coupling extension tube for the downstream end.

        Work to incorporate a new cell pull off design is also being discussed.

    Steve Lassiter discussed the field gradient due to the septum magnet:
        Steve created a better model to calculate the field gradient due to the presence of
    the septum.  From Steve's simulations,  field clamps will work.  Most of the gradients
    are below 30 mG/cm, expect for the dB_z/dy component, which is ~ 52 mG/cm using
    +/- 10 cm above and below the beam line in y.

        Alexandre Deur is working on correction coils to compensate for the remaining
    gradients.

     Scott Higgins gave an update on the Septum controls:
          Scott has been working on getting things ready for when the PLC arrives.  The
    field control software is ready for the NMR probes.  The interface software for the
    PLC is finished and tested.  There will be supervisory controls to monitor the
    magnets through EPICS and a few active control points.

        Controls for the gradient and correction coils will be available.

    Alexandre Deur discussed issues and preparation for the experiment:
        Though the experiment has been delayed, only one septum magnet will be ready
    for the running period.  Only one good cell exists with the new Ice cone cell design.
    The problem with production remains unexplained.

        Since the last collaboration meeting, the field gradient problem has lessened
    due to new calculations.  Field clamps will now be used with correction coils to
    compensate for the gradients.   Designs for correction coils are being finished by
    Al Gavalya.  Once the design and fabrication work is completed, the winding for
    the coils will be done.

        Due to the rising tails seen during the original GDH experiment, saGDH requires
    good beam quality and alignment.  After the commissioning period, Alexandre would
    like to check the rising tails.

    Doug Higinbotham discussed the Septum Optics commissioning:
        Doug will be the run coordinator for the optics commissioning period, which is
    scheduled for mid December.  One day is needed by John LeRose for the beam tune.
    Carbon and elastic ³He data will be taken at three beam energies.

        Data was taken with the spectrometers vacuum coupled to the scattering chamber.
    There should be sufficient manpower for the analysis.

    Matt Poelker discussed the Beam:
        Able to achieve ~ 75% beam polarization and about 30 uA maximum current with
    diode laser.  Hall A will have an independent current ramp to reduce affects to other
    halls.  Leakage from G0 beam is very small

     Xiaodong Jiang discussed helicity monitoring:

     The G0 helicity scheme will be used for saGDH.  Helicity is predicted and nobody
    knows the helicity in-time.  It is important that scalers are recorded for each pulse.

        Xiaodong had made the necessary changes in ESPACE to accommodate the helicity
    scheme.  Source code was released October 17th.  DAQ deadtime should be less than
    20 to 30%.

    David Lhuillier gave an update on the Compton polarimeter:
        The main systematic error is probably due to the calibration of the polarimeter.
    New analysis code has been installed on-line and is ready for use.  Compton is very
    sensitive to the beam quality, so saGDH should try to get a good beam tune.
    During the experiment a day will be needed to check things out.

        To get better results at the lower energies, David will try to increase the gain and
    do tests during the experiment.

    Eugene Chudakov discussed the Moller Polarimeter:
         Moller works fine with the new helicity scheme.  Measurement error is dominated
    by the polarization of the foil.  Systematic error for the measurement is 3.4%.

    Bob Michaels gave an update on the DAQ and Raster systems:
         There is a problem with the charge asymmetry.  The charge asymmetry depends
    on the helicity order RL vs LR.  A check will be made into the electronics and Parity
    DAQ.  It is hoped that installation of a new high voltage switch will help fix the
    problem.

      An independent L-arm DAQ will be available.

    Ron Gilman discussed detectors:
       The L-arm detectors that will be used for saGDH are fine.  The L-arm gas
    Cherenkov has new PMTs.  For the R-arm Seonho Choi and Vince Sulkosky will
    check the gas Cherenkov.

    Nilanga Liyanage discussed online monitoring:
        For the optics commissioning, the software is ready.  Code to read scalers need
    some work.  Bob Michaels has ROOT macros, if anyone wants to use them.

        Seonho Choi will work on code for beam trips and beam ramping.