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:  October 18 or 25 2002
 
 

    Kees de Jager opened the meeting by discussing the schedule:
         At best the first septum will arrive by Friday, August 23, 2002, and Ed Folts has
    said the Hall will be ready by September 18.  There will be no second septum for the
    running period this fall, and due to the possible late arrival of the second, the
    experiment could be extended.

        Two installation issues that Kees reminded the collaboration about are a solution to
    the field gradients and using the left spectrometer for false asymmetry measurements.
    The use of the left HRS is a 'like', if time permits.

    Alexandre Deur discussed issues and the runplan:
         There are four major issues for the experiment:  the septa, field gradients, Ice cone
    cells, and the beam halo.  We will only have the R-arm septa for the experiment, and
    the delivery date can still slip.  The septa causes field gradients in the target area
    ~ 140 mG/cm.  Usual compensation coils will not work, but Alexandre is working on
    a new concept and design.

        For the Ice cone cells, the first good cell exploded (Victor), and since then have
    only produce marginal and bad cells.  But the most recent cell Patton has
    ~ 61 hour lifetime.

        Alexandre has been working on understanding the raising tails in the elastic
    scattering cross section from the GDH experiment and the impact on SAGDH.
   By reducing the thickness of the Al and Be windows from 10 mil to a single 4 mil
   Be window, the impact on SAGDH will be small.  But there may be problems finding
    a 4 mil window that will work for the experiment.

        The runplan is ready with 11 kinematics.  Coverage includes low Q2 points with
    one point overlap with E94010.  Will Switch cell after low energy running is completed.

    Jian-ping Chen discussed the status of the septum magnets:
        The first septum is primarily put together.  Delay of about a week due to a leak
    repair.  Situation still pretty good, but from Paul's estimates there is a lot of work left
    that could take 10 days to 2 weeks to complete.

    Ed Folts discussed the target and septum installation:
        The target platform is in place, and the platform for the magnets should arrive by
    the end of the week.  The laser hut is in place with plans to finish installation on
    Saturday.  Ed estimates it will take 3-4 weeks once the septum arrives to have
    everything ready for the experiment.

   Al Gavalya discussed the design Status:
        The design work has progressed well with finishing touches being applied.  Al is
    working on the collimator mounts.  Susan is working on making the pick-up coil
    mounts removable, and Joyce is working on a designs to place a target down stream
    for monitoring the false asymmetry with the Left HRS.

        Al is also working on the oven flux lines to prevent the oven shifts that were
    seen during last year's experiments.  A major concern for design work that remains
    is designing the gradient compensation coils.

    Steve Lassiter discussed solutions for the field gradient:
        From earlier simulations, Steve found that a 1" field clamp sucks the flux away
    from the helmholtz coils.  Since the discovery Vince Sulkosky and Alexandre Deur
    have been working with Steve to find a solution to the gradients from the septum.
    But the current correction coils are not adequate to compensate for the gradients.

        Steve discussed one possible solution that would enclose the coils by an iron box
    with 1/4" or 1/8" walls.  The technique has been used successfully before.  Steve and
    Paul Brindza will look into the possibility next week.  One major draw back will be
    that the target area will be a closed area with potential radioactive materials and ODH
    concerns.

        In the meantime, Alexandre will continue looking into a new design for
    compensation coils that could use 8 coils and 4 power supplies.  The  power
    supplies should be selected so that they can easily be incorporated into EPICS.

    Scott Higgins gave an update on the Septum controls:
           An IOC has been installed for the septum controls, and a driver to talk to the
    PCL was tested several months ago.  Settings for the septum magnets will be
    integrated into P0 on the HRS, which will take a couple weeks once the
    septum arrives.

    Doug Higinbotham discussed the Septum Optics commissioning:
        Doug will be the run coordinator for the optics commissioning period.  John LeRose
    will take care of tuning and the initial database.  Werner Boeglin will work on testing,
    while the graduate students will take care of the on-line analysis.  Plus additional help
    is available from Nilanga and possibly FIU.

        For the sieve slits, is an OSP needed to put the sieve slits in and out?  The
    commissioning period is 11 days but can be shortened for a single septum.

    Nilanga Liyanage discussed online monitoring:
        We will use the "official" version of ESPACE, which has all the detectors we will
    use and column wise ntuples.  Kumac files will need to be updated to take into
    account the new variable names.  Files ready in 2-3 weeks for detector tests.

        For physics analysis, we will need a new optics database.  Take about a week
    of work to get an online database.

    Ron Gilman discussed detectors and helicity monitoring:
        Ron gave an update on the hardware changes for the G0 helicity system.
    Bob Michaels will be responsible for scaler readout changes and helicity info
    in events.  Xiaodong will take care of the ESPACE upgrade.

        For the helicity system, signals to the counting house had problems that were traced
    to glitches in the pseudorandom sequence.  Cabling for the L-arm should be ready by
    end of the month.  DAQ will be set up in several days.  Collaboration wants to look
    into getting in time helicity signals to Hall A.

    Bob Michaels gave an update on the DAQ, trigger, and Raster systems:
         The R-arm 2nd Fastbus crate is installed, and expect 3 kHz with 20% DT.  L-arm
    DAQ will work independently.  Experiment will use two independent DAQ's like last
    summer.  Parity charge asymmetry feedback is ready.  Bob Michaels will provide a
    new detector map.  Spot++ has been updated to provide BPMA and BPMB as well.

    H. Areti discussed the Beam:
        G0 needs an average current of 40 uA.  Bleedthrough less than 20 nA with fully
    opened Hall B chopper slit.  To generate G0 beam needed to modify Ti-sapp laser.
    Still much work to be done.  Should discuss beam requirements for SAGDH next week
    at a scheduled meeting between Accelerator and the collaboration.

    Sirish Nanda gave an update on the compton polarimeter:
        Fabrey-Perot cavity is operational.  Spare mirrors should arrive in a month or two.
    Compton console still in the back room.  Need trained operators for the experiment.
    One possibility is to use an xterm to monitor Compton from the front room.  Issue to
    implement G0 Helicity scheme, need software modifications.

   Eugene Chudakov discussed the Moller Polarimeter:
       A new detector will be installed for Moller.  Eugene needs some help to mount the
    new detector in about 2 weeks.  The detector has been checked and is ready for
    installation.  No problem with implementing the G0 Helicity scheme.  Systematic error
    for Moller is about 3%.   Will need to measure polarization for each energy and any
    configuration changes.  Approximately 2 measurements a week.

    Discussion of Beam energy measurements:
        Use both ep and ARC measurements and Tiefenbach.