Minutes of the E00102 meeting
Thursday, September 20, 2001
BR

present:

DH  Douglas Higinbotham
WH  Wendy Hinton
JLR John LeRose
DM  Dave Meekins
BM  Bob Michaels
BR  Bodo Reitz
AS  Arun Saha

1.) Target (DM reported)

    Pressure test of the target went fine, after using
    new flanges. The required overpressure of 20 psi was reached.
    Leak tests went fine.

    DM is going to equip the ladder with solid targets, but has
    no BeO Target yet. The whereabout of the one used with
    the cryotarget is unknown. It might be broken or at RadCon.
    There is a BeO mounted on the polHe-3 . Hall C might have
    one to borrow.

    WH asked for target thickness (BeO) and the possibility of
    using a "multifoil" BeO target, to compensate for a smaller
    thickness, and for the limited beam current, (5 uA if we do
    not want to use raster)

    DM said, Stack of BeO targets is not doable in time, thickness is yet
    not known.

    JLR suggested to use the raster: optics and acceptance of the
    HRS are not changed, so there shouldn't be any problem.

    AS asked for some kind of target training for shift workers.
    DM reported that everything in normal mode is straight forward.
    But we will need a set of people, to be "on-call", just in case.

2.) Shift-work

    AS reported, that we have new shift workers, who will probably
    arrive after the start of the experiment. Asked JLR about the
    necessity of the Hall A walk through. This topic has to be
    discussed with Kees.

3.) Collimators

    JLR reported, that one can always use "software collimation",
    which is fully understood. For the hadron arm, the collimators
    can lead to additional background due to scattering from their
    edges. For the electron arm, the acceptance is not really limited
    (defined) by the collimators anyhow. So the only advantage in
    using them, might be to reduce some background from crappy
    events. BM pointed out, that this might be helpfull if
    we are operating with very high single rates (electronics deadtime).
    So the suggestion is: not to use collimators on the hadron arm,
    to test at the beginning of the experiment, if they are helpfull
    at the electron arm.

4.) DAQ

    Bob Michaels reported, about the upcoming work on the trigger:
    - cleanup double pulsing   ***
    - width adjusters          ***
    - R-arm trigger supervisor ***
    - coincidence trigger      ***
    - install S0                **
    - install RICH              **
    - Scaler readout 30 Hz       *
    - Mods to dataspy and dhist  *
    (*** essential for the experiment, ** nice to have, * not necessary)
    He pointed out that a R-arm TS is necessary, only if we have
    to go below 1 GeV/c with the hadron arm, whereas it is easier
    for the RICH installation, if it remains on the left arm.
    WH checked, that there is no setting, neither in the
    commissioning nor in the production phase, below 1 GeV/c,
    so we told Bob, to leave it on the left arm.

5.) detailed RunPlan (WH)

    WH presented an example from KF, how a detailed runplan for
    each kinematic could look like.
    - they final numbers might slightly change: if beam energy is
      slightly different, some angle might be different
      we have to learn about the right beam position numbers
      (or we have to change the offsets)
    - collimater setting has to be adjusted during the experiment
    - according to BM, prescaling the single rates down to 5 Hz
      is fine, at least for settings lasting for many hours
    - DM suggested, that for the fast kinematics, we might
      consider taking special runs, with other prescale factors

6.) The question of the maximum beam current into Hall A was
    mentionned by AS. He will discuss it with Kees.