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    User name E. Schulte

    Log entry time 11:11:09 on November 06, 2007

    Entry number 212901

    This entry is a followup to: 212747

    keyword=Updated plans for the next few days

    At the morning MCC meeting we discussed the issues surrounding the energy
    change this week.

    The issue of when to perform the energy change arose after the Hall was
    informed by the Cryo Group of the need to defrost the heat exchanger and
    warm return line to the CHL. To do this the coolant to the Hall targets
    needed to be shut off. This renders the targets out of use until coolant
    to the cryostat can be returned. It is estimated to take approximately 2
    days time to defrost the heat exchange equipment and warm return line to
    an acceptable level. The hope is that allowing for this two day warm up
    and defrosting will allow the Hall to keep the targets cold until they
    are idled for the Thanksgiving Holiday in about two weeks time.

    A pass change from 2-Pass to 4-Pass was scheduled for today, with the
    energy change to 800 MeV/pass to follow on Wednesday. With the target
    warmup this pass change was rendered unusable at this time. As a result
    yesterday (11/05) we requested a shifting of the energy change by 2 days
    from Wednesday to Friday. Hall C reluctantly agreed on Monday (11/05);
    however, Hall B was opposed, as was MCC.

    MCC was concerned, justifiably about slipping the schedule in this
    manner. During this morning's 07:45 meeting MCC suggested moving the
    energy change up one day to today (Tuesday 11/06) if the staff could be
    coordinated to perform the energy change. Hall's B & C were agreeable to
    this scheduling change. After some looking into the schedule, and
    coordination among the halls, D. Skopik, and the MCC, the decision to
    move the energy to today was decided upon. The energy change started at
    10:00 today.

    Thus, the ARC energy measurement, bull's-eye scan, and current
    calibration originally set for today will NOT take place today. We will
    have to reorganize these tasks for after the beam returns.

    Tomorrow we will go to Restricted Access for the surveys of the
    spectrometers and target harps. The target harps were moved about last
    week to correct/understand why we were not seeing all three wires on harp
    1H03B. Several people have asked to go into the hall to look at some
    issues which have arisen (such as Cerenkov channel 10 HRS-L, moving gas
    bottles in for the targets, etc.). After the survey of the spectrometers
    is complete, they are to be moved to 120 degrees.

    The following will need to be scheduled/rescheduled:

    1) 3-Pass beam at 700 MeV/pass: On or about 12/15 (to compensate for
    the loss of 4-Pass beam at 500 MeV/pass)
    2) 2-Pass beam at 800 MeV/pass: Between 11/14 and 11/19. The plan is
    to shift the 2-Pass Hall A running and Hall B 4-Pass running (where we
    should have come up after the energy change tomorrow (11/07)) to the end
    of the 800 MeV/pass running period just before the Thanksgiving holiday
    break.
    3) The other associated beam study activities,
    a) ARC energy measurement
    b) Current calibration
    c) Bull's-Eye scan
    and so on.


    A copy of this log entry has been emailed to: jpchen@jlab.org, choi@jlab.org, kees@jlab.org