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    User name nakahara

    Log entry time 07:59:37 on April 11,2004

    Entry number 82033

    keyword=Owl Shift Summary

    Owl SHIFT SUMMARY, Sunday April 11, 2004


    Leader: K.Nakahara

    Target: T.Porcelli

    Worker: M.Pitt, J.Arvieux





    The Halo rates and the position difference widths seem to "rise"
    after beam trips. Halo rates typically go beyond 20kHz, and
    position difference widths go as high as 20um.





    00:00 - Smooth running

    00:55 - changed RHWP, since PZTY was slowly going out of
    range.

    01:05 - DAQ crash. Killed codamaster and restarted it.

    01:05 - Halo rates jump on Halo3 to about 10kHz. MCC will try to
    steer this out.

    03:37 - Target alarm. PV12 closed. Going to controlled access
    to reset it. If it doesn't reset, we'll bypass it, and run like
    this til Monday when the Hall opens up.

    04:25 - Looks like we're having the same Halo trouble we had last
    night. HallB = 25nA, HallC = 2uA, and the halo rates are over
    100kHz (on Halo3). The BPMs are alive on the G0 girder. With
    JUST HallB on, and the HallC slit open, we see about 90kHz on
    Halo3. Could the bleedthrough from B be directly hitting the
    Halo target (or possibly just being sprayed into the Hall)?

    04:42 - MCC calls. They are taking beam away to check for
    separation (I take it this is RF separation for Halls B and C).

    05:15 - Detector HV trips. They were sending low current (1.5uA
    CW). We'll keep the HV off until the beam returns. Also, the
    tungsten radiator seems to be heating up whenever they send beam
    to Hall.

    05:20 - MCC calls. They will try 40uA now.

    05:45 - MCC calls. They are unable to send more than 36uA
    without getting a BCM trip. In order to fix this, they would
    have to do some extended studies (no time estimates, but expected
    to be long). Called the RC. We've decided to run like this
    until 7am when we can evaluate the beam quality again. 


    
BPM	x	y
    
H00A	-.34	-.97
    
H00C	-.72	0.08
    
G0	-1.17	-2.01
    
G0B	-1.58	1.84
    

    
Halo1	3.9Hz
    
Halo2	0Hz
    
Halo3	4.4kHz
    
Halo4	7kHz
    
Halo5	33kHz
    
Halo6	25kHz

    The positions are quite a bit off from nominal. MCC retuned the
    beam to a position where the halo rates are reduced.

    06:00 - VESDA alarm goes off.

    06:00 - See HREF="http://opweb.acc.jlab.org/CSUEApps/elog02/elog_item.php?elog_id=1205746">ELOG
    entry 1205746. There seems to be significant scraping at 3C01.

    06:05 - Halo rates go up to 10kHz on Halo3. Asked MCC to try and
    reduce it. We now have new positions again


    
BPM	x	y
    
H00A	-.97	-1.04
    
H00C	-1.25	-0.02
    
G0	-1.77	-2.19
    
G0B	-2.12	-1.68



    06:13 - MCC's investigation on halo rate change, position shift,
    and energy shift continues in HREF="http://opweb.acc.jlab.org/CSUEApps/elog02/elog_item.php?elog_id=1205747">Elog
    entry 1205747.

    06:55 - MCC's investigation on south linac energy shift continues
    in HREF="http://opweb.acc.jlab.org/CSUEApps/elog02/elog_item.php?elog_id=1205751">Elog
    entry 1205751

    06:55 - Another Detector ion chamber trip. HV turns off.
    Reseting interlock board.

    07:20 - Called MCC after consulting with RC. We ask them to take
    the beam to concentrate on fixing the problems that we have.

    07:30 - Just to make sure, called MCC to tell them that this is
    counted as BNA (especially after seeing Jacque's entry of the
    helicity correlated differences...the diverging energy
    differences in particular).

    07:40 - MCC taking beam to do some further investigating into our
    problem. Moving target out of beam.




    Runs taken:


    21310 LH2 production - continuing from previous shift.

    21311 RHWP

    21312 LH2 production. DAQ crash...run didn't start

    21313 LH2 production

    21314 LH2 production

    21315 LH2 production

    21316 junk

    21317 LH2 production

    21318 LH2 production - Detector ion chamber trip

    21319 LH2 production