• Main INDEX
  • Monthly INDEX
  • PREV
  • NEXT

    User name sarty

    Log entry time 07:31:04 on May22,2002

    Entry number 3920

    keyword=Owl Shift Summary

    **************** Executive Summary: ************************
    .
    - couldn't get raster to work properly, even after much effort & discussions with
    MCC; eventually MCC needed an access to hard-reset an IOC (at ~03:00).
    - the IOC reset created some havoc with cryolevels in the hall, and right arm Q2
    and Q3 tripped off, and we then set right fields all to zero because of dropping
    cryo levels. Mark Stephens came in, but eventually all cryolevls recovered and
    magnets got turned back on (by 05:10).
    - Discovered after all this (by 05:25), that raster still suffered same problem as before.
    Accelerator raster-expert (Bill Gunnings) suspects a hardware problem, but won't
    be able to get into the Lab until about 08:00 - he'll (hopefully) fix raster problem
    then.
    - Decide to use rest of time (before opening up for survey at end of shift) to set up
    for BCM calibration. (In the meantime, Q3 right arm trips a couple of times...still
    from low cryo levles). This starts for real at 06:50
    (Run 1751, BCM logfile at /usr/opdata/bcm_hallA/BcmLog_67).
    .
    - at 7:10am ask for access to prepare for surveyers to arrive.
    .
    ************ The Gory Details **********************************
    .
    00:00 Take over with Kin "O" ready to try starting production running - energy
    change completed last shift, harp-scan done to verify good intrinsic beam spot-size,
    and carbon pointing run done.
    00:00-00:40 .. Take a couple of "junk runs" to get raster set properly (1741,1742,
    1743) - raster pattern too small, and MCC needs to call somebody to figure out how
    to increase size of raster above 1mm x 0.75 mm (according to spot++).
    .
    00:40 - 01:20 .. We discovered (ok, we were told by MCC experts) that we, in the
    Hall A Counting House, have control over raster gains (the knobs below the raster
    scope). So, we increased the raster gain with these knobs (after confirming with
    Bodo that this really is ok), and worked to get spot back to correct size.
    01:20 - 01:50 .. Waited while MCC worked on recovering beam ("orbit problems")
    .
    01:55 - MCC cannot turn raster back on ... has us page their expert, Bill Gunning.
    He doesn't respond; MCC operator visits the counting house. Raster appears "on",
    but at very low gain (even with our counting house raster-gain knobs maxed out).
    MCC will now try to just reboot the controller to see if that brings back the raster
    (this controller also has the Moeller quad, so we have to wait for this to be cycled).
    Our guess is that this rebooting will work (based on vague recollections from 2
    years ago with similar problems...).
    03:00 - Upon trying to reboot the IOC that controls the raster, MCC was unable to
    regain communication with this IOC. They have called in people, and will likely
    need an access to look directly at the IOC. So we wait.
    .
    03:10 - While waiting, HRS-Right Q3 trips off. Won't reset..page Mark Stephens.
    Go downstairs, along with accelerator folk (Yves Roblin) who resets IOC in
    corridor to Hall A.

    03:50 - MCC calls to say that the radiator radback is 0 V (supposed to be 5 volts). Call J-P to verify that this is the old radiator which is not being used and also not physically present. Tell MCC to mask the error.
    .
    04:20 - Back up from trying to reset Q3 (and then also Q2) on right arm...couldn't do it; Reason - cryo levels are low and dropping. Set Right arm momentum to zero
    since Dipole cryo level dropping too. Called in cryo-expert-on-call to help (and it
    turned out he was already present in MCC). Apparently either the IOC that needed
    rebooting (or another one?) controls cryo levels in the hall (and maybe other
    places too?), and this remains not working properly - this is the root cause of our
    magnet tripping problems now.
    .
    05:10 - Cryo levels back, magnets back. Just waiting now for Right dipole to settle
    (had to turn it off while cryo levels were low). MCC will bring beam back, and
    we will try to re-check if the raster can now be set properly...By 5:25, we find
    that we still cannot set the raster (looks the same as it did at 1:55).
    .
    05:35 - Accelerator raster expert (Bill Gunning) isn't able to come in until about 8am
    (he is pretty sure there is a hardware problem). Also at 5:35am, Q3 Right trips off
    (looks like cryo levels low again...).
    .
    05:40 - Decide to use intervening time to calibrate BCMs. Ask for 80 microamps.
    MCC will set up to do BCM calibration, but we will wait until Hall B is ready for
    us to do the test, since we need to take beam away from Hall B to do it.
    .
    06:25 - Q3 trips again.
    06:40 - Start Run 1750 for BCM Calibration (Linearity test, more properly). Didn't
    work properly, junk it.
    06:50 - Start Run 1751 for BCM Calibration!
    (BCM logfile at /usr/opdata/bcm_hallA/BcmLog_67 )
    07:10 - Done! Ask for access for surveyers to come.