• Main INDEX
  • Monthly INDEX
  • PREV
  • NEXT

    User name Armstrong

    Log entry time 19:26:48 on July27,2005

    Entry number 149705

    keyword=phase advance test

    MCC has loaded new optics after FOPT studies of the Hall A line.
    This should lead to good vertical phase advance. 
    I run a HAPPEX run (3878) - this was at 10 µA with no
    target. No data seen in dithering plot - must be the low beam cut.
    Try another run at 30 µA. This is run 3879.
    Error on my part lead to no dithering cycle in the data (I started dithering 
    before the run started, and the run was not  long enough to see a dither cycle 
    (every 8 minutes or so, says Kent). 
     Nonetheless, I see from the natural beam motion that the situation is still 
    bad: BPM4BY and BPM4AY are 100% correlated (the x's show
    nice differences). Thus there is still no Y phase advance seen.
    See figures below. 
    This is despite Jay's optics model doing a great job of predicting the response 
    of all the other BPMS in the Hall A line to various correcter kicks (with 
    FOPT). Unfortunately, the FOPT program doesn't have our 4A and 4B BPMS in the 
    configuration file so we can't see the effect directly in the FOPT test.