• Main INDEX
  • Monthly INDEX
  • PREV
  • NEXT

    User name R. Michaels

    Log entry time 05:27:14 on September27,2005

    Entry number 156173

    keyword=dipole scan

    Armed with our new detector HV, we repeat the dipole scan
    that was done Aug 15.

    Run 2770 was a baseline at "0%". After doing 2% by changing
    the momentum setting, we started to change only dipole current
    (leaving quads alone). As usual, only the Left HRS.

    Spectr. DAQ Run .... dp/p

    2770 .... 0
    2771 .... +2%
    2772 .... +4% (dipole only, left quads alone)
    Oops !! Runs 2771 & 2 are junk, for 2 reasons: 1) We didn't turn
    off NMR regulation (affects run 2772), and 2) We need prescales
    to emphasize L-HRS T4.
    Repeating ... now only changing dipole current.
    We find that the fastest way to proceed is to leave NMR on,
    change P setting, then put quads back by hand. For such a
    crude scan, it doesn't matter very much.
    2773 .... +2%
    2774 .... +4%
    2775 .... +8%
    2776 .... +12%
    2777 .... +14%
    2778 .... +20%

    To compare the counting mode to integrating mode, I used the integ-
    rating data from Aug 15 (halog 151958). The two DAQs agree better
    now (rough online result in fig 1) because the counting mode "sees"
    more of the background that the HAPPEX DAQ sees -- in counting mode,
    it is a tail of low energy stuff near pedestal, like I've been saying.



    FIGURE 1