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User name Pitt
Log entry time 13:26:15 on February 03, 2007
Entry number 132464
keyword=Sudden improvement in beam conditions
MCC has been having trouble with halo for the last 45 minutes or so. The
halos had risen to ~ 100 Hz/uA. It was clearly non-linear with current
because at currents below 10 uA it looked fine (about 30 Hz/uA).
MCC tried a lot of steering, but the halo didn't seem to show any
improvement. Finally, they tried a minor change to a quad upstream of
the Hall C arc (3C08) and they had a dramatic reduction in the halo
values. The current values are (at 35 uA):
Halo 3: 23 Hz/uA
Halo 4: 26 Hz/uA
Herbert's paddle: 5.95 uA at 35 uA