Shift started off with CCR tuning the beam for about 2 hours.
Initial slit adjustemt by Doug was done in the control room while
using the beam halo/qual monitors (BQM) as a rate reference.
Further optimization was attempted by adjusting the two sets of
steering magnets that are just upstream of BLAST. The offered only modest
reduction in halo for a large sacrifice in lifetime so it was deemed that
the BQM values for slit position were optimum.
It was noted that, upon re-injection, the normalized BQM rates were higher
by about a factor of two when compared with the rates seen during
optimization. The BQM normalized rates do not seem to be linear.
RUNS were taken with 0.1 SCCM Hydrogen in the target and it was seen
that we did experience a drop in WC signal to noise from the "good
reference" ratio of 8:1 to 3:1 in the inner chambers. This is thought to
have occurred during the initial part of the lifetime when the BQM norm
rates were doubled.
A slit optimization using physics 5&6 trigger rates was done starting from
the BQM optimum slit positions. A slight adjustment was made but this was
accompanied by a minor compromise with lifetime.
After doing these studies it seems that the best thing to do is to let the
machine physicists tune the beam tomorrow using the beam halo monitor.
DH, MK, PK
----------------------------------------------
Pete Karpius
Graduate Research Assistant
Nuclear Physics Group
University of New Hampshire
phone: (603)862-1220
FAX: (603)862-2998
email: karpiusp@einstein.unh.edu
http://pubpages.unh.edu/~pkarpius/homepage.htm
----------------------------------------------
This archive was generated by hypermail 2.1.2 : Mon Feb 24 2014 - 14:07:29 EST