Experiment shifts are on as of now, but the program is still predominantly
beam tuning. Stored beam in the ring has been established, but it has
proven difficult to reproduce the conditions of the last run. At this
point, it is unclear whether the new target cell and collimator are
limiting the beam current and lifetime. However, the halo rates that have
been attained so far are significantly worse than during the last year's
run (higher by factor of 3). Maximum achievable current is about 100 mA
and lifetime has gotten up to 25 minutes but is highly unstable.
The detector HV was turned on to take data for a test run at 50 mA. Rates
were very high, but the detectors were able to hold voltage. A few
problems were found, one pertaining to wire chamber time spectra for left
TDC6 and another to a lack of elastic triggers in the data stream,
although they show up in the scalers. These are documented in the
log book and are under investigation. The computer live time is very high
due to the data acquisition improvements.
The plan for the evening is to continue investigating steering in the ring
to see if beam conditions can be stabilized. If so, we can resume taking
empty target data and debugging the experiment. Jan van der Laan may come
in to help out later tonight with the beam tuning.
-- ********************************************************************** Wilbur A. Franklin * Phone: 617-253-9518 Bates Linear Accelerator Center * FAX: 617-253-9599 P.O. Box 846 * Email: wafrankl@mit.edu Middleton, MA 01949 * **********************************************************************
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