This morning, the ABS strong field transition unit failed in a manner
which prohibited any further operation. A final test determined that the
problem was internal to the ABS vacuum system, and at the Bates Operation
Meeting, the decision was made to open up and fix it. It is expected that
running with the polarized target will not be possible until at least
Friday.
However, vacuum in the ring will be preserved and it will still be
possible to take data with the empty target and unpolarized gas system.
This means that by default, BLAST shifts are ON. The presently envisioned
schedule for the week looks roughly as follows:
Mon. 5/10
Day: Work in South Hall. Preparation to pull out ABS. Access to pit
required and BLAST split.
Late afternoon: Close BLAST, clear Hall and take data until morning.
Tues. 5/11
Day: Work in South Hall. ABS pulled out and brought upstairs for bench
tests.
Late afternoon: Close hall and take data.
Wed. 5/12
South Hall remains closed while ABS worked on upstairs. Continue to take
data.
Thurs. 5/13
Day: Open South Hall to re-install ABS.
Night: ABS pumps down. Take unpolarized data.
Friday 5/14
Day: Get ABS tuned up. Prepare to take polarized data over weekend.
Clearly, all of this is very tentative and subject to change. Repair of
the ABS has the highest priority and any time in the Hall which is needed
to do this will be granted. The run plan will be revisited on a daily
basis at the 3:00 meeting and a decision on whether to cancel any shifts
will be made at that time. Anyone with questions about whether to report
for shift should check in with the run coordinator (me until Wed. morning,
Tancredi after that). More detailed questions about the ABS work should
be referred to one of the target experts.
Bill
-- ********************************************************************** 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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