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Archived Messages for TAGGER@cebaf.gov: Update
Update
B. L. Berman (berman@gwis2.circ.gwu.edu)
Mon, 20 Apr 1998 21:14:25 -0400 (EDT)
Dear Photofission folks:
As the clock begins to run out, here is where we stand. We got about 15M
events at 4 GeV (out of 20M needed for 3% statistics) before we were shut
down to install the polarized source. This installation cost us 5 shifts
and much misery since. In spite of this, we ran well at 1.7 GeV, and
achieved our goal of 15M events by about noon today. We then changed to
one-pass beam, about 870 MeV, and got beam a few hours ago, but it was
unstable, had a halo, etc., and was scraping the beam pipe in the
extraction area. Now we are off, waiting for Hall A to complete some
measurement, after which time the accelerator people will try to find and
fix our problem. But the beam is very unstable, which might be the
polarized source expiring, but may be mere optics. If we can get beam for
even one shift, we can take some data, but that has to be regarded now as
not terribly likely.
In any case, I think we can say, as near as we can tell right now, that
the experiment was a success, at least at 4.0 and 1.7 GeV.
Wish us luck with one-pass beam!
Cheers, Barry
Barry L. Berman
Professor and Chair
Department of Physics
The George Washington University
Corcoran Hall, Suite 208
725 21st Street NW
Washington, DC 20052
Telephone: (202) 994-7192
Secretary: (202) 994-6276
Fax: (202) 994-3001
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