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Archived Messages for CLAS_PHOTON@cebaf.gov: minutes of 5/19/98 photon analysis meeting
minutes of 5/19/98 photon analysis meeting
Burin Asavapibhop (burin@jlab.org)
Wed, 20 May 1998 08:43:01 -0400 (EDT)
In attendance: Eric Anciant, Burin Asavapibhop, Thierry Auger, Steve Barrow,
Barry Berman, Mike Dugger, Laurent Farhi, Rob Feuerbach,
Dave Jenkins, Rory Miskimen, Gordon Mutchler, Sasha Philips,
Elton Smith, Simon Taylor, Amrit Yegneswaren, Sylvain ???
Report:
Marco Battaglieri reported by email that he analysed the G1 cooked data and he
had to do run-to-run recalibration for TOF and noted the time offset between ST
and Tag seem to move. In response, there is a question whether the calibration
done during E1 is also good for G1. There is also an issue about the accuracy
of momentum reconstruction from tracking which also can contribute to the
shift in mass spectrum. Theirry will look into this momentum reconstruction
with gamma p --> pi+ pi- p reaction.
Eric gave a brief explanation of the tagger result bank(TAGR). The time from
TAGR bank is the time when photon radiated from radiator relative to the
trigger time. This time has been already fit into the RF bucket.
Burin presented the results analysed using the tagger time to get the event
starttime. He observed 4 obvious peaks for the starttime which gave the wrong
beta and mass. There was a discussion on this but right after the meeting Eric
realised that the run Burin used was not good due to some hardware problem
in a tagger TDC. Simon and Burin will analyse the run 11578 taken yesterday
with 250pA and no prescale for comparison.
CAUTION: Run#11245-#11446 have the above TDC problem. Handle with care!
We will try to have this meeting every week.
Next meeting: Tuesday 26 10am L207(We will confirm again)