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User name R. Michaels
Log entry time 04:45:48 on August 4,2006
Entry number 177331
This entry is a followup to: 177305
keyword=T2 check (R-arm)
The fact that T2 rate exceeds T1 rate intrigued me, so we set ps2=20
for run 20607. Now I can see that ~98% of T2 don't even have a hit
in the VDCs. Even T1 is mostly junk, 92% with no hit. But I think I
know why: The momentum setting is the beam energy and the angle is 28
degrees, so the elastic peak will sit at P = 345 MeV which is dp/p = 4.6%
which is just outside the acceptance, probably hitting Q3 and producing
background and a lot of neutrals. If the idea of this R-HRS was to
monitor the elastic peak, it should be set for P=345 MeV by my calcuation.
In any case, it is premature to worry about T2 trigger with such data.