Ran polarized ABS. nozzle started freezing at 10:30, ligit pressure
dropped by a factor of 2 in 3 hours. at this piont we stopped and
switched over to unpolarized.
runs 322-328 (polarized) ~ 600 Kevents
runs 330-332 unpolarized ~ 200 Kevents
Vitaliy warmed up the target, line pressure went from 12.3 to 11.5 tor,
then started cooling down the target again. Hopefully polarized target
will be available for the night shift.
One problem that Vitaliy noticed is that CCR was taking the 1/2
waveplate in and out during the fill (when the current dropped below 40
mA). this of course does not change the helicity state of the real beam
in the ring, but it does change the epics variable from which we read
the beam helicity, which means that for every fill, all events that come
after the beam drops to 40 mA have the wrong helicity value written for
them. CCR now only flips the beam helicity once we ask for a fill, so
this shouldn't be a problem for future runs. Tancredi hacked a fix into
lrn.C and we re-crunched all ntuples from run 303. so these runs should
have the proper value for 'hel' for example.
one minor problem with the wire chambers came up. groups of five cells
were missing from each of three sense wires. this corresponds to a box
tripping. We ran setup to restart everything, and the cells came back.
tried to find asymmetries, but so far there is no clear asymmetry. for
those of you coming on shift, try out 'show_test.C' which is in devel.
this script calculates the asymmetry as a function of electron
scattering angle on the left side and the right side, and also forms the
super ratio between the left and right asymmetries. currently, you'll
have to find the inhibited charge from charge.C, and put them into
show_test.C by hand so that the different histograms will be properly
normalized.
JS VZ
-- -------------------------------------------------------------------- jason seely 26.650.b massachusetts institute of technology 77 massachusetts avenue cambridge, ma 02139-4307email: seely@mit.edu phone: 617.253.4772/6734 html: web.mit.edu/seely/www --------------------------------------------------------------------
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