Compton Polarimeter people had the beam all night. I took an empty
target run while they worked.
2940: 0 sccm; beam: 14 mA/40 min.; field off
besides this, i worked on LR asymmetry study, mostly testing out pete's
calibration for the tdc offsets. i used his tdc_offsets.C macro to
generate 'blast_sc.cal' for a set of runs (2749-2769), then used that
calibration file to produce new ntuples for those runs (i moved the
original ntuples to eep-noff-* ), then ran various incarnations of
'show_protons' on them. the offsets seem to be roughly ok. that is,
when i plot ttr:ttl and look for the protons, the bunches are roughly in
the same place (between 2000 and 2400 channels), which makes it possible
to define a universal cut (cutting directly on the proton tt). however,
there is some variation from paddle to paddle which makes these cuts not
so good (to see this, try running 'show_proton_tdc.C' in devel/ on one
of the runs mentioned above). anyway, i managed to get asymmetries out
of this (using 'show_LRasym.C', plot in log book), and the peaks that
remain after the cuts (oh, i also did a '-c pjadc') are pretty clean.
part of the asymmetry may have to do with the fact that the left and
right cuts are not the same, so may be more noise in one than the other,
but it's hard to say much about the asymmetries right now. basically,
the tdc offset work that pete has done seems very encouraging.
js
-- -------------------------------------------------------------------- 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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