some thoughts:
In red/black DOTS the beam current from the inhibit/not inhibited charge
scaler as a function of time (the curve is "coda" events). In the bad.gif
attach the bg-scaler clearly counts during a fill. The fill takes some
time at around 80 mA between (1355.12-1355.14)*1e4 seconds (seconds are
counted since 00:00:00 01/01/03...)
So without precautions in this fill we'd integrate about 200 s in a given
beam helicity state. This problem was caused by the fact that the daq-inhibit
control was over-ridden in epics hv (see prev mails).
The work-around is to cut the charge/asymm data according to the ratio
bgbeam/beam. If I do such cut the bgate charge essentially is counted
only during the stable part of the fill (good.gif)
So I added this to charge and ran
root charge.C -ltmax 0.995 -ltmin 0.0 705-709 711-718 (710 is a bad run)
to write the right charge files (takes 5 mins). For consistency we should
analyze/re-analyze other charge files with the *same* cut. Otherwise we
can not cumulate statistics properly (or easily)
-----
Asymmetry
for the asymmetry I do
root show_ep_asym.C -c truew -c lvtime -c zlrw_tight -c coplaw_tight -c padcq_cc 705-709 711-718
note that -c lvtime corresponds to the above cut on bgbeam/beam (from
scalers), i.e. livetime between 0.0 and 0.995 to "remove" the events taken
with stby/ramping hv, during a fill. It is one of the nice features of the
recent changes in lrn.C
Of course the asymmetry macro has no hardcoded cut, except the ones needed
to sort out spin states. You have to source cut definitions from cuts.C
Note the difference between padc_cc and padcq_cc. It is just not enough to
require a CC "hit", I also require a non-zero adc.
-----------
Analysis:
Are we sure that the beam helicity is the same in + and - state????
Yesterday's email shows it is was not (+88 , -66) which is the size
of our "signal".
Some compton analysis would be welcome
----------------
I'd not time to look back at compare.C. It should work, but i ve not
checked.
--
________________________________________________________________________________
Tancredi Botto, phone: +1-617-253-9204 mobile: +1-978-490-4124
research scientist MIT/Bates, 21 Manning Av Middleton MA, 01949
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