_ Problem with Rtof11(top) was chased down extensively (cable change,
changed ecl fan unit, swapped 11 w/ 12 at patch) but still no solution. I
had to drop this job at some point. Anyways, the problem is not so much
the annoying spurious Rtof11(top) TDC but rather that if I trigger on
Rtof11 I only have the *bottom* TDC and so no good TDC information for
that scintillator
_ regulated offset at C analog adder. C pedestals are all above channel
100 of ADC now
_ At run 728, it was realized that yesterday, after equalizing L-sector
and R-sector large time offsets, we actually lost the good e-p coincs
(with a start counter plugged in the left sector trigger, but physically
on the right, your coincs will mostly be electrons on left and protons on
right). More details on why this could have happened are in the logbook.
Anyways, since you now want protons on right sector (before, you wanted
e- on right, for timing purposes) L-R prompt triggers could have been
pushed away up to 30 ns, largely due to the longer (up to 20ns) protons
tof and the adjustment made.
The problem is really because we have overlap (not coinc) of top/bot/mean
for each scintillator channel which gives us very little width to play
with (overlap must be found in 60 ns) We also discussed what a possible
workaround could be (use discriminators after MLU!). However, can also try
to maximize overlap with width of CFD top/bot width and avoid the
constraint introduced by the start counter in the e-p trigger. Will be
investigated tomorrow during hall access
Went back to "original" configuration with the left and right sector
again 14 ns apart (for electrons) and start counter in the trigger.
left sector (with the start counter) comes in later which lines up well
with a right sector proton.
REMEMBER TO TURN HV OFF AT MIDNIGHT!!
________________________________________________________________________________
Tancredi Botto, phone: +1-617-253-9204 fax: +1-617-253-9599
research scientist MIT/Bates, 21 Manning Av Middleton MA, 01949
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