This sounds plausible but we can always check the TOF gains using recent
cosmic data - just in case of a gain shift. I am not sure that enough
data is accumulated each run with the onine GUI to do this.
Pete
On Tue, 2 Nov 2004, Tancredi Botto wrote:
>
> Hi chris,
> I understand you missed most of your events in the forward region, for e-
> corrisponding to proton paddles 9-14.
>
> It can not be rad tail since that is continuous. However the front tofs
> are only 15 cm wide. Assuming (for discussion sake) they really project
> out 15 cm perpendicularly to the e-track (it could be less becuase of the
> angle) than 7 % would be a 1 cm gap (7 mm for a 10 cm projection).
>
> This number a bit high but maybe not completely unreasonable. We may be
> less efficient when a track traverse part of the 1" thickness (which adds
> to the definition of the gap..).
>
> Or maybe a part of these events are random hits that somehow make it
> through your cuts (z? coplanar ? "proton" adc ?)
>
> -- tancredi
>
> P.S.
> Certainly 93 % is not a very good number for tof efficiency for e- !
> I understand it is a worst case scenario number
>
> ________________________________________________________________________________
> Tancredi Botto, phone: +1-617-253-9204 mobile: +1-978-490-4124
> research scientist MIT/Bates, 21 Manning Av Middleton MA, 01949
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
> On Tue, 2 Nov 2004, Chris Crawford wrote:
>
> > being concerned about rates in some of the tof scalers, i decided to
> > look at the tof efficiency in the recent 32deg and 45deg runs. i looked
> > at events with good wc tracks in both the left and right sectors, and
> > then counted the percentage of events missing either the left or right
> > tof. so this gives information about the efficiency, but is is smeared,
> > since the efficiency is not as a function of the missed tof, but instead
> > the paddle number of the corresponding tof in the other sector. the
> > missing tof events were unprescaled according to the trigger number.
> > anyways, the conclusion is that 17 TOF's were at least 98% efficient,
> > while the rest were at least 93% efficient. this does not take into
> > account space inbetween the paddles, etc, but gives a general impression
> > of the performance.
> > --chris
> >
>
>
----------------------------------------------
Pete Karpius
Graduate Research Assistant
Nuclear Physics Group
University of New Hampshire
phone: (603)978-6152
FAX: (603)862-2998
email: karpiusp@einstein.unh.edu
http://pubpages.unh.edu/~pkarpius/homepage.htm
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