Chi-
I am glad you pointed this out. I was using runs 1348-1799 for a
new offset determination. This shift would certainly throw things off. I
assume the other runs before 1703 and after 1713 have the same offsets?
Pete
On Sun, 17 Aug 2003, zhangchi wrote:
>
> Hi all,
>
> I spot a shift in TOF tdc in run 1703 to 1713 against other runs from 1642
> to 1799. please see the atatched figure. it plots ttl with ntl==0
> and qwl ==-1 (average TOF tdc channel numbers after offset subtraction, in
> left paddle 0, generated mostly by electrons).
>
> the lower peak at left are runs 1703-1713, the higher peak at right are
> the rest of the runs in the range quoted above.
>
> these are all unpol deuterium runs taken during a few days running.
>
> It could be a real shift in electronics or due to a temporary change in
> offset file. No way to tell at this moment. It may be useful to save
> offset values with our data ntuple. it takes just another 200 float
> numbers at most into our root file.
>
> I believe all paddles on both sector are shifted together but need to
> look at TDC spectra in other paddles to confirm.
>
> Just want to let you know this and consider possible effects.
>
> Chi
>
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Pete Karpius
Graduate Research Assistant
Nuclear Physics Group
University of New Hampshire
phone: (603)862-1220
FAX: (603)862-2998
email: karpiusp@einstein.unh.edu
http://pubpages.unh.edu/~pkarpius/homepage.htm
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