[d2n-analysis-talk] Fwd: LHRS Scintillator Calibration Study

[David Flay]

On Wed, Mar 3, 2010 at 3:37 PM, Chiranjib Dutta <chiran at jlab.org> wrote:

>  Hi David,
>           Sorry I could not get back to you last night. I am just screwed
> up with all different things and I am going to Colorado
> tomorrow.
>  I think your offsets look good. Now go to:
>
>  /w/work5602/transversity/chiranjib/analysis/replay/DB/20081116 and then
>
>  db_L.s1.dat and db_L.s2.dat
>
>  I would not trust too much on the s1 database as I did not do any time
> offsets there. But I think I did the timewalk.
>
>  S2 should be fine.
>
>  Let me know if you happen to run into problems !!
>


I am having a strange problem... if I check the scintillators for different
momenta, it seems all good for elastic run 1229, and 20145 (p = 0.6 GeV,
5-pass -- as opposed to 4-pass that I showed you just now).

However, with seemingly increasing momentum, I get strange behavior
(particularly in S1 time avg) -- see attached plots.  Note -- beta also
isn't that consistent as p changes..

This doesn't make sense to me -- I'm using the same DB file for every run,
to my knowledge when I made the updates.  I've seen no HV changes in the
HALOG... it would make more sense to me if I saw the time offset change in
S1 as well, but it's still ~ 1 or 2 ns if not 0... There are fluctuations in
the time offsets if you look paddle by paddle -- but that structure in the
time avg for S1 is baffling (see 20263 plots -- p = 1.42 GeV, 5-pass.  If I
go higher in p, the effect seems to become more and more pronounced..)

I originally thought this calibration should be momentum independent...


P.S. -- How did your interview go?  If you didn't have it yet, good luck!


-- 
-----------------------------------------------------------
David Flay
Physics Department
Temple University
Philadelphia, PA 19122

office: Barton Hall, BA319
phone: (215) 204-1331

e-mail: flay at jlab.org
           flay at temple.edu

website: http://www.jlab.org/~flay
             http://quarks.temple.edu
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