Re: BCAL timing from beam test - bafflement - please look

[Alex Dzierba <dzierba@indiana.edu>]

Yes - thanks - I understand that - I'm starting off by assuming
nothing and trying to figure this out for myself.  Right now I'm
ignoring the beam time into and am just using another TDC
in BCAL for reference.  I'm getting nice time-walk
corrections and now trying to get sigma_t as a  function of
energy.   I'm not getting good fits to a simple
a/sqrt(E) \oplus b  for time difference vs E for a single
segment (one of 18)  (fits to a/E \oplus b works better and I
seem to remember that you saw this as well) - will
now move on to energy weighted time differences
summed over a cluster.  Clearly the mean time is going to
require more work on tagger - as you already know.  I'm
not sure that, at least for now, using tagger as a reference
for doing time walk corrections is a good idea.  Using
another BCAL time ref seems to work better.  I should
also say that the fit coefficients I get to a/sqrt(E) \oplus b
for time diff (actually 1/2 dif) are not far from yours




At 10:10 AM -0600 2/15/08, Blake Leverington wrote:
>Hi Alex,
>
>Are you referencing the times for the BCAL with another signal? 
>Remember, this needs to be done with all the timing info. Which is 
>why the the timing with the tagger was such a problem.
>
>-Blake
>
>Alex Dzierba wrote:
>>Dear Calorimeter Crazies
>>
>>I decided to start looking that BCAL timing information from the beam
>>test and am immediately baffled by timing I see in the data for
>>Run 2334 (beam normally incident at module center).  Please look at:
>>http://dustbunny.physics.indiana.edu/~dzierba/ARDGlueX/BCAL/timing
>>
>>Am I missing something that has been discussed before?   I want to
>>know before I proceed further.  Please let me know.
>>
>>Cheers
>>Alex


-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Alex R. Dzierba
Chancellor's Professor of Physics (Emeritus)
Department of Physics / Indiana U / Bloomington IN 47405 / 812-855-9421
JLab Visiting Fellow
Jefferson Lab / 12000 Jefferson Ave / Newport News, VA 23606 / 757-269-7577
Home Phone: 812-825-4063  Cell:  812-327-1881  Fax: 866-541-1263
http://www.dzre.com/alex
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