From: Xu, Zhangbu (xzb_at_bnl.gov)
Date: Wed May 14 2003 - 09:40:47 EDT
Hi,
I have no much beam and today is the last day we will take TOFr trigger
data.
Thanks!
ZHangbu
-----Original Message-----
From: W.J. Llope [mailto:llope_at_physics.rice.edu]
Sent: Tuesday, May 13, 2003 11:19 PM
To: tofp_at_physics.rice.edu
Subject: recent data (folks please this whole message !!! thanks)
from localmon_to4133058.dat - which is 4131031 < run <= 4133058....
Found 44608 beam events out of 76253 >>--> ratio = 0.585
- ~446k physics triggers in this sample
- lots of data including the pvpd+tofr trigger obviously...
from the hit patterns
~1k hits/ch for tofp - no new bad chs for the last ~6 weeks...
~8-10k hits/ch for tofr...
those chs that went sick again a few days ago are still sick...
i took another look at the hit patterns from this run -
i now think it's possible one can point this
effect to a tdc (contrary to what i said yesterday, but there's
an important caveat mentioned below!)...
this effect has been rare since the start of run-3
but looking at where these channels are, it is also consistent w/
a range of channels in tofr TDC #5.
the caveat (comments?):
the one thing that makes me wonder though is that the number of
"adc hits" is also a factor of very roughly ~2 "low" (evaluated
by eye from the generic hit patterns)... this is what
lead me to believe earlier that this was a fee or det problem (so
i'm still thinknig about this too)...
given the intermittent nature of the effect, and assuming the
problem is indeed not inside the pole tip,
it's possible that simply carefully reseating this tdc could
stabilize this... i see no harm whatsoever in trying this
if there is an access...
this i bring up since this unit generally works fine -
i.e. it was fine through all of the dAuTOF running...
otherwise (and assuming we can indeed isolate it to the tdc)
we could consider replacing this tdc but
we have to decide if just reseating it is worth an attempt...
that's becuase if we just replace it we'll have to time-calibrate
both this tdc and the replacement separately during the offline
analyses if we want to use all the p+p data ...
but by the next real spill these channels may come alive again
just by themselves if history is any guide... sigh.
we have to decide what action we want to take here... comments?
suggestions? thanks, regards
bill
_________________________________________________________
W.J. Llope, Ph.D. Res. Assoc. Professor
http://wjllope.rice.edu/default.html
llope_at_physics.rice.edu
T.W. Bonner Nuclear Lab.
Rice University, MS-315
6100 S. Main phone: 713-348-4741
Houston, TX 77005-1892 fax: 713-348-5215
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