From: W.J. Llope (llope_at_physics.rice.edu)
Date: Sat Apr 26 2003 - 20:54:27 EDT
hi lijuan,
i'm still not sure if i understand whether there's
a problem here or not... in your code (which i'm assuming is
working in 'absolute timing' space) somewhere there must
be a statement of the form
time[i] = tdc[i]*slope[i];
where i assme you have slope[i] as some fixed number for
each channel which is on the order of 50ps.
have you tried replacing (e.g.)
time[i] = tdc[i]*slope[i];
with
time[i] = tdc[i]*funTDC[i]->Eval(tdc[i]);
where funTDC[i] is just the (appropriately inverted) fit polynomials
to TDC vs delay?
in 'relative timing' space (where all the TOFp calibrations
are done), such a polynomial would first be converted
to a function describing the TDC bin width (in ps)
vs the TDC value, and used as such.... in this approach,
the offsets are 'passed along' (and nence vastly less
bookkeeping wrt offsets is required)....
either way, it would seem this would have to help...
and it seems this would be practically *rigorous*, modulo
a future comparison of these TDC vs delay curves that we will
measure in the coming shutdown w/ an Ortec time calibrator.
anyway, have you tried an explicit use of the
measured TDC vs delay curves in your stop-side analysis
at the point where you convert TDC values to times?
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
This archive was generated by hypermail 2.1.4 : Thu Jul 24 2003 - 00:39:41 EDT