systematic contributions to time-of-flight resolution

[Simon Taylor <staylor@jlab.org>]

Hi, everyone.

I have started looking at the contribution to the time-of-flight
resolution due to the momentum resolution, path length variations, and
z-vertex position variations.  I have attached a plot of
resolution in the difference between the true flight time to either the BCAL
or the TOF (as determined from the MC truth points) and the reconstructed
flight time using the path length derived from swimming the reconstructed
track from the vertex position to either the first TOF plane or the inner
BCAL radius.  I threw 1.0, 2.0, and 3.0 GeV/c pions from the center of the
target uniformly in phi and flat in theta from 126 degrees to ~0.5
degrees.  I find that the time resolution does not depend on the momentum
in the barrel region but does for tracks that would hit the TOF.
Comments welcome.

Simon

timing_res_1_2_3gev_pions.gif