1 research outputs found
Possible Discrimination between Gamma Rays and Hadrons using Cerenkov Photon Timing Measurements
Atmospheric \v{C}erenkov Technique is an established methodology to study
energy gamma rays. However the challenging problem has always been the
poor signal to noise ratio due to the presence of abundant cosmic rays. Several
ingenious techniques have been employed to alleviate this problem, most of
which are centred around the \v{C}erenkov image characteristics. However there
are not many techniques available for improving the signal to noise ratio of
the data from wavefront sampling observations. One such possible technique is
to use the \v{C}erenkov photon arrival times and identify the species dependent
characteristics in them. Here we carry out systematic monte carlo simulation
studies of the timing information of \v{C}erenkov photons at the observation
level. We have parameterized the shape of the \v{C}erenkov shower front as well
as the pulse shapes in terms of experimentally measurable quantities. We
demonstrate the sensitivity of the curvature of the shower front, pulse shape
parameters as well as the photon arrival time jitter to primary species and
show their efficiency in improving the signal to noise ratio. The effect of
limiting the \v{C}erenkov telescope opening angle by using a circular focal
point mask, onthe efficacy of the parameters has also been studied for each of
the parameters. Radius of the shower front, pulse decay time and photon arrival
time jitter have been found to be the most promising parameters which could be
used to discriminate ray events from the background. We also find
that the efficiency of the first two parameters increases with zenith angle and
efficiency of pulse decay time decreases with increasing altitude of
observation.Comment: 30 pages, 5 postscript figures, uses elsart.sty; To appear in
Astroparticle Physic