Reflector simulation program for an imaging air Cherenkov
telescope

Abstract: In the last 20 years the ground-based telescopes have opened a new
observation window at very high energies (VHE) between 100 GeV and 10 TeV,
with the application of imaging air Cherenkov technique. Here the Cherenkov
light from secondary particles produced in electromagnetic cascades,
initiated from a primary gamma-photon or a charged particle, is measured. As
the Cherenkov light flashes are very faint and short, a large reflector as
well as a high sensitivity photo-multiplier camera is used. From the images
of the air shower, the identity and energy of the primary particle could be
reconstructed. The base for this reconstruction is the comparison with
artificial air showers produced by Monte Carlo simulations and processed
through a complete detector simulation. The current generation of large
Imaging Air Cherenkov telescopes, as MAGIC or H.E.S.S is not practical for
long time monitoring of certain sources, mainly for cost reasons. Therefore
a new instrument is proposed, which is dedicated to long time observations
of bright nearby blazars. It is based on a technical upgrade of one of the
former Cherenkov telescopes of the HERGA experiment. The observation targets
are extragalactic objects, that show non-thermal broad band emission from
the radio band up to VHE gamma-rays. Among the most extreme astrophysical
objects, blazers emit most of their energy at gamma-rays and show time
variability in scales from years down to several minutes. So far, long term
monitoring lack from the small sampling of the light curve at VHE. For the
ongoing studies of the instrument and coming data analysis, a new detector
simulation is necessary. In this work, the reflection of Cherenkov photons,
produced with the air shower simulation program CORSIKA[Heck et al.(1998)],
at a user-defined reflector with user-defined properties is simulated and
introduced in the existing framework MARS. The detector simulations
presented in the end show comparable results to the MAGIC reflector.