  The Cherenkov Telescope Array (CTA) is a future very high energy gamma-ray
observatory. CTA will be comprised of small-, medium- and large-size telescopes
covering an energy range from tens of GeV to hundreds of TeV and will surpass
existing telescopes in sensitivity by an order of magnitude. The aim of our
study is to find the optimal design for the medium-size telescopes (MSTs),
which will determine the sensitivity in the key energy range between a few
hundred GeV to about ten TeV. To study the effect of the telescope design
parameters on the array performance, we simulated arrays of 61 MSTs with 120 m
spacing and a variety of telescope configurations. We investigated the
influence of the primary telescope characteristics including optical
resolution, pixel size, and light collection area on the total array
performance with a particular emphasis on telescope configurations with imaging
performance similar to the proposed Davis-Cotton (DC) and Schwarzschild-Couder
(SC) MST designs. We compare the performance of these telescope designs,
especially the achieved gamma-ray angular resolution and differential
point-source sensitivity.
