Optimization of angular resolution for air Cherenkov detector arrays for observations of cosmic rays

Abstract

A recently proposed detector for extremely high energy cosmic rays might exploit the unique properties of air Cherenkov light to optically observe cosmic rays during night, twilight, and possibly during the daytime. We present a method that can be used to accurately reconstruct the direction of the primary cosmic ray. An optimization of the detector station design has been performed via Monte Carlo simulation to maximize angular resolution and minimize cost. Results indicate a configuration consisting of five panels yeidls the best response. These panels are oriented with one panel pointing directly at zenith, while the other four panels are tilted at 60° with respect to the zenith and spaced equally in azimuth. Using this panel configuration we find the original primary shower direction can be reconstructed to an accuracy of 0.3–3°, depending upon the zenith angle of the primary cosmic ray, and the ambient sky background noise. This angular reconstruction accuracy is similar to or better than the traditional angular reconstruction provided by examining the arrival times of charged particles in the extensive air showers.