ABSTRACT
This chapter discusses techniques for understanding extensive air showers (EAS) that hopefully are more accurate. The aim is to measure the spectrum and composition of ultrahigh energy cosmic rays (UHECR), and to search for anisotropy in the directions from which they arrive. We will see that Monte Carlo simulations of EAS are very important for these studies. Considerable effort has been put into developing Monte Carlo programs to simulate cosmic ray air showers. The quantities that have the largest effect on predictions of event’s energy for hadronic generator routines are the p-p total cross section, and the multiplicity and elasticity of high energy p-p interactions. The general outline of the efficiency calculation in surface detector (SD) analysis is the same as described for a Fluorescence Detector, but there are some important differences. In particular, a SD, which consists of scintillation counters or water tanks spread out in an array, can cover a large area and be sensitive to UHECR.
