Studies on some important properties of UHE air showers

Abstract

The title of the thesis is quotStudies on some important properties of UHE air showersquot.The thesis comprises of seven chapters. Abstracts of different chapters are given below. Chapter 1: Introduction In the first chapter important characteristics of primary cosmic rays (CR) such as origin, energy spectra and mass composition, development of extensive air shower (EAS) along with GZK cut off, LPM shower, development of pre-shower in the magnetosphere are given. Theoretical background of longitudinal development and lateral distribution of electron- photon cascade are described in detail in this chapter. Chapter 2: Studies on Lateral Distribution of the Electron Component of EAS and Characteristics of Age Parameter [ A review ] Theoretical as well as experimental investigation on lateral distribution of electron component of EAS with primary energy (Ep) in the range ~ 1015 eV -~ 1020 eV made by different workers are reviewed in this chapter. This chapter also includes a review on different important properties of age parameter (s). A brief note on the present work alongwith its justification are also presented. The present work aims at the following aspects. (i) To make a comparative study of different LDFs on the basis of age parameter (a) for Ep lt~1017 eV and also (b) for Epgt~1019eV. (ii) To study the following characteristics of age parameter for giant air showers with Ep gt~1019 eV (a) Variation of s with zenith angle (0) for small bins of Nc (b) Variation of s with No for different small bins of 0. (c) Variation of s with Ep for different small bins of 0. (d) Variation of s with atmospheric depth beyond shower maximum for small bins of No(iii) Identification of the primary particle for energy in the range ~1015- ~1016eV and gt~1019eV using Fenyves model and modified Fenyves model respectively For the above studies, data of the Gauhati University Air Shower Array (GUASA) and the Giant Air Shower Laboratories viz. Yakutsk, Russia and Volcano Ranch, USA are used. Chapter 3: EAS Detection System The existing GUASA is...