This thesis covers the work of the author as a postgraduate student at the University of Glasgow, between October 1982 and September 1985. The experiment WA70 was designed to study the production of high transverse momentum direct photons in hadron-hadron interactions. The experiment took place at the CERN laboratory in Switzerland. The apparatus used was the OMEGA spectrometer facility, and a purpose built electromagnetic calorimeter. Data was taken with a hadron beam, at an energy of 280 GeV, incident on a liquid hydrogen target. The beam composition could be selected to be either negative pions, or unseparated protons and positive pions. One of the principal features of the calorimeter was its source calibration system. Sixteen radioactive sources could be positioned within the calorimeter to provide calibration data. Much of the author's work in the early stages of the experiment was on setting up and understanding the calibration system, and on applying the results to the experiment. The work done, and the results obtained, are presented here. One of the requirements of an experiment studying direct photon physics is the ability to accurately identify background sources of photons. The main source of such background is the decay of high transverse momentum pi s, and to a lesser extent, ns. The study of the production of pi s and ns is therefore important to the experiment. The latter part of this thesis presents the work of the author on the study of these mesons. The aim of the analysis is to derive the cross sections for the production of high transverse momentum pi and n mesons. The method of analysis and the results are presented
