High-Energy Bremsstrahlung and Electron Pair Production in Thin Crystals

A survey of theoretical and experimental methods now available for calculating, producing, and measuring high-energy coherent bremsstrahlung (HEB) and electron pair production (EPP) is presented.After an introduction in which the historical development of the subject matter is sketched, a preliminary theoretical approach is outlined. A rough classical argument is shown, and a formal expression of the Laue-Bragg law suitable for the next calculation is deduced, together with some fundamental kinematics of the HEB and EPP processes. The structure factors for the cubic, face-centered cubic, and diamond lattice are deduced and some qualitative features of the interferential cross sections are shown.A complete calculation of the HEB and EPP cross sections is carried out. HEB polarized and unpolarized cross sections as functions of recoil momentum are obtained and then integrated over all the reciprocal lattice space. Corresponding results for EPP cross sections are expressed and numerical calculation results are shown.The last part of the paper deals with experimental methods and techniques used in different laboratories in order to produce and measure high-energy coherent bremsstrahlung suitable for photoproduction experiments by polarized photons. Experimental apparatus and results are described in some detail. Finally, concluding remarks are made concerning the topics omitted.