Spectral Distributions of Scattered X Rays at Points Lying off the Beam Axis

Abstract

A modification of a scintillation spectrometer so that it may be rotated about 2 mutually perpendicular axes is described. This arrangement greatly simplifies measurement and subsequent integration of scattered spectra at points not on axes of radial symmetry. This apparatus was used to measure scattered spectra at points at the centre and near the edge of beams of 140 and 280 kVp radiation. For each point spectral distributions were measured for 30 different directions. These were then integrated to obtain the spectrum incident from all angles. These spectra were compared with those calculated using a Monte Carlo method.