التفاعل المتبادل بين إشعاعات جاما والمادة

Abstract

The aim of this experiment was become familiarized to study the interaction of gamma-rays with matter through three processes, these include photoelectric absorption, Compton scattering, and pair production set-up. This consisted of a high purity germanium (HPGe) detector with energy between [121 keV-1408 keV] rang and a Multichannel Analyzer (MCA) a radioactive source and absorber to calibration. The results of the graph show that an incident photon loses its intensity with every increase in the absorber. The rate at which this happens depends on the absorber material and the atomic number Z. the gamma rays where shown to follow beers law where the mass attenuation coefficient for each peak energy of153 Eu was found to decrease as the peak energy increase. The second part of the experiment was set up by using a Nal (TI) scintillation crystal spectrometer, and 137Cs source to produce γ-ray with energy 662kev. The Compton scattering was investigated the interaction of photon with free electrons. It is deflected through an angle with right direction, as a result the Compton scattering from the aluminium rod was measured by scattered radiation. The relation between the scattered radiations of energy count versus the angle was obtained. It was discovered that low angle the measured value fell below the prediction of klein- Nishina formula but it tend to meet at higher values of the rotation angle. It can be seen clearly from these results that the energy count decrease as the scattering angle increase, by using these data, the graph of 1/Eγ a giant (1-cosθ) was plotted. The result was in straight line with intercept of (1.5114 ±) and gradient of (1.9522±) that were good agreement with theory.