Technical applications of an imaging Gamma-ray Compton Backscattering device and simulation using GEANT4

The γ-backscattering imaging techniques are alternative methods to the transmission techniques to determine the amount and distribution of matter in objects. These are very useful techniques when the access to both sides of the sample, unlike in the transmission case, is not possible. A γ-backscattering imaging device dubbed Compton Camera, developed at GSI (Darmstadt, Germany) and studied and modi d by the Nuclear Physics Group of National University in Bogot , uses the so called Compton Gamma-ray Backscattering (GCB) technique, which has been successfully tested in different situations. The Compton Camera makes the most of back-to-back emission of two γ-rays, from positron annihilation, to construct a bi-dimensional image representing the distribution of matter of the sample in the ld-of-view of the camera. The backscattering imaging method can be used to identify and study structural defects, to help ding hidden objects, to name just two cases. In this work, the images resulting from different experimental conditions in the study and analysis of metallic surfaces will be shown. Furthermore, some experimental limits of the actual prototype are set. In order to increase the understanding of the image formation process and to assist in the data analysis, a simulation of the camera was developed using the GEANT4 simulation toolkit. The simulated images and their comparison with the experimental ones suggest already methods to improve the present experimental device