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Abstract

To explore physical phenomena beyond the Standard Model of particle physics, it is essential to look at so-called rare events like e.g. the neutrinoless double beta decay. To be able to detect these rare events, the radioactive background in the experiments has to be suppressed as much as possible. Already during the selection process of the materials, an extremely low contamination is minded. For this purpose the activity of the material samples must be determined very accurately, which is done with low-level gamma spectrometers. At the MPIK in Heidelberg a new gamma spectrometer, called GIOVE (Germanium Inner and Outer VEto), is being built. It should reach a better background suppression than the already existing gamma spectrometer at the MPIK due to a specifically designed shield and it should be able to detect even the smallest amounts of radioactivity. To exactly determine the sample activity in the future, a simulation of the detector is needed. In this Bachelor thesis the geometry of the GIOVE detector was coded in the simulation software MaGe up to the first lead shield and different parameters were established to match the simulation to the real situation as well as possible. This includes the position of the diode in the detector, which was determined with the help of a collimated ²⁴¹Am-source. A displacement of the diode to its position in the construction plans was discovered and was implemented in the simulation accordingly. Another parameter is the dead layer thickness. Measurements with an uncollimated ¹³³Ba-source in different distances to the detector have been made to estimate it. These measurements were simulated and by comparing the simulations and the measurements a value of x = (1,44+/-0,04)mm for the mean dead layer thickness was found.