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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.
