非表示:
キーワード:
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要旨:
An increasing number of underground experiments looking for phenomena beyond the standard model substantially rely on environmental background reduction. Therefore it is crucial to any of these experiments to conduct a precise material selection in order to ensure high radio-purity near the detector volume. In many cases, this can be achieved by low level gamma-spectroscopy. This thesis summarizes the efforts contributing to the development of an advanced shielding against gamma rays, muons and induced neutrons for a new germanium detector by the means of experiments and simulations. After collecting basic experience of the various background components by optimizing an existing muon veto, a first experimental setup is aimed at measuring the neutron attenuation power of both pure and boronated hydrocarbonic material. In addition neutron flux reduction was being investigated within a real detector environment by inserting layers of boronated polyethylene into a surrounding lead shield. Both experiments indicate a high efficiency in preventing the neutron background when adding a boronated moderator into the overall shield. Furthermore, a computer simulation was developed, addressing the problem of finding the best readout configuration for organic scintillators. The results will be used for the installation of the upcoming veto system of the future spectrometer. The final part of the thesis summarizes the results of radioactivity measurements taken of various samples, which were part of the regular scrutiny programme.
