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Germanium detectors are a choice technology in fundamental research. They are suitable for the\nsearch for rare events due to their high sensitivity and excellent energy resolution. As an example, the GERDA (GERmanium Detector Array) experiment searching for neutrinoless double\nbeta decay is described. The observation of this decay would resolve the fundamental question\nwhether the neutrino is its own antiparticle. Especially adapted detector technologies and low\nbackground rates needed to detect very rare events such as neutrinoless double beta decays are\ndiscussed. The identification of backgrounds originating from the interaction of radiation, especially alpha-particles, is a focus of this thesis. Low background experiments face problems from alpha-particles due to unavoidable surface contaminations of the germanium detectors. The segmentation of detectors is used to obtain information about the special characteristics of selected events. The high precision test stand GALATEA was especially designed for surface scans of germanium detectors. As part of this work, GALATEA was completed and commissioned. The final\ncommissioning required major upgrades of the original design which are described in detail. Collimator studies with two commercial germanium detectors are presented. Different collimation\nlevels for a beta-source were investigated and crystal axis effects were examined. The first scan with an alpha-source of the passivated end-plate of a special 19-fold segmented prototype detector mounted in GALATEA is described. The alpha-induced surface events were studied and characterized. Crosstalk and mirror pulses seen in the segments of the germanium detector were analyzed. The detector studies presented in this thesis will help to further improve the design of germanium detectors for low background experiments.