Pulse-shape discrimination of surface events in CdZnTe detectors for the COBRA experiment

Abstract

Events near the cathode and anode surfaces of a coplanar grid CdZnTe detector are identifiable by means of the interaction depth information encoded in the signal amplitudes. However, the amplitudes cannot be used to identify events near the lateral surfaces. In this paper a method is described to identify lateral surface events by means of their pulse shapes. Such identification allows for discrimination of surface alpha particle interactions from more penetrating forms of radiation, which is particularly important for rare event searches. The effectiveness of the presented technique in suppressing backgrounds due to alpha contamination in the search for neutrinoless double beta decay with the COBRA experiment is demonstrated.

15 pages, 13 figures

Cited by in corpus (6)

• Quenching of $g_{\mathrm{A}}$ deduced from the $\beta$-spectrum shape of ${}^{113}$Cd measured with the COBRA experiment
• Results of a search for neutrinoless double-beta decay using the COBRA demonstrator
• The COBRA demonstrator at the LNGS underground laboratory
• Confirmation of $g_{\mathrm{A}}$ quenching using the revised spectrum-shape method for the analysis of the ${}^{113}$Cd $\beta$-decay as measured with the COBRA demonstrator
• Long-Term Stability of Underground Operated CZT Detectors Based on the Analysis of Intrinsic ${}^{113}$Cd β${}^{-}$-Decay
• Suppression of alpha-induced lateral surface events in the COBRA experiment using CdZnTe detectors with an instrumented guard-ring electrode