Darmstadt 2016 – scientific programme

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HK: Fachverband Physik der Hadronen und Kerne

HK 52: Instrumentation XIII

HK 52.3: Talk

Thursday, March 17, 2016, 14:30–14:45, S1/01 A3

Design and performance of an ionisation chamber for the measurement of low alpha-activities — •Heinrich Wilsenach and Kai Zuber — Institut für Kern- und Teilchenphysik, Technische Universität Dresden

The study of alpha decay has been important for the understanding of nuclei and their properties for more than a century. Currently these studies still have impact in various areas of nuclear physics, providing information which is valuable and often not accessible otherwise. The measurement of half-lifes from alpha decays of the order of 1×10¹⁵ yr is of particular interest. A measurement of such a long lived decay imposes, however, a series of challenges, where the correct discrimination between background and true signal is critical.

This work discusses an ionisation chamber used for low rate alpha-spectroscopy. The measurement makes use of pulse shape analysis to discriminate between signal and background events. The design and performance of the chamber is described in this work. A background rate of (10.9±0.6) counts per day in the energy region of 1 MeV to 9 MeV was achieved with a run period of 30.8 days, this will also be presented. The remeasurement of the half-life of ¹⁴⁷Sm will also be presented here, as well as a discussion on the current half-life values.