Pulse Shape Discrimination with a Multi-Parameter Data-Acquisition System

Abstract 2 At the Nuclear Physics Techniques group an ion beam is used to perform material analysis. One of the analysis techniques is the Elastic Recoil Detection Analysis (ERDA) technique, which is applied for depth profiling light elements, like C,O and N, in a heavy matrix, like Si. It can be combined with Pulse Shape Discrimination (PSD) to separate the recoiled particles from the scattered He2+ projectiles that are also detected. For this purpose a detector with a thin depletion layer (e.g. 15 µm) is used. Recoils, which are stopped within the depletion layer produce fast output pulses because the charge they liberate is collected quickly. Scattered projectiles on the other hand are mostly stopped behind the depletion layer and the charge they liberate is collected more slowly by diffusion processes and the detector output pulse is slow. Discrimination between the recoils and the projectiles can be based on analysis of the detector output pulse shape. A multi-parameter data-acquisition system has been developed during this master o