A digital pulse fitting method for the α decay studies of short-lived nuclei

. When studying short-lived nuclei via α spectroscopic methods at recoil separators, the decay events tend to happen immediately after the recoil implantations or the decays of parent nuclei and therefore pile-up pulses are often encountered. Digital acquisition systems now allow the recording of waveforms of pile-up events rather than rejecting them as in traditional analog systems. Therefore, the extraction of the energy and time information stored in pile-up events with suitable precision is of great significance to the measurements of short-lived nuclei. In this paper, a pulse shape fitting method for processing pile-up events from silicon detectors are proposed. The method is developed on the basis of an improved analytical function for describing the shapes of preamplifier signals. The validity of the method is demonstrated by the experimental data of some short-lived nuclei produced in the reaction 40 Ca + 184 W.