Pulse shape discrimination at low energies with a double sided, small-pitch strip silicon detector

Abstract

We achieved particle separation of proton, deuteron and triton at energies ranging between 2 and 10MeV by the processing of digitized signals obtained with a double-sided, 485-μm pitch strip, 500-μm thick neutron transmutation doped (nTD) silicon detector. We produced the light charged particles in a nuclear reaction induced by a 34-MeV beam of 7Li impinging on a 12C target. We analyzed offline the signals with the goal of a simplified, possibly analog, front-end electronics in mind for the processing of the 15,000 channels of the new state-of-the-art detectors for low energy nuclear physics like GASPARD, HYDE and TRACE which should make use of such methods. At the optimum bias, using the current amplitude versus charge correlation, we obtain a separation of 3FWHM between protons and deuteron, and 2FWHM between deuteron and triton at energies as low as 2MeV; with a square bipolar filter, suited for simple implementation, we separate them by 4.3 and 2.7FWHM respectively at 5MeV.