Optimising resistive charge-division strip detectors for low energy charged-particle spectroscopy

Abstract

Two novel approaches to improving the signal-to-background ratio (SBR) for silicon resistive charge-division strip detectors (RSDs), when performing low energy charged-particle spectroscopy, are presented. Firstly, the normally-unutilised rear contact of the detector was used to veto events where the charge collected by this rear face did not match the sum of the charges collected by the strips on the front. Secondly, leading edge discriminator time walk was used to determine complementary information about the hit position along a strip. Using this alongside the position extracted from the charge division allowed clearer identification of true events over background, leading to an improved SBR. These methods were tested by measuring radiation from a triple-α source and then the 12C(4He, α)ααα breakup reaction at 40 MeV beam energy. The first method was found to improve the SBR by a factor of 4.0(2). The second method gave a SBR improvement of factor of 3.7(4). When both methods are applied together, a total improvement by a factor of 5.7(3) was measured.