Diamond detectors for fast neutron measurements at pulsed spallation sources

Abstract

The performance of a single crystal diamond (4.7x4.7x0.5mm3 active volume) detector was tested in the ISIS pulsed neutron beam using biparametric (time of flight and pulse height) data acquisition. Three characteristic regions in the biparametric spectra are observed: i) low pulse height events with very short time of flight induced by γ-rays; ii) low pulse height events at longer flight times (i.e. neutron energies En > 3.5–6 MeV), possibly due to neutron elastic scattering off 12C; iii) events with large pulse height and flight times corresponding to En > 6 MeV mainly due to inelastic reactions such as 12C(n,α)9Be and 12C(n,n')3α. The potential use of this detector is discussed in relation to the ChipIr neutron beam line for fast neutron irradiation of electronic components at the ISIS spallation source.