Diamond detectors for fast neutron measurements at pulsed spallation sources

The performance of a single crystal diamond (4.7x4.7x0.5mm3 active volume) detec- tor 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 12 C(n,α )9 Be and 12 C(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.