Thin CVD diamond film detector for slow neutrons with buried graphitic electrode

We fabricated neutron detectors based on thin epitaxial CVD diamond films grown on single crystal diamond substrates, with a buried graphitic electrode produced by ion implantation and annealing. The spectra of 5.5 MeV alpha particles were measured with ≈3.5% energy resolution, and, based on the features of those spectra, a precise assessment of the film thickness was able achieved. A 10 μm thick detector was tested for 252Cf neutron and γ-radiation source, using 10B and 6Li isotopes as converters. Due to the small film thickness the contribution from the γ-quanta background to the spectra was restricted by energies below 200 keV, and could be easily discriminated from the neutron related signals. The performance of the detectors was tested for 5.5 MeV α-particles at fluences up to 109cm−2, and no detrimental polarization effect was observed for the best sample.