CVD diamond as a high bandwidth neutron detector for inertial confinement fusion diagnostics

Abstract

We characterize the response of chemical vapor deposition (CVD) diamond detectors to inertial confinement fusion (ICF) neutrons generated at the OMEGA laser fusion facility in Rochester, NY. Four detectors are tested: three utilizing “optical grade” CVD diamond, and one utilizing “electronic grade” CVD diamond. Using a 50 Ω measurement system, we find that the optical grade wafers, biased to 1000 V/mm, have an average sensitivity of 0.24 μV ns/n for 2.5 MeV (DD fusion) neutrons and 0.62 μV ns/n for 14.0 MeV (DT fusion) neutrons. At the same E field, the electronic grade wafer has a sensitivity of 0.56 and 1.43 μV ns/n for 2.5 and 14 MeV neutrons, respectively. Linear dynamic range for the optical grade material is shown to be at least 105. Average full width at half maximum response times, as measured with pulsed laser and 3 GHz scope, are 376 and 880 ps for optical and electronic grades, respectively. These characteristics make CVD diamond suitable for ICF applications such as neutron time-of-flight spectroscopy, bang time measurements, and ion temperature measurements.