Real-time study of radiation damage in monocrystalline diamond sensors

Being an excellent radiation hard material, diamond is preferred as an ionizing radiation sensor in radiation harsh environments. In this study, radiation damage from a beam of 67.5 MeV protons at the Crocker Nuclear Laboratory on the campus of the University of California, Davis, was used to determine exposure lifetime in detectors made from a thinned (∼ 40 μ m) monocrystalline CVD (chemical vapor deposition) diamond substrate. The sensor response was sampled in real time as the sensor was exposed to a total fluence of ∼ 4×10 16 / cm 2 , yielding an overall damage constant of k = (3.3 ± 0.3) × 10 -18 cm 2 / p - μ m. Damage levels were later confirmed using a non-destructive x-ray technique at the LINAC Coherent Light Source (LCLS) at the SLAC National Accelerator Laboratory. Results are presented on the real-time degradation of the charge collection efficiency as a function of proton fluence.