Geometrical non-uniformities in the sensitivity of polycrystalline diamondradiation detectors

Chemical vapour deposited (CVD) diamond is a remarkable material for the fa brication of photon and particle detectors. However, little is known about the perturbations induced by the polycrystalline nature of this material. F or this purpose, we have used a micrometer size X-ray beam generated from a synchrotron light source to induce photocurrents in a CVD diamond-based de tector. By comparing the measured currents in the device as the beam intera ction position is moved on the sample with the topographical image of the s urface observed using a scanning electron microscope (SEM), a significant n on-uniformity has been observed that could be correlated with the grain str ucture. (C) 2000 Elsevier Science B.V. All rights reserved.