Reproducibility analysis of diamond pixel detectors for large ionizing radiation fields

This work reports on reproducibility tests performed on 20 high-quality single-crystal chemical vapour deposition (scCVD) diamond samples. By the analysis of the average mobility-lifetime product of the photogenerated carriers, 12 samples were selected and arranged as pixels in a 2.5 × 2.5 cm2 mosaic detector. Measurements carried out under a large (4 cm diameter) X-ray beam show a very high pixel response uniformity (< 1% standard deviation relative to the mean photocurrent value) for a wide range of applied bias voltages (20 ÷ 80 V). Results suggest a very high level of reproducibility, mostly due to the excellent quality of the bulk material, meeting the requirements for monitoring large ionizing radiation fields with no need for individual pixel calibration. Moreover, mobility-lifetime product demonstrated to be the most effective figure of merit for the selection of CVD diamond samples with reproducible detection performance.