Evaluating the Dosimetric and Sensitivity Mapping Performance of CVD Diamond Radiation Detector with X-Ray Tube and Dual Synchrotron Micro-Beams

This study presents a comprehensive investigation of the dosimetric characteristics and sensitivity mapping of a CVD diamond radiation detector (VS-Pt) fabricated with platinum metal contacts. The detector’s performance was evaluated through a series of measurements, including I–V characteristics, signal-to-noise ratio, dose rate dependence, linearity, photoconductive gain, sensitivity, rise time, and reproducibility, using an X-ray tube source. The device underwent annealing, which led to improvements in sensitivity, with a linear response and increased photoconductive gain. The reproducibility of the device was found to be slightly higher than the IAEA’s recommended limit. Following this, a comparative sensitivity mapping study was performed using two synchrotron micro-beam facilities—NSLS and DLS—employing different micro-beam sizes. The investigation explored the effects of beam size, bias polarity, and step displacement on the spatial resolution and sensitivity of the device. Results showed that sensitivity was influenced by beam size, with smaller beam and step sizes yielding higher sensitivity, likely due to the priming effect. Bias polarity also played a significant role, with negative bias producing higher photocurrents, particularly near nitrogen lines in the diamond. Additionally, the annealed sample exhibited better homogeneity and faster rise times compared to the un-annealed version. The findings highlight the optimal conditions for synchrotron-based dosimetric measurements, providing valuable insights for improving detector performance in applications such as radiotherapy dosimetry, radiobiology, and beam monitoring at synchrotron facilities.