Responsivity of Diamond X-ray Photodiodes Calibrated at NSLS

Single crystal, high purity synthetic diamond is used as photoabsorption and carrier transport medium in x-ray photodiodes. While the thermal / mechanical robustness and high x-ray transmission of diamond make such devices attractive for synchrotron instrumentation, state-of-the-art quality material and electrical interfaces further make such detectors feasible. The present work develops methodology for attaining calculable responsivity (photocurrent yield) over a wide range of photon energies (0.2 to 28 keV) to within 5% accuracy. These methods achieve linear response for up to 0.2 W absorbed x-ray power and response time as low as 1 ns. Details of contact formation / robustness and bias configuration are explored.