X-Ray Detection by Using CVD Single Crystal Diamond Detector

A number of diamond detectors, obtained by a two-step growing procedure by chemical vapour deposition (CVD) technique, have been grown on a low cost commercial high temperature high pressure (HTHP) Ib single crystal diamond. The first diamond layer is 15 mu m thick and heavily doped by boron. A 35 mu m thick layer of intrinsic high purity and high quality CVD diamond is then grown on top of the doped diamond. A metal contact (aluminium 100 nm thick) is deposited on top of the intrinsic diamond. One of these devices has been placed in the beam of the station 9.1 of Synchrotron Radiation Source at Daresbury laboratory (UK) and several tests have been performed to assess the linearity of responsivity as a function of the photon flux, the long term stability, and the response to the sudden onset of radiation. The device shows an excellent linearity and long term stability (tested in the order of hours), while the response to the onset of radiation have still to be understood. The results obtained can open up the path to the construction of extremely radiation hard devices to be exploited as X-ray beam monitor.