X-ray spectroscopy based on polycrystalline diamond

Detectors suitable for x-ray spectroscopy were realized and tested. Thick columnar samples fabricated from mechanically polished diamond deposits were selected for devices development. Grid and micro-strip structures were tested with the aim of reducing the coupling capacitances and to allow characterization tests in planar and sandwich configuration. The x-ray sensitivity has been tested monitoring the photocurrent as a function of the applied voltage under continuous 8.05 keV Cu Kα irradiation. Source intensity was controlled with interposition of Aluminum filters. Studies in pulsed mode by using a commercial miniature x-ray source were also performed. Pulse height distributions were carried out with a system composed of a high gain charge-sensitive preamplifier and a digital pulse processor multi-channel analyzer. Analysis was carried out around Ta Lα and Cu Kα characteristic lines which are 90 eV apart. Realized prototypes were able to resolve such two characteristic lines with FWHM equal to 30 eV at 8.14 keV (about 0.4%) of Ta Lα line. Such very good resolving power and discrimination, addresses the suitability of polished polycrystalline diamond for a fruitful application in x-ray spectroscopy. ©2008 IEEE.