Superior radiation hardness of a single crystal CVD diamond detector under proton beam bombardment
Sato, Yuki ; Murakami, Hiroyuki*; Shimaoka, Takehiro*; Tsubota, Masakatsu*; Kaneko, Junichi*
Diamond crystals have long been recognized as an attractive material for radiation detectors because of their unique properties. The high electrical resistivity and high band gap energy of diamond crystal, compared with silicon-based solid-state detectors, makes it possible to operate with low noise performance. Fast responses with superior timing resolution are possible because of high carrier saturation velocities under high breakdown electric fields. Additionally, because of their high displacement energy, it is expected that diamond detectors will show superior radiation hardness compared with detectors made of other materials such as silicon. We have fabricated a charged-particle detector using single crystal (sc) diamond grown by chemical vapor deposition (CVD) to investigate the radiation hardness of the diamond detector. The radiation dose dependence of the output pulse height from the diamond detector was measured using proton beams generated by a pelletron accelerator. The total kinetic energy of accelerated protons was 2.4 MeV and the incident side of the detector was Au electrode. During an operation of the diamond detector under the proton beam bombardment, the polarization effect was not observed. Additionally, the radiation hardness performance for light ions was compared with that of silicon surface barrier detectors, and the diamond detector showed radiation hardness superior that of the silicon detectors.