CVD-synthesis of detector quality diamond for radiation hardness detectors of ionizing radiation

An advanced microwave plasma reactor ARDIS 300 was used to synthesize homoepitaxial structures of monocrystal diamond films at Project Center ITER. High-quality epitaxial diamond films were grown on boron-doped monocrystal diamond substrates using microwave plasma-assisted chemical vapor deposition from methane-hydrogen mixture. Structural and impurity perfection of diamond films were characterized by Raman spectroscopy, photoluminescence, and optical absorption. Prototypes of radiation detectors were created on the basis of grown diamond films with thickness 70–80 $\mu$m. The $p$-type substrate with boron concentration $\sim$100 ppm served as an electrical contact. Detectors were irradiated by 5.5 MeV particles and 14.7 MeV neutrons, corresponding pulse height spectra were measured and detector sensitivities were determined. Charge collection efficiency for synthesized diamond was shown to achieve 94% and 91% when $\sim$4 V/$\mu$m electric field applied.