Development and application of CVD diamond detectors to 14 MeV neutron flux monitoring.

CVD diamond is an interesting material for radiation detection, its atomic number (Z = 6) is close to that of soft tissues (Z = 7.1) and it can also work in harsh environments. Since many years CVD diamond films have been grown at the Faculty of Engineering, Rome 'Tor Vergata' University, and in 1998 a collaboration with ENEA Fusion Division was established to develop fast neutron monitors to be used in fusion tokamak environment. In this paper the first test of a 120 microm thick polycrystalline CVD diamond detector used for monitoring 14.7 MeV neutrons emission produced with the Frascati Neutron Generator (FNG) is reported. The detector operates in air and in pulse mode. The time irradiation profiles recorded with the CVD diamond detector were compared with those recorded by the standard monitors available at FNG (SSD, fission chamber, NE-213). Good stability and capability to operate in neutron flux up to 1.5 x 10(8) n cm(-2) s(-1) was observed. The radiation hardness property was also investigated using a 460 microm thick film and these results are also reported.