Radiation and thermal stress test on diamond detectors for the Radial Neutron Camera of ITER

The Radial Neutron Camera (RNC) of ITER (International Thermonuclear Experimental Reactor) is a multichannel detection system designed to measure the uncollided neutron flux from the fusion plasma, providing information on the neutron emissivity profiles and source strength. Fission chambers and diamond detectors are candidate detectors for the RNC In-port subsystem. This is a high radiation environment (up to 5 MGy gamma dose and n/cm2 neutron fluence) where about 500 baking cycles up to 240 °C are foreseen over the whole ITER lifetime. In order to assess the feasibility of using diamond detectors in such harsh conditions, and to study the best technological solutions, we are currently performing a set of tests to understand the behavior of diamond detectors under radiation and thermal stresses: (1) thermal stress tests at constant temperature of 240 °C and thermal cycling between 100 °C and 240 °C; (2) gamma-hardness test up to a total dose of 4.7 MGy; (3) neutron-hardness test (limited to 2 14 n/cm2 in this work).