Mosaic diamond detectors for fast neutrons and large ionizing radiation fields

Single-crystal Diamond Detectors (SDDs) are excellent candidates as fast neutron detectors in environments where high neutron flux is an issue, such as spallation neutron sources and the next generation thermonuclear fusion plasmas (ITER experiment). Recent measurements have demonstrated the SDD capability of measuring the neutron flux with a good energy resolution and at high rates. In this work, we present a novel mosaic detector based on a 12-pixel SDD matrix. Each pixel was characterized and calibrated by using a 241Am source: energy resolution mean value was evaluated to be 1.73% in air at 5.5 MeV. Moreover, measurements carried out under a large (3x3 cm2) X-ray beam showed a very high response uniformity (<1% standard deviation relative to photocurrent mean) for a wide range of applied bias voltages (20 ÷ 100 V). Results suggest very high level of reproducibility, due to the quality of bulk material, as well as to the reliable technology of metal contacts, meeting the requirements for monitoring of large ionizing radiation fields with no need for individual calibration.