Mosaic diamond detectors for fast neutrons and large ionizing radiation fields

First neutron and X-ray beam tests on a novel 12-pixel single-crystal diamond mosaic detector are presented and discussed. Preliminary characterization of single-pixel electronic properties, performed with alpha particles, results in charge carrier mobilities >2000 cm2/ Vs and saturation velocities of the order of 10^7 cm/s. Signal stability over time, measured with a 241Am source (37 kBq activity), is longer than 5 h. Tests under an intense X-ray beam (1 Gy/ h dose-rate) show a very good response uniformity (down to about 1% of relative standard deviation from mean value), suggesting a high level of pixel reproducibility at intermediate bias voltages (ranging from 20 to 100 V). Response uniformity reduces at voltages >200 V, due presumably to radiation-assisted detrapping effects. Preliminary results of 12-pixel simultaneous acquisitions of X-ray beam profiles and pulse height spectra under a fast neutron beam (14 MeV) are also presented.