Neutron radiation of an electronic sensor using coincidence method for an active dosimeter

Results on the modeling and experimentation on a preliminary structure to be used in neutron dosimetry are presented. The structure consists of a thin reactive layer deposited on two facing diodes. The sensor has been developed mainly to solve the problem of neutron dosimetry in the intermediate energy range (0.5 eV to 500 keV) for which the existing electronic systems are ineffective. The use of a coincidence method for the detection of the nuclear reaction products allows the discrimination of the γ interactions. The system can also be used down to thermal energies for which the sensitivity is considerably higher. The sensor response depends on the thickness of the reactive layer which defines the neutron sensitivity and has an influence on the slowing down and absorption of emitted particles, the depletion layer which has to be optimized for a given energy range, the thickness of the dead layer of each detector. For experimentations with an Am–Be source, we have chosen following parameters: 100 nm for reactive and dead layers, and 150 μm for depleted layer. First analysis of results has been made in taking into account only the thermal neutron response.