Separation of the neutron signal from the gamma component in (n-gamma) fields using differential pulse analysis techniques with a double silicon diode

An individual electronic neutron dosemeter based on a combination of a polyethylene converter with a double diode (Canberra CD-NEUT-200-DBL) has been studied. The dosemeter has been irradiated by monoenergetic neutron beams of energies from 73 keV to 2.5 MeV with dose equivalents between 0.3 and 5.7 mSv. The differential method has been applied to separate the neutron response from the gamma contribution. The energy response of the dosemeter has been studied for these neutron energies. Linearity has been studied for 1.2 MeV neutrons. Simulation of the response of this dosemeter using a Monte Carlo code agrees with the experimental results obtained and confirms an energy threshold of the order of 250 keV for neutron detection. It is inferred from simulation that the neutron dose equivalent response varies about +/-50% in the energy range from 570 keV to 15 MeV, if the actual device with a 20 mu m thick polyethylene converter is used.