A photo-neutron source for time-of-flight measurements at the radiation source ELBE

To reduce the radiation background at the measurement position, the neutrons are decoupled from the radiator at an angle of about 90° with respect to the impinging electrons. Particle transport calculations using the Monte Carlo codes MCNP and FLUKA predict a neutron source strength in the range of 7.9×1012n/s to 2.7×1013n/s for electron energies between Ee-=20 and 40 MeV. At the measuring place 3.9 m away from the radiator, a neutron flux of about 1.5×107n/(cm2s) will be obtained. The short beam pulses allow for a neutron energy resolution of better than 1% for neutron energies between En=50keV and 5 MeV. The usable energies range up to about 10 MeV.