Measurement of fast neutrons with U-238-coated fission chamber

PurposeA fission chamber with two layers of U-238 fissile materials has been developed for the measurements of fast neutrons.MethodsThe developed fission chamber has been tested by Co-60 gamma source and Cf-252 neutron source.ResultsThe results have indicated that it is very easy to cut off the gamma rays from the neutrons by using a discriminator, when the fission chamber works in the pulse mode. The detector works well, even if the static air is used as the filling gas.ConclusionTo discuss the application of the detector, Monte Carlo simulations have been performed by considering four U-238-coated fission chambers located outside the spallation target for the fast neutron measurement from spallation reaction. The simulation results have indicated that the detector can be used to measure the fast neutron flux and neutron flux ratio of four fission chambers. Furthermore, a U-238-coated fission chamber can be used within a reactor for longer time, in comparison with a U-235-coated fission chamber.