Effect Evaluation of the Converter/Absorber for Measuring 14 MeV Fast Neutron

This paper describes the design and the optimization of a 14 MeV neutron detector based on the gas detector. In this study, Effects with respect to detection efficiency of polyethylene thickness as a converter and aluminum as an absorber were simulated using the MCNPX. The two reactions employed in fusion experiments (D-D and D-T) yield 2.5 and 14 MeV neutrons, respectively. These two neutron components must be measured separately in future fusion reactors such as ITER. The development of new detection systems for the 14 MeV neutrons suitable to fusion reactors is still an open challenge, although liquid scintillators and diamond detectors already represent a viable chance. Compact dimensions, high counting rate capability good detection efficiency, stability under electromagnetic fields, radiation resistance, and insensitivity to gamma-ray are key requirements. Possible good candidates for fast neutron detection in fusion devices are gas detectors concept. The gas chamber detectors have been successfully used for neutron detection due to their high counting rate capability, they can play an important role also for neutron diagnostics in fusion devices. A gas chamber detector was designed to measure 14 MeV fast neutron for fusion applications. Polyethylene and thin aluminum sheet are used as a converter and an absorber. Using the MCNPX code, optimized thickness of the converter and effect of the absorber was calculated and evaluated to obtain the highest detection efficiency of recoil proton and effects of the absorber was confirmed