Design, fabrication and installation of cryogenic target system for 14 MeV neutron irradiation on superconducting magnet materials

A large scale superconducting magnet system is indispensable to realize a fusion reactor and researches on fusion neutron irradiation effects on the magnet materials must be performed continuously and systematically to promote an establishment of reasonable design and fabrication of a fusion reactor. Since pure 14 MeV neutrons are expected to give clear results easily understood in comparison with energy-distributed neutrons, a new cryogenic target system has been installed in Fusion Neutronics Source at Japan Atomic Energy Research Institute under collaboration among Universities, National Institutes and JAERI. The new system has the potential to perform the electrical measurement at cryogenic temperature without warm-up of the samples. This report describes the design and installation of the cryogenic target system for 14 MeV neutron irradiation and some performance test results. The cold target is able to be cooled down within 2 h and there is no temperature rise during a 3 h neutron irradiation