2021 年 31 巻 2 号 p. 78-80
For the production of the high-intensity pulse neutrons, a 3-GeV proton-beam transport facility (3NBT) had constructed to deliver the high-intensity proton beam to Material Life Science Experiment Facility (MLF) at J-PARC. In order to construct a facility using the beam intensity of about 200 times in Japan when the construction has started, various research and developments (R&Ds) were carried out such as magnets withstanding under the high radiation fields and the beam shape flattening technique based on nonlinear beam optics to mitigate the damage on the neutron production target. As a result of R&Ds, it was demonstrated that MLF can continuously produce high-intensity pulse neutrons using 1-MW proton beam without any issues for long duration.