Study of beam target materials for a 3-MeV LINAC at J-PARC

Hirano, Koichiro  ; Fukuda, Makoto*; Ezato, Koichiro*; Tokunaga, Kazutoshi*

Tungsten is used in beam targets and experimental fusion reactor (ITER) divertors as a material with low activation, high thermal conductivity and high strength properties. Using a 3 MeV linac with negative hydrogen ion beam energy, multiple irradiation tests were conducted on tungsten materials meeting the ITER requirements, in which temperature changes of heating and cooling were repeatedly given at 5 Hz cycles. As a result, protrusions and cracks were observed on the surface of the test piece using SEM device, which were presumably caused by repeated expansion and contraction due to rapid pulse-like temperature change.