Developments of a thick and large solid hydrogen target for radioisotope beams

A thick and large solid hydrogen target (SHT) for radioisotope (RI) beams was developed. A target with 100 mm thickness and 50 mm diameter equipped with thin Kapton windows (25 μm) was achieved. We developed a new method to fill solid hydrogen into a large target cell by eliminating any void or porous regions. The expansion of thin Kapton windows and the real thickness of SHT were measured by a laser distance meter and an energy-loss of RI beams, respectively. They gave the same thickness confirming the complete solidification of hydrogen in the cell. We obtained a window expansion of about 2.5 mm (about 1.25 mm for each side).