| 摘要 |
A cryogenic refrigerator (1) includes a cylinder (12), a displacer (14) accommodated in the cylinder (12) so as to reciprocate inside the cylinder (12) with a gap (40) formed between the periphery of the displacer (14) and the interior surface of the cylinder (12), and a depressed part (38) formed on at least one of the periphery of the displacer (14) and the interior surface of the cylinder (12). The ratio of the volume of the depressed part (38) to the volume of the gap (40) satisfies a condition of 8 ‰¤ Vd/Vg ‰¤ 75, where Vd is the volume of the depressed part (38) and Vg is the volume of the gap (40). |
