Abstract: A cooling system is provided with a refrigerator using helium gas, a compressor that compresses the helium gas returned from the refrigerator and supplies the gas to the refrigerator, and a control unit. The control unit includes a measurement acquisition unit that acquires measurements of a plurality of different parameters representing a status of the refrigerator, or the compressor, or both, and an analysis unit that conducts multivariate analysis of the measurements acquired by the measurement acquisition unit.

Abstract: A cooling system is provided with a GM refrigerator using helium gas, a compressor that compresses the helium gas returned from the GM refrigerator and supply the gas to the GM refrigerator, and a control unit. The control unit includes a measurement acquisition unit that acquires measurements of a plurality of different parameters representing a status of the GM refrigerator, or the compressor, or both, and an analysis unit that conducts multivariate analysis of the measurements acquired by the measurement acquisition unit.

Abstract: A disclosed displacer to be inserted into a cylinder to expand a compressed working fluid inside the cylinder by reciprocation of the displacer inside the cylinder includes a cylindrical member; and a regenerative material included inside the cylindrical member, wherein a groove is formed on an outer peripheral surface of the cylindrical member, the outer peripheral surface facing the cylinder, and a sealing film is continuously formed on the outer peripheral surface and the groove over an area where the groove is formed in a longitudinal direction.