Abstract: A cryocooler diagnostic system includes a cryocooler including a pressure sensor that measures a pressure inside the cryocooler, a calculation processing device configured to receive a measured pressure waveform indicating the pressure inside the cryocooler measured by the pressure sensor, and calculate an amplitude of a drive frequency of the cryocooler or of a frequency component that is an integer multiple of the drive frequency from the measured pressure waveform, and a diagnostic device configured to receive the amplitude calculated by the calculation processing device and diagnose the cryocooler based on the amplitude.

Abstract: Provided is a method of disassembling a cold head provided with a displacer that extends in an axial direction, a cylinder that accommodates the displacer, and a displacer drive unit that is fastened to the cylinder and is connected to the displacer such that the displacer is driven in the axial direction, the method including mounting a lifting-up jig onto the displacer drive unit, unfastening the displacer drive unit and the cylinder from each other, and operating the lifting-up jig such that the displacer drive unit is lifted up from the cylinder together with the displacer.

Abstract: Provided is a method of disassembling a cold head provided with a displacer that extends in an axial direction, a cylinder that accommodates the displacer, and a displacer drive unit that is fastened to the cylinder and is connected to the displacer such that the displacer is driven in the axial direction, the method including mounting a lifting-up jig onto the displacer drive unit, unfastening the displacer drive unit and the cylinder from each other, and operating the lifting-up jig such that the displacer drive unit is lifted up from the cylinder together with the displacer.