Cryocooler and control device of cryocooler

A cryocooler comprising:

• a cold head;
• a valve that comprises:
• a rotary valve configured to periodically switch a pressure of a working gas in the cold head between a first high pressure and a second high pressure lower than the first high pressure, and
• a valve motor configured to rotate the rotary valve, the valve having a rotation angle range in which the rotary valve seals the working gas having the second high pressure in the cold head;
• a cryocooler controller configured to control the valve motor;
• a cryocooler stop instruction signal generator configured to output a cryocooler stop instruction signal to the cryocooler controller;
• a pressure sensor configured to measure a pressure of the working gas;
• and
• a valve stop timing controller configured to:
• control, according to the cryocooler stop instruction signal, the valve motor to stop the rotary valve in the rotation angle range, and
• determine, based on the pressure measured by the pressure sensor, a stop timing of the valve motor such that the rotary valve stops in the rotation angle range.

A control device of a cryocooler,

• the cryocooler comprising:
• a cold head,
• a valve that comprises:
• a rotary valve configured to periodically switch a pressure of a working gas in the cold head between a first high pressure and a second high pressure lower than the first high pressure, and
• a valve motor configured to rotate the rotary valve, the valve having a rotation angle range in which the rotary valve seals the working gas having the second high pressure in the cold head, a cryocooler controller configured to control the valve motor,
• a cryocooler stop instruction signal generator configured to output a cryocooler stop instruction signal to the cryocooler controller, and
• a rotation angle sensor configured to measure a rotation angle of the rotary valve, the control device comprising:
• a valve stop timing controller configured to:
• control, according to the cryocooler stop instruction signal, the valve motor to stop the rotary valve in the rotation angle range, and
• determine, based on the rotation angle measured by the rotation angle sensor, a stop timing of the valve motor such that the rotary valve stops in the rotation angle range.

A control device of a cryocooler,

• the cryocooler comprising:
• a cold head,
• a valve that comprises:
• a rotary valve configured to periodically switch a pressure of a working gas in the cold head between a first high pressure and a second high pressure lower than the first high pressure, and
• a valve motor configured to rotate the rotary valve, the valve having a rotation angle range in which the rotary valve seals the working gas having the second high pressure in the cold head,
• a cryocooler controller configured to control the valve motor, a cryocooler stop instruction signal generator configured to output a cryocooler stop instruction signal to the cryocooler controller, and
• a pressure sensor configured to measure a pressure of the working gas,
• the control device comprising:
• a valve stop timing controller configured to control, according to the cryocooler stop instruction signal, the valve motor to stop the rotary valve in the rotation angle range, and
• determine, based on the pressure measured by the pressure sensor, a stop timing of the valve motor such that the rotary valve stops in the rotation angle range.