Cooling device and cold head replacement method

Abstract

A refrigerator port includes a sleeve and a pedestal. A pipe is drawn out from the refrigerator port. The pipe is provided with a valve. Before a cold head is pulled out, helium gas in a tank is supplied to a port space via the pipe. Accordingly, a pressure in the port space becomes the atmospheric pressure or approaches the atmospheric pressure. A pressure adjustment facility can also function when residual gas is discharged from the port space. Thus, the load of an operation of pulling out the cold head from the refrigerator port is reduced.

1 . A cooling device comprising:
 a vacuum container accommodating an object to be cooled;   a refrigerator port provided in the vacuum container and including a port space in which a cold head of a refrigerator configured to cool the object to be cooled is accommodated in a replaceable manner; and   a pressure adjustment facility configured to supply gas to the port space to increase a pressure in the port space before the cold head is pulled out.   
     
     
         2 . The cooling device according to  claim 1 , wherein
 the pressure adjustment facility includes:   a pipe including a gas flow path communicating with the port space and drawn out from the refrigerator port; and   a valve provided in the pipe, and configured to close the gas flow path during operation of the refrigerator and allow supply of the gas to the gas flow path during replacement of the cold head.   
     
     
         3 . The cooling device according to  claim 2 , wherein
 the refrigerator port includes a bellows configured to expand and contract in a port central axis direction, and   the pipe is drawn out from a room temperature side of the bellows in the refrigerator port.   
     
     
         4 . The cooling device according to  claim 1 , wherein
 the refrigerator port includes:   a sleeve surrounding the port space; and   a pedestal that is a member provided on a cooling-side end portion of the sleeve, and is directly or indirectly connected to a stage of the cold head, and   the cooling device further comprising:   an elastic mechanism configured to apply an elastic force to the pedestal so as to increase a connecting force between the pedestal and the stage.   
     
     
         5 . The cooling device according to  claim 1 , wherein
 the port space includes a first port space and a second port space arranged in a port central axis direction,   the refrigerator port includes:   a first sleeve surrounding the first port space;   a second sleeve surrounding the second port space;   a first pedestal that is a member provided on a cooling-side end portion of the first sleeve, and is directly or indirectly connected to a first stage of the cold head; and   a second pedestal that is provided on a cooling-side end portion of the second sleeve, and is directly or indirectly connected to a second stage of the cold head, and   the cooling device further comprising:   a first elastic mechanism configured to apply an elastic force to the first pedestal so as to increase a connecting force between the first pedestal and the first stage; and   a second elastic mechanism configured to apply an elastic force to the second pedestal so as to increase a connecting force between the second pedestal and the second stage.   
     
     
         6 . The cooling device according to  claim 5 , wherein
 the first elastic mechanism includes a plurality of first support elements provided around the first sleeve,   each of the first support elements includes an elastic member,   the second elastic mechanism includes a plurality of second support elements provided around the first sleeve and the second sleeve, and   each of the second support elements includes an elastic member.   
     
     
         7 . The cooling device according to  claim 1 , wherein
 a heater configured to prevent liquefaction of the gas supplied to the port space is provided in the refrigerator port.   
     
     
         8 . A cold head replacement method comprising:
 in a state where a cold head of a refrigerator is disposed in a refrigerator port provided in a vacuum container, supplying gas from an outside to a port space in the refrigerator port and thereby increasing a pressure in the port space; and   pulling out the cold head from the refrigerator port after the pressure in the port space is increased.   
     
     
         9 . The cold head replacement method according to  claim 8 , further comprising:
 discharging the gas in the port space to the outside after a new cold head is disposed in the refrigerator port.