Pulse tube refrigerator

Abstract

A pulse tube refrigerator includes a regenerator tube; a pulse tube; and a condenser condensing an atmospheric gas and disposed at cold ends of the regenerator tube and the pulse tube so as to also function as a cooling stage. The condenser includes a first surface and a second surface facing each other, a flow path having two openings on the first surface and connecting the cold end of the regenerator tube and the cold end of the pulse tube, and multiple holes extending from the second surface. The holes formed in an area of the condenser defined by a circle having the center on a straight line connecting the centers of the openings of the flow path do not pass through the condenser up to the first surface. The circle is the smallest circle enclosing the openings or a circumscribed circle circumscribing the openings.

1 . A pulse tube refrigerator, comprising:
 a regenerator tube;   a pulse tube; and   a condenser condensing an atmospheric gas and disposed at cold ends of the regenerator tube and the pulse tube so as to also function as a cooling stage,   wherein the condenser includes
 a first surface and a second surface facing each other, 
 a flow path having two openings on the first surface and connecting the cold end of the regenerator tube and the cold end of the pulse tube, and 
 multiple holes extending from the second surface; 
   wherein when viewed from a direction parallel to an axis of the regenerator tube or the pulse tube, the holes formed in an area of the condenser defined by a circle having a center on a straight line connecting centers of the openings of the flow path do not pass through the condenser up to the first surface;   wherein the circle is a smallest circle enclosing the openings of the flow path or a circumscribed circle circumscribing the openings of the flow path.   
     
     
         2 . The pulse tube refrigerator as claimed in  claim 1 , wherein
 the condenser further includes a side surface connecting the first surface and the second surface; and   at least one of the holes has an opening on the side surface.   
     
     
         3 . The pulse tube refrigerator as claimed in  claim 1 , wherein
 the condenser further includes a side surface connecting the first surface and the second surface;   the side surface has an indented part along a circumference of the side surface; and   at least one of the holes has an opening on the indented part.   
     
     
         4 . The pulse tube refrigerator as claimed in  claim 1 , wherein all of the holes are not through holes. 
     
     
         5 . A pulse tube refrigerator, comprising:
 a regenerator tube;   a pulse tube;   a condenser condensing an atmospheric gas; and   a cooling stage disposed on the condenser,   wherein the cooling stage includes
 a first surface and a second surface facing each other, and 
 a flow path having two openings on the first surface and connecting a cold end of the regenerator tube and a cold end of the pulse tube; 
   wherein the condenser includes
 a third surface and a fourth surface facing each other, the third surface being closer than the fourth surface to the second surface of the cooling stage, and 
 multiple holes extending from the fourth surface; 
   wherein when viewed from a direction parallel to an axis of the regenerator tube or the pulse tube, the holes formed in an area of the condenser defined by a circle having a center on a straight line connecting centers of the openings of the flow path do not pass through the condenser up to the third surface;   wherein the circle is a smallest circle enclosing the openings of the flow path or a circumscribed circle circumscribing the openings of the flow path.   
     
     
         6 . The pulse tube refrigerator as claimed in  claim 1 , wherein the pulse tube refrigerator is a multi-stage pulse tube refrigerator and the atmospheric gas is a helium gas. 
     
     
         7 . The pulse tube refrigerator as claimed in  claim 6 , wherein the cooling stage provides a lowest temperature in the pulse tube refrigerator. 
     
     
         8 . The pulse tube refrigerator as claimed in  claim 6 , further comprising:
 a liquid helium tank disposed to face the second surface of the condenser.   
     
     
         9 . The pulse tube refrigerator as claimed in  claim 1 , wherein the pulse tube refrigerator is a single-stage pulse tube refrigerator and the atmospheric gas is a nitrogen gas.