Cryopump

Abstract

A cryopump includes a gas flow regulation member which deflects a flow of gas, which flows in from a shield main opening, from a cryocooler structural portion. The gas flow regulation member is disposed to be adjacent to the cryocooler structural portion such that the gas flow regulation member is in contact with neither a second cooling stage nor a second cryopanel unit of a cryocooler. The gas flow regulation member may be thermally connected to a first cooling stage of the cryocooler.

What is claimed is: 
     
         1 . A cryopump comprising:
 a cryocooler which includes a first cooling stage which is cooled to a first cooling temperature, a second cooling stage which is cooled to a second cooling temperature which is lower than the first cooling temperature, and a cryocooler structural portion which structurally supports the second cooling stage to the first cooling stage;   a radiation shield which includes a shield main opening for receiving a gas, is thermally connected to the first cooling stage, and includes a shield side portion which encloses the second cooling stage, wherein a shield side opening into which the cryocooler structural portion is inserted is on the shield side portion;   a cryopanel unit which is thermally connected to the second cooling stage, wherein the cryopanel and the second cooling stage are enclosed by the shield side portion; and   a gas flow regulation member which is in contact with neither the second cooling stage nor the cryopanel unit, and is disposed to be adjacent to the cryocooler structural portion such that the gas flow regulation member deflects the flow of the gas which flows in from the shield main opening, from the cryocooler structural portion,   wherein the cryopanel unit includes a top cryopanel which faces the shield main opening, and the top cryopanel is disposed to forma gap region between the top cryopanel and the cryocooler structural portion, and   wherein the gas flow regulation member includes an inner edge portion which enters the gap region, and the inner edge portion is covered with the top cryopanel.   
     
     
         2 . The cryopump according to  claim 1 ,
 wherein the gas flow regulation member is thermally connected to the first cooling stage.   
     
     
         3 . The cryopump according to  claim 1 ,
 wherein the gas includes a second kind of gas which is not condensed at the first cooling temperature and is condensed at the second cooling temperature, and   wherein the gas flow regulation member is configured to reflect the second kind of gas.   
     
     
         4 . The cryopump according to  claim 1 ,
 wherein the gas flow regulation member extends from the shield side portion or the first cooling stage toward the gap region.   
     
     
         5 . The cryopump according to  claim 1 ,
 wherein the radiation shield includes a shield front end which defines the shield main opening, and the shield side portion extends from the shield front end toward a side opposite to the shield main opening, and   wherein the gas flow regulation member includes an outer edge portion which faces the shield main opening, and the outer edge portion is mounted on the shield side portion between the shield front end and the shield side opening.   
     
     
         6 . The cryopump according to  claim 1 ,
 wherein the cryocooler structural portion includes a cryocooler cylinder which connects the second cooling stage to the first cooling stage, and   wherein the gas flow regulation member includes a flat plate, a curved plate, a bent plate, or a tubular plate which is disposed along the cryocooler cylinder in a state where a clearance is provided between the cryocooler cylinder and the plate.