Vacuum ion-getter pump with cryogenically cooled cathode

Abstract

A vacuum ion-getter pump includes a vacuum chamber having a pumping port, an anode positioned in the vacuum chamber, a cathode positioned in the vacuum chamber in proximity to the anode, a voltage source coupled between the anode and the cathode, a magnet assembly to produce a magnetic field in the vacuum chamber, and a cooling device thermally coupled to the cathode. The cooling device may be a cryogenic cooling device.

1 . A vacuum ion-getter pump comprising:
 a vacuum chamber having a pumping port;   an anode positioned in the vacuum chamber;   a cathode positioned in the vacuum chamber in proximity to the anode;   a voltage source coupled to between the anode and cathode;   a magnet assembly to produce a magnetic field in the vacuum chamber; and   a cooling device thermally coupled to the cathode.   
   
   
       2 . The vacuum ion-getter pump as defined in  claim 1 , where in the cooling device comprises a cryogenic cooling device. 
   
   
       3 . The vacuum ion-getter pump as defined in  claim 2 , wherein the cryogenic cooling device comprises a closed cycle refrigerator having a cold head in thermal contact with the cathode. 
   
   
       4 . The vacuum ion-getter pump as defined in  claim 2 , wherein the cooling device operates at temperatures used in cryogenic vacuum pumps. 
   
   
       5 . The vacuum ion-getter pump as defined in  claim 3 , wherein the cryogenic cooling device is based on the Gifford-McMahon cycle. 
   
   
       6 . The vacuum ion-getter pump as defined in  claim 1 , wherein the cooling device comprises a cryogenic refrigerator. 
   
   
       7 . The vacuum ion-getter pump as defined in  claim 2 , wherein the cathode comprises spaced-apart cathode plates and wherein the anode comprises a plurality of anode cells positioned between the cathode plates. 
   
   
       8 . The vacuum ion-getter pump as defined in  claim 2 , wherein the magnet assembly comprises permanent magnets positioned outside the vacuum chamber. 
   
   
       9 . The vacuum ion-getter pump as defined in  claim 2 , wherein the anode operates at or near room temperature. 
   
   
       10 . The vacuum ion-getter pump as defined in  claim 2 , wherein the anode is thermally coupled to a cryogenic cooling device. 
   
   
       11 . The vacuum ion-getter pump as defined in  claim 2 , wherein the voltage source maintains a voltage in a range of 3 to 9 kilovolts between the anode and the cathode. 
   
   
       12 . A method for operating a vacuum ion-getter pump of the type including an anode and a cathode positioned in a vacuum chamber, the method comprising:
 cooling the cathode.   
   
   
       13 . The method as defined in  claim 12 , wherein cooling the cathode comprises cryogenically cooling the cathode. 
   
   
       14 . The method as defined in  claim 12 , wherein cooling the cathode comprises operating the cathode at temperatures used in cryogenic vacuum pumps. 
   
   
       15 . The method as defined in  claim 13 , further comprising operating the anode at room temperature. 
   
   
       16 . The method as defined in  claim 13 , further comprising cooling the anode. 
   
   
       17 . The method as defined in  claim 12 , further comprising:
 coupling the vacuum chamber to an enclosure to be evacuated;   applying a voltage between the anode and the cathode; and   producing a magnetic field in the vacuum chamber.   
   
   
       18 . A vacuum ion-getter pump comprising:
 a vacuum chamber having a pumping port;   an anode positioned in the vacuum chamber;   a cathode positioned in the vacuum chamber; and   a cryogenic cooling device thermally coupled to the cathode.   
   
   
       19 . The vacuum ion-getter pump as defined in  claim 18 , further comprising a magnet to produce a magnetic field in the vacuum chamber.