Cryostat configuration

Abstract

A cryostat configuration with a vacuum vessel ( 1 ) and a cryogen vessel ( 2 ) built into it, and a sleeve ( 8 ), into which a cryocooler ( 7 ) is built, wherein the upper, warm end of the sleeve is connected to the outer jacket and the lower, cold end facing the cryogen vessel is hermetically sealed by a sleeve base ( 9 ) is characterized in that the cryogen vessel is hermetically sealed except for a gas capillary ( 13 ) and filled with gaseous fluid ( 12 ) at a pressure below the vapor pressure of the liquid phase of the fluid at the corresponding operating temperature and the coldest stage of the cryocooler is connected to the heat exchanger ( 11 ) disposed inside the cryogen vessel in a manner that ensures good thermal conduction.

1 . A cryostat configuration comprising:
 a vacuum vessel having an outer jacket;   a cryogen vessel disposed within said vacuum vessel, said cryogen vessel being substantially hermetically sealed;   a sleeve having an upper, warm end connected to said outer jacket and a lower, cold end facing said cryogen vessel, said lower, cold end being hermetically sealed by a sleeve base;   a cryocooler disposed within said sleeve, said cryocooler having a coldest stage;   a superconducting magnet configuration disposed within said cryogen vessel;   a gas capillary, said gas capillary disposed, structured and dimensioned to fill said cryogen vessel with gaseous fluid at a pressure below a vapor pressure of a liquid phase of the gaseous fluid at an operating temperature; and   a heat exchanger disposed within said cryogen vessel, said heat exchanger in heat communication with said coldest stage of said cryocooler in a manner that ensures good thermal conduction.   
     
     
         2 . The cryostat configuration of  claim 1 , wherein said heat exchanger disposed inside said cryogen vessel has a surface area of at least 1000 cm 2 . 
     
     
         3 . The cryostat configuration of  claim 1 , wherein said heat exchanger disposed inside said cryogen vessel comprises a helical tube, which is filled at room temperature with a gas comprising helium, hydrogen, neon or nitrogen and is then hermetically sealed. 
     
     
         4 . The cryostat configuration of  claim 1 , wherein said sleeve is filled with a gas or gas mixture comprising helium, hydrogen, neon or nitrogen and a gas pressure is set such that liquid forms at said lower end of said sleeve. 
     
     
         5 . The cryostat configuration of  claim 4 , wherein said coldest stage of said cryocooler is mounted without contact with said sleeve and said sleeve base. 
     
     
         6 . The cryostat configuration of  claim 4 , further comprising a thermosiphon mounted between said sleeve and said heat exchanger, said thermosiphon connected to said heat exchanger in a manner that ensures good thermal conduction such that said liquid evaporates in said thermosiphon and vapor is guided back into said sleeve above a liquid level. 
     
     
         7 . The cryostat configuration of  claim 1 , wherein said superconducting magnet configuration is part of an apparatus for nuclear magnetic resonance, for magnetic resonance imaging or for magnetic resonance spectroscopy. 
     
     
         8 . A method for operating the cryostat configuration of  claim 1 , wherein said cryogen vessel is filled via said gas capillary before cooling and is then hermetically sealed at room temperature with helium gas at 1 bar.