Cooling device with controllable evaporation temperature

Abstract

A cooling device for cooling a test sample has at least two cascade cooling stages, each with at least one coolant line, one compressor ( 1.1, 2.1 ), one relief throttle ( 1.4, 2.4 ), one evaporator ( 6, 7 ) and one liquefier ( 3, 6 ). The cooling device has an additional relief throttle disposed between the evaporator ( 7 ) of the last cascade cooling stage and the compressor ( 2.1 ) of the last cascade cooling stage. This represents a simple possibility of adjusting the cooling temperature, thereby avoiding the use of valves that can be adjusted at low temperatures, since these are complex and expensive.

1 . A cooling device for cooling a test sample, the cooling device comprising:
 at least one first cascade non-final cooling stage, said first non-final cooling stage having at least one first coolant line, a first compressor, a first relief throttle, a first evaporator and a first liquefier; and   a second final cascade cooling stage, said second final cascade cooling stage having at least one second coolant line, a second compressor, a second relief throttle, a second evaporator, a second liquefier and an additional relief throttle disposed between said second evaporator and said second compressor.   
     
     
         2 . The cooling device of  claim 1 , wherein said additional relief throttle is designed in two stages as a parallel arrangement of a bypass valve and an invariable relief throttle. 
     
     
         3 . The cooling device of  claim 1 , wherein said additional relief throttle is designed as a variable adjustable relief throttle. 
     
     
         4 . The cooling device of  claim 1 , wherein said second evaporator is designed as a heat exchanger, wherein a cooling gas enters said heat exchanger through a gas inlet, dissipates heat, exits said heat exchanger again through a gas outlet and is guided to the test sample for cooling thereof. 
     
     
         5 . The cooling device of  claim 1 , wherein the cooling device is structured for use in a nuclear magnetic resonance spectroscopy apparatus. 
     
     
         6 . The cooling device of  claim 1 , wherein the cooling device is structured for use in an X-ray spectroscopy apparatus. 
     
     
         7 . The cooling device of  claim 1 , wherein the cooling device is structured for use in an EPR apparatus.