Cryogen-free cooling apparatus

Abstract

The disclosure relates to a cryogen-free cooling apparatus for cooling a sample, comprising a vacuum chamber, a first cooling device which is configured to generate a first temperature in the vacuum chamber to provide a main thermal bath, a second cooling device, which is in connection with a sample stage on which a sample is to be arranged, wherein the second cooling device is a solid state cooler which is configured to provide a second temperature to the sample stage, and wherein the second temperature is different from the first temperature, and a sample loading device which is configured to change the sample while operating the first cooling device and the second cooling device, wherein the sample stage is held in the vacuum chamber by a plurality of first fibers of low thermal conductivity such that the sample stage is thermally decoupled from the main thermal bath.

1 .- 13 . (canceled) 
     
     
         14 . A cryogen-free cooling apparatus for cooling a sample, comprising
 a vacuum chamber providing a main thermal insulation vacuum;   a sample stage arranged in the main thermal insulation vacuum and fluidly immersed in the main thermal vacuum, the sample stage being configured to directly couple to a sample loaded onto the sample stage by a sample loading device;   a first cooling device arranged in the main thermal insulation vacuum, the first cooling device being configured to generate a first temperature in the vacuum chamber to provide a main thermal bath; and   a second cooling device arranged in the main thermal insulation vacuum, the second cooling device being in connection with the sample stage, wherein the second cooling device is configured to provide a second temperature to the sample stage, and wherein the second temperature is different from the first temperature.   
     
     
         15 . The cryogen-free cooling apparatus of  claim 14 , further including the sample loading device configured to change the sample on the sample stage inside the main thermal insulation vacuum. 
     
     
         16 . The cryogen-free cooling apparatus of  claim 15 , wherein the sample loading device is configured to load the sample directly into the main thermal insulation vacuum. 
     
     
         17 . The cryogen-free cooling apparatus of  claim 14 , further including a first mechanical suspension holding the sample stage in the vacuum chamber and in the main thermal insulation vacuum, wherein the first mechanical suspension is of low thermal conductivity such that the sample stage is thermally decoupled from the main thermal bath. 
     
     
         18 . The cryogen-free cooling apparatus of  claim 17 , wherein the first mechanical suspension has a thermal conductivity of less than 0.1 W/(Km). 
     
     
         19 . The cryogen-free cooling apparatus of  claim 17 , wherein the first mechanical suspension is provided by a plurality of first fibers or wires. 
     
     
         20 . The cryogen-free cooling apparatus of  claim 19 , wherein the first fibers or wires have a thickness of less than 0.1 mm. 
     
     
         21 . The cryogen-free cooling apparatus of  claim 19 , further including a strain mechanism configured to apply tension to the plurality of first fibers or wires. 
     
     
         22 . The cryogen-free cooling apparatus of  claim 14 , further including a sample stage locking device configured to mechanically lock the sample stage in place. 
     
     
         23 . The cryogen-free cooling apparatus of  claim 22 , wherein the sample stage locking device is configured to mechanically lock the sample stage in place during loading of the sample. 
     
     
         24 . The cryogen-free cooling apparatus of  claim 22 , wherein the sample stage locking device includes one or more shafts configured to be inserted in corresponding holes of the sample stage to mechanically lock the sample stage in place. 
     
     
         25 . The cryogen-free cooling apparatus of  claim 22 , wherein the sample stage locking device does not touch the sample stage in an unlocked state. 
     
     
         26 . The cryogen-free cooling apparatus of  claim 22 , wherein the sample stage locking device is configured to provide a thermal link to the main thermal bath in a locked state. 
     
     
         27 . The cryogen-free cooling apparatus of  claim 14 , further including:
 a sample radiation shield which surrounds the sample stage; and   a second mechanical suspension holding the sample radiation shield in the vacuum chamber and in the main thermal insulation vacuum, wherein the second mechanical suspension is of low thermal conductivity such that the sample radiation shield is thermally decoupled from the main thermal bath.   
     
     
         28 . The cryogen-free cooling apparatus of  claim 27 , wherein the second mechanical suspension is provided by a plurality of second fibers. 
     
     
         29 . The cryogen-free cooling apparatus of  claim 14 , wherein the second temperature provided by the second cooling device is lower than the first temperature provided by the first cooling device. 
     
     
         30 . The cryogen-free cooling apparatus of  claim 14 , wherein the first temperature provided by the first cooling device is in the range of 2K to 4K. 
     
     
         31 . The cryogen-free cooling apparatus of  claim 14 , wherein the second temperature provided by the second cooling device is 300 mK or less, or 50 mK or less. 
     
     
         32 . The cryogen-free cooling apparatus of  claim 14 , wherein the first cooling device is a mechanical cooling device and the second cooling device is a solid state cooler. 
     
     
         33 . The cryogen-free cooling apparatus of  claim 14 , wherein the second cooling device is a magnetic cooler, an adiabatic demagnetization refrigerator, a barocaloric refrigerator, a multi-stage cooling device or a thermoelectric cooler. 
     
     
         34 . The cryogen-free cooling apparatus of  claim 14 , wherein the sample stage includes:
 an electrical connector configured to establish an electrical connection to the sample;   an optical connector configured to provide an optical access to the sample;   at least one magnetic field sensor;   at least one temperature sensor; or   a heater.