• He3 closed cycle cryostat insert for solenoids

The INMAGN-112-03-He3 cryostat-insert secures the temperature within 0.3 - 1.4 K region on the cold copper flange to which the sample is mounted. The cryostat-insert introduced to the cryostat with superconducting solenoid places the sample in the center of the magnetic field. The operation of the insert bases on the repeating cycles related to the condensation and pumping of liquid He3. The main part of the cryostat-insert is the condensation chamber for He3 located inside the He4 chamber used as a heat exchanger. The preliminary pumping of the He4 chamber secures the temperature 1.4 K. During the following filling of the He3 chamber, the gaseous He3 condensates on the cold outer walls of the He4 chamber and the liquid He3 fills out the bottom part of the chamber. Then the liquid He3 pumped out by adsorption pump secures the minimal temperature 0.3 K at minuimum vapour pessure. The sample attached to the cold flange has the same temperature as the bottom part of the He3 chamber. For optical measurements, an optical fiber line completes the insert. The optimized distance between the bottom of the He4 chamber and the cold flange of the He3 chamber reduces the heat flow between them.