The Design of Cryogen-Free Cryostat for Pulsed High Magnetic Field Based on GM Cryocooler

Based on a small GM cryocooler, a cryogen-free insert cryostat for physics experiment in a pulsed high magnetic field has been designed. The GM cryocooler is used as the cooling source. The sample is cooled by liquid helium for the low temperatures and by helium gas for the high temperatures. The inner diameter of the cryostat is 8 mm and the outer diameter of the tail is 16 mm, thus it can be inserted into a 60 T pulsed magnet. Experimental results show that the temperature can be controlled from 1.5 K to 300 K easily. In the sample region, stability of the temperature is obtained: ±0.1 K at 20 K-300 K, ±0.2 K at 5 K-20 K and ±0.02K at 1.5 K-5 K. The system may be used for electrical transport and magnetization measurements in a pulsed high magnetic field.