The performance test of a small size refrigerator has been done. The type of the refrigerator is two‐stage Gifford‐McMahon(GM). The electric power consumption is 1.3 kW at60 Hz. One of the purposes of this GM refrigerator is to using for physical properties measurement. A hybrid type regenerator material is filled in the 2nd‐stage regenerator to obtain the cooling temperature of 4 K level. The 2nd‐stage of the GM refrigerator cooled from room temperature to 3.2 K in about 3.5 hours and the 1st‐stage temperature was 33.7 K. The cooling power of the 2nd‐stage was 50 mW at 4.2 K. It succeeded in the measurement of the resistivity characteristics depending on temperatture of copper wire. This GM refrigerator has the acrylic chamber instead of the stainless steel chamber to visualizing the 2nd‐stage. It will be enabled to carry out many experiments.
Small size GM refrigerator
4 K level
Physical properties measurement