Performance improvement of a pulse tube cooler below 4 K by use of GdAlO3 regenerator material

The cooling power and coefficient of performance of a two-stage pulse tube cooler below 4 K have been increased greatly by using the newly developed ceramic magnetic regenerative material GdAlO3 (GAP). Cooling powers of 200 mW at 2.8 K, 300 mW at 3.13 K, and 400 mW at 3.70 K have been achieved with a compressor input power of about 4.8 kW. The results show that the cooling power near 3.0 K increases by 150% compared to that of the same pulse tube cooler (PTC) employing only conventional HoCu2 and ErNi regenerator materials.