~3He/~4He dilution refrigerator with pulse-tube refrigerator precooling

摘要

A dilution refrigerator is described which is precooled by a two-stage pulse-tube refrigerator and thus no cryoliquids are needed to operate this millikelvin cooler. The cool-down process from room temperature to a precooling temperature below 3 K is automatic, and operating the dilution refrigerator is convenient. It takes about two hours to condense the ~3He/~4He mash; with just a standard rotary pump to circulate the ~3He in the dilution circuit and a very simple dilution unit we reached a final temperature of 15 mK.