 Mixing chamber of a dilution refrigerator

The mixing chamber of a dilution refrigerator is the cold region where helium-3 crosses from a concentrated phase into a dilute helium-3/helium-4 phase. The enthalpy difference absorbs heat, providing cooling when helium-3 circulation is maintained.

A sample is thermally connected to this region. Its actual temperature depends on heat loads and thermal links, rather than simply equaling a nominal refrigerator specification. The dilution refrigerator still removes helium-3 from the circulating dilute mixture at a warmer stage.^[ref]