Abstract: A cryogenic refrigerator uses a mixture of helium-3 and helium-4. Gaseous helium is pumped from a reservoir containing a liquid mixture of helium-3 and helium-4 to cause cooling and a phase separation into an upper helium-3 rich phase which floats at the top for further evaporation and a lower dilute phase below the helium-3 rich phase. This separation enables operation at temperatures typical of a helium-3 refrigerator while initial liquefaction of the mixture is easier than liquefaction of pure helium-3 and can use a smaller amount of helium-3. Embodiments of the refrigerator can provide continuous cooling.