A He-3/He-4 dilution refrigerator is described where a commercial two-
stage Gifford-McMahon refrigerator (Leybold RGD 210) cools the dilutio
n unit and the radiation shields of the cryostat. This work is a conti
nuation of previously described experiments where a more powerful clos
ed cycle refrigerator had been used for the same dilution cycle; in co
mparison with those experiments the construction of the new apparatus
has now been simplified and improved, and the mixing chamber temperatu
re lowered.