Bottom-loading dilution refrigerator with ultrahigh vacuum deposition capability

A Kelvinox 400 dilution refrigerator with the ability to load samples onto the mixing chamber from the bottom of the cryostat has been combined with an ultrahigh-vacuum (UHV) deposition chamber equipped with molecular beam sources. The liquid-helium-cooled sample transfer mechanism is used in a manner that allows films to be grown on substrates which are kept at temperatures of order 8 K with chamber pressures in the 10−9 to 10−10 Torr range. This system facilitates the growth of quench-condensed ultrathin films which must always be kept below ∼12 K in an UHV environment during and after growth. Measurements can be made on the films down to milliKelvin temperatures and in magnetic fields up to 15 T.