Pre-Cooling A He-3/He-4 Dilutor Module With A Sealed Closed-Cycle Continuous Cooler

A continuous closed cycle cooler to operate at a base temperature below 300 mK has been successfully designed and tested by Chase Research Cryogenics in collaboration with Cardiff University Astronomical Instrumentation Group. This compact, relatively low-cost unit has temperature and heat load capability of around 200 mu W at 340 mK, and 400 mu W at 450 mK. Here we discuss the suitability of this unit for precooling a miniature self-contained dilution module to produce a cryogen-free cooling platform capable of achieving a useful cooling power at temperatures of less than 100 mK.