ABSTRACT
This chapter introduces the dilution refrigeration concepts. It examines the relevant formulas and tables to be able to design its own custom miniature dilution refrigerator. Dilution refrigeration is the most used technique to reach temperatures below 100 mK. The typical dilution refrigerator system consists of a cryostat containing the cold stages serviced with external pumps, compressor and a gas handling system. In dilution refrigerators where base temperature of a few mK are sought, a combination of continuous and step heat exchangers is used. Dilution systems using only continuous heat exchangers have demonstrated to be capable of reaching temperatures as low as 22 mK. In 1984, Mikheev have proposed the use of charcoal pumps to keep the 3 $ ^3 $ He always cold and to pump efficiently the 3 $ ^3 $ He gas from the still. They built a system using two charcoal pumps working alternatively in desorption/absorption to make the dilution process continuous.
