A millikelvin dilution refrigerator with plastic exchangers

It is now easy to produce temperatures of the order of 20 to 30 mK with very simple dilution refrigerators, but it is possible to reach much lower temperatures in the mK range by taking into account more carefully the parameters involved in the process. The low-temperature part of a refrigerator is described, which allows the performance of experiments down to 5.8 mK in a permanent mode. The different arrangements which led to the final form are outlined. (author)