Nuclear demagnetisation and brute force polarisation

The techniques of adiabatic demagnetization and brute force are described extensively. Special attention is paid to the thermostatic aspects and the problems caused by heat leaks and thermal barriers. Some thermometric experiments on copper are reported concerning the heat exchange between the nuclear spin system and the conduction electron system. A brute force experiment on 95Nb yielded a nuclear magnetic moment of μ = (6.3 +- 0.1)μsub(n). A feasibility study is made on the use of PrCu6 hyperfine enhanced paramagnet instead of the paramagnetic salt used as a intermediate cooling stage between the dilution refrigerator and the purely nuclear refrigeration stage. This will allow for experiments of long duration (one hour and more) in the sub-milli-kelvins temperature region