Polarised targets‐what is happening

The starting point for any general discussion of polarized targets must be the magnetic moment of the particle of interest, the proton or the deuteron. In the early 1960s a very productive collaboration between solid state physicists and high energy physicists resulted in the development of a technique which enabled very high polarizations to be obtained at quite reasonable magnetic fields and temperatures. The ultimate polarized target - polarized atomic hydrogen - is now conceivable, and perhaps for certain types of experiment even practical. However the nucleon densities which seem likely to be achieved - say 10/sup 18/ cm/sup -3/ - are low indeed compared with the density in normal solid materials. 11 references, 4 figures.