Solid polarized targets for nuclear and particle physics experiments

Abstract

The development, in the early 1960s, of the dynamic nuclear polarization process in solid diamagnetic materials, doped with paramagnetic radicals, led to the use of solid polarized targets in numerous nuclear and particle physics experiments. Since then steady progress has been made in all contributing subsystems so that proton polarizations near 100% and deuteron polarizations higher than 50% have been achieved in various materials. More radiation-resistant materials, such as ammonia, have made it possible to perform experiments with high beam intensities and experiments that benefit from 4He cooling at 1K and high magnetic fields. The development of dilution refrigerators have allowed frozen spin operation so that experiments with large angular acceptance for the scattered particles have become routine. Many experiments have taken advantage of these developments and many more are being planned, especially with electromagnetic probes.