New Uses of Polarized Beams

Abstract

Several novel and important uses of polarized beams have beet, developed over the past few years. It has been demonstrated that in nuclear reactions appreciable polarization is transferred from the incident beam to the residual nuclei. Successful techniques have been found to maintain the polarization of these nuclei if they are allowed to implant into suitable solid state environments. In the case of ß-active nuclei, the polarization can be measured by means of the asymmetric ß-decay. The nuclear moments of these nuclei can then be measured by observing the NMR destruction of the polarization at the resonant condition. The detection of the polarization of product nuclei has also been used to study the polarization transfer mechanism itself in both light and heavy ion reactions. The polarization of implanted nuclei also serves as a very useful probe of solid state properties such as spin-lattice and spin-spin relaxation, hyperfine fields, radiation damage and the nature of the implantation sites. The ß-decay process itself can be studied by measuring the ß-asymmetry as a function of the ß-energy in the decay of these polarized nuclei. A search for second-class currents in ß-decay is presently being carried out. Polarized neutral beams from polarized ion sources are presently being used to produce polarized gas jets for use as polarized targets in nuclear physics research. These crossed-beam experiments make possible the study of polarized-polarized reactions and of polarized heavy-ion reactions. Polarized beams have also been used to study the scattering from polarized targets produced by cryogenic methods.