Recent development of the University of Washington crossed beams polarized ion source

A colliding-beams polarized ion source has been in operation for nuclear physics experiments at the University of Washington tandem-linac facility since late 1987. Thermal beams of polarized atomic hydrogen or deuterium are ionized by charge exchange collisions with a collinear, fast, neutral cesium beam. Negative ions are extracted, and the polarization symmetry axis is precessed to any desired direction in a crossed-fields spin precessor. The design of the cesium beam system differs from previous designs in that magnetic deflection and focussing are used. A brief description of the source, the recent development and present status of the source are presented. (author)