Recent Advances in Polarized Ion Sources

Much higher beam currents can now be obtained from polarized proton and deuteron ion sources. In the case of polarized positive H⁺ and D⁺ ions, beam currents of 60 μA can be achieved in continuotus operation, and more than 100 μA in pulsed operation. This represents nearly an order of magnitude increase over the past two to three years. The gain has resulted from improvement of the intensity that can be achieved with neutral atomic hydrogen beams, and the efficiency with which the neutral beam can be ionized by electron bombardment1. In the case of polarized negative H^- and D^-ions, beam currents of 3 μA have recently been produced² by colliding a fast beam of 40 keV cesium atoms with a polarized thermal hydrogen beam. This technique is still at an early stage of development but nevertheless has already produced improvements in beam current of a factor of 3 to 10 , and shows considerable potential for future development.