Source of Polarized Lithium and Cesium Ions

A source for polarized Li+, Li++, Cs+, Cs++, and Cs+++ ions is described. The ions are produced by electron bombardment of polarized Li0 or Cs0 atoms. The ion currents obtained are 3.3×10−8 A Li+, 1.3×10−9 A Li++, 6.0×10−8 A Cs+++, 1.4×10−7 A Cs++, and 6.6×10−7 A Cs+. The background current of these ions is negligible. The polarization of the ions was not measured, but a discussion of the polarization is presented. This discussion leads to the conclusion that the nuclear vector polarization of 7Li+ is about 25% and the electronic polarization of 7Li++ is about 9.4%. Possible applications of the Li++ and Cs++ beams are discussed. An interesting result from this work is the average cross section for incident electrons of 200 to 325 eV energy for the process e−+Li0 → Li+++3e−, which has the value 3.5×10−18 cm2.