SENSITIVITY OF ION TRAPS FOR SPECTROSCOPIC APPLICATIONS

Ba+ ions, created by surface ionization near one endcap of an rf quadrupole trap were slowed down by collisions with the background gas. At He pressures of 10-6 mbar or more 2% of the primary ions could be trapped. The sensitivity of ion detection by fluorescence radiation allows spectroscopic experiments, starting from less than 107 particles. The observation of the ground-state hyperfine splitting of137Ba+ is given as an example. © 1979 Springer-Verlag.