Isotope Shift between ^209Bi and 63-day ^206Bi

The hyperfine structures of ²⁰⁶Bi (6.3 day) and ²⁰⁹Bi (10¹⁸ year) have been measured with the use of a 10-m focal-length Czerny–Turner grating monochromator, and the isotope shift between them was obtained. The radioactive isotope ²⁰⁶Bi was produced by proton bombardment of ²⁰⁸Pb. A radiochemical procedure was developed for separating the radioactive bismuth from the lead target and transferring it into an electrodeless lamp. The light source contained about 10 ng of ²⁰⁶Bi. From an analysis of the hfs in the $6p^3\hspace{0.17em}{{}^{4}S}_{\frac{1}{2}}$ and $6p^{2}7s\hspace{0.17em}{{}^{4}P}_{\frac{1}{2}}$ states, a value of 121±13 mK was obtained for the ²⁰⁶Bi–²⁰⁹Bi isotope shift in the 3067-Å resonance line. The possible effect on this value of perturbations by other isotopes is discussed.