Role of the spectral contrast of laser radiation in separation of ytterbium-168 in weighable quantities

Theoretical and experimental investigations were made of requirements in respect of the spectral energy contrast of laser radiation at the second excitation stage ensuring selective ionisation of ¹⁶⁸Yb. Use of laser radiation with a high (in excess of 200) spectral energy contrast made it possible to attain a concentration of ~97% of ¹⁶⁸Yb ions in a plasma when the natural abundance of this isotope in the initial material was 0.14%.