Isotopically selective photoionization of calcium atoms
Three-stage selective photoionization of calcium atoms was investigated using cw dye lasers. Selective excitation was due to an intercombination transition 4s2 1S0→4s4p 3P1 (λ = 657.3 nm), additional excitation by a transition 4s4p 3P1→4s5s 3S1 (λ = 612.2 nm), followed by final ionization at λ = 488.0 nm from an argon laser. The photoion currents of different nuclides were determined using an MKh-7303 mass spectrometer. The ratios of the ion currents were used to find the separation coefficients a which were ~ 900 for 48Ca, ~ 1400 for 44Ca, and ~ 5500 for 42Ca.