Krypton and argon isotope analysis by collinear fast beam diode laser spectroscopy

Argon and Krypton ions are accelerated and focused through a Cs-vapour charge exchange cell. Neutral atoms in the emerging beam are optically excited from the metastable 1s5 state to the 2pg state by tunable cw diode lasers at 811.5nm. At 10keV beam energy the spectra of Ar and Kr are separated by ∼0.5nm with counterpropagating beams and by less than 0.1 nm with copropagating beams. The absorption lines of the individual isotopes cover a spectral range of ∼10GHz for each element. Linewidths of less than 100 MHz were observed