Laser resonant ionization of plutonium

Resonance ionization mass spectrometry (RIMS) has been tested for the isotope-selective determination of trace amounts of plutonium. An atomic beam is formed by evaporating plutonium atoms from a rhenium-filament heated to 18000C. The radiation of a pulsed dye laser excites the atoms in a two-photon process (lambda=595.2 nm) followed by photoionization of the excited atoms. Mass selectivity is obtained by use of a time-of-flight spectrometer. A resonant signal of 239Pu was measured with 1013 atoms deposited on the filament. (orig.)