Ultrasensitive detection of actinides and technetium by laser resonance ionization mass spectrometry

The application of laser resonance ionization mass spectrometry for the detection of extremely small numbers of atoms has been explored in the very recent years. High sensitivity and unambiguity in element and isotope identification can be achieved by three-step photoionization of the elements in the atomic state followed by time-of-flight mass analysis. The laser system for photoionization consists of three dye lasers which are pumped simultaneously by a copper vapor laser. For mass determination a time-of-flight spectrometer with a mass resolution better than 1500 is used. By ionization via autoionizing states and by saturation in each excitation step a detection limit of about 107 atoms of actinides or of technetium in the sample has been obtained