PNNL

Abstract

41 Ca ultratrace determination by diode-laser-based resonance ionization mass spectrometry with ex-tremely high isotopic selectivity is presented. Application to environmental dosimetry of nuclear reactor compo-nents, to cosmochemical investigations of production cross sections, and biomedical isotope-tracer studies of human calcium kinetics are discussed. Future investiga-tions are possible use in 41 Ca-radiodating. Depending on the application, 41 Ca isotopic abundances in the range of 10 -9 to 10 -15 relative to the dominant stable isotope 40 Ca must be determined. Either double- or triple-resonance optical excitation with narrow-band extended cavity diode lasers and subsequent non-resonant photoionization of calcium in a collimated atomic beam were used. The re-sulting photoions are detected with a quadrupole mass spectrometer optimized for background reduction and neighboring mass suppression.