title: 41Ca ultratrace determination with isotopic selectivity > 10(12) by diode-laser-based RIMS.
abstract: 41Ca ultratrace determination by diode-laser-based resonance ionization mass spectrometry with extremely high isotopic selectivity is presented. Application to environmental dosimetry of nuclear reactor components, to cosmochemical investigations of production cross sections, and biomedical isotope-tracer studies of human calcium kinetics are discussed. Future investigations are possible use in 41Ca-radiodating. Depending on the application, 41Ca isotopic abundances in the range of 10(-9) to 10(-15) relative to the dominant stable isotope 40Ca 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 resulting photoions are detected with a quadrupole mass spectrometer optimized for background reduction and neighboring mass suppression. Applying the full triple-resonance scheme provides a selectivity of approximately 5 x 10(12) in the suppression of neighboring isotopes and > 10(8) for isobars, together with an overall detection efficiency of approximately 5 x 10(-5). Measurements on a variety of sample types are discussed; the accuracy and reproducibility of the resulting 41Ca/40Ca isotope ratios was better than 5%.
authors.affiliation: Institut für Physik, Johannes Gutenberg-Universität, Mainz, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Müller
authors.forename: B A
authors.initials: BA
authors.lastname: Bushaw
authors.forename: K
authors.initials: K
authors.lastname: Blaum
authors.forename: S
authors.initials: S
authors.lastname: Diel
authors.forename: C
authors.initials: C
authors.lastname: Geppert
authors.forename: A
authors.initials: A
authors.lastname: Nähler
authors.forename: N
authors.initials: N
authors.lastname: Trautmann
authors.forename: W
authors.initials: W
authors.lastname: Nörtershäuser
authors.forename: K
authors.initials: K
authors.lastname: Wendt
mesh_terms: D002132:Calcium Radioisotopes / Q000652:urine*; D006801:Humans; D013058:Mass Spectrometry
chemical_list: D002132:Calcium Radioisotopes