Resonance ionization mass spectrometry for precise measurements of iostope ratios.

Journal Article · Sun Nov 01 04:00:00 EST 2009 · Int. J. Mass Spectrometry

DOI:https://doi.org/10.1016/j.ijms.2009.07.013· OSTI ID:994073

Levine, J; Savina, M R; Stephan, T; Dauphas, N; Davis, A M; Knight, K B; Pellin, M J; LLNL,

Resonance ionization mass spectrometry offers extremely high sensitivity and elemental selectivity in microanalysis, but the isotopic precision attainable by this technique has been limited. Measured isotope ratios are sensitive to small fluctuations in the pointing, pulse timing, and wavelength of the resonance lasers. We show that, by minimizing these fluctuations using feedback controls and by power-broadening the optical transitions, we are able to measure chromium isotope ratios with statistics-limited precision better than 1%. Small additional improvements in reproducibility come from careful shaping of the electric field in the region where atoms are photoionized and from minimizing pulse-to-pulse variations in the time-of-flight mass spectrometer through which the photoions travel. The increased reproducibility of isotopic measurements on standard materials has enabled us to detect anomalous chromium isotopic abundances in presolar SiC grains extracted from primitive meteorites.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: SC; NASA
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 994073
• Report Number(s): ANL/MSD/JA-68568
• Journal Information: Int. J. Mass Spectrometry, Journal Name: Int. J. Mass Spectrometry Journal Issue: Nov./Dec. 2009 Vol. 288; ISSN 1387-3806
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ACCURACY
CHROMIUM ISOTOPES
FEEDBACK
ISOTOPE RATIO
METEORITES
MICROANALYSIS
RESONANCE IONIZATION MASS SPECTROSCOPY
SENSITIVITY
SILICON CARBIDES