skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: High Useful Yield and Isotopic Analysis of Uranium by Resonance Ionization Mass Spectrometry

Abstract

Useful yields from resonance ionization mass spectrometry can be extremely high compared to other mass spectrometry techniques, but uranium analysis shows strong matrix effects arising from the tendency of uranium to form strongly bound oxide molecules that do not dissociate appreciably on energetic ion bombardment. Here, we demonstrate a useful yield of 24% for metallic uranium. Modeling the laser ionization and ion transmission processes shows that the high useful yield is attributable to a high ion fraction achieved by resonance ionization. We quantify the reduction of uranium oxide surface layers by Ar + and Ga + sputtering. The useful yield for uranium atoms from a uranium dioxide matrix is 0.4% and rises to 2% when the surface is in sputter equilibrium with the ion beam. The lower useful yield from the oxide is almost entirely due to uranium oxide molecules reducing the neutral atom content of the sputtered flux. We also demonstrate rapid isotopic analysis of solid uranium oxide at a precision of <0.5% relative standard deviation using relatively broadband lasers to mitigate spectroscopic fractionation.

Authors:
ORCiD logo [1];  [1];  [1];  [1];  [2];  [3];  [4];  [1]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Nuclear and Chemical Sciences Division
  2. Univ. of Newcastle, NSW (Australia)
  3. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). National Security Engineering Division
  4. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Global Security Computing Division
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1368017
Report Number(s):
LLNL-JRNL-727677
Journal ID: ISSN 0003-2700
Grant/Contract Number:
AC52-07NA27344; HSHQDN-16-X-0023; HDTRA 135636-M
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Analytical Chemistry
Additional Journal Information:
Journal Volume: 89; Journal Issue: 11; Journal ID: ISSN 0003-2700
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; 11 NUCLEAR FUEL CYCLE AND RUEL MATERIALS; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY

Citation Formats

Savina, Michael R., Isselhardt, Brett H., Kucher, Andrew, Trappitsch, Reto, King, Bruce V., Ruddle, David, Gopal, Raja, and Hutcheon, Ian. High Useful Yield and Isotopic Analysis of Uranium by Resonance Ionization Mass Spectrometry. United States: N. p., 2017. Web. doi:10.1021/acs.analchem.7b01204.
Savina, Michael R., Isselhardt, Brett H., Kucher, Andrew, Trappitsch, Reto, King, Bruce V., Ruddle, David, Gopal, Raja, & Hutcheon, Ian. High Useful Yield and Isotopic Analysis of Uranium by Resonance Ionization Mass Spectrometry. United States. doi:10.1021/acs.analchem.7b01204.
Savina, Michael R., Isselhardt, Brett H., Kucher, Andrew, Trappitsch, Reto, King, Bruce V., Ruddle, David, Gopal, Raja, and Hutcheon, Ian. Tue . "High Useful Yield and Isotopic Analysis of Uranium by Resonance Ionization Mass Spectrometry". United States. doi:10.1021/acs.analchem.7b01204. https://www.osti.gov/servlets/purl/1368017.
@article{osti_1368017,
title = {High Useful Yield and Isotopic Analysis of Uranium by Resonance Ionization Mass Spectrometry},
author = {Savina, Michael R. and Isselhardt, Brett H. and Kucher, Andrew and Trappitsch, Reto and King, Bruce V. and Ruddle, David and Gopal, Raja and Hutcheon, Ian},
abstractNote = {Useful yields from resonance ionization mass spectrometry can be extremely high compared to other mass spectrometry techniques, but uranium analysis shows strong matrix effects arising from the tendency of uranium to form strongly bound oxide molecules that do not dissociate appreciably on energetic ion bombardment. Here, we demonstrate a useful yield of 24% for metallic uranium. Modeling the laser ionization and ion transmission processes shows that the high useful yield is attributable to a high ion fraction achieved by resonance ionization. We quantify the reduction of uranium oxide surface layers by Ar+ and Ga+ sputtering. The useful yield for uranium atoms from a uranium dioxide matrix is 0.4% and rises to 2% when the surface is in sputter equilibrium with the ion beam. The lower useful yield from the oxide is almost entirely due to uranium oxide molecules reducing the neutral atom content of the sputtered flux. We also demonstrate rapid isotopic analysis of solid uranium oxide at a precision of <0.5% relative standard deviation using relatively broadband lasers to mitigate spectroscopic fractionation.},
doi = {10.1021/acs.analchem.7b01204},
journal = {Analytical Chemistry},
number = 11,
volume = 89,
place = {United States},
year = {Tue May 09 00:00:00 EDT 2017},
month = {Tue May 09 00:00:00 EDT 2017}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 2works
Citation information provided by
Web of Science

Save / Share:
  • The technique of resonance ionization mass spectrometry (RIMS) has been applied to the measurement of U and Pu isotope ratios. The RIMS technique offers the advantage of high elemental selectivity compared to conventional thermal ionization mass spectrometry. Measurements of selectivity ratios for U vs. Pu are presented at two different wavelengths of laser excitation. The precision obtained for replicate analyses of NBS standard reference materials is equal to that obtained by single-filament thermal ionization methods. Sample sizes of 10 ng for each element were adequate for measurement of the /sup 240/Pu//sup 239/Pu, /sup 241/Pu//sup 239/Pu, and /sup 235/U//sup 238/U isotopemore » ratios. Sensitivity was enhanced by using a pulsed thermal atomization technique which resulted in a 10-fold improvement in sample usage compared to continuous atomization. The RIMS technique is, therefore, potentially useful in safeguards and nuclear materials accountancy, where precise and accurate isotope ratio measurements are important. 18 references, 2 tables, 1 figure.« less
  • We have developed continuous-wave resonance ionization mass spectrometry (cw-RIMS) methods to measure [sup 230]Th/[sup 232]Th isotopic ratios. The overall Th ionization detection efficiency using a 1 + 1 RIMS process (narrow-band laser for the resonant step and a high-power ultraviolet- (UV-) Ar[sup +] laser for the ionization step) is 0.10%. Measurement of the [sup 230]Th/[sup 232]Th ratio (4.096 x 10[sup [minus]4]) of a laboratory standard shows that the cw-RIMS method has internal precision comparable to thermal ionization mass spectrometry measurements ([approximately] 0.5%, 2[sigma][sub m]), but introduces a small bias (2-4%), which is correctable by calibration with an isotopic standard. Themore » bias is due to intrinsic laser-induced biases in the 1 + 1 RIMS process and in a nonresonant process due to the UV-Ar[sup +] laser alone, which contributes approximately 3% to the total Th[sup +] signal. Laser power dependence experiments show that neither the resonant nor the ionization step is entirely saturated; therefore, the isotopic bias is probably due to differences in the transition strengths of the isotopes. The reproducibility of the RIMS-induced bias is dependent on the reproducibility of the laser parameters, but can be kept within the precision of the measurements ([approximately] 0.5%). Ratio measurements of the 4.096 x 10[sup [minus]4] standard and of a sample of Table Mountain Latite demonstrates that cw-RIMS can accurately measure [sup 230]Th/[sup 232]Th ratios when the laser-induced biases are calibrated and kept constant. 41 refs.., 8 figs., 3 tabs.« less
  • Resonance Ionization Mass Spectrometry (RIMS) combines the selectivity and sensitivity of resonance ionization spectroscopy (RIS) with high performance mass spectrometry. Results from our laboratory and elsewhere have been reported for a variety of elements using thermal vaporization sources to produce the atom reservoir for laser-induced resonance ionization. In this paper we describe the use of ion beam sputtering as an ultrasensitive method of atom formation for RIMS. A commercial ion microprobe mass analyzer (IMMA) has been interfaced with a tunable pulsed dye laser for carrying out resonance ionization mass spectrometry of sputtered atoms. This paper will describe the changes necessarymore » to adapt the IMMA instrument for resonance ionization, along with preliminary results for the elements Sm and U. 14 refs., 5 figs.« less
  • We describe our development of resonance ionization mass spectrometry (RIMS) using continuous-wave lasers toward the measurement of isotopic ratios important in geochemistry and geochronology. Specifically, we compare the precision and accuracy of $[sup 230]Th/[sup 232]Th isotopic ratios measured by cw RIMS using both broad-band and narrow-band lasers. We also discuss the effectiveness of frequency-stabilizing techniques, i.e., external frequency locking of a broad-band dye laser and computer-controlled frequency centering of a narrow-band Ti:sapphire laser. 26 refs., 2 figs., 1 tab.