The bound coherent neutron scattering length of the oxygen isotopes

Journal Article · Sun Jan 01 00:00:00 EST 2012 · Journal of Physics: Condensed Matter

DOI:https://doi.org/10.1088/0953-8984/24/50/505105· OSTI ID:1057937

Fischer, Henry E ^[1]; Neuefeind, Joerg C ^[2]; Lemmel, Hartmut ^[3]; Rauch, Helmut ^[4]; ten,; Zeidler, Anita ^[5]; Salmon, Phil ^[5]

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1. Institut Laue-Langevin (ILL)
2. ORNL
3. Technical University Vienna
4. E141 Atominstitut der Ö
5. University of Bath

The technique of neutron interferometry was used to measure the bound coherent neutron scattering length bcoh of the oxygen isotopes 17O and 18O. From the measured difference in optical path between two water samples, either H2 17O or H2 18O versus H2 natO, where nat denotes the natural isotopic composition, we obtain bcoh , 17O = 5.867(4) fm and bcoh , 18O = 6.009(5) fm, based on the accurately known value of bcoh , natO = 5.805(4) fm which is equal to bcoh , 16O within the experimental uncertainty. Our results for bcoh , 17O and bcoh , 18O differ appreciably from the standard tabulated values of 5.6(5) fm and 5.84(7) fm, respectively. In particular, our measured scattering length contrast of 0.204(3) fm between 18O and natO is nearly a factor of 6 greater than the tabulated value, which renders feasible neutron diffraction experiments using 18O isotope substitution and thereby offers new possibilites for measuring the partial structure factors of oxygen-containing compounds, such as water.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1057937
• Journal Information: Journal of Physics: Condensed Matter, Vol. 24, Issue 50; ISSN 0953--8984
• Country of Publication: United States
• Language: English