New measurements of the coherent and incoherent neutron scattering lengths of 13C

Journal Article · Wed Jan 30 04:00:00 EST 2008 · Journal of Physics: Condensed Matter

DOI:https://doi.org/10.1088/0953-8984/20/04/045221· OSTI ID:931034

Fischer, Henry E ^[1]; Neuefeind, Joerg C ^[2]; Loidl, Rudolf ^[1]; Rauch, Helmut ^[3]; ten,

---

1. Institut Laue-Langevin (ILL)
2. ORNL
3. E141 Atominstitut der Ö

The techniques of neutron interferometry and neutron diffraction were used to determine the coherent and incoherent neutron scattering lengths of 13C. From a neutron interferometry measurement of the optical path difference in liquid samples: 13CS2 versus natCS2, we obtain a bound coherent scattering length of bcoh,13C = 6.502 0.003 fm which differs appreciably from the standard tabulated value of 6.19 0.09 fm. The resulting contrast of only 0.146(3) fm with respect to bcoh,natC = 6.6484 0.0013 fm has consequences for neutron diffraction experiments involving 13C isotopic substitution. Combining our result for bcoh,13C with precise neutron diffraction measurements of the self-scattering intensities of liquid samples: 13CS2 versus natCS2, and 13CO2 versus 12CO2, we deduce a bound incoherent scattering length of bincoh,13C = −0.73 0.14 fm that is consistent with the standard tabulated value of −0.52 0.09 fm. The results presented here have required accurate measurements of small effects, for which particular attention has been given to the data analysis.

• Research Organization: Oak Ridge National Laboratory (ORNL); Center for Nanophase Materials Sciences (CNMS); Spallation Neutron Source
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 931034
• Journal Information: Journal of Physics: Condensed Matter, Journal Name: Journal of Physics: Condensed Matter Journal Issue: 4 Vol. 20; ISSN 0953-8984; ISSN JCOMEL
• Country of Publication: United States
• Language: English

Related Subjects

carbon isotopes
neutron interferometry
neutron scattering lengths