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Boehm KJ, Hash N, Barker D, Döppner T, Farrell MP, Fitzsimmons P, Kaczala D, Kraus D, Maranville B, Mauldin M, Neumayer P, Segraves K. Design and Engineering of a Target for X-Ray Thomson Scattering Measurements on Matter at Extreme Densities and Gigabar Pressures. Fusion Science and Technology 2016. [DOI: 10.13182/fst15-242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- K.-J. Boehm
- General Atomics, P.O. Box 85608, San Diego, California 92186
| | - N. Hash
- General Atomics, P.O. Box 85608, San Diego, California 92186
| | - D. Barker
- Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550
| | - T. Döppner
- Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550
| | - M. P. Farrell
- General Atomics, P.O. Box 85608, San Diego, California 92186
| | - P. Fitzsimmons
- General Atomics, P.O. Box 85608, San Diego, California 92186
| | - D. Kaczala
- General Atomics, P.O. Box 85608, San Diego, California 92186
| | - D. Kraus
- University of California, Department of Physics, Berkeley, California 94720
| | - B. Maranville
- Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550
| | - M. Mauldin
- General Atomics, P.O. Box 85608, San Diego, California 92186
| | - P. Neumayer
- GSI Helmholtzzentrum fuer Schwerionenforschung, Planckstrasse 1, 64291 Darmstadt, Germany
| | - K. Segraves
- Schafer Corporation, 303 Lindbergh Avenue, Livermore, California 94551
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Abstract
A method is described for determining the neutron scattering length density distribution of a molecular-scale object directly from phase-sensitive small-angle neutron scattering (SANS). The structure factor amplitude is obtained through the use of a reference structure for a collection of randomly oriented, identical objects in the dilute solution limit (negligible interparticle correlations). This work extends some of the techniques developed in recent years for phase-sensitive specular neutron reflectometry to SANS, although the approach presented here is applicable only within the range of validity of the Born approximation. The scattering object is treated as a composite consisting of an `unknown' part of interest plus a reference component, the real-space structure of the latter being completely known. If, for example, the reference part of the object is composed of a ferromagnetic material (the magnetization of which is saturated), then polarized neutron beams can be employed to extract the information required for an unambiguous inversion of the scattering data without chemical substitution. The angular averaging over all possible relative orientations of the composite object does not result in a cancellation of the phase information since the reference and unknown parts of each object have a fixed spatial relationship. The new approach proposed here is not simply another type of isomorphic substitution, but also involves a reformulation of the underlying mathematical analysis of this particular scattering problem.
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Baxamusa SH, Bhandarkar SD, Reynolds JL, Maranville B, Horner J, Mason DC, Heinbockel CL, Antipa NA, Conder AD. A Solvent Cleaning Process for the Outer Surface of Plastic ICF Capsules. Fusion Science and Technology 2013. [DOI: 10.13182/fst13-tfm20-27] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- S. H. Baxamusa
- Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550
| | - S. D. Bhandarkar
- Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550
| | - J. L. Reynolds
- Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550
| | - B. Maranville
- Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550
| | - J. Horner
- Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550
| | - D. C. Mason
- Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550
| | - C. L. Heinbockel
- Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550
| | - N. A. Antipa
- Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550
| | - A. D. Conder
- Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550
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Ashkar R, Stonaha P, Washington AL, Shah VR, Fitzsimmons MR, Maranville B, Majkrzak CF, Lee WT, Schaich WL, Pynn R. Dynamical theory calculations of spin-echo resolved grazing-incidence scattering from a diffraction grating. J Appl Crystallogr 2010. [DOI: 10.1107/s0021889810010642] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Neutrons scattered or reflected from a diffraction grating are subject to a periodic potential analogous to the potential experienced by electrons within a crystal. Hence, the wavefunction of the neutrons can be expanded in terms of Bloch waves and a dynamical theory can be applied to interpret the scattering phenomenon. In this paper, a dynamical theory is used to calculate the results of neutron spin-echo resolved grazing-incidence scattering (SERGIS) from a silicon diffraction grating with a rectangular profile. The calculations are compared with SERGIS measurements made on the same grating at two neutron sources: a pulsed source and a continuous wave source. In both cases, the spin-echo polarization, studied as a function of the spin-echo length, peaks at integer multiples of the grating period but there are some differences between the two sets of data. The dynamical theory explains the differences and gives a good account of both sets of results.
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