Spin echo modulated small-angle neutron scattering using superconducting magnetic Wollaston prisms

Fankang Li; Steven R. Parnell; Hongyu Bai; Wencao Yang; William A. Hamilton; Brian B. Maranville; Rana Ashkar; David V. Baxter; J. Ted Cremer; Roger Pynn

doi:10.1107/S1600576715021573

Spin echo modulated small-angle neutron scattering using superconducting magnetic Wollaston prisms

Fankang Li, Steven R. Parnell, Hongyu Bai, Wencao Yang, William A. Hamilton, Brian B. Maranville, Rana Ashkar, David V. Baxter, J. Ted Cremer, Roger Pynn

Research output: Contribution to journal › Article › peer-review

24 Scopus citations

Abstract

The spin echo modulated small-angle neutron scattering technique has been implemented using two superconducting magnetic Wollaston prisms at a reactor neutron source. The density autocorrelation function measured for a test sample of colloidal silica in a suspension agrees with that obtained previously by other neutron scattering methods on an identically prepared sample. The reported apparatus has a number of advantages over competing technologies: it should allow larger length scales (up to several micrometres) to be probed; it has very small parasitic neutron scattering and attenuation; the magnetic fields within the device are highly uniform; and the neutron spin transport across the device boundaries is very efficient. To understand quantitatively the results of the reported experiment and to guide future instrument development, Monte Carlo simulations are presented, in which the evolution of the neutron polarization through the apparatus is based on magnetic field integrals obtained from finite-element simulations of the various magnetic components. The Monte Carlo simulations indicate that the polarization losses observed in the experiments are a result of instrumental artifacts that can be easily corrected in future experiments.

Original language	English
Pages (from-to)	55-63
Number of pages	9
Journal	Journal of Applied Crystallography
Volume	49
DOIs	https://doi.org/10.1107/S1600576715021573
State	Published - Feb 2016
Externally published	Yes

Funding

The conceptual design and simulations of the first HTS Wollaston prism were supported by the National Science Foundation (grant No. DMR-0956741). The design and construction of the two magnetic Wollaston prisms were supported by the STTR program of the US Department of Energy (grant No. DE-SC0009584). We would like to extend our gratitude to Dr J. Plomp (Delft University of Technology) for providing the current-sheet flipper, J. Doskow (Indiana University Bloomington) for designing the vacuum chamber, and the members of the sample environment team at the NCNR, Tanya Dax and Qiang (Alan) Ye, for their help with the cryogenics. We also acknowledge the support of the National Institute of Standards and Technology, US Department of Commerce, in providing access to the neutron research facilities, supported in part by the National Science Foundation under grant No. DMR-0944772. Construction of LENS was supported by the National Science Foundation grants DMR-0220560 and DMR-0320627, the 21st Century Science and Technology fund of Indiana, Indiana University, and the Department of Defense.

Funders	Funder number
US Department of Energy	DE-SC0009584
National Science Foundation	DMR-0956741
U.S. Department of Defense
National Institute of Standards and Technology
U.S. Department of Commerce	DMR-0220560, DMR-0320627, DMR-0944772
Indiana University
NIST Center for Neutron Research
Technische Universiteit Delft

Keywords

Larmor labeling
correlation functions
magnetic Wollaston prisms
neutron spin echo
spin echo modulated small-angle neutron scattering (SEMSANS)

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title = "Spin echo modulated small-angle neutron scattering using superconducting magnetic Wollaston prisms",

abstract = "The spin echo modulated small-angle neutron scattering technique has been implemented using two superconducting magnetic Wollaston prisms at a reactor neutron source. The density autocorrelation function measured for a test sample of colloidal silica in a suspension agrees with that obtained previously by other neutron scattering methods on an identically prepared sample. The reported apparatus has a number of advantages over competing technologies: it should allow larger length scales (up to several micrometres) to be probed; it has very small parasitic neutron scattering and attenuation; the magnetic fields within the device are highly uniform; and the neutron spin transport across the device boundaries is very efficient. To understand quantitatively the results of the reported experiment and to guide future instrument development, Monte Carlo simulations are presented, in which the evolution of the neutron polarization through the apparatus is based on magnetic field integrals obtained from finite-element simulations of the various magnetic components. The Monte Carlo simulations indicate that the polarization losses observed in the experiments are a result of instrumental artifacts that can be easily corrected in future experiments.",

keywords = "Larmor labeling, correlation functions, magnetic Wollaston prisms, neutron spin echo, spin echo modulated small-angle neutron scattering (SEMSANS)",

author = "Fankang Li and Parnell, {Steven R.} and Hongyu Bai and Wencao Yang and Hamilton, {William A.} and Maranville, {Brian B.} and Rana Ashkar and Baxter, {David V.} and Cremer, {J. Ted} and Roger Pynn",

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doi = "10.1107/S1600576715021573",

language = "English",

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T1 - Spin echo modulated small-angle neutron scattering using superconducting magnetic Wollaston prisms

AU - Li, Fankang

AU - Parnell, Steven R.

AU - Bai, Hongyu

AU - Yang, Wencao

AU - Hamilton, William A.

AU - Maranville, Brian B.

AU - Ashkar, Rana

AU - Baxter, David V.

AU - Cremer, J. Ted

AU - Pynn, Roger

N1 - Publisher Copyright: © International Union of Crystallography 2016.

PY - 2016/2

Y1 - 2016/2

N2 - The spin echo modulated small-angle neutron scattering technique has been implemented using two superconducting magnetic Wollaston prisms at a reactor neutron source. The density autocorrelation function measured for a test sample of colloidal silica in a suspension agrees with that obtained previously by other neutron scattering methods on an identically prepared sample. The reported apparatus has a number of advantages over competing technologies: it should allow larger length scales (up to several micrometres) to be probed; it has very small parasitic neutron scattering and attenuation; the magnetic fields within the device are highly uniform; and the neutron spin transport across the device boundaries is very efficient. To understand quantitatively the results of the reported experiment and to guide future instrument development, Monte Carlo simulations are presented, in which the evolution of the neutron polarization through the apparatus is based on magnetic field integrals obtained from finite-element simulations of the various magnetic components. The Monte Carlo simulations indicate that the polarization losses observed in the experiments are a result of instrumental artifacts that can be easily corrected in future experiments.

AB - The spin echo modulated small-angle neutron scattering technique has been implemented using two superconducting magnetic Wollaston prisms at a reactor neutron source. The density autocorrelation function measured for a test sample of colloidal silica in a suspension agrees with that obtained previously by other neutron scattering methods on an identically prepared sample. The reported apparatus has a number of advantages over competing technologies: it should allow larger length scales (up to several micrometres) to be probed; it has very small parasitic neutron scattering and attenuation; the magnetic fields within the device are highly uniform; and the neutron spin transport across the device boundaries is very efficient. To understand quantitatively the results of the reported experiment and to guide future instrument development, Monte Carlo simulations are presented, in which the evolution of the neutron polarization through the apparatus is based on magnetic field integrals obtained from finite-element simulations of the various magnetic components. The Monte Carlo simulations indicate that the polarization losses observed in the experiments are a result of instrumental artifacts that can be easily corrected in future experiments.

KW - Larmor labeling

KW - correlation functions

KW - magnetic Wollaston prisms

KW - neutron spin echo

KW - spin echo modulated small-angle neutron scattering (SEMSANS)

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SP - 55

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JO - Journal of Applied Crystallography

JF - Journal of Applied Crystallography

ER -

Spin echo modulated small-angle neutron scattering using superconducting magnetic Wollaston prisms

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