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Larmor labeling of neutron spin usin...

Li, Fankang.

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Larmor labeling of neutron spin using superconducting Wollaston prisms.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Larmor labeling of neutron spin using superconducting Wollaston prisms./
Author:	Li, Fankang.
Published:	Ann Arbor : ProQuest Dissertations & Theses, : 2016,
Description:	162 p.
Notes:	Source: Dissertation Abstracts International, Volume: 77-08(E), Section: B.
Contained By:	Dissertation Abstracts International77-08B(E).
Subject:	Physics. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=10076257
ISBN:	9781339585598

Larmor labeling of neutron spin using superconducting Wollaston prisms.
Li, Fankang.

Larmor labeling of neutron spin using superconducting Wollaston prisms. - Ann Arbor : ProQuest Dissertations & Theses, 2016 - 162 p.

Source: Dissertation Abstracts International, Volume: 77-08(E), Section: B.

Thesis (Ph.D.)--Indiana University, 2016.

Neutron spin Larmor labeling using magnetic Wollaston prisms (WP) provides a way to overcome some of the limitations arising from the nature of neutron beams: low flux and divergence. Using superconducting films and tapes, a series of strong, well-defined shaped magnetic fields can be produced due to both the zero-resistance and Meissner effect in superconductors. Using finite element simulations, the criterion to build a superconducting magnetic Wollaston prism with high encoding efficiency and low Larmor phase aberrations are presented. To achieve a high magnetic field and simplify the maintenance, we optimize the design using careful thermal analysis. The measured neutron spin flipping efficiency is measured to be independent of both the neutron wavelength and energizing current, which is a significant improvement over other devices with similar functions. A highly linear variation of the Larmor phase is measured across the device, which ensures a highly uniform encoding of scattering angles into the neutron spin Larmor phase. Using two WPs, the correlation function for a colloidal silica sample was measured by spin echo modulated small angle neutron scattering (SEMSANS) and agrees well with other techniques. Using Monte Carlo code (McStas), we further investigated the SEMSANS setup and showed the requirements to improve its performance. We have proposed a new technique to implement neutron spin echo on a triple axis neutron spectrometer to achieve high resolution measurements of the lifetime of dispersive phonon excitations. The spin echo is tuned by appropriate choice of magnetic fields instead of physically tilting the coils used in traditional methods. This new approach allows a higher energy resolution and a larger effective tilting angle and hence larger group velocity to be measured.

ISBN: 9781339585598Subjects--Topical Terms:

516296
Physics.

Larmor labeling of neutron spin using superconducting Wollaston prisms.
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100 1 $a Li, Fankang. $3 3282327
245 1 0 $a Larmor labeling of neutron spin using superconducting Wollaston prisms.
260 1 $a Ann Arbor : $b ProQuest Dissertations & Theses, $c 2016
300 $a 162 p.
500 $a Source: Dissertation Abstracts International, Volume: 77-08(E), Section: B.
500 $a Advisers: Roger Pynn; David V. Baxter.
502 $a Thesis (Ph.D.)--Indiana University, 2016.
520 $a Neutron spin Larmor labeling using magnetic Wollaston prisms (WP) provides a way to overcome some of the limitations arising from the nature of neutron beams: low flux and divergence. Using superconducting films and tapes, a series of strong, well-defined shaped magnetic fields can be produced due to both the zero-resistance and Meissner effect in superconductors. Using finite element simulations, the criterion to build a superconducting magnetic Wollaston prism with high encoding efficiency and low Larmor phase aberrations are presented. To achieve a high magnetic field and simplify the maintenance, we optimize the design using careful thermal analysis. The measured neutron spin flipping efficiency is measured to be independent of both the neutron wavelength and energizing current, which is a significant improvement over other devices with similar functions. A highly linear variation of the Larmor phase is measured across the device, which ensures a highly uniform encoding of scattering angles into the neutron spin Larmor phase. Using two WPs, the correlation function for a colloidal silica sample was measured by spin echo modulated small angle neutron scattering (SEMSANS) and agrees well with other techniques. Using Monte Carlo code (McStas), we further investigated the SEMSANS setup and showed the requirements to improve its performance. We have proposed a new technique to implement neutron spin echo on a triple axis neutron spectrometer to achieve high resolution measurements of the lifetime of dispersive phonon excitations. The spin echo is tuned by appropriate choice of magnetic fields instead of physically tilting the coils used in traditional methods. This new approach allows a higher energy resolution and a larger effective tilting angle and hence larger group velocity to be measured.
590 $a School code: 0093.
650 4 $a Physics. $3 516296
650 4 $a Condensed matter physics. $3 3173567
650 4 $a Materials science. $3 543314
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710 2 $a Indiana University. $b Physics. $3 3282328
773 0 $t Dissertation Abstracts International $g 77-08B(E).
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