publication . Doctoral thesis . 2003

Spin-Echo Small-Angle Neutron Scattering Development

Uca, O.;
Open Access English
  • Published: 03 Feb 2003
  • Publisher: Delft University Press
  • Country: Netherlands
Abstract
Spin-Echo Small-Angle Neutron Scattering (SESANS) instrument is a novel SANS technique which enables one to characterize distances from a few nanometers up to the micron range. The most striking difference between normal SANS and SESANS is that in SESANS one gets information in real space, whereas in a SANS measurement one obtains data in reciprocal space which has to be Fourier transformed. Another important difference is that a fully divergent beam can be used which means high counting statistics. Larmor precession is the basic physical principle for SESANS: When a neutron enters a magnetic field the spin of the neutron precesses around the magnetic field. Lar...
Subjects
free text keywords: sesans, neutron scattering, correction coils
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Doctoral thesis . 2003
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1 Introduction 1 1.1 Layout of the thesis . . . . . . . . . . . . . . . . . . . . . . . . 5 1.2 Polarization and polarizers . . . . . . . . . . . . . . . . . . . . 6 1.3 Larmor precession . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.4 Flippers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.5 Magnetic foils as polarisation manipulators . . . . . . . . . . . 7 1.5.1 Single foils to start and stop precession . . . . . . . . . 9 1.5.2 Double foils as a π rotator . . . . . . . . . . . . . . . . 10 1.6 The SESANS principle . . . . . . . . . . . . . . . . . . . . . . 10 1.7 Multiple scattering . . . . . . . . . . . . . . . . . . . . . . . . 13 1.8 Different options for SESANS . . . . . . . . . . . . . . . . . . 15

2 Magnetic design of a Spin-Echo Small-Angle Neutron Scattering instrument 21 2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 2.2 Calculation of the magnetic fields . . . . . . . . . . . . . . . . 23 2.3 Magnetic field homogeneity . . . . . . . . . . . . . . . . . . . 24 2.4 Saturation effect and thickness of the yoke and core . . . . . . 25 2.5 Line integral homogeneity . . . . . . . . . . . . . . . . . . . . 27 2.5.1 Dependence on pole gap . . . . . . . . . . . . . . . . . 30 2.5.2 Dependence on pole angle . . . . . . . . . . . . . . . . 30 2.5.3 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . 30 2.6 Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 2.7 Guide field coils . . . . . . . . . . . . . . . . . . . . . . . . . . 33 2.8 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

4 Model calculations for the Spin-Echo Small-Angle Neutron Scattering instrument 57 4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 4.2 Spherical systems . . . . . . . . . . . . . . . . . . . . . . . . . 59 4.2.1 Polydisperse systems . . . . . . . . . . . . . . . . . . . 60 4.2.2 Effect of structure factor; hard-sphere model . . . . . . 61 4.2.3 Effect of structure factor; sticky hard-sphere model . . 63 4.3 Multishell model . . . . . . . . . . . . . . . . . . . . . . . . . 65 4.4 Ellipsoid of revolution . . . . . . . . . . . . . . . . . . . . . . 68 4.5 Cylindrical model . . . . . . . . . . . . . . . . . . . . . . . . . 69 4.6 Debye-Lorentz model . . . . . . . . . . . . . . . . . . . . . . . 70 4.7 Small-angle approximation . . . . . . . . . . . . . . . . . . . . 74 4.8 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

5 Measurements 77 5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 5.2 Limestone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 5.3 Multiple scattering . . . . . . . . . . . . . . . . . . . . . . . . 80 5.4 SESANS measurements on colloids . . . . . . . . . . . . . . . 81 5.5 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 Wim G. Bouwman, Oktay Uca, Serguei V. Grigoriev, Wicher H. Kraan, Jeroen Plomp and M. Theo Rekveldt, ”First quantitative test of spin-echo small-angle neutron scattering”, accepted for publication in Applied Physics A (2002)

[1] A.P. Radlinski and A.L. Hinde. Small angle neutron scattering and petroluem geology. Neutron News, 13:10-14, 2002. [OpenAIRE]

[2] F. Mezei (edited by). Lecture notes in physics. Springer-Verlag, 128:183- 188, 1979.

[3] R. Pynn. Neutron spin-echo and three-axis spectrometers. J. Phys. E:Sci. Instrum, 11:1133-1140, 1978.

[4] V.T. Lebedev, A.D. Dudakov, L. Cser, L. Rosta, and Gy. Torok. Real space small-angle scattering device. Journal De Physique IV, 3:481-485, 1993. [OpenAIRE]

[5] T. Keller, R. G¨ahler, H. Kunze, and R. Golub. Features and performance of an nrse spectrometer at bensc. Neutron News, 6:16-18, 1995.

[6] M. Th. Rekveldt. Novel sans instrument using neutron spin echo. Nucl. Instr. & Methods in Phys. Res. B, 114:366-370, 1996. [OpenAIRE]

[7] J.Baruchel, J.Hodeau, M.Lehmann, J.Regnard, and C.Schlenker. Neutron and synchrotron radiation for condensed matter studies, Volume 1. springer-verlag, 1995.

[35] T.M. Sabine and W.K. Bertram. The use of multiple-scattering data to enhance small-angle neutron scattering experiments. Acta Cryst., A55:500-5007, 1999.

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