Introduction to Soft Matter Neutron Scattering

Inhaltsverzeichnis

1. Frontmatter

2. Chapter 1. Introduction

   Mitsuhiro Shibayama

   Abstract

   After an overview of the discovery of the neutron, the history of scientific progress using neutrons, X-rays, and light, and a survey of global neutron facilities, the purpose of this book will be stated by posing the questions of why neutron scattering is necessary and what makes it useful. Subsequently, the organization of this book will be described.

3. Chapter 2. Physical and Mathematical Aspects of Scattering

   Mitsuhiro Shibayama

   Abstract

   This chapter begins with the mathematical representation of waves, reviewing concepts such as the principle of superposition, standing waves, and beats. It then progresses to the exponential representation of waves, Fourier series, and the Fourier transform. Finally, applications of the Fourier transform are introduced, including topics such as the spectral analysis of sound waves and the Fourier transform and filtering of images.

4. Chapter 3. Neutron Basics

   Mitsuhiro Shibayama

   Abstract

   In this chapter, we will begin by explaining the fundamental properties of the neutron, namely, its nature as a particle, its nature as a wave, and the fact that it possesses neutron spin. We will then compare the neutron’s energy with the interaction energy of matter. Furthermore, we will explain from their foundations the concepts of the differential scattering cross section, the neutron scattering length, and the scattering vector, which are essential for understanding scattering theory. Additionally, we will provide a clear explanation of scattering and absorption, coherent and incoherent scattering, and elastic and inelastic scattering.

5. Chapter 4. Small-Angle Neutron Scattering

   Mitsuhiro Shibayama

   Abstract

   Small-angle neutron scattering (SANS) is a technique that literally deals with “scattering at small angles” and has been developed as a method for investigating nanoscale structures. While its theoretical background is largely the same as small-angle X-ray scattering (SAXS), SANS is highly valued for its excellent material penetration and the ability to selectively visualize structures using techniques like deuterium labeling. In this chapter, we’ve strived to express the scattering intensity distribution in a unified and consistent manner as the Fourier transform of the scattering length density distribution. The subjects cover range from dilute particle systems like colloidal dispersions to semi-concentrated and bulk systems, where evaluating interactions is crucial. Furthermore, the chapter extends beyond particle systems to include non-particulate systems such as single-phase systems with fluctuations, two-phase and multi-component systems with sea-island structures, as well as scattering from fractal and polymer systems.

6. Chapter 5. Neutron Reflectometry

   Mitsuhiro Shibayama

   Abstract

   Neutron reflectometry is a technique that evolved from X-ray reflectometry. While its theoretical underpinnings are largely the same, neutron reflectometry leverages the superior material penetration of neutrons and their unique sensitivity to light elements, which differs from X-rays. It’s an indispensable technique in soft matter science, particularly because deuterium substitution can create a large difference in scattering length density (SLD). Reflectometry is a powerful tool for obtaining information about the depth profile of thin films via a one-dimensional Fourier transform of the reflectivity. This makes it easier to understand than small-angle scattering, which requires a three-dimensional Fourier transform. Furthermore, the reflectivity equation can be derived more simply by expressing the SLD profile in differential form, making it easier to compare experimental data with theoretical models. This chapter will provide an overview of these features and key points of neutron reflectometry.

7. Chapter 6. Quasielastic Neutron Scattering

   Mitsuhiro Shibayama

   Abstract

   When neutrons are scattered by interacting with atomic nuclei in a material, both their direction and energy generally change. Up to the previous chapter, we have dealt with scattering where the energy does not change, namely, elastic scattering. In this chapter, however, we will discuss scattering where the energy changes slightly, that is, quasielastic neutron scattering. We will start with the differences between quasielastic and elastic scattering, and then describe the information that can be obtained from quasielastic neutron scattering using the dynamic structure factor and the space-time correlation function. Furthermore, we will also provide an overview of the high-energy-resolution Neutron Spin Echo spectroscopy.

8. Chapter 7. Neutron Imaging

   Mitsuhiro Shibayama

   Abstract

   Neutron imaging is a radiography technique that makes maximum use of the excellent penetrating power of neutrons, a method that represents neutrons transmitted through a substance as a positional distribution in a projection. A major difference from the preceding chapters, which were set in reciprocal space, is that neutron imaging is concerned with real space. In this chapter, we will begin with the principles of neutron imaging, and then describe methods such as total cross-sectional contrast imaging, energy-resolved imaging, and magnetic field contrast imaging. Furthermore, we will explain neutron tomography, which reconstructs the neutron transmittance of a material in three dimensions, and the Radon transform, which provides its theoretical basis.

9. Chapter 8. Neutron Scattering Measurement Methods, Neutron Scattering Facilities and Instruments

   Mitsuhiro Shibayama

   Abstract

   This chapter begins by introducing the two major neutron scattering measurement methods: the angle-dispersive method and the time-of-flight method. It then provides an overview of the main neutron scattering experimental techniques and instruments, explaining the advantages and disadvantages of each. Next, it describes two neutron counting methods: the histogramming method and the event-recording method. Finally, it introduces the major neutron scattering facilities in Japan.

10. Chapter 9. Appendix

    Mitsuhiro Shibayama

11. Backmatter