This introductory chapter provides a self-contained survey of the merits, strengths, and conceptual framework underpinning the use of neutrons as a probe of the structure and dynamics of materials. We also take the opportunity to illustrate important concepts using examples taken from the scientific literature, as well as establish the basic notation that will be used throughout, and listed in more detail in the List of Commonly Used Symbols.

In this chapter, neutron experimental techniques are described. The chapter covers the basics of neutron scattering, neutron source characteristics, diffraction techniques, inelastic neutron scattering, instruments for semi-macroscopic structure analysis, detectors, optics, choppers, and some concepts for instrument design. Techniques for both steady and pulsed sources are described, with more emphasis on the latter in view of the recent worldwide trend toward pulsed sources, generally pulsed spallation sources. The source character, even within the class of pulsed sources, has a significant influence on instrument design. Inelasticity effects in the total scattering technique are clearly specified in the chapter. Some details of chopper instruments, including resolution effects, are described, since this class of instruments has recently received considerable innovative development and use over a wide range of science. Recent developments in scintillation detectors are discussed as an alternative technology to more conventional 3He detectors. Optical components are becoming more and more important not only for neutron transport but also for background reduction. Neutron spin-echo techniques are presented as an example of the exploitation of polarized neutrons.

This chapter reviews the most significant developments that have taken place in the design, construction, and operation of new neutron sources as well as the refurbishment programs of others already serving the neutron-scattering community. Such advances in neutron production devices are to be considered in conjunction with impressive achievements in the optimization of neutron delivery systems as well as in neutron instrumentation which overall resulted in a truly remarkable improvement in neutron count rates. As a result, the capabilities of experimental neutron sources are nowadays larger than ever before, despite there being fewer sources available. It is also worth remarking the coming into line of compact, accelerator-driven neutron sources as well as work carried out at small research reactors which, as exemplified during the past decade, have played an important role in helping the large, user-based facilities to carry out development work geared toward the achievement of full performance.

Investigating the structure of a material is the first essential step in understanding its macroscopic properties. Getting insights of the interatomic and inter/intra-molecular interactions that influence the stability and the chemical behavior of a given compound allows its application in the best possible conditions and opens the way to design new materials with tailored properties. Neutron diffraction is a fundamental tool in structural characterization. Few examples concerning chemical crystallography, will be given to illustrate the properties that make neutrons the ideal probe for locating light atoms in the presence of heavy, electron-rich ones, and accurately determine atomic position and displacement parameters.

The aim of this chapter is to show how inelastic and quasielastic neutron scattering can be used to study dynamics in a range of materials varying from simple model systems to complex systems that are close to those used in technologically important applications. After a brief overview of the theoretical and instrumental concepts, we use examples to show how different types of atomic and molecular motions can be understood using neutron scattering experiments, frequently in combination with atomistic modeling methods. We cover aspects of physics, chemistry, biology, and materials science, but with the main focus on functional materials.

Large-scale structures encompass a broad area of science involving soft matter, biomaterials, and nanotechnology, defined by relatively weak interactions and length scales that extend from nanometer to micrometer. The key features of such systems that require characterization and quantification are surfaces and interfaces, adsorption, thin films, and self-assembly and hierarchical structures in solution and the solid phase. The neutron scattering techniques of neutron reflectivity and small-angle neutron scattering have emerged over the past two decades as important probes of these characteristic features of large-scale structures. In this chapter, the fundamentals of the two techniques are described in detail and the important experimental aspects summarized. Their application over a broad range of science is presented, in a way that highlights their unique properties and their important contribution to the field.

Neutron scattering is arguably the most powerful technique available for looking inside materials and seeing what the atoms are doing. This textbook provides a comprehensive and up-to-date account of the many different ways neutrons are being used to investigate the behaviour of atoms and molecules in bulk matter. It is written in a pedagogical style, and includes many examples and exercises. Every year, thousands of experiments are performed at neutron scattering facilities around the world, exploring phenomena in physics, chemistry, materials science, as well as in interdisciplinary areas such as biology, materials engineering, and cultural heritage. This book fulfils a need for a modern and pedagogical treatment of the principles behind the various different neutron techniques, in order to provide scientists with the essential formal tools to design their experiments and interpret the results. The book will be of particular interest to researchers using neutrons to study the atomic-scale structure and dynamics in crystalline solids, simple liquids and molecular fluids by diffraction techniques, including small-angle scattering and reflectometry, and by spectroscopic methods, ranging from conventional techniques for inelastic and quasielastic scattering to neutron spin-echo and Compton scattering. A comprehensive treatment of magnetic neutron scattering is given, including the many and diverse applications of polarized neutrons.