Introduction to material evaluation/structure analyses by quantum beam “neutron” is given on the occasion of the commencement of public access to J-PARC/MLF (Japan Proton Accelerator Research Complex/Materials and Life Science Laboratory), Tokai, Japan. Japan now has two major neutron beam sources in Tokai, i. e., J-PARC/MLF and the Japan Research Reactor 3 (JRR-3), at Japan Atomic Energy Agency (JAEA) and one in Kumatori, Osaka, Kyoto University Reactor (KUR). Starting with an introduction of the suchness of “neutron”, unique properties of neutron beam and its application to material evaluation and structure analyses are described together with various types of neutron instruments at these facilities.
Neutron depth profiling (NDP) is a non-destructive analytical technique used for the analysis of elemental depth distributions at the near surface of materials. Profiles are determined by measuring the energy loss of charged particles produced by (n, α) or (n, p) reactions. Technologically important light elements like B and Li are easily analyzed which are not often possible to accurately analyze by other methods. Since the use of cold neutron beams for NDP guided from nuclear reactors, the applications have expanded substantially including microelectronics. This paper reviews the fundamental principle and characteristics, analysis systems and method, as well as uses of NDP. As for applications of NDP, the paper focuses on modern applications reported since 1990s; such as diamond, diamond like carbon (DLC) and cubic-boron nitride (c-BN), electrochromic devices, lithium ion batteries, nuclear fusion reactor materials, and high level radioactive-waste processing related materials. Finally, the author suggests starting an NDP research program using low energy guided neutrons at JRR-3M in Japan.
During the last 20 years neutron reflectivity has emerged as a powerful and important technique for the study of soft materials surfaces and interfaces. The selectivity and sensitivity afforded by deuterium/hydrogen labeling makes the technique particularly attractive for application to characterization of surface and interface, but also water/solid interface. This review provides a brief introduction of applications of neutron reflectivity to analyses of soft materials surface and interfaces.
Techniques of Small-Angle Neutron and X-ray Scattering (SANS & SAXS) are overviewed from principle to applications. Importance of characterizing composition of nano-size heterogeneity is explained based on the results obtained by combination of SANS and SAXS.
The present brief review describes the application of neutron powder diffractometry and maximum-entropy method to the studies of crystal structure and diffusional pathways of mobile ions in ionic conducting ceramic materials. La0.62Li0.16TiO3 and Li0.6FePO4 exhibit two- and one-dimensional networks of Li cation diffusional pathways, respectively. In the fluorite-structured ionic conductors such as ceria solid solution Ce0.93Y0.07O1.96, bismuth oxide solid solution δ-Bi1.4Yb0.6O3 and copper iodide CuI, a similar curved diffusion pathway along the ‹100› directions is observed. In the cubic ABO3 perovskite-type ionic conductor, lanthanum gallate solid solution, the mobile ions diffuse along a curved line keeping the interatomic distance between the B cation and O2- anion. We have experimentally confirmed that the anisotropic thermal motions of the apex O2 atom and the interstitial O3 atoms are essential for the high oxygen permeability of the K2NiF4-type mixed conductor. Diffusion paths of proton are visualized along c axis in hexagonal hydroxyapatite.
Atomic resolution holography with neutrons offers 3D nucleus images around specific nuclei. This method will explore a new stage of local structure analysis, such as environmental structure around hydrogen or local magnetic structure, which cannot be obtained by other methods. In the present article, we explicate theory and experimental setup for the neutron holography. Moreover, two experimental examples of hydrogen storage material and dopant are shown. Finally, we discuss perspective of neutron holography with a pulse neutron source.
The neutron interference imaging technique has been developed for these years with several methods. Here we introduce recent results of neutron interference method. The neutron interference imaging experiment with two absorption gratings has been done. We develop new way to fabricate absorption gratings for neutron with the pitch of 150 μm, 180 μm, and 200 μm. Small break in an acrylic plate was observed. We expect that the neutron interference imaging method can become new method of a nondestructive inspection method for reinforced plastics and composite material such as CFRP and so on especially installed at compact neutron source which is being developed in RIKEN now.
Neutron scattering is one of most powerful probes to study magnetism in condensed matter, having significant advantages over other experimental techniques in the elucidation of magnetic structure and dynamics. They provide the most direct information on the arrangement of magnetic moments in a specimen. In contrast to well-developed environment of Rietveld analysis on crystal structure, magnetic structure refinement, however, cannot be easily done by non-expertized experimentalists. Here we make every effort to illustrate on how to analyze magnetic structures. This aims to provide readers with opportunities to grasp procedures of the analysis. The manuscript consists of examples of bulk compounds based on our recent results; iron-based compounds BaFe2Se3 and CaFe4As3 where representation analysis is applied, and low-dimensional magnet NiGa2S4 with short-range magnetic correlation.