English Abstract

Novel Neutron Microscope to Observe Industrial Product as It Is.
\Pulsed Neutron Small Angle Scattering Combined with Dynamic Nuclear Polarization\

Yohei NODA
Tomoki MAEDA
Takumi INADA
Institute of Quantum Beam Science, Ibaraki University, Naka-gun, Ibaraki, Japan
Nippon Gomu Kyokaishi,(2021),94(12),387-394 General Review in Japanese

Ibaraki university developed the novel neutron microscope on the instrument iMATERIA at MLF of J-PARC, which was originally a powder diffractometer, recently reinforced by detecting small-angle scattering. The method of dynamic nuclear polarization (DNP) for protons was combined with small angle neutron scattering (SANS)(DNP-SANS). In a long course of history of DNP, our activity is the world's first challenge to incorporate DNP-SANS for routine industry uses. This “neutron microscope" provides us multiple reciprocal space images by changing scattering lengths of proton, in turn by varying “contrast" of individual scattering components. Conventionally, for the contrast variation, chemical treatments are required to substitute protons with deuterons. The DNP approach is suitable for industry application (for example to observe tire rubbers), because we do not need highly-specialized deuterium substitution. In this article, we describe theoretical background of DNP including scattering functions and the experimental of 7T super-conductive magnet, NMR to evaluate proton spin polarization, and microwave to change polarization. The sample preparation to dope radicals into sample specimens are necessary. We review the studies on homopolymers of polystyrene and polyethylene, poly (styrene-b-isoprene) diblock copolymer, and vulcanized SBR rubber.

Keywords: Small Angle Neutron Scattering, Contrast Variation, Dynamic Nuclear Polarization, Industrial Use.