Development of dynamic nuclear polarization system for small-angle neutron scattering study in JAEA

Kumada, Takayuki   ; Hashimoto, Takeji; Koizumi, Satoshi

The scattering length of thermal or cold neutrons by proton varies with their relative nuclear-spin orientation, viz. parallel or anti-parallel. If protons in a sub-domain of soft materials are selectively polarized, contrast can be produced in the pattern for small-angle neutron scattering (SANS), which reflect its meso-scale structure. Advantage of this technique is that contrast can be produced without isotope substitution of samples. Moreover, combining contrast variations by spins and isotope substitution, we can determine structures of multiple domain components in complicated materials such as biological systems. The technique of spin-contrast variation by DNP has had a disadvantage, that is, DNP has required large-scale setup. The problem has been overcome by PSI's group. They constructed the DNP system using modern electric devices such as superconducting magnet and miliwave oscillator made of semiconductor devices, which are very compact and easily control nuclear spin polarization. Based on their system, we will develop the compact DNP system designed for SANS study in JAEA.