|
内容記述 |
Low energy neutron (thermal neutron) sources are widely used in various fields such as neutron radiography, neutron diffraction, and Boron Neutron Capture Therapy (BNCT). Spin-polarized neutrons are also considered as one of the next generation quantum sources, enabling the analysis of magnetic structures in materials. Laser-driven neutron sources are considered promising due to their point source and short pulse. The generation of thermal neutrons by lasers has been studied by using specially designed moderators [1-3]. In this study, we propose a novel method based on the Stern–Gerlach principle, where neutrons are spatially separated into fully spin-polarized states by a magnetic field gradient. By combining a laser-driven neutron source with a laser-driven magnetic field, this method enables the generation of spin-polarized neutrons with both point-source characteristic and short pulse duration.The experiment is conducted at GEKKO XII–LFEX laser facility at Institute of Laser Engineering, The University of Osaka [3]. Photonuclear reactions induced by deuterons were utilized to produce thermal neutrons without any moderators. The LFEX laser generates x-rays, which then induce neutron production by a deuterated plastic target. The resulting neutron spectrum spans a broad energy range from meV to MeV. A magnetic field is subsequently generated using GEKKO XII laser triggered after the LFEX pulse.Preliminary experimental data confirm that thermal neutrons are successfully detected by the detector package, although spin-polarized neutrons have not yet been identified due to an insufficient signal-to-background ratio.References[1] S.R. Mirfayzi, et, al, Sci. Rep, 10, 20157 (2020). [2] S. R. Mirfayzi et al., Appl. Phys. Lett. 116, 174102 (2020). [3] A. Yogo et al., Appl. Phys. Express 14 106001 (2021). |
