量研学術機関リポジトリ「QST-Repository」は、国立研究開発法人 量子科学技術研究開発機構に所属する職員等が生み出した学術成果（学会誌発表論文、学会発表、研究開発報告書、特許等）を集積しインターネット上で広く公開するサービスです。 Welcome to QST-Repository where we accumulates and discloses the academic research results(Journal Publications, Conference presentation, Research and Development Report, Patent, etc.) of the members of National Institutes for Quantum Science and Technology.
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We generated high-energy neutrons by (d, n) and (p, n) reactions on a Be target with protons and deuterons that were accelerated up to 30 and 10 MeV/u, respectively, by laser-plasma interactions. Thermal neutrons were subsequently generated through deceleration by a small moderator with conjunction on the Be target. Here we report the measurements on the thermal neutron fluence using the activation method with/without Cd filters. The unstable isotopes of 198Au, 56Mn, 60Co, and 181Hf were produced through (n, γ) reactions by a single laser shot. The nuclear reaction rates were evaluated by measurring the γ-rays emitted from these unstable isotopes. The thermal neutron fluences from the four nuclides are consistent within their experimental uncertainties. The fluence is evaluated to be (2.2±0.4)×105 neutrons/cm2 at the distance of approximately 9-
mm at 90◦ against the laser axis. The present result shows that the method to generate thermal neutrons from a compact neutron source with a diamater of 44 mm and length of 46 mm is expected to be a useful tool for various nuclear experiments.
雑誌名
Journal of Physics G: Nuclear and Particle Physics
Thermal neutron fluence measurement by Cadmium differential method at laser-driven neutron source
