Direct evaluation of high neutron density environment using (n,2n) reaction induced by laser-driven neutron source
| Autor: | Takehito Hayakawa, Tianyun Wei, Yuki Honoki, Shinsuke Fujioka, Akifumi Yogo, Ryosuke Kodama, D. Golovin, S. R. Mirfayzi, T. Mori, Yasunobu Arikawa, Zechen Lan, Hiroaki Nishimura, Yuki Abe, Mitsuo Nakai, Kunioki Mima |
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| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | Physical Review C. 104 |
| ISSN: | 2469-9993 2469-9985 |
| Popis: | We demonstrate that $(n,2n)$ reactions are induced by a high-flux pulse of fast neutrons ($\ensuremath{\sim}{10}^{10}$ neutrons in $\ensuremath{\sim}1\phantom{\rule{0.16em}{0ex}}\mathrm{ns}$) provided from a laser-driven neutron source (LDNS). The maximum energy of the broadband neutrons reaches a few tens MeV. Several kinds of metal targets are exposed to the fast neutrons. As a result, unstable isotopes, such as $^{54}\mathrm{Mn}, ^{58}\mathrm{Co}, ^{175}\mathrm{Hf}$, and $^{196}\mathrm{Au}$ are produced by $(n,2n)$ reactions and $^{180}\mathrm{Hf}^{m}, ^{181}\mathrm{Hf}, ^{56}\mathrm{Mn}, ^{198}\mathrm{Au}$, and $^{60}\mathrm{Co}$ are produced by $(n,\ensuremath{\gamma})$ reactions. We evaluate the neutron fluence and energy spectrum using the activation method in conjunction with a time-of-flight measurement. The neutron fluence is determined to be $(4.3\ifmmode\pm\else\textpm\fi{}0.5)\ifmmode\times\else\texttimes\fi{}{10}^{8}\phantom{\rule{0.16em}{0ex}}\mathrm{neutrons}/\mathrm{c}{\mathrm{m}}^{2}$ in the energy range from approximately 8 to 20 MeV at 8-mm downstream of the neutron source. The present scheme provides a method to evaluate high-density neutrons seen in stellar environments, which are expected to be generated from future LDNSs. |
| Databáze: | OpenAIRE |
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