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Nucleosynthesis, Cosmic Radiation, and the Universe
Published in Ivan G. Draganić, Zorica D. Draganić, Jean-Pierre Adloff, Radiation and Radioactivity on Earth and Beyond, 2020
Ivan G. Draganić, Zorica D. Draganić, Jean-Pierre Adloff
Depending on available targets and their “avidity” for neutrons, reactions in the star cores require a considerable amount of time in comparison with terrestrial standards. Despite the fact that the fluxes are rather impressive, amounting to 1016 neutrons per second and per square centimeter, the capture of one neutron requires a time ranging from 100 to 100,000 years. On the whole, the buildup can last for 10 million years or more. This progressive and slow addition of neutrons is called the slow process (s-process).
Japanese evaluated nuclear data library version 5: JENDL-5
Published in Journal of Nuclear Science and Technology, 2023
Osamu Iwamoto, Nobuyuki Iwamoto, Satoshi Kunieda, Futoshi Minato, Shinsuke Nakayama, Yutaka Abe, Kohsuke Tsubakihara, Shin Okumura, Chikako Ishizuka, Tadashi Yoshida, Satoshi Chiba, Naohiko Otuka, Jean-Christophe Sublet, Hiroki Iwamoto, Kazuyoshi Yamamoto, Yasunobu Nagaya, Kenichi Tada, Chikara Konno, Norihiro Matsuda, Kenji Yokoyama, Hiroshi Taninaka, Akito Oizumi, Masahiro Fukushima, Shoichiro Okita, Go Chiba, Satoshi Sato, Masayuki Ohta, Saerom Kwon
In the case of 13C, the most important reaction may be 13C()14C which produces an unwished radioactive isotope 14C ( y) in nuclear engineering. The reaction is also known as ‘neutron poisons’ in the s-process – a neutron absorber in the nucleosynthesis. In the present study, the 13C()14C cross section was estimated with the Reich-Moore approximation [203] putting the distant poles as pseudo resonances for p-waves to mimic the direct process. As illustrated in Figure 53, we found that such a technical approach to the direct reaction, together with estimation of the -ray width for the first resonance () at keV, was necessary to obtain evaluation consistent measured data [204,205] as shown in the top panel. Since those experimental data are given sparsely, we also used Maxwellian-Averaged Cross Sections (MACS) estimated by Wallner et al. [205] to determine the resonance parameter values as shown in the bottom panel. Although MACS is not a pure measurements, we thought it could be a useful guide for the data evaluation in this case.