{"title":"240Pu(n, F)、239Pu(n, F)和238U(n, F)的瞬发裂变中子谱","authors":"V. M. Maslov","doi":"10.1134/S1547477123040490","DOIUrl":null,"url":null,"abstract":"<p>Pre-fission neutron spectra are indicators of the distribution of fission reaction energy between the kinetic energy of fragments and prompt fission neutrons. Using the <sup>240</sup>Pu(<i>n</i>, <i>F</i>), <sup>239</sup>Pu(<i>n</i>, <i>F</i>), and <sup>238</sup>U(<i>n</i>, <i>F</i>) reactions as an example, it is shown how the shape of the observed prompt fission neutron spectra (PFNS) depends on the fissility (fission probability) of compound and residual nuclei. A correlation of this effect with the contributions of the (<i>n</i>, <i>xnf</i>) emission fission to the observed fission cross section and the competition of the (<i>n</i>, <i>n</i>γ) and (<i>n</i>, <i>xn</i>)<sup>1,<i>...x</i></sup> reactions is established. The exclusive spectra of the (<i>n</i>, <i>xnf</i>)<sup>1,...<i>x</i></sup> neutrons correspond to the consistent description of the observed cross sections for the <sup>240</sup>Pu(<i>n</i>, <i>F</i>), <sup>239</sup>Pu(<i>n</i>, <i>F</i>), <sup>238</sup>Pu(<i>n</i>, <i>F</i>), <sup>237</sup>Pu(<i>n</i>, <i>F</i>), and <sup>236</sup>Pu(<i>n</i>, <i>F</i>) fission reactions, as well as <sup>239</sup>Pu(<i>n</i>, <i>xn</i>) neutron emission spectra for neutrons with energies up to 20 MeV. The initial values of the model parameters for describing the <sup>240</sup>Pu(<i>n</i>, <i>F</i>) PFNS are fixed when describing the prompt neutron spectra of <sup>240</sup>Pu(<i>sf</i>) spontaneous fission. Taking into account the influence of the exclusive spectra of <sup>240</sup>Pu (<i>n</i>, <i>xnf</i>)<sup>1,...<i>x</i></sup> prefission neutrons, the prompt fission neutron spectra, the total kinetic energy (TKE) of fragments and fission products, and the average number of <sup>240</sup>Pu(<i>n</i>, <i>F</i>) prompt fission neutrons are predicted.</p>","PeriodicalId":730,"journal":{"name":"Physics of Particles and Nuclei Letters","volume":"20 4","pages":"565 - 576"},"PeriodicalIF":0.4000,"publicationDate":"2023-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Prompt Fission Neutron Spectra of 240Pu(n, F), 239Pu(n, F), and 238U(n, F)\",\"authors\":\"V. M. Maslov\",\"doi\":\"10.1134/S1547477123040490\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>Pre-fission neutron spectra are indicators of the distribution of fission reaction energy between the kinetic energy of fragments and prompt fission neutrons. Using the <sup>240</sup>Pu(<i>n</i>, <i>F</i>), <sup>239</sup>Pu(<i>n</i>, <i>F</i>), and <sup>238</sup>U(<i>n</i>, <i>F</i>) reactions as an example, it is shown how the shape of the observed prompt fission neutron spectra (PFNS) depends on the fissility (fission probability) of compound and residual nuclei. A correlation of this effect with the contributions of the (<i>n</i>, <i>xnf</i>) emission fission to the observed fission cross section and the competition of the (<i>n</i>, <i>n</i>γ) and (<i>n</i>, <i>xn</i>)<sup>1,<i>...x</i></sup> reactions is established. The exclusive spectra of the (<i>n</i>, <i>xnf</i>)<sup>1,...<i>x</i></sup> neutrons correspond to the consistent description of the observed cross sections for the <sup>240</sup>Pu(<i>n</i>, <i>F</i>), <sup>239</sup>Pu(<i>n</i>, <i>F</i>), <sup>238</sup>Pu(<i>n</i>, <i>F</i>), <sup>237</sup>Pu(<i>n</i>, <i>F</i>), and <sup>236</sup>Pu(<i>n</i>, <i>F</i>) fission reactions, as well as <sup>239</sup>Pu(<i>n</i>, <i>xn</i>) neutron emission spectra for neutrons with energies up to 20 MeV. The initial values of the model parameters for describing the <sup>240</sup>Pu(<i>n</i>, <i>F</i>) PFNS are fixed when describing the prompt neutron spectra of <sup>240</sup>Pu(<i>sf</i>) spontaneous fission. Taking into account the influence of the exclusive spectra of <sup>240</sup>Pu (<i>n</i>, <i>xnf</i>)<sup>1,...<i>x</i></sup> prefission neutrons, the prompt fission neutron spectra, the total kinetic energy (TKE) of fragments and fission products, and the average number of <sup>240</sup>Pu(<i>n</i>, <i>F</i>) prompt fission neutrons are predicted.</p>\",\"PeriodicalId\":730,\"journal\":{\"name\":\"Physics of Particles and Nuclei Letters\",\"volume\":\"20 4\",\"pages\":\"565 - 576\"},\"PeriodicalIF\":0.4000,\"publicationDate\":\"2023-08-08\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Physics of Particles and Nuclei Letters\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://link.springer.com/article/10.1134/S1547477123040490\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q4\",\"JCRName\":\"PHYSICS, PARTICLES & FIELDS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Physics of Particles and Nuclei Letters","FirstCategoryId":"1085","ListUrlMain":"https://link.springer.com/article/10.1134/S1547477123040490","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"PHYSICS, PARTICLES & FIELDS","Score":null,"Total":0}
Prompt Fission Neutron Spectra of 240Pu(n, F), 239Pu(n, F), and 238U(n, F)
Pre-fission neutron spectra are indicators of the distribution of fission reaction energy between the kinetic energy of fragments and prompt fission neutrons. Using the 240Pu(n, F), 239Pu(n, F), and 238U(n, F) reactions as an example, it is shown how the shape of the observed prompt fission neutron spectra (PFNS) depends on the fissility (fission probability) of compound and residual nuclei. A correlation of this effect with the contributions of the (n, xnf) emission fission to the observed fission cross section and the competition of the (n, nγ) and (n, xn)1,...x reactions is established. The exclusive spectra of the (n, xnf)1,...x neutrons correspond to the consistent description of the observed cross sections for the 240Pu(n, F), 239Pu(n, F), 238Pu(n, F), 237Pu(n, F), and 236Pu(n, F) fission reactions, as well as 239Pu(n, xn) neutron emission spectra for neutrons with energies up to 20 MeV. The initial values of the model parameters for describing the 240Pu(n, F) PFNS are fixed when describing the prompt neutron spectra of 240Pu(sf) spontaneous fission. Taking into account the influence of the exclusive spectra of 240Pu (n, xnf)1,...x prefission neutrons, the prompt fission neutron spectra, the total kinetic energy (TKE) of fragments and fission products, and the average number of 240Pu(n, F) prompt fission neutrons are predicted.
期刊介绍：
The journal Physics of Particles and Nuclei Letters, brief name Particles and Nuclei Letters, publishes the articles with results of the original theoretical, experimental, scientific-technical, methodological and applied research. Subject matter of articles covers: theoretical physics, elementary particle physics, relativistic nuclear physics, nuclear physics and related problems in other branches of physics, neutron physics, condensed matter physics, physics and engineering at low temperatures, physics and engineering of accelerators, physical experimental instruments and methods, physical computation experiments, applied research in these branches of physics and radiology, ecology and nuclear medicine.
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