{"title":"观测重离子诱导裂变中质子的近裂变 \"极 \"和 \"赤道 \"发射","authors":"","doi":"10.1016/j.physletb.2024.139014","DOIUrl":null,"url":null,"abstract":"<div><p>Proton and <em>α</em>-particle energy spectra were measured in coincidence with fission fragments at different relative angles in <sup>16</sup>O (96 MeV) + <sup>232</sup>Th reaction. The multiplicity spectra were analyzed within the framework of a Moving Source Disentangling Analysis (MSDA) to determine contributions from different emission stages. The MSDA conclusively shows “Near Scission Emission (NSE)” as an essential component in the multiplicity spectra. In contrast to NSE <em>α</em> particles which emit mainly perpendicular (“equatorial emission”), the NSE protons are observed to be emitted perpendicular as well as parallel (“polar emission”) to the fission axis with similar intensities (~20% for each). Thus, around 40% of total pre-scission protons are emitted near the scission stage, whereas the same fraction for <em>α</em> particles is only around 10%. The inevitable presence of “polar” and “equatorial” NSE protons in a heavy-ion induced fission has been observed for the first time. Present results open up a new avenue to study the heavy-ion induced fission dynamics.</p></div>","PeriodicalId":20162,"journal":{"name":"Physics Letters B","volume":null,"pages":null},"PeriodicalIF":4.3000,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0370269324005720/pdfft?md5=5f43a9eca3aee81267bf01eabcc1c99c&pid=1-s2.0-S0370269324005720-main.pdf","citationCount":"0","resultStr":"{\"title\":\"Observation of near-scission “polar” and “equatorial” proton emission in heavy-ion induced fission\",\"authors\":\"\",\"doi\":\"10.1016/j.physletb.2024.139014\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Proton and <em>α</em>-particle energy spectra were measured in coincidence with fission fragments at different relative angles in <sup>16</sup>O (96 MeV) + <sup>232</sup>Th reaction. The multiplicity spectra were analyzed within the framework of a Moving Source Disentangling Analysis (MSDA) to determine contributions from different emission stages. The MSDA conclusively shows “Near Scission Emission (NSE)” as an essential component in the multiplicity spectra. In contrast to NSE <em>α</em> particles which emit mainly perpendicular (“equatorial emission”), the NSE protons are observed to be emitted perpendicular as well as parallel (“polar emission”) to the fission axis with similar intensities (~20% for each). Thus, around 40% of total pre-scission protons are emitted near the scission stage, whereas the same fraction for <em>α</em> particles is only around 10%. The inevitable presence of “polar” and “equatorial” NSE protons in a heavy-ion induced fission has been observed for the first time. Present results open up a new avenue to study the heavy-ion induced fission dynamics.</p></div>\",\"PeriodicalId\":20162,\"journal\":{\"name\":\"Physics Letters B\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":4.3000,\"publicationDate\":\"2024-09-11\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://www.sciencedirect.com/science/article/pii/S0370269324005720/pdfft?md5=5f43a9eca3aee81267bf01eabcc1c99c&pid=1-s2.0-S0370269324005720-main.pdf\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Physics Letters B\",\"FirstCategoryId\":\"101\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0370269324005720\",\"RegionNum\":2,\"RegionCategory\":\"物理与天体物理\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"ASTRONOMY & ASTROPHYSICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Physics Letters B","FirstCategoryId":"101","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0370269324005720","RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ASTRONOMY & ASTROPHYSICS","Score":null,"Total":0}
Observation of near-scission “polar” and “equatorial” proton emission in heavy-ion induced fission
Proton and α-particle energy spectra were measured in coincidence with fission fragments at different relative angles in 16O (96 MeV) + 232Th reaction. The multiplicity spectra were analyzed within the framework of a Moving Source Disentangling Analysis (MSDA) to determine contributions from different emission stages. The MSDA conclusively shows “Near Scission Emission (NSE)” as an essential component in the multiplicity spectra. In contrast to NSE α particles which emit mainly perpendicular (“equatorial emission”), the NSE protons are observed to be emitted perpendicular as well as parallel (“polar emission”) to the fission axis with similar intensities (~20% for each). Thus, around 40% of total pre-scission protons are emitted near the scission stage, whereas the same fraction for α particles is only around 10%. The inevitable presence of “polar” and “equatorial” NSE protons in a heavy-ion induced fission has been observed for the first time. Present results open up a new avenue to study the heavy-ion induced fission dynamics.
期刊介绍:
Physics Letters B ensures the rapid publication of important new results in particle physics, nuclear physics and cosmology. Specialized editors are responsible for contributions in experimental nuclear physics, theoretical nuclear physics, experimental high-energy physics, theoretical high-energy physics, and astrophysics.