Compound-Nucleus and Doorway-State Decays of β-Delayed Neutron Emitters 51,52,53K
Abstract
We investigated decays of 51,52,53K at the ISOLDE Decay Station at CERN in order to understand the mechanism of the 𝛽-delayed neutron-emission (𝛽𝑛) process. The experiment quantified neutron and 𝛾-ray emission paths for each precursor. We used this information to test the hypothesis, first formulated by Bohr in 1939, that neutrons in the 𝛽𝑛 process originate from the structureless “compound nucleus.” The data are consistent with this postulate for most of the observed decay paths. The agreement, however, is surprising because the compound-nucleus stage should not be achieved in the studied 𝛽 decay due to insufficient excitation energy and level densities in the neutron emitter. In the 53K 𝛽𝑛 decay, we found a preferential population of the first excited state in 52Ca that contradicted Bohr’s hypothesis. The latter was interpreted as evidence for direct neutron emission sensitive to the structure of the neutron-unbound state. We propose that the observed nonstatistical neutron emission proceeds through the coupling with nearby doorway states that have large neutron-emission probabilities. The appearance of “compound-nucleus” decay is caused by the aggregated small contributions of multiple doorway states at higher excitation energy.
Main Authors
Format
Articles
Research article
Published
2024
Series
Subjects
Publication in research information system
Publisher
American Physical Society
The permanent address of the publication
https://urn.fi/URN:NBN:fi:jyu-202408015293Käytä tätä linkitykseen.
Review status
Peer reviewed
ISSN
0031-9007
DOI
https://doi.org/10.1103/PhysRevLett.133.042501
Language
English
Published in
Physical Review Letters
Citation
- Xu, Z. Y., Grzywacz, R., Gottardo, A., Madurga, M., Alonso, I. M., Andreyev, A. N., Benzoni, G., Borge, M. J. G., Cap, T., Costache, C., De Witte, H., Dimitrov, B. I., Escher, J. E., Fijalkowska, A., Fraile, L. M., Franchoo, S., Fynbo, H. O. U., Gonsalves, B. C., Gross, C. J., . . . Yuan, C. X. (2024). Compound-Nucleus and Doorway-State Decays of β-Delayed Neutron Emitters 51,52,53K. Physical Review Letters, 133(4), Article 042501. https://doi.org/10.1103/PhysRevLett.133.042501
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Funder(s)
European Commission
Funding program(s)
Research infrastructures, H2020
Research infrastructures, H2020
Additional information about funding
This project was supported by the European Unions Horizon 2020 research and innovation programme under the Grant Agreement No. 654002 (ENSAR2) and the Marie Skłodowska-Curie Grant Agreement No. 101032999 (BeLaPEx), by the Office of Nuclear Physics, U.S. Department of Energy under Award No. DE-FG02-96ER40983 (UTK) and DE-AC05-00OR22725 (ORNL), by the auspices of the National Nuclear Security Administration of the U.S. Department of Energy at Los Alamos National Laboratory under Contract No. 89233218CNA000001, by the auspices of the U.S. Department of Energy at Lawrence Livermore National Laboratory under Contract No. DE-AC52-07NA27344, by the National Nuclear Security Administration under the Stewardship Science Academic Alliances program through DOE Award No. DE-436NA0003899, No. DE-NA0002132, and No. DE-NA0004068, by the Romanian IFA grant CERN/ISOLDE and Nucleu Project No. PN 23 21 01 02, by the Research Foundation Flanders (FWO, Belgium) and by BOF KU Leuven (C14/22/104), by the German BMBF under Contracts No. 05P18PKCIA and No. 05P21PKCI1 in Verbundprojekte 05P2018 and 05P2021, by the UK Science and Technology Facilities Research Council (STFC) of the UK Grants No. ST/R004056/1, No. ST/P004598/1, No. ST/P003885/1, No. ST/V001027/1, and No. ST/V001035/1, by the Guangdong Major Project of Basic and Applied Basic Research under Grant No. 2021B0301030006, by the Polish National Science Center under Grant No. 2020/39/B/ST2/02346, by the Polish Ministry of Education and Science under Contract No. 2021/WK/07, by Spanish MCIN/AEI/10.13039/501100011033 under Grants No. PGC2018-093636-B-I00, No. RTI2018-098868-B-I00, No. PID2019-104390 GB-I00, No. PID2019-104714 GB-C21, No. PID2021-126998OB-I00, and No. PID2022-140162NB-I00, by Generalitat Valenciana, Conselleria de Innovación, Universidades, Ciencia y Sociedad Digital under Grant No. CISEJI/2022/25, and by Universidad Complutense de Madrid (Spain) through Grupo de Física Nuclear (910059).
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