Evidence of nonstatistical neutron emission following β decay near doubly magic Sn 132

IDS Collaboration

doi:10.1103/PhysRevC.108.024311

Evidence of nonstatistical neutron emission following β decay near doubly magic Sn 132

IDS Collaboration

Research output: Contribution to journal › Article › peer-review

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Abstract

Models of the β-delayed neutron emission (βn) assume that neutrons are emitted statistically via an intermediate compound nucleus post β decay. Evidence to the contrary was found in an In134β-decay experiment carried out at ISOLDE CERN. Neutron emission probabilities from the unbound states in Sn134 to known low-lying, single-particle states in Sn133 were measured. The neutron energies were determined using the time-of-flight technique, and the subsequent decay of excited states in Sn133 was studied using γ-ray detectors. Individual βn probabilities were determined by correlating the relative intensities and energies of neutrons and γ rays. The experimental data disagree with the predictions of representative statistical models which are based upon the compound nucleus postulate. Our results suggest that violation of the compound nucleus assumption may occur in β-delayed neutron emission. This impacts the neutron-emission probabilities and other properties of nuclei participating in the r-process. A model of neutron emission, which links the observed neutron emission probabilities to nuclear shell effects, is proposed.

Original language	English
Article number	024311
Journal	Physical Review C
Volume	108
Issue number	2
DOIs	https://doi.org/10.1103/PhysRevC.108.024311
State	Published - Aug 2023
Externally published	Yes

Funding

This research was sponsored in part by the Office of Nuclear Physics, U. S. Department of Energy under Award No. DE-FG02-96ER40983 (UTK) and No. DE-AC05-00OR22725 (ORNL), and by the National Nuclear Security Administration under the Stewardship Science Academic Alliances program through DOE Award No. DE-NA0002132. M.P.-S. acknowledges the funding support from the Polish National Science Center under Grant No. 2019/33/N/ST2/03023 and No. 2020/36/T/ST2/00547. A.K. was partially funded by the Polish National Science Center Grant No. 2020/39/B/ST2/02346. T.K. carried out this work under the auspices of the National Nuclear Security Administration of the U. S. Department of Energy at Los Alamos National Laboratory under Contract No. 89233218CNA000001. J.E.E. carried out this work under the auspices of the U. S. Department of Energy at Lawrence Livermore National Laboratory under Contract No. DE-AC52-07NA27344. A.N.A., L.J.H-.B., D.S.J., R.D.P., and Zs.P. were supported by the UK Science and Technology Facilities Council (STFC). A.A. acknowledges partial support of the Ministerio de Ciencia e Innovacion Grant No. PID2019-104714GB-C21. A.M. acknowledges support from the Spanish Ministerio de Econom\u00EDa, Industria y Competitividad under Grant No. IJCI-2014-19172. N.W. acknowledges support from the German BMBF under Contract No. 05P18PKCIA and No. 05P21PKCI1 in Verbundprojekte 05P2018 and 05P2021. C.X.Y. acknowledges the National Natural Science Foundation of China under Grant No. 11775316 for support. This work was in part supported by the Research Foundation Flanders (FWO, Belgium), by GOA/2015/010 (BOF KU Leuven), the Interuniversity Attraction Poles Programme initiated by the Belgian Science Policy Office (BriX network P7/12). This work was supported in part by Spanish National Project No. RTI2018-098868-B-I00 and No. PID2019-104390GB-I00. The support by the European Union Horizon 2020 through ENSAR2 (Grant Agreement No. 654002) is acknowledged. This work was supported in part by the Romanian IFA project CERN/ISOLDE.

Funders	Funder number
National Nuclear Security Administration
Science and Technology Facilities Council
Oak Ridge National Laboratory
BOF KU Leuven
Fonds Wetenschappelijk Onderzoek
Institutul de Fizică Atomică
ISOLDE
CERN
Nuclear Physics
Horizon 2020
Lawrence Livermore National Laboratory	DE-AC52-07NA27344
Narodowe Centrum Nauki	2020/36/T/ST2/00547, 2020/39/B/ST2/02346, 2019/33/N/ST2/03023
U.S. Department of Energy	DE-AC05-00OR22725, DE-FG02-96ER40983, DE-NA0002132
National Natural Science Foundation of China	11775316
Los Alamos National Laboratory	89233218CNA000001
Bundesministerium für Bildung und Forschung	05P2021, 05P18PKCIA, 05P2018, 05P21PKCI1
Belgian Federal Science Policy Office	P7/12
Horizon 2020 Framework Programme	654002
Ministerio de Asuntos Económicos y Transformación Digital, Gobierno de España	IJCI-2014-19172
Ministerio de Ciencia e Innovación	PID2019-104714GB-C21
Spanish National Project	RTI2018-098868-B-I00, PID2019-104390GB-I00

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10.1103/PhysRevC.108.024311

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@article{3e4efeded5e44be4bf8203c1c20ad2ad,

title = "Evidence of nonstatistical neutron emission following β decay near doubly magic Sn 132",

abstract = "Models of the β-delayed neutron emission (βn) assume that neutrons are emitted statistically via an intermediate compound nucleus post β decay. Evidence to the contrary was found in an In134β-decay experiment carried out at ISOLDE CERN. Neutron emission probabilities from the unbound states in Sn134 to known low-lying, single-particle states in Sn133 were measured. The neutron energies were determined using the time-of-flight technique, and the subsequent decay of excited states in Sn133 was studied using γ-ray detectors. Individual βn probabilities were determined by correlating the relative intensities and energies of neutrons and γ rays. The experimental data disagree with the predictions of representative statistical models which are based upon the compound nucleus postulate. Our results suggest that violation of the compound nucleus assumption may occur in β-delayed neutron emission. This impacts the neutron-emission probabilities and other properties of nuclei participating in the r-process. A model of neutron emission, which links the observed neutron emission probabilities to nuclear shell effects, is proposed.",

author = "{IDS Collaboration} and J. Heideman and R. Grzywacz and Xu, {Z. Y.} and M. Madurga and Escher, {J. E.} and T. Kawano and A. Algora and Andreyev, {A. N.} and J. Benito and T. Berry and Borge, {M. J.G.} and C. Costache and {De Witte}, H. and A. Fijalkowska and Fraile, {L. M.} and Fynbo, {H. O.U.} and A. Gottardo and C. Halverson and Harkness-Brennan, {L. J.} and A. Illana and Janiak and Judson, {D. S.} and King, {T. T.} and A. Korgul and T. Kurtukian-Nieto and I. Lazarus and R. Licǎ and R. Lozeva and N. Marginean and R. Marginean and C. Mazzocchi and C. Mihai and Mihai, {R. E.} and Morales, {A. I.} and Page, {R. D.} and J. Pakarinen and M. Piersa-Si{\l}kowska and Zs Podoly{\'a}k and M. Singh and C. Sotty and M. Stepaniuk and O. Tengblad and A. Turturica and {Van Duppen}, P. and V. Vedia and S. Vi{\~n}als and N. Warr and R. Yokoyama and Yuan, {C. X.}",

note = "Publisher Copyright: {\textcopyright} 2023 American Physical Society.",

year = "2023",

month = aug,

doi = "10.1103/PhysRevC.108.024311",

language = "English",

volume = "108",

journal = "Physical Review C",

issn = "2469-9985",

publisher = "American Physical Society",

number = "2",

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T1 - Evidence of nonstatistical neutron emission following β decay near doubly magic Sn 132

AU - IDS Collaboration

AU - Heideman, J.

AU - Grzywacz, R.

AU - Xu, Z. Y.

AU - Madurga, M.

AU - Escher, J. E.

AU - Kawano, T.

AU - Algora, A.

AU - Andreyev, A. N.

AU - Benito, J.

AU - Berry, T.

AU - Borge, M. J.G.

AU - Costache, C.

AU - De Witte, H.

AU - Fijalkowska, A.

AU - Fraile, L. M.

AU - Fynbo, H. O.U.

AU - Gottardo, A.

AU - Halverson, C.

AU - Harkness-Brennan, L. J.

AU - Illana, A.

AU - Janiak,

AU - Judson, D. S.

AU - King, T. T.

AU - Korgul, A.

AU - Kurtukian-Nieto, T.

AU - Lazarus, I.

AU - Licǎ, R.

AU - Lozeva, R.

AU - Marginean, N.

AU - Marginean, R.

AU - Mazzocchi, C.

AU - Mihai, C.

AU - Mihai, R. E.

AU - Morales, A. I.

AU - Page, R. D.

AU - Pakarinen, J.

AU - Piersa-Siłkowska, M.

AU - Podolyák, Zs

AU - Singh, M.

AU - Sotty, C.

AU - Stepaniuk, M.

AU - Tengblad, O.

AU - Turturica, A.

AU - Van Duppen, P.

AU - Vedia, V.

AU - Viñals, S.

AU - Warr, N.

AU - Yokoyama, R.

AU - Yuan, C. X.

PY - 2023/8

Y1 - 2023/8

N2 - Models of the β-delayed neutron emission (βn) assume that neutrons are emitted statistically via an intermediate compound nucleus post β decay. Evidence to the contrary was found in an In134β-decay experiment carried out at ISOLDE CERN. Neutron emission probabilities from the unbound states in Sn134 to known low-lying, single-particle states in Sn133 were measured. The neutron energies were determined using the time-of-flight technique, and the subsequent decay of excited states in Sn133 was studied using γ-ray detectors. Individual βn probabilities were determined by correlating the relative intensities and energies of neutrons and γ rays. The experimental data disagree with the predictions of representative statistical models which are based upon the compound nucleus postulate. Our results suggest that violation of the compound nucleus assumption may occur in β-delayed neutron emission. This impacts the neutron-emission probabilities and other properties of nuclei participating in the r-process. A model of neutron emission, which links the observed neutron emission probabilities to nuclear shell effects, is proposed.

AB - Models of the β-delayed neutron emission (βn) assume that neutrons are emitted statistically via an intermediate compound nucleus post β decay. Evidence to the contrary was found in an In134β-decay experiment carried out at ISOLDE CERN. Neutron emission probabilities from the unbound states in Sn134 to known low-lying, single-particle states in Sn133 were measured. The neutron energies were determined using the time-of-flight technique, and the subsequent decay of excited states in Sn133 was studied using γ-ray detectors. Individual βn probabilities were determined by correlating the relative intensities and energies of neutrons and γ rays. The experimental data disagree with the predictions of representative statistical models which are based upon the compound nucleus postulate. Our results suggest that violation of the compound nucleus assumption may occur in β-delayed neutron emission. This impacts the neutron-emission probabilities and other properties of nuclei participating in the r-process. A model of neutron emission, which links the observed neutron emission probabilities to nuclear shell effects, is proposed.

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U2 - 10.1103/PhysRevC.108.024311

DO - 10.1103/PhysRevC.108.024311

M3 - Article

AN - SCOPUS:85170667113

SN - 2469-9985

VL - 108

JO - Physical Review C

JF - Physical Review C

IS - 2

M1 - 024311

ER -

Evidence of nonstatistical neutron emission following β decay near doubly magic Sn 132

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