High-K multi-quasiparticle states in 254No

R. M. Clark; K. E. Gregorich; J. S. Berryman; M. N. Ali; J. M. Allmond; C. W. Beausang; M. Cromaz; M. A. Deleplanque; I. Dragojević; J. Dvorak; P. A. Ellison; P. Fallon; M. A. Garcia; J. M. Gates; S. Gros; H. B. Jeppesen; D. Kaji; I. Y. Lee; A. O. Macchiavelli; K. Morimoto; H. Nitsche; S. Paschalis; M. Petri; L. Stavsetra; F. S. Stephens; H. Watanabe; M. Wiedeking

doi:10.1016/j.physletb.2010.04.079

High-K multi-quasiparticle states in ²⁵⁴No

R. M. Clark, K. E. Gregorich, J. S. Berryman, M. N. Ali, J. M. Allmond, C. W. Beausang, M. Cromaz, M. A. Deleplanque, I. Dragojević, J. Dvorak, P. A. Ellison, P. Fallon, M. A. Garcia, J. M. Gates, S. Gros, H. B. Jeppesen, D. Kaji, I. Y. Lee, A. O. Macchiavelli, K. MorimotoH. Nitsche, S. Paschalis, M. Petri, L. Stavsetra, F. S. Stephens, H. Watanabe, M. Wiedeking

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Abstract

We report results from an experiment on the decay of the high-K isomers in ²⁵⁴No. We have been able to establish the decay from the known high-lying four-quasiparticle isomer, which we assign as a K^π = 16⁺ state at an excitation energy of E_x = 2.928 (3) MeV. The decay of this state passes through a rotational band based on a previously unobserved state at E_x = 2.012 (2) MeV, which we suggest is based on a two-quasineutron configuration with K^π = 10⁺. This state in turn decays to a rotational band based on the known K^π = 8^- isomer, which we infer must also have a two quasineutron configuration. We are able to assign many new gamma-rays associated with the decay of the K^π = 8^- isomer, including the identification of a highly K-forbidden Δ K = 8 E1 transition to the ground-state band. These results provide valuable new information on the orbitals close to the Fermi surface, pairing correlations, deformation and rotational response, and K-conservation in nuclei of the deformed trans-fermium region.

Original language	English
Pages (from-to)	19-24
Number of pages	6
Journal	Physics Letters B
Volume	690
Issue number	1
DOIs	https://doi.org/10.1016/j.physletb.2010.04.079
State	Published - Jun 7 2010
Externally published	Yes

Funding

We thank the operations staff of the 88-Inch Cyclotron. We thank T.L. Khoo and D. Seweryniak for technical discussions and participating in an earlier test experiment. One of us (R.M.C.) would like to express gratitude to Anna Hillgruber for her invaluable help during the experiment. This work has been supported in part by the US DoE under Contract No. DE-AC02-05CH11231 (LBNL) and under Grant Nos. DE-FG52-06NA26206 and DE-FG02-05ER41379. P.A.E. was supported by a US DoE NNSA Stewardship Science Graduate Fellowship. Part of this work was performed under the auspices of the US Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344.

Funders	Funder number
U.S. Department of Energy	DE-AC02-05CH11231, DE-FG02-05ER41379, DE-FG52-06NA26206
Lawrence Livermore National Laboratory	DE-AC52-07NA27344

Keywords

Gamma-ray spectroscopy
Heavy elements
High-K isomers

Access to Document

10.1016/j.physletb.2010.04.079

Cite this

Clark, R. M., Gregorich, K. E., Berryman, J. S., Ali, M. N., Allmond, J. M., Beausang, C. W., Cromaz, M., Deleplanque, M. A., Dragojević, I., Dvorak, J., Ellison, P. A., Fallon, P., Garcia, M. A., Gates, J. M., Gros, S., Jeppesen, H. B., Kaji, D., Lee, I. Y., Macchiavelli, A. O., ... Wiedeking, M. (2010). High-K multi-quasiparticle states in ²⁵⁴No. Physics Letters B, 690(1), 19-24. https://doi.org/10.1016/j.physletb.2010.04.079

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title = "High-K multi-quasiparticle states in 254No",

abstract = "We report results from an experiment on the decay of the high-K isomers in 254No. We have been able to establish the decay from the known high-lying four-quasiparticle isomer, which we assign as a Kπ = 16+ state at an excitation energy of Ex = 2.928 (3) MeV. The decay of this state passes through a rotational band based on a previously unobserved state at Ex = 2.012 (2) MeV, which we suggest is based on a two-quasineutron configuration with Kπ = 10+. This state in turn decays to a rotational band based on the known Kπ = 8- isomer, which we infer must also have a two quasineutron configuration. We are able to assign many new gamma-rays associated with the decay of the Kπ = 8- isomer, including the identification of a highly K-forbidden Δ K = 8 E1 transition to the ground-state band. These results provide valuable new information on the orbitals close to the Fermi surface, pairing correlations, deformation and rotational response, and K-conservation in nuclei of the deformed trans-fermium region.",

keywords = "Gamma-ray spectroscopy, Heavy elements, High-K isomers",

author = "Clark, {R. M.} and Gregorich, {K. E.} and Berryman, {J. S.} and Ali, {M. N.} and Allmond, {J. M.} and Beausang, {C. W.} and M. Cromaz and Deleplanque, {M. A.} and I. Dragojevi{\'c} and J. Dvorak and Ellison, {P. A.} and P. Fallon and Garcia, {M. A.} and Gates, {J. M.} and S. Gros and Jeppesen, {H. B.} and D. Kaji and Lee, {I. Y.} and Macchiavelli, {A. O.} and K. Morimoto and H. Nitsche and S. Paschalis and M. Petri and L. Stavsetra and Stephens, {F. S.} and H. Watanabe and M. Wiedeking",

year = "2010",

month = jun,

day = "7",

doi = "10.1016/j.physletb.2010.04.079",

language = "English",

volume = "690",

pages = "19--24",

journal = "Physics Letters B",

issn = "0370-2693",

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Clark, RM, Gregorich, KE, Berryman, JS, Ali, MN, Allmond, JM, Beausang, CW, Cromaz, M, Deleplanque, MA, Dragojević, I, Dvorak, J, Ellison, PA, Fallon, P, Garcia, MA, Gates, JM, Gros, S, Jeppesen, HB, Kaji, D, Lee, IY, Macchiavelli, AO, Morimoto, K, Nitsche, H, Paschalis, S, Petri, M, Stavsetra, L, Stephens, FS, Watanabe, H & Wiedeking, M 2010, 'High-K multi-quasiparticle states in ²⁵⁴No', Physics Letters B, vol. 690, no. 1, pp. 19-24. https://doi.org/10.1016/j.physletb.2010.04.079

TY - JOUR

T1 - High-K multi-quasiparticle states in 254No

AU - Clark, R. M.

AU - Gregorich, K. E.

AU - Berryman, J. S.

AU - Ali, M. N.

AU - Allmond, J. M.

AU - Beausang, C. W.

AU - Cromaz, M.

AU - Deleplanque, M. A.

AU - Dragojević, I.

AU - Dvorak, J.

AU - Ellison, P. A.

AU - Fallon, P.

AU - Garcia, M. A.

AU - Gates, J. M.

AU - Gros, S.

AU - Jeppesen, H. B.

AU - Kaji, D.

AU - Lee, I. Y.

AU - Macchiavelli, A. O.

AU - Morimoto, K.

AU - Nitsche, H.

AU - Paschalis, S.

AU - Petri, M.

AU - Stavsetra, L.

AU - Stephens, F. S.

AU - Watanabe, H.

AU - Wiedeking, M.

PY - 2010/6/7

Y1 - 2010/6/7

N2 - We report results from an experiment on the decay of the high-K isomers in 254No. We have been able to establish the decay from the known high-lying four-quasiparticle isomer, which we assign as a Kπ = 16+ state at an excitation energy of Ex = 2.928 (3) MeV. The decay of this state passes through a rotational band based on a previously unobserved state at Ex = 2.012 (2) MeV, which we suggest is based on a two-quasineutron configuration with Kπ = 10+. This state in turn decays to a rotational band based on the known Kπ = 8- isomer, which we infer must also have a two quasineutron configuration. We are able to assign many new gamma-rays associated with the decay of the Kπ = 8- isomer, including the identification of a highly K-forbidden Δ K = 8 E1 transition to the ground-state band. These results provide valuable new information on the orbitals close to the Fermi surface, pairing correlations, deformation and rotational response, and K-conservation in nuclei of the deformed trans-fermium region.

AB - We report results from an experiment on the decay of the high-K isomers in 254No. We have been able to establish the decay from the known high-lying four-quasiparticle isomer, which we assign as a Kπ = 16+ state at an excitation energy of Ex = 2.928 (3) MeV. The decay of this state passes through a rotational band based on a previously unobserved state at Ex = 2.012 (2) MeV, which we suggest is based on a two-quasineutron configuration with Kπ = 10+. This state in turn decays to a rotational band based on the known Kπ = 8- isomer, which we infer must also have a two quasineutron configuration. We are able to assign many new gamma-rays associated with the decay of the Kπ = 8- isomer, including the identification of a highly K-forbidden Δ K = 8 E1 transition to the ground-state band. These results provide valuable new information on the orbitals close to the Fermi surface, pairing correlations, deformation and rotational response, and K-conservation in nuclei of the deformed trans-fermium region.

KW - Gamma-ray spectroscopy

KW - Heavy elements

KW - High-K isomers

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DO - 10.1016/j.physletb.2010.04.079

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