Microsecond and nanosecond isomers populated in fission reactions

G. A. Jones; P. M. Walker; Zs Podolyák; P. H. Regan; S. J. Williams; M. P. Carpenter; J. J. Carroll; R. S. Chakrawarthy; P. Chowdhury; I. J. Cullen; G. D. Dracoulis; A. B. Garnsworthy; G. Hackman; R. V.F. Janssens; T. L. Khoo; F. G. Kondev; G. J. Lane; Z. Liu; D. Seweryniak; N. J. Thompson; S. Zhu

doi:10.1063/1.2338400

Microsecond and nanosecond isomers populated in fission reactions

G. A. Jones^*, P. M. Walker, Zs Podolyák, P. H. Regan, S. J. Williams, M. P. Carpenter, J. J. Carroll, R. S. Chakrawarthy, P. Chowdhury, I. J. Cullen, G. D. Dracoulis, A. B. Garnsworthy, G. Hackman, R. V.F. Janssens, T. L. Khoo, F. G. Kondev, G. J. Lane, Z. Liu, D. Seweryniak, N. J. ThompsonS. Zhu

^*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution › peer-review

2 Citations (Scopus)

Abstract

Fusion-fission reactions were induced by bombarding a thick ²⁷Al target with ¹⁷⁸Hf projectiles at a laboratory energy of 1150 MeV using the ATLAS accelerator at Argonne National Laboratory. The subsequent γ-ray decays were measured using the GAMMASPHERE germanium detector array. The beam was pulsed at two different ON/OFF cycles of 82.5/825 ns and 25/75 μs in order to observe the γ rays from the decay of isomeric states. In ¹²¹Sb 2721+Δ keV, I^π=(25/2⁺) and 2434 keV, I^π=19/2^- states have measured half-lives of T_1/2=200(30) μs and 8.2(2) ns respectively. The 2614+Δ keV, I^π=(27/2⁺) and 2486 keV, I^π=19/2 ⁺ states in ¹²³Sb have measured half-lives of T _1/2=52(3) μs and 7.9(4) ns respectively. The positive parity isomers in these nuclei correspond to a πd_5/2 or πg _7/2 configuration, in ¹²¹Sb and ¹²³Sb respectively, coupled to aligned (h_11/2)² neutrons. The I^π=19/2^- isomeric state in ¹²¹Sb is proposed to have a νh_11/2 ⊗ νd_3/2 ⊗ πd _5/2 configuration. A previously unobserved isomer has been identified in ⁹⁹Mo at an energy of 3010 keV, decaying with T _1/2=18(5) ns. This state is interpreted as an energetically favoured 3 quasi-particle alignment of ν(_d5/2 g_7/2) ⊗π(g_9/2)² configuration which is observed systematically in the even-Z N=57 isotones.

Original language	English
Title of host publication	Fusion06
Subtitle of host publication	Reaction Mechanisms and Nuclear Structure at the Coulomb Barrier
Pages	342-349
Number of pages	8
DOIs	https://doi.org/10.1063/1.2338400
Publication status	Published - 2006
Event	FUSION06: Reaction Mechanisms and Nuclear Structure at the Coulomb Barrier - San Servolo, Venezia, Italy Duration: 19 Mar 2006 → 23 Mar 2006

Publication series

Name	AIP Conference Proceedings
Volume	853
ISSN (Print)	0094-243X
ISSN (Electronic)	1551-7616

Conference

Conference	FUSION06: Reaction Mechanisms and Nuclear Structure at the Coulomb Barrier
Country/Territory	Italy
City	San Servolo, Venezia
Period	19/03/06 → 23/03/06

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Jones, G. A., Walker, P. M., Podolyák, Z., Regan, P. H., Williams, S. J., Carpenter, M. P., Carroll, J. J., Chakrawarthy, R. S., Chowdhury, P., Cullen, I. J., Dracoulis, G. D., Garnsworthy, A. B., Hackman, G., Janssens, R. V. F., Khoo, T. L., Kondev, F. G., Lane, G. J., Liu, Z., Seweryniak, D., ... Zhu, S. (2006). Microsecond and nanosecond isomers populated in fission reactions. In Fusion06: Reaction Mechanisms and Nuclear Structure at the Coulomb Barrier (pp. 342-349). (AIP Conference Proceedings; Vol. 853). https://doi.org/10.1063/1.2338400

@inproceedings{0cba84941bae4e4db3b0f60a38c9d4c7,

title = "Microsecond and nanosecond isomers populated in fission reactions",

abstract = "Fusion-fission reactions were induced by bombarding a thick 27Al target with 178Hf projectiles at a laboratory energy of 1150 MeV using the ATLAS accelerator at Argonne National Laboratory. The subsequent γ-ray decays were measured using the GAMMASPHERE germanium detector array. The beam was pulsed at two different ON/OFF cycles of 82.5/825 ns and 25/75 μs in order to observe the γ rays from the decay of isomeric states. In 121Sb 2721+Δ keV, Iπ=(25/2+) and 2434 keV, Iπ=19/2- states have measured half-lives of T1/2=200(30) μs and 8.2(2) ns respectively. The 2614+Δ keV, Iπ=(27/2+) and 2486 keV, Iπ=19/2 + states in 123Sb have measured half-lives of T 1/2=52(3) μs and 7.9(4) ns respectively. The positive parity isomers in these nuclei correspond to a πd5/2 or πg 7/2 configuration, in 121Sb and 123Sb respectively, coupled to aligned (h11/2)2 neutrons. The Iπ=19/2- isomeric state in 121Sb is proposed to have a νh11/2 ⊗ νd3/2 ⊗ πd 5/2 configuration. A previously unobserved isomer has been identified in 99Mo at an energy of 3010 keV, decaying with T 1/2=18(5) ns. This state is interpreted as an energetically favoured 3 quasi-particle alignment of ν(d5/2 g7/2) ⊗π(g9/2)2 configuration which is observed systematically in the even-Z N=57 isotones.",

keywords = "Fusion-fission reactions, Gamma-ray spectroscopy, Isomeric half-lives",

author = "Jones, {G. A.} and Walker, {P. M.} and Zs Podoly{\'a}k and Regan, {P. H.} and Williams, {S. J.} and Carpenter, {M. P.} and Carroll, {J. J.} and Chakrawarthy, {R. S.} and P. Chowdhury and Cullen, {I. J.} and Dracoulis, {G. D.} and Garnsworthy, {A. B.} and G. Hackman and Janssens, {R. V.F.} and Khoo, {T. L.} and Kondev, {F. G.} and Lane, {G. J.} and Z. Liu and D. Seweryniak and Thompson, {N. J.} and S. Zhu",

year = "2006",

doi = "10.1063/1.2338400",

language = "English",

isbn = "073540349X",

series = "AIP Conference Proceedings",

pages = "342--349",

booktitle = "Fusion06",

note = "FUSION06: Reaction Mechanisms and Nuclear Structure at the Coulomb Barrier ; Conference date: 19-03-2006 Through 23-03-2006",

}

Jones, GA, Walker, PM, Podolyák, Z, Regan, PH, Williams, SJ, Carpenter, MP, Carroll, JJ, Chakrawarthy, RS, Chowdhury, P, Cullen, IJ, Dracoulis, GD, Garnsworthy, AB, Hackman, G, Janssens, RVF, Khoo, TL, Kondev, FG, Lane, GJ, Liu, Z, Seweryniak, D, Thompson, NJ & Zhu, S 2006, Microsecond and nanosecond isomers populated in fission reactions. in Fusion06: Reaction Mechanisms and Nuclear Structure at the Coulomb Barrier. AIP Conference Proceedings, vol. 853, pp. 342-349, FUSION06: Reaction Mechanisms and Nuclear Structure at the Coulomb Barrier, San Servolo, Venezia, Italy, 19/03/06. https://doi.org/10.1063/1.2338400

TY - GEN

T1 - Microsecond and nanosecond isomers populated in fission reactions

AU - Jones, G. A.

AU - Walker, P. M.

AU - Podolyák, Zs

AU - Regan, P. H.

AU - Williams, S. J.

AU - Carpenter, M. P.

AU - Carroll, J. J.

AU - Chakrawarthy, R. S.

AU - Chowdhury, P.

AU - Cullen, I. J.

AU - Dracoulis, G. D.

AU - Garnsworthy, A. B.

AU - Hackman, G.

AU - Janssens, R. V.F.

AU - Khoo, T. L.

AU - Kondev, F. G.

AU - Lane, G. J.

AU - Liu, Z.

AU - Seweryniak, D.

AU - Thompson, N. J.

AU - Zhu, S.

PY - 2006

Y1 - 2006

N2 - Fusion-fission reactions were induced by bombarding a thick 27Al target with 178Hf projectiles at a laboratory energy of 1150 MeV using the ATLAS accelerator at Argonne National Laboratory. The subsequent γ-ray decays were measured using the GAMMASPHERE germanium detector array. The beam was pulsed at two different ON/OFF cycles of 82.5/825 ns and 25/75 μs in order to observe the γ rays from the decay of isomeric states. In 121Sb 2721+Δ keV, Iπ=(25/2+) and 2434 keV, Iπ=19/2- states have measured half-lives of T1/2=200(30) μs and 8.2(2) ns respectively. The 2614+Δ keV, Iπ=(27/2+) and 2486 keV, Iπ=19/2 + states in 123Sb have measured half-lives of T 1/2=52(3) μs and 7.9(4) ns respectively. The positive parity isomers in these nuclei correspond to a πd5/2 or πg 7/2 configuration, in 121Sb and 123Sb respectively, coupled to aligned (h11/2)2 neutrons. The Iπ=19/2- isomeric state in 121Sb is proposed to have a νh11/2 ⊗ νd3/2 ⊗ πd 5/2 configuration. A previously unobserved isomer has been identified in 99Mo at an energy of 3010 keV, decaying with T 1/2=18(5) ns. This state is interpreted as an energetically favoured 3 quasi-particle alignment of ν(d5/2 g7/2) ⊗π(g9/2)2 configuration which is observed systematically in the even-Z N=57 isotones.

AB - Fusion-fission reactions were induced by bombarding a thick 27Al target with 178Hf projectiles at a laboratory energy of 1150 MeV using the ATLAS accelerator at Argonne National Laboratory. The subsequent γ-ray decays were measured using the GAMMASPHERE germanium detector array. The beam was pulsed at two different ON/OFF cycles of 82.5/825 ns and 25/75 μs in order to observe the γ rays from the decay of isomeric states. In 121Sb 2721+Δ keV, Iπ=(25/2+) and 2434 keV, Iπ=19/2- states have measured half-lives of T1/2=200(30) μs and 8.2(2) ns respectively. The 2614+Δ keV, Iπ=(27/2+) and 2486 keV, Iπ=19/2 + states in 123Sb have measured half-lives of T 1/2=52(3) μs and 7.9(4) ns respectively. The positive parity isomers in these nuclei correspond to a πd5/2 or πg 7/2 configuration, in 121Sb and 123Sb respectively, coupled to aligned (h11/2)2 neutrons. The Iπ=19/2- isomeric state in 121Sb is proposed to have a νh11/2 ⊗ νd3/2 ⊗ πd 5/2 configuration. A previously unobserved isomer has been identified in 99Mo at an energy of 3010 keV, decaying with T 1/2=18(5) ns. This state is interpreted as an energetically favoured 3 quasi-particle alignment of ν(d5/2 g7/2) ⊗π(g9/2)2 configuration which is observed systematically in the even-Z N=57 isotones.

KW - Fusion-fission reactions

KW - Gamma-ray spectroscopy

KW - Isomeric half-lives

UR - http://www.scopus.com/inward/record.url?scp=33846186352&partnerID=8YFLogxK

U2 - 10.1063/1.2338400

DO - 10.1063/1.2338400

M3 - Conference contribution

SN - 073540349X

SN - 9780735403499

T3 - AIP Conference Proceedings

SP - 342

EP - 349

BT - Fusion06

T2 - FUSION06: Reaction Mechanisms and Nuclear Structure at the Coulomb Barrier

Y2 - 19 March 2006 through 23 March 2006

ER -

Microsecond and nanosecond isomers populated in fission reactions

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