Decays of new nuclides and isomers beyond the proton drip line: the influence of neutron configurations

R. D. Page, L. Bianco, I. G. Darby, D. T. Joss, J. Simpson, J. S. Al-Khalili, A. J. Cannon, R. J. Cooper, S. Eeckhaudt, S. Erturk, B. Gall, T. Grahn, P. T. Greenlees, B. Hadinia, P. M. Jones, D. S. Judson, R. Julin, S. Juutinen, S. Ketelhut, M. Labiche & 14 others M. Leino, A. -P. Leppanen, M. Nyman, D. O'Donnell, P. Rahkila, P. J. Sapple, J. Saren, C. Scholey, A. N. Steer, P. D. Stevenson, E. B. Suckling, J. Thomson, J. Uusitalo, M. Venhart

Research output: Contribution to journalArticle

Abstract

The energy of the vh9/2vh9/2 orbital in nuclei above N = 82N = 82 drops rapidly in energy relative to the vf7/2vf7/2 orbital as the occupancy of the πh11/2πh11/2 orbital increases. These two neutron orbitals become nearly degenerate as the proton drip line is approached. In this work, we have discovered the new nuclides 161Os161Os and 157W,157W, and studied the decays of the proton emitter 160Re160Re in detail. The 161Os161Os and 160Re160Re nuclei were produced in reactions of 290, 300 and 310 MeV 58Ni58Ni ions with an isotopically enriched 106Cd106Cd target, separated in‐flight using the RITU separator and implanted into the GREAT spectrometer. The 161Os161Os α a decays populated the new nuclide 157W,157W, which decayed by β‐particle emission. The β decay fed the known α‐decaying 1/2+1/2+ and 11/2⎯11/2− states in 157Ta,157Ta, which is consistent with a vf7/2vf7/2 ground state in 157W.157W. The measured α‐decay energy and half‐life for 161Os161Os correspond to a reduced α‐decay width that is compatible with s‐wave α‐particle emission, implying that its ground state is also a vf7/2vf7/2 state. Over 7000 160Re160Re nuclei were produced and the γ decays of a new isomeric state feeding the πd3/2πd3/2 level in 160Re160Re were discovered, but no evidence for the proton or a decay of the expected πh11/2πh11/2 state could be found. The isomer decays offer a natural explanation for this non‐observation and provides a striking example of the influence of the near degeneracy of the vh9/2vh9/2 and vf7/2vf7/2 orbitals on the properties of nuclei in this region.
Original languageEnglish
Pages (from-to)172-178
Number of pages7
JournalAIP Conference Proceedings
Volume1072
Issue number1
DOIs
Publication statusPublished - 2008
Externally publishedYes

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nuclides
isomers
neutrons
protons
decay
configurations
orbitals
nuclei
particle emission
ground state
separators
energy
emitters
spectrometers

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Page, R. D., Bianco, L., Darby, I. G., Joss, D. T., Simpson, J., Al-Khalili, J. S., ... Venhart, M. (2008). Decays of new nuclides and isomers beyond the proton drip line: the influence of neutron configurations. AIP Conference Proceedings, 1072(1), 172-178. https://doi.org/10.1063/1.3039824
Page, R. D. ; Bianco, L. ; Darby, I. G. ; Joss, D. T. ; Simpson, J. ; Al-Khalili, J. S. ; Cannon, A. J. ; Cooper, R. J. ; Eeckhaudt, S. ; Erturk, S. ; Gall, B. ; Grahn, T. ; Greenlees, P. T. ; Hadinia, B. ; Jones, P. M. ; Judson, D. S. ; Julin, R. ; Juutinen, S. ; Ketelhut, S. ; Labiche, M. ; Leino, M. ; Leppanen, A. -P. ; Nyman, M. ; O'Donnell, D. ; Rahkila, P. ; Sapple, P. J. ; Saren, J. ; Scholey, C. ; Steer, A. N. ; Stevenson, P. D. ; Suckling, E. B. ; Thomson, J. ; Uusitalo, J. ; Venhart, M. / Decays of new nuclides and isomers beyond the proton drip line: the influence of neutron configurations. In: AIP Conference Proceedings. 2008 ; Vol. 1072, No. 1. pp. 172-178.
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title = "Decays of new nuclides and isomers beyond the proton drip line:: the influence of neutron configurations",
abstract = "The energy of the vh9/2vh9/2 orbital in nuclei above N = 82N = 82 drops rapidly in energy relative to the vf7/2vf7/2 orbital as the occupancy of the πh11/2πh11/2 orbital increases. These two neutron orbitals become nearly degenerate as the proton drip line is approached. In this work, we have discovered the new nuclides 161Os161Os and 157W,157W, and studied the decays of the proton emitter 160Re160Re in detail. The 161Os161Os and 160Re160Re nuclei were produced in reactions of 290, 300 and 310 MeV 58Ni58Ni ions with an isotopically enriched 106Cd106Cd target, separated in‐flight using the RITU separator and implanted into the GREAT spectrometer. The 161Os161Os α a decays populated the new nuclide 157W,157W, which decayed by β‐particle emission. The β decay fed the known α‐decaying 1/2+1/2+ and 11/2⎯11/2− states in 157Ta,157Ta, which is consistent with a vf7/2vf7/2 ground state in 157W.157W. The measured α‐decay energy and half‐life for 161Os161Os correspond to a reduced α‐decay width that is compatible with s‐wave α‐particle emission, implying that its ground state is also a vf7/2vf7/2 state. Over 7000 160Re160Re nuclei were produced and the γ decays of a new isomeric state feeding the πd3/2πd3/2 level in 160Re160Re were discovered, but no evidence for the proton or a decay of the expected πh11/2πh11/2 state could be found. The isomer decays offer a natural explanation for this non‐observation and provides a striking example of the influence of the near degeneracy of the vh9/2vh9/2 and vf7/2vf7/2 orbitals on the properties of nuclei in this region.",
author = "Page, {R. D.} and L. Bianco and Darby, {I. G.} and Joss, {D. T.} and J. Simpson and Al-Khalili, {J. S.} and Cannon, {A. J.} and Cooper, {R. J.} and S. Eeckhaudt and S. Erturk and B. Gall and T. Grahn and Greenlees, {P. T.} and B. Hadinia and Jones, {P. M.} and Judson, {D. S.} and R. Julin and S. Juutinen and S. Ketelhut and M. Labiche and M. Leino and Leppanen, {A. -P.} and M. Nyman and D. O'Donnell and P. Rahkila and Sapple, {P. J.} and J. Saren and C. Scholey and Steer, {A. N.} and Stevenson, {P. D.} and Suckling, {E. B.} and J. Thomson and J. Uusitalo and M. Venhart",
year = "2008",
doi = "10.1063/1.3039824",
language = "English",
volume = "1072",
pages = "172--178",
journal = "AIP Conference Proceedings",
issn = "0094-243X",
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Page, RD, Bianco, L, Darby, IG, Joss, DT, Simpson, J, Al-Khalili, JS, Cannon, AJ, Cooper, RJ, Eeckhaudt, S, Erturk, S, Gall, B, Grahn, T, Greenlees, PT, Hadinia, B, Jones, PM, Judson, DS, Julin, R, Juutinen, S, Ketelhut, S, Labiche, M, Leino, M, Leppanen, A-P, Nyman, M, O'Donnell, D, Rahkila, P, Sapple, PJ, Saren, J, Scholey, C, Steer, AN, Stevenson, PD, Suckling, EB, Thomson, J, Uusitalo, J & Venhart, M 2008, 'Decays of new nuclides and isomers beyond the proton drip line: the influence of neutron configurations' AIP Conference Proceedings, vol. 1072, no. 1, pp. 172-178. https://doi.org/10.1063/1.3039824

Decays of new nuclides and isomers beyond the proton drip line: the influence of neutron configurations. / Page, R. D.; Bianco, L.; Darby, I. G.; Joss, D. T.; Simpson, J.; Al-Khalili, J. S.; Cannon, A. J.; Cooper, R. J.; Eeckhaudt, S.; Erturk, S.; Gall, B.; Grahn, T.; Greenlees, P. T.; Hadinia, B.; Jones, P. M.; Judson, D. S.; Julin, R.; Juutinen, S.; Ketelhut, S.; Labiche, M.; Leino, M.; Leppanen, A. -P.; Nyman, M.; O'Donnell, D.; Rahkila, P.; Sapple, P. J.; Saren, J.; Scholey, C.; Steer, A. N.; Stevenson, P. D.; Suckling, E. B.; Thomson, J.; Uusitalo, J.; Venhart, M.

In: AIP Conference Proceedings, Vol. 1072, No. 1, 2008, p. 172-178.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Decays of new nuclides and isomers beyond the proton drip line:

T2 - the influence of neutron configurations

AU - Page, R. D.

AU - Bianco, L.

AU - Darby, I. G.

AU - Joss, D. T.

AU - Simpson, J.

AU - Al-Khalili, J. S.

AU - Cannon, A. J.

AU - Cooper, R. J.

AU - Eeckhaudt, S.

AU - Erturk, S.

AU - Gall, B.

AU - Grahn, T.

AU - Greenlees, P. T.

AU - Hadinia, B.

AU - Jones, P. M.

AU - Judson, D. S.

AU - Julin, R.

AU - Juutinen, S.

AU - Ketelhut, S.

AU - Labiche, M.

AU - Leino, M.

AU - Leppanen, A. -P.

AU - Nyman, M.

AU - O'Donnell, D.

AU - Rahkila, P.

AU - Sapple, P. J.

AU - Saren, J.

AU - Scholey, C.

AU - Steer, A. N.

AU - Stevenson, P. D.

AU - Suckling, E. B.

AU - Thomson, J.

AU - Uusitalo, J.

AU - Venhart, M.

PY - 2008

Y1 - 2008

N2 - The energy of the vh9/2vh9/2 orbital in nuclei above N = 82N = 82 drops rapidly in energy relative to the vf7/2vf7/2 orbital as the occupancy of the πh11/2πh11/2 orbital increases. These two neutron orbitals become nearly degenerate as the proton drip line is approached. In this work, we have discovered the new nuclides 161Os161Os and 157W,157W, and studied the decays of the proton emitter 160Re160Re in detail. The 161Os161Os and 160Re160Re nuclei were produced in reactions of 290, 300 and 310 MeV 58Ni58Ni ions with an isotopically enriched 106Cd106Cd target, separated in‐flight using the RITU separator and implanted into the GREAT spectrometer. The 161Os161Os α a decays populated the new nuclide 157W,157W, which decayed by β‐particle emission. The β decay fed the known α‐decaying 1/2+1/2+ and 11/2⎯11/2− states in 157Ta,157Ta, which is consistent with a vf7/2vf7/2 ground state in 157W.157W. The measured α‐decay energy and half‐life for 161Os161Os correspond to a reduced α‐decay width that is compatible with s‐wave α‐particle emission, implying that its ground state is also a vf7/2vf7/2 state. Over 7000 160Re160Re nuclei were produced and the γ decays of a new isomeric state feeding the πd3/2πd3/2 level in 160Re160Re were discovered, but no evidence for the proton or a decay of the expected πh11/2πh11/2 state could be found. The isomer decays offer a natural explanation for this non‐observation and provides a striking example of the influence of the near degeneracy of the vh9/2vh9/2 and vf7/2vf7/2 orbitals on the properties of nuclei in this region.

AB - The energy of the vh9/2vh9/2 orbital in nuclei above N = 82N = 82 drops rapidly in energy relative to the vf7/2vf7/2 orbital as the occupancy of the πh11/2πh11/2 orbital increases. These two neutron orbitals become nearly degenerate as the proton drip line is approached. In this work, we have discovered the new nuclides 161Os161Os and 157W,157W, and studied the decays of the proton emitter 160Re160Re in detail. The 161Os161Os and 160Re160Re nuclei were produced in reactions of 290, 300 and 310 MeV 58Ni58Ni ions with an isotopically enriched 106Cd106Cd target, separated in‐flight using the RITU separator and implanted into the GREAT spectrometer. The 161Os161Os α a decays populated the new nuclide 157W,157W, which decayed by β‐particle emission. The β decay fed the known α‐decaying 1/2+1/2+ and 11/2⎯11/2− states in 157Ta,157Ta, which is consistent with a vf7/2vf7/2 ground state in 157W.157W. The measured α‐decay energy and half‐life for 161Os161Os correspond to a reduced α‐decay width that is compatible with s‐wave α‐particle emission, implying that its ground state is also a vf7/2vf7/2 state. Over 7000 160Re160Re nuclei were produced and the γ decays of a new isomeric state feeding the πd3/2πd3/2 level in 160Re160Re were discovered, but no evidence for the proton or a decay of the expected πh11/2πh11/2 state could be found. The isomer decays offer a natural explanation for this non‐observation and provides a striking example of the influence of the near degeneracy of the vh9/2vh9/2 and vf7/2vf7/2 orbitals on the properties of nuclei in this region.

U2 - 10.1063/1.3039824

DO - 10.1063/1.3039824

M3 - Article

VL - 1072

SP - 172

EP - 178

JO - AIP Conference Proceedings

JF - AIP Conference Proceedings

SN - 0094-243X

IS - 1

ER -