Статья

Decay of a<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>π</mml:mi><mml:msub><mml:mi>h</mml:mi><mml:mrow><mml:mn>11</mml:mn><mml:mo>/</mml:mo><mml:mn>2</mml:mn></mml:mrow></mml:msub><mml:mo>⊗</mml:mo><mml:mi>ν</mml:mi><mml:msub><mml:mi>h</mml:mi><mml:mrow><mml:mn>11</mml:mn><mml:mo>/</mml:mo><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>microsecond isomer in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msubsup><mml:mi/><mml:mrow><mml:mn>61</mml:mn></mml:mrow><mml:mrow><mml:mn>136</mml:mn></mml:mrow></mml:msubsup></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mi>Pm</mml:mi><mml:mrow><mml:mn>75</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>

S. V. RigbySchuster Laboratory, School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, United KingdomD. M. CullenSchuster Laboratory, School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, United KingdomPaolo MasonSchuster Laboratory, School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, United KingdomD. T. ScholesSchuster Laboratory, School of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, United KingdomC. ScholeyDepartment of Physics, University of Jyväskylä, Jyväskylä, FIN-40014, FinlandP. RahkilaDepartment of Physics, University of Jyväskylä, Jyväskylä, FIN-40014, FinlandS. EeckhaudtDepartment of Physics, University of Jyväskylä, Jyväskylä, FIN-40014, FinlandT. GrahnDepartment of Physics, University of Jyväskylä, Jyväskylä, FIN-40014, FinlandP. T. GreenleesDepartment of Physics, University of Jyväskylä, Jyväskylä, FIN-40014, FinlandPeter G. JonesDepartment of Physics, University of Jyväskylä, Jyväskylä, FIN-40014, FinlandR. JulinDepartment of Physics, University of Jyväskylä, Jyväskylä, FIN-40014, FinlandS. JuutinenDepartment of Physics, University of Jyväskylä, Jyväskylä, FIN-40014, FinlandH. KettunenDepartment of Physics, University of Jyväskylä, Jyväskylä, FIN-40014, FinlandM. LeinoDepartment of Physics, University of Jyväskylä, Jyväskylä, FIN-40014, FinlandA.-P. LeppänenDepartment of Physics, University of Jyväskylä, Jyväskylä, FIN-40014, FinlandP. NieminenDepartment of Physics, University of Jyväskylä, Jyväskylä, FIN-40014, FinlandM. NymanDepartment of Physics, University of Jyväskylä, Jyväskylä, FIN-40014, FinlandJ. PakarinenDepartment of Physics, University of Jyväskylä, Jyväskylä, FIN-40014, FinlandJ. UusitaloDepartment of Physics, University of Jyväskylä, Jyväskylä, FIN-40014, Finland

2008lv

ABI

Аннотация

An experiment has been performed to populate several extremely neutron-deficient nuclei around the mass-140 region of the nuclear chart, using a beam of $^{54}\mathrm{Fe}$ on a $^{92}\mathrm{Mo}$ target at an energy of 315 MeV. Analysis of these data using recoil-isomer tagging has established that the yrast $\ensuremath{\pi}{h}_{11/2}\ensuremath{\bigotimes}\ensuremath{\nu}{h}_{11/2},{J}^{\ensuremath{\pi}}=({8}^{+})$, bandhead state in $^{136}\mathrm{Pm}$ is isomeric with a half-life of 1.5(1) \ensuremath{\mu}s. This isomeric state decays via a 43-keV, probable-$E1$ transition to a ${J}^{\ensuremath{\pi}}=({7}^{\ensuremath{-}}$) state. Consideration of the theoretical Nilsson orbitals near the Fermi surface suggests that the ${J}^{\ensuremath{\pi}}=({8}^{+})$ state has a $\ensuremath{\nu}{h}_{11/2}[505]{\frac{11}{2}}^{\ensuremath{-}}\ensuremath{\bigotimes}\ensuremath{\pi}{h}_{11/2}[532]{\frac{5}{2}}^{\ensuremath{-}}$ configuration, which decays to the ${J}^{\ensuremath{\pi}}=({7}^{\ensuremath{-}})$ state with a $\ensuremath{\nu}{h}_{11/2}[505]{\frac{11}{2}}^{\ensuremath{-}}\ensuremath{\bigotimes}\ensuremath{\pi}{d}_{5/2}[411]{\frac{3}{2}}^{+}$ configuration. Differences in the shape-driving effects for these two configurations is reasoned to be responsible for the long half-life of the ${J}^{\ensuremath{\pi}}=({8}^{+})$ isomeric state. The non-observation of other $\ensuremath{\gamma}$ rays in prompt or delayed coincidence with the 43-keV transition suggests that this transition may feed another, longer lived isomeric state with a half-life of the order of milliseconds or greater. However, the present experiment was not sensitive to the decay of this new ${J}^{\ensuremath{\pi}}=({7}^{\ensuremath{-}}$) state by internal conversion or even $\ensuremath{\beta}$ decay.

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Идентификаторы

DOI: 10.1103/physrevc.78.034304

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Цитирований: 2Использованных источников: 0

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