| 1. |
- Gillespie, S. A., et al.
(författare)
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Identification of a 6.6 μ s isomeric state in Ir 175
- 2019
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Ingår i: Physical Review C. - 2469-9985. ; 99:6
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Tidskriftsartikel (refereegranskat)abstract
- An experiment has been performed to study excited states in the neutron-deficient nucleus Ir175 via the use of the JUROGAM II high-purity germanium detector array and the RITU gas-filled separator at JYFL, Jyväskylä. By using isomer tagging, an isomeric state with a half-life of 6.58(15) μs has been observed in Ir175 for the first time. It has been established that the isomer decays via a 45.2 (E1)-26.1 (M1) keV cascade to new states below the previously reported ground state in Ir175 with Iπ=(5/2-). We now reassign this (5/2-) state to the isomeric state discovered in this study.
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| 2. |
- Gillespie, S. A., et al.
(författare)
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Identification of sub- μ s isomeric states in the odd-odd nucleus Au 178
- 2021
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Ingår i: Physical Review C. - 2469-9985. ; 103:4
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Tidskriftsartikel (refereegranskat)abstract
- The neutron-deficient gold (Z=79) isotopes in the vicinity of the neutron midshell N=104 provide prolific examples of shape coexistence and isomerism at low excitation energy. They can be probed via a number of different experimental techniques. In this study, two new isomeric states with half-lives of 294(7) and 373(9) ns have been observed in the neutron-deficient odd-odd nuclide Au178 (N=99) in an experiment at the RITU gas-filled separator at JYFL, Jyväskylä. This result was achieved due to the use of a segmented planar germanium detector with a high efficiency at low energies. By applying the recoil-decay tagging technique, they were assigned to decay to two different long-lived α-decaying states in Au178.
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| 3. |
- Auranen, K., et al.
(författare)
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Prompt and delayed spectroscopy of At-203 : Observation of a shears band and a 29/2(+) isomeric state
- 2018
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Ingår i: Physical Review C. - : American Physical Society. - 2469-9985 .- 2469-9993. ; 97:2
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Tidskriftsartikel (refereegranskat)abstract
- Using fusion-evaporation reactions, a gas-filled recoil separator, recoil-gating technique and recoil-isomer decay tagging technique we have extended the level scheme of At-203 (N = 118) significantly. We have observed an isomeric [tau = 14.1(3) mu s] state with a spin and parity of 29/2(+). The isomeric state is suggested to originate from the pi(h(9/2)) circle times |Po-202; 11(-)> coupling, and it is depopulated through 286 keV E2 and 366 keV E3 transitions. In addition, we have observed a cascade of magnetic-dipole transitions which is suggested to be generated by the shears mechanism.
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| 4. |
- Badran, H., et al.
(författare)
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Decay spectroscopy of Pb-179(82)97 and evidence for a 9/2(-) intruder state in Tl-179(81)98
- 2017
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Ingår i: Physical Review C. - 2469-9985 .- 2469-9993. ; 96:6
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Tidskriftsartikel (refereegranskat)abstract
- The very neutron-deficient isobars Pb-179 and Tl-179 have been produced using the fusion-evaporation reactions Pd-104(Kr-78,xpyn), where x <= 1 and y >= 2. The gas-filled separator RITU was employed to transport and separate the recoiling nuclei of interest from the scattered beam and unwanted products. The GREAT spectrometer was used to study the decay properties through alpha-alpha and alpha-gamma correlations, which has allowed the ground state of Pb-179 to be assigned as I-pi = 9/2(-). The decay of Pb-179 was measured to have an alpha-particle energy and half-life of E-alpha = 7348(5) keV and t(1/2) = 2.7(2) ms, respectively. A search for a nu i(13/2) state in Pb-179 was performed, but only a limit of excitation energy and half-life was obtained. In Tl-179 a t(1/2) = 114(-10)(+18) ns isomeric state, likely at an excitation energy of 904.5(9) keV, was identified and is tentatively assigned to be a 9/2(-) proton intruder state.
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| 5. |
- Jakobsson, Ulrika, et al.
(författare)
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Spectroscopy of Low-lying States in Neutron-deficient Astatine and Francium Nuclei
- 2015
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Ingår i: NUCLEAR STRUCTURE AND DYNAMICS '15. - : American Institute of Physics (AIP). - 9780735413283
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Konferensbidrag (refereegranskat)abstract
- Low-lying states in neutron-deficient astatine and francium nuclei have been studied by means of in-beam and delayed spectroscopy. The 13/2(+) state has been observed in francium nuclei with a similar down-sloping trend as in neighbouring astatine and bismuth isotopes, as a function of decreasing neutron number. A systematic trend can also now be seen for the 1/2(+) state both in astatine and francium nuclei, where the level energy decreases steeply as a function of neutron number when moving further away from the neutron shell closure. This trend is very similar between astatine nuclei and their francium isotones. Moreover, shape coexistence has been observed between the 13/2(+) state and the spherical 9/2(-) ground state in Fr-203 and Fr-205.
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| 6. |
- Auranen, K., et al.
(författare)
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Experimental study of isomeric intruder 1/2(+) states in At-197,At-203
- 2017
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Ingår i: Physical Review C. - : AMER PHYSICAL SOC. - 2469-9985 .- 2469-9993. ; 95:4
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Tidskriftsartikel (refereegranskat)abstract
- A newly observed isomeric intruder 1/2(+) state [T-1/2 = 3.5( 6) ms] is identified in At-203 using a gas-filled recoil separator and fusion-evaporation reactions. The isomer is depopulated through a cascade of E3 and mixed M1/E2 transitions to the 9/2(-) ground state, and it is suggested to originate from the pi(s(1/2))(-1) configuration. In addition, the structures above the 1/2(+) state in At-203 and At-197 are studied using in-beam gamma-ray spectroscopy, recoil-decay tagging, and recoil-isomer decay tagging methods. The 1/2(+) state is fed from 3/2(+) and 5/2(+) states, and the origin of these states are discussed.
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| 7. |
- Badran, H., et al.
(författare)
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Confirmation of the new isotope Pb-178
- 2016
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Ingår i: PHYSICAL REVIEW C. - 2469-9985. ; 94:5
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Tidskriftsartikel (refereegranskat)abstract
- The extremely neutron-deficient isotope Pb-178 has been produced. The GREAT spectrometer at the focal plane position of the gas-filled separator RITU was used to study the alpha decay of Pb-178 and its alpha-decay chain through alpha-alpha correlations. The alpha decay was measured to have an energy and half-life of E-alpha = 7610(30) keV and t(1/2) = 0.21(-0.08)(+0.21) ms, respectively. The half-life is consistent with recent theoretical calculations using the Coulomb and proximity potential model. The alpha-decay reduced width and hindrance factor for Pb-178 were deduced and correspond to an unhindered Delta l = 0 transition. In addition, the mass excess of Pb-178 and the alpha-decay Q value were calculated from the experimental results and compared to theoretical values.
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