Discovery of Highly Excited Long-Lived Isomers in Neutron-Rich Hafnium and Tantalum Isotopes through Direct Mass Measurements

Reed, M. W.; Cullen, I. J.; Walker, P. M.; Litvinov, Yu. A.; Blaum, Klaus; Bosch, F.; Brandau, C.; Carroll, J. J.; Cullen, D. M.; Deo, A. Y.; Detwiller, B.; Dimopoulou, C.; Dracoulis, George; Farinon, F.; Geißel, H.; Haettner, E.; Heil, M.; Kempley, R.S.; Knöbel, R.; Kozhuharov, C.; Kurcewicz, J.; Kuzminchuk, N.; Litvinov, S.; Liu, Z.; Mao, Ruishi; Nociforo, C.; Nolden, F.; Plaß, W. R.; Procházka, A.; Scheidenberger, C.; Steck, M.; Stöhlker, Th.; Sun, B.; Swan, T.; Trees, G.; Weick, H.; Winckler, N.; Winkler, M.; Woods, P. J.; Yamaguchi, Takayuki

doi:10.1103/physrevlett.105.172501

Cited by 74 publications

(39 citation statements)

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“…IV C) but all the corresponding energies are more than 300 keV too low. The isomer energies in 187 Ta, an isotone of 186 Hf, are also substantially underpredicted [19] unless the neutron single-particle energies are adjustedin that case to give better agreement for known single-particle states in 187 W. Therefore, for 186 Hf, it may be that the K π = 17 + assignment is correct, but that a systematic reevaluation of the model parameters is required for the neutron-rich region, in order to obtain the correct single-particle energies. It is hoped that isomer studies such as those presented here will motivate further theoretical work of this kind.…”

Section: Review Of Multi-quasiparticle Calculationsmentioning

confidence: 99%

“…[19] 187 Ta m1 isomer were observed, most of which decayed, some as γ decays to the ground state (8 ions) while others were lost from the ring (5 ions). The latter have been attributed to β decays given the short loss time, from which a half-life of 22(9) s has been deduced.…”

Section: G 187 Tamentioning

confidence: 99%

“…In this section, comparison is made between the experimental energies for even-even hafnium four-quasiparticle states and the results of MQP calculations, as illustrated in [7,19]. Using the Nilsson model with blocked-BCS pairing [54], a systematic set of calculations was carried out by Walker and Dracoulis [7], ranging from 172 Hf to 190 Hf.…”

Section: Review Of Multi-quasiparticle Calculationsmentioning

confidence: 99%

“…IV C). However, new calculations [19], which include Lipkin-Nogami pairing, favor a K π = 15 + configuration (given in Sec. IV B) where the energy is calculated to be 2369 keV, i.e., 110 keV too low.…”

Section: Review Of Multi-quasiparticle Calculationsmentioning

confidence: 99%

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Long-lived isomers in neutron-richZ=72–76 nuclides

et al. 2012

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A study of neutron-rich isotopes in the A = 185 region of the nuclear chart has uncovered long-lived (>1 s) isomers in several isotopes of hafnium, tantalum, tungsten, rhenium, and osmium. The region was accessed via the use of projectile fragmentation with the UNILAC-SIS accelerators at GSI. Fragmentation products of 197 Au were passed through the fragment separator (FRS) and injected into the experimental storage ring (ESR), where single-ion identifications could be made. Evidence is presented for isomers in 183,184,186 Hf, 186,187 Ta, 186 W, 190,192,194 Re, and 195 Os with excitation energies in the range of 0.1-3.0 MeV. The lightest of these nuclides have well deformed prolate shapes, while the heaviest are transitional and susceptible to shape changes. Their properties are interpreted with the help of multi-quasiparticle and potential-energy-surface calculations.

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Section: Review Of Multi-quasiparticle Calculationsmentioning

confidence: 99%

Section: G 187 Tamentioning

confidence: 99%

Section: Review Of Multi-quasiparticle Calculationsmentioning

confidence: 99%

Section: Review Of Multi-quasiparticle Calculationsmentioning

confidence: 99%

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Long-lived isomers in neutron-richZ=72–76 nuclides

et al. 2012

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“…As an example, one 208 Hg nucleus was identified as a H-like ion during a two-week experiment; this mass is crucial to addressing the proton-neutron interaction strength around the doubly magic 208 Pb nucleus [48]. The sensitivity to single stored ions in SMS has been used to resolve low-lying isomeric states with excitation energies higher than about 100 keV [49][50][51][52][53].…”

Section: The Achievable Relative Precision Of Pmts With the Tof-icr Tmentioning

confidence: 99%

Toward precision mass measurements of neutron-rich nuclei relevant to r-process nucleosynthesis

et al. 2015

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The open question of where, when, and how the heavy elements beyond iron enrich our Universe has triggered a new era in nuclear physics studies. Of all the relevant nuclear physics inputs, the mass of very neutron-rich nuclides is a key quantity for revealing the origin of heavy elements beyond iron. Although the precise determination of this property is a great challenge, enormous progress has been made in recent decades, and it has contributed significantly to both nuclear structure and astrophysical nucleosynthesis studies. In this review, we first survey our present knowledge of the nuclear mass surface, emphasizing the importance of nuclear mass precision in r-process calculations. We then discuss recent progress in various methods of nuclear mass measurement with a few selected examples. For each method, we focus on recent breakthroughs and discuss possible ways of improving the weighing of r-process nuclides.

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Expanding Nuclear Physics Horizons with the Gamma Factory

et al. 2022

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The Gamma Factory (GF) is an ambitious proposal, currently explored within the CERN Physics Beyond Colliders program, for a source of photons with energies up to ≈400 MeV and photon fluxes (up to ≈1017 photons s−1) exceeding those of the currently available gamma sources by orders of magnitude. The high‐energy (secondary) photons are produced via resonant scattering of the primary laser photons by highly relativistic partially‐stripped ions circulating in the accelerator. The secondary photons are emitted in a narrow cone and the energy of the beam can be monochromatized, down to 10−3–10−6 level, via collimation, at the expense of the photon flux. This paper surveys the new opportunities that may be afforded by the GF in nuclear physics and related fields.

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Discovery of Highly Excited Long-Lived Isomers in Neutron-Rich Hafnium and Tantalum Isotopes through Direct Mass Measurements

Cited by 74 publications

References 33 publications

Long-lived isomers in neutron-richZ=72–76 nuclides

Long-lived isomers in neutron-richZ=72–76 nuclides

Toward precision mass measurements of neutron-rich nuclei relevant to r-process nucleosynthesis

Expanding Nuclear Physics Horizons with the Gamma Factory

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