100 years of nuclear isomers—then and now

Walker, P. M.; Podolyák, Z

doi:10.1088/1402-4896/ab635d

Cited by 60 publications

(25 citation statements)

References 179 publications

(301 reference statements)

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“…Measurements of isomers and their properties continue to be a point of experimental interest for a variety of reasons, including not only as astrophysical model inputs, but also for applications in industry, medicine, and tests of fundamental nuclear physics [7][8][9][10][11][12][13][14][15][16][17]. For a recent review, see [18]. Astrophysical nucleosynthesis simulations usually take one of two approaches to the distribution of nuclear states: either they assume a thermal equilibrium distribution, or they use only the ground state (GS) properties.…”

Section: Introductionmentioning

confidence: 99%

Sensitivity of Neutron-Rich Nuclear Isomer Behavior to Uncertainties in Direct Transitions

et al. 2021

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Nuclear isomers are populated in the rapid neutron capture process (r process) of nucleosynthesis. The r process may cover a wide range `of temperatures, potentially starting from several tens of GK (several MeV) and then cooling as material is ejected from the event. As the r-process environment cools, isomers can freeze out of thermal equilibrium or be directly populated as astrophysically metastable isomers (astromers). Astromers can undergo reactions and decays at rates very different from the ground state, so they may need to be treated independently in nucleosythesis simulations. Two key behaviors of astromers—ground state ↔ isomer transition rates and thermalization temperatures—are determined by direct transition rates between pairs of nuclear states. We perform a sensitivity study to constrain the effects of unknown transitions on astromer behavior. Detailed balance ensures that ground → isomer and isomer → ground transitions are symmetric, so unknown transitions are equally impactful in both directions. We also introduce a categorization of astromers that describes their potential effects in hot environments. We provide a table of neutron-rich isomers that includes the astromer type, thermalization temperature, and key unmeasured transition rates.

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Section: Introductionmentioning

confidence: 99%

Sensitivity of Neutron-Rich Nuclear Isomer Behavior to Uncertainties in Direct Transitions

et al. 2021

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“…Their existence is typically attributed to large differences in spin, shape or K quantum number, between the isomer and the lower‐lying levels. [ 24,25 ] In an advantageous configuration of the nuclear excited levels, once the excitation occurs from the isomeric state to an upper gateway level, the subsequent nuclear decay may proceed directly to a state below the isomer, thus reaching the ground state in a fast cascade. Such a process is called isomer depletion, since it allows for the depopulation of the isomeric state and thus a controlled release of the energy stored in the metastable state.…”

Section: Nuclear Spectroscopy In the Ion Beammentioning

confidence: 99%

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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“…Excited states in nuclei usually have very short lifetimes, in the order of picoseconds or even less. In contrast, isomeric (or metastable) states live much longer [346]. In addition of being special, the measurement of the lifetimes allow the determination of the reduced transition strength of the deexciting γ -ray transitions, which in turn provide information about the wave functions of the involved nuclear states.…”

Section: Isomeric States and Selection Rulesmentioning

confidence: 99%

Gamma spectroscopy with AGATA in its first phases: New insights in nuclear excitations along the nuclear chart

Bracco

Duchêne

Podolyák

et al. 2021

Progress in Particle and Nuclear Physics

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The Advanced GAmma Tracking Array (AGATA), the new generation high-resolution γray spectrometer, has seen the realization of the first phases of its construction and exploitation. A number of nuclear structure studies based on experiments utilizing the principle of γ -ray tracking were carried out in this decade. The combination of highest detection efficiency and position sensitivity allowed very selective spectroscopic studies with stable beams and the use of instable ion beams with the lowest intensities. Nuclear-structure studies commenced already at INFN-LNL (Legnaro, Italy) with a first implementation of the array consisting of five AGATA modules. A larger array of AGATA modules was used at GSI (Darmstadt, Germany) for experiments with unstable ion beams at relativistic energies. The spectrometer was then mounted in a beam line at GANIL (Caen, France). This review discusses several of the obtained results, underlying the progress made and future perspectives. The performed experiments give insights into nuclear structure issues which are connected to single particles, collective degrees of freedom, nucleon interactions and symmetries. Most of the investigated nuclei are located outside the stability line and for stable nuclei the investigations concern unexplored configurations. Altogether the obtained results represent advances which could test theory in exclusive way and motivate new theoretical developments.Opportunities for further γ -ray spectroscopy with the foreseen more advanced phase of the AGATA emerge in the discussions of the presented data.

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100 years of nuclear isomers—then and now

Cited by 60 publications

References 179 publications

Sensitivity of Neutron-Rich Nuclear Isomer Behavior to Uncertainties in Direct Transitions

Sensitivity of Neutron-Rich Nuclear Isomer Behavior to Uncertainties in Direct Transitions

Expanding Nuclear Physics Horizons with the Gamma Factory

Gamma spectroscopy with AGATA in its first phases: New insights in nuclear excitations along the nuclear chart

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