Measurement of the 
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mmultiscripts><mml:mrow><mml:mi>Th</mml:mi></mml:mrow><mml:mprescripts /><mml:none /><mml:mrow><mml:mn>229</mml:mn></mml:mrow></mml:mmultiscripts></mml:mrow></mml:math>
 Isomer Energy with a Magnetic Microcalorimeter

Sikorsky, Tomas; Geist, Jeschua; Hengstler, D.; Kempf, Sebastian; Gastaldo, L.; Enss, C.; Mokry, C.; Runke, J.; Düllmann, Ch. E.; Wobrauschek, P.; Beeks, Kjeld; Rosecker, Veronika; Sterba, Johannes H.; Kazakov, G.; Schumm, Thorsten; Fleischmann, Andreas

doi:10.1103/physrevlett.125.142503

Cited by 122 publications

(89 citation statements)

References 39 publications

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“…Version available at http://www.nndc.bnl.gov/ensarchivals/ accessed on 17 September 2020) [6]. 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].…”

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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“…a)transition energy from, refs. [26, 27] and radiative transition rate deduced using theoretical predictions in ref. [28];…”

Section: Nuclear Spectroscopy In the Ion Beammentioning

confidence: 99%

“…Considerable interest in both theory and experiment has been paid in the past years to the lowest‐known nuclear excited state, lying at only ≈8 eV above the ground state of 229 Th. [ 26,27 ] 229 Th belongs to the light actinide nuclear mass region known for the presence of enhanced collectivity and shape‐dynamic properties. [ 34 ] The single‐particle states of the odd neutron determine the 229 Th ground state with

K^{\pi }=5/2^{+}

and the isomeric state with

K^{\pi }=3/2^{+}

based on the

5/2^+[633]

and

3/2^+[631]

single‐particle orbitals.…”

Section: Nuclear Spectroscopy In the Ion Beammentioning

confidence: 99%

“…In addition, it also opened a new route for the determination of the 229 m Th energy, [ 39,40 ] though so far less precisely than the best prior measurements. [ 26,27 ] However, one of the drawbacks for NRS experiments is the use of solid‐state targets, in which the predominant nuclear decay is via internal conversion, quenching the isomeric state in microseconds. [ 38 ] This is where the unique capabilities of the storage‐ring experiments can come into play.…”

Section: Nuclear Spectroscopy In the Ion Beammentioning

confidence: 99%

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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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“…The nuclear first excited state in 229 Th is in the focus of nuclear as well as atomic physics research. Due to its low excitation energy in the range of ≈8.2 eV (we took the mean value of the two most recent energy determinations [1,2]), the first nuclear excited state plays an exceptional role with the possibility to be excited by laser light. This led to the proposal to use the 229 Th nucleus as a basis for a nuclear optical clock [3].…”

Section: Introductionmentioning

confidence: 99%

Extending Our Knowledge about the 229Th Nuclear Isomer

Moritz

Scharl

Ding

et al. 2022

Atoms

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The first nuclear excited state in 229Th possesses the lowest excitation energy of all currently known nuclear levels. The energy difference between the ground- and first-excited (isomeric) state (denoted with 229mTh) amounts only to ≈8.2 eV (≈151.2 nm), which results in several interesting consequences: Since the excitation energy is in the same energy range as the binding energy of valence electrons, the lifetime of 229mTh is strongly influenced by the electronic structure of the Th atom or ion. Furthermore, it is possible to potentially excite the isomeric state in 229Th with laser radiation, which led to the proposal of a nuclear clock that could be used to search for new physics beyond the standard model. In this article, we will focus on recent technical developments in our group that will help to better understand the decay mechanisms of 229mTh, focusing primarily on measuring the radiative lifetime of the isomeric state.

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Measurement of the Th229 Isomer Energy with a Magnetic Microcalorimeter

Cited by 122 publications

References 39 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

Extending Our Knowledge about the 229Th Nuclear Isomer

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