The measurement of the lifetimes of excited nuclear states

Nolan, P. J.; Sharpey‐Schafer, J. F.

doi:10.1088/0034-4885/42/1/001

Cited by 114 publications

(44 citation statements)

References 243 publications

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“…The fast timing method is a well-established tool for measuring lifetimes of excited nuclear states [1,2]. Especially since γ-γ fast timing in the sub-nanosecond region has become feasible using LaBr 3 (Ce) scintillators, many studies in different mass regions have employed this method, more and more also in studies of very exotic nuclei using radioactive beams (e.g.…”

Section: Introductionmentioning

confidence: 99%

Fast Timing Measurement Using an LaBr$_3$(Ce) Scintillator Detector Array Coupled with Gammasphere

Rüdigier¹,

Lalkovski²,

Gamba³

et al. 2017

Acta Phys. Pol. B

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A fast-timing experiment was performed at the Argonne National Laboratory in December 2015 and January 2016, measuring decay radiation of fission products from a 252 Cf fission source. Details of the set-up, integration with Digital Gammasphere, and the data acquisition system are presented. The timing performance of the set-up, capable of measuring lifetimes from the nanosecond region down to tens of picoseconds, is discussed. First preliminary results from the fast-timing analysis of the fission fragment data are presented.

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Section: Introductionmentioning

confidence: 99%

Fast Timing Measurement Using an LaBr$_3$(Ce) Scintillator Detector Array Coupled with Gammasphere

Rüdigier¹,

Lalkovski²,

Gamba³

et al. 2017

Acta Phys. Pol. B

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“…to extract the Doppler-shift attenuation factor F(τ) [6]. Here, E 0 γ denotes the unshifted γ-ray energy, Θ is the angle between the direction of motion of the reaction product and the direction of γ-ray emission, and v 0 denotes the initial recoil velocity.…”

Section: Introductionmentioning

confidence: 99%

Lifetime measurement of excited low-spin states via the (p,p′γ) reaction

Hennig

Derya

Mineva

et al. 2015

Nuclear Instruments and Methods in Physics Research Section A:

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In this article a method for lifetime measurements in the sub-picosecond regime via the Doppler-shift attenuation method (DSAM) following the inelastic proton scattering reaction is presented. In a pioneering experiment we extracted the lifetimes of 30 excited low-spin states of 96 Ru, taking advantage of the coincident detection of scattered protons and de-exciting γ-rays as well as the large number of particle and γ-ray detectors provided by the SONIC@HORUS setup at the University of Cologne. The large amount of new experimental data shows that this technique is suited for the measurement of lifetimes of excited low-spin states, especially for isotopes with a low isotopic abundance, where (n, n γ) or -in case of investigating dipole excitations -(γ, γ ) experiments are not feasible due to the lack of sufficient isotopically enriched target material.

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“…It was verified that both 1018-and 1246-keV lines do not show any broadening, i.e., lifetimes longer than 2 ps are expected for the 0 þ 2 and 0 þ 3 states. In contrast, the 1546-keV peak (shown in the inset), is more complex: besides the broadening, which was used to extract a lifetime of 1.4(2) ps for the 3 þ state at 2971.0 keV (with the Doppler shift attenuation method [38]), a weak satellite line is observed on the right-hand side shoulder. We hypothesized that this satellite line, at approximate energy of 1549 keV, may be a transition from the 0 þ 4 state of 66 Ni to the first excited 2 þ state, which would then place this 0 þ excitation at 2974 keV.…”

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confidence: 99%

Multifaceted Quadruplet of Low-Lying Spin-Zero States in Ni66 : Emergence of Shape Isomerism in Light Nuclei

Leoni¹,

Fornal²,

Mărginean³

et al. 2017

Phys. Rev. Lett.

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þ states, pointing to the oblate, spherical, and prolate nature of the consecutive excitations. In addition, they account for the hindrance of the E2 decay from the prolate 0 þ 4 to the spherical 2 þ 1 state, although overestimating its value. This result makes 66 Ni a unique nuclear system, apart from 236;238 U, in which a retarded γ transition from a 0 þ deformed state to a spherical configuration is observed, resembling a shape-isomerlike behavior. DOI: 10.1103/PhysRevLett.118.162502 The concept of potential energy surface (PES) is central in many areas of physics. Usually, the PES displays the potential energy of the system as a function of its geometry. As an example, the PES of a molecule expressed in such coordinates as bond length, valence angles, etc., can be used for finding the minimum energy shape or calculating chemical reaction rates [1]. The idea of potential energy surface in deformation space has also been widely applied to the nucleus at a given spin. For an even-even nucleus at spin 0, the lowest PES minimum corresponds to the ground state (g.s.), while there may exist additional (secondary) minima in which excited 0 þ states can reside: they can be interpreted as ground states of different shapes [2][3][4][5][6]. When a secondary minimum is separated from the main minimum by a high barrier, in the extreme case a long-lived isomer, called shape isomer, can be formed [7]. Shape isomerism at spin zero, so far, has clearly been observed only in actinide nuclei -these isomers decay mainly by fission, and in two cases only, 236 U and 238 U, by very retarded γ-ray branches [8][9][10][11].The existence of shape isomers in lighter systems has been a matter of debate for a long time. Already in the 1980s, a study based on microscopic Hartree-Fock plus BCS calculations, in which a large number of nuclei was surveyed, identified ten isotopes in which a deformed 0 þ state is separated from a spherical structure by a significantly high barrier:66 Ni and 68 Ni, 190;192 Pt, 206;208;210 Os, and 194;196;214

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The measurement of the lifetimes of excited nuclear states

Cited by 114 publications

References 243 publications

Fast Timing Measurement Using an LaBr$_3$(Ce) Scintillator Detector Array Coupled with Gammasphere

Fast Timing Measurement Using an LaBr$_3$(Ce) Scintillator Detector Array Coupled with Gammasphere

Lifetime measurement of excited low-spin states via the (p,p′γ) reaction

Multifaceted Quadruplet of Low-Lying Spin-Zero States in Ni66 : Emergence of Shape Isomerism in Light Nuclei

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