Lifetime Measurements of Excited Nuclear Levels by Doppler-Shift Methods

Alexander, T.K.; Forster, J.S.

doi:10.1007/978-1-4757-4401-9_3

Cited by 126 publications

(46 citation statements)

References 206 publications

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“…Though this method has been exploited already some decades ago [10,11], those experiments were suffering from low statistics due to the coincidence requirement and the small number of detectors used [7]. In the present experiment on 96 Ru, 14 HPGe detectors of a γ-ray spectrometer were used in combination with six detectors of a particle-detector array.…”

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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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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“…To extract the lifetimes of excited states in the subpicosecond regime, the Doppler-shift attenuation method (DSAM) [33,34] is usually the method of choice. However, no lifetimes could be extracted from the experiment at WNSL since the energy-bin width of 1 keV in the γ-ray spectra acquired with the 4k analog-to-digital converters (ADCs) did not allow for an extraction of Dopplershifts in the sub-keV regime.…”

Section: Methodsmentioning

confidence: 99%

Collective excitations ofRu96by means of(p,p′γ)experiments

et al. 2015

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Background: One-phonon mixed-symmetry quadrupole excitations are a well-known feature of near-spherical, vibrational nuclei. Their interpretation as a fundamental building block of vibrational structures is supported by the identification of multi-phonon states resulting from a coupling of fullysymmetric and mixed-symmetric quadrupole phonons. In addition, the observation of strong M 1 transitions between low-lying 3 − and 4 + states has been interpreted as an evidence for one-phonon mixed-symmetry excitations of octupole and hexadecapole character. Purpose: The aim of the present study is to identify collective one-and two-phonon excitations in the heaviest stable N = 52 isotone 96 Ru based on a measurement of absolute M 1, E1, and E2 transition strengths. Methods: Inelastic proton-scattering experiments have been performed at the Wright Nuclear Structure Laboratory (WNSL), Yale University, and the Institute for Nuclear Physics (IKP), University of Cologne. From the acquired proton-γ and γγ coincidence data we deduced spins of excited states, γ-decay branching ratios, and multipole mixing ratios, as well as lifetimes of excited states via the Doppler-shift attenuation method (DSAM). Results: Based on the new experimental data on absolute transition strengths, we identified the 2 + and 3 + members of the two-phonon mixed-symmetry quintuplet (2 + 1,ms ⊗ 2 + 1,s ). Furthermore, we observed strong M 1 transitions between low-lying 3 − and 4 + states suggesting one-phonon symmetric and mixed-symmetric octupole and hexadecapole components in their wave functions, respectively. The experimental results are compared to sdg-IBM-2 and shell-model calculations. Conclusions: Both, the sdg-IBM-2 and the shell-model calculations, are able to describe key features of mixed-symmetry excitations of 96 Ru. Moreover, they support the one-phonon mixedsymmetry hexadecapole assignment of the experimental 4 + 2 state.

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“…Ref. [24] and references therein). We have performed two parallel analyses of the line shapes; in the first analysis, labelled here Analysis I, we used a Monte Carlo (MC) simulation by means of a modified [25,26] version of the program DESASTOP [27] in order to describe the slowing down of the recoiling nuclei.…”

Section: Identification Of the One-phononmentioning

confidence: 99%

Search for mixed-symmetry states of nuclei in the vicinity of the double-magic nucleus²⁰⁸Pb

Kocheva

Stegmann

Rainovski

et al. 2016

EPJ Web of Conferences

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Abstract. In this work we present the results from two experiments dedicated to search for quadrupolecollective isovector valence-shell excitation, the states with so-called mixed proton-neutron symmetry (MSS), in nuclei around the doubly magic nucleus 208 Pb. 212 Po was studied in an α-transfer reaction. 204 Hg was studied in an inverse kinematics Coulomb excitation reaction on a carbon target. Both experiments provide indications for existence of one-phonon MSSs. Those are the first experimentally identified MSSs in the mass A ≈ 208 region.

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Lifetime Measurements of Excited Nuclear Levels by Doppler-Shift Methods

Cited by 126 publications

References 206 publications

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

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

Collective excitations ofRu96by means of(p,p′γ)experiments

Search for mixed-symmetry states of nuclei in the vicinity of the double-magic nucleus²⁰⁸Pb

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Lifetime Measurements of Excited Nuclear Levels by Doppler-Shift Methods

Cited by 126 publications

References 206 publications

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

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

Collective excitations ofRu96by means of(p,p′γ)experiments

Search for mixed-symmetry states of nuclei in the vicinity of the double-magic nucleus208Pb

Contact Info

Product

Resources

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Search for mixed-symmetry states of nuclei in the vicinity of the double-magic nucleus²⁰⁸Pb