In-beam spectroscopic study of 244Cf

The ground-state rotational band of the neutron-deficient californium (Z = 98) isotope 244Cf was identified for the first time and measured up to a tentative spin and parity of I = 20+. The observation of the rotational band indicates that the nucleus is deformed. The kinematic and dynamic moments of inertia were deduced from the measured gamma-ray transition energies. The behavior of the dynamic moment of inertia revealed an up-bend due to a possible alignment of coupled nucleons in high-j orbitals starting at a rotational frequency of about hw = 0.20 MeV. The results were compared with the systematic behavior of the even-even N = 146 isotones as well as with available theoretical calculations that have been performed for nuclei in the region

In-beam spectroscopic study of Cf-244

The ground-state rotational band of the neutron-deficient californium (Z = 98) isotope 244Cf was identified for the first time and measured up to a tentative spin and parity of I I-pi = 20(+). The observation of the rotational band indicates that the nucleus is deformed. The kinematic and dynamic moments of inertia were deduced from the measured gamma-ray transition energies. The behavior of the dynamic moment of inertia revealed an up-bend due to a possible alignment of coupled nucleons in high-j orbitals starting at a rotational frequency of about (h) over bar (omega) = 0.20 MeV. The results were compared with the systematic behavior of the even-even N = 146 isotones as well as with available theoretical calculations that have been performed for nuclei in the region.Peer reviewe

STUDY OF OCTUPOLE COLLECTIVITY IN Nd-146 AND Sm-148 USING THE NEW COULOMB EXCITATION SET-UP AT ALTO

For certain combinations of protons and neutrons in atomic nuclei, a rise of a reflection asymmetry is expected. Experimental E3 strengths, which as a function of the neutron number peak at around N ≈ 88 and N ≈ 134, indicate enhanced octupole correlations as predicted by theory. Low-energy Coulomb excitation is a highly successful method for establishing the evolution of nuclear shapes, through the measurement of cross sections, to populate excited states that can be directly related to the static and dynamic moments of the charge distribution of the nucleus. A Coulomb excitation experiment at the ALTO facility, Orsay was performed recently to study collective properties of 146Nd and 148Sm. In particular, the strengths of the ⟨3−||E3||0+⟩ and ⟨1−||E3||4+⟩ matrix elements will provide a clear distinction between octupole vibration and rigid deformation.status: publishe

STUDY OF OCTUPOLE COLLECTIVITY IN Nd-146 AND Sm-148 USING THE NEW COULOMB EXCITATION SET-UP AT ALTO

For certain combinations of protons and neutrons in atomic nuclei, a rise of a reflection asymmetry is expected. Experimental E3 strengths, which as a function of the neutron number peak at around N approximate to 8 8 and N approximate to 1 3 4, indicate enhanced octupole correlations as predicted by theory. Low-energy Coulomb excitation is a highly successful method for establishing the evolution of nuclear shapes, through the measurement of cross sections, to populate excited states that can be directly related to the static and dynamic moments of the charge distribution of the nucleus. A Coulomb excitation experiment at the ALTO facility, Orsay was performed recently to study collective properties of Nd-146 and Sm-148. In particular, the strengths of the and matrix elements will provide a clear distinction between octupole vibration and rigid deformation

Study of Octupole Collectivity in 146Nd and 148Sm Using the New Coulomb Excitation Set-up at ALTO

International audienceFor certain combinations of protons and neutrons in atomic nuclei, a rise of a reflection asymmetry is expected. Experimental E3 strengths, which as a function of the neutron number peak at around N approximate to 8 8 and N approximate to 1 3 4, indicate enhanced octupole correlations as predicted by theory. Low-energy Coulomb excitation is a highly successful method for establishing the evolution of nuclear shapes, through the measurement of cross sections, to populate excited states that can be directly related to the static and dynamic moments of the charge distribution of the nucleus. A Coulomb excitation experiment at the ALTO facility, Orsay was performed recently to study collective properties of Nd-146 and Sm-148. In particular, the strengths of the and matrix elements will provide a clear distinction between octupole vibration and rigid deformation

In-beam γ-ray and electron spectroscopy of Md249,251

The odd-Z 251Md nucleus was studied using combined γ-ray and conversion-electron in-beam spectroscopy. Besides the previously observed rotational band based on the [521]1/2− configuration, another rotational structure has been identified using γ−γ coincidences. The use of electron spectroscopy allowed the rotational bands to be observed over a larger rotational frequency range. Using the transition intensities that depend on the gyromagnetic factor, a [514]7/2− single-particle configuration has been inferred for this band, i.e., the ground-state band. A physical background that dominates the electron spectrum with an intensity of ≃60% was well reproduced by simulating a set of unresolved excited bands. Moreover, a detailed analysis of the intensity profile as a function of the angular momentum provided a method for deriving the orbital gyromagnetic factor, namely gK=0.69+0.19−0.16 for the ground-state band. The odd-Z 249Md was studied using γ-ray in-beam spectroscopy. Evidence for octupole correlations resulting from the mixing of the Δl=Δj=3 [521]3/2− and [633]7/2+ Nilsson orbitals were found in both 249,251Md. A surprising similarity of the 251Md ground-state band transition energies with those of the excited band of 255Lr has been discussed in terms of identical bands. Skyrme-Hartree-Fock-Bogoliubov calculations were performed to investigate the origin of the similarities between these bands.peerReviewe

Towards saturation of the electron-capture delayed fission probability: The new isotopes Es-240 and Bk-236

The new neutron-deficient nuclei 240Es and 236Bk were synthesised at the gas-filled recoil separator RITU. They were identified by their radioactive decay chains starting from 240Es produced in the fusion–evaporation reaction 209Bi(34S,3n)240Es. Half-lives of View the MathML source6(2)s and View the MathML source22−6+13s were obtained for 240Es and 236Bk, respectively. Two groups of α particles with energies View the MathML sourceEα=8.19(3)MeV and View the MathML source8.09(3)MeV were unambiguously assigned to 240Es. Electron-capture delayed fission branches with probabilities of 0.16(6)0.16(6) and 0.04(2)0.04(2) were measured for 240Es and 236Bk, respectively. These new data show a continuation of the exponential increase of ECDF probabilities in more neutron-deficient isotopes.status: publishe