The gamma strength function and level density of 1^{-} states in ^{96}Mo have been extracted from a high-resolution study of the (pover →, pover →^{'}) reaction at 295 MeV and extreme forward angles. ...By comparison with compound nucleus γ decay experiments, this allows a test of the generalized Brink-Axel hypothesis in the energy region of the pygmy dipole resonance. The Brink-Axel hypothesis is commonly assumed in astrophysical reaction network calculations and states that the gamma strength function in nuclei is independent of the structure of the initial and final state. The present results validate the Brink-Axel hypothesis for ^{96}Mo and provide independent confirmation of the methods used to separate gamma strength function and level density in γ decay experiments.
Bremsstrahlung emission by relativistic electrons in collisions with medium heavy spin-zero nuclei is calculated within the plane-wave Born approximation. Coulomb distortion is estimated by a ...comparison with the Dirac partial-wave theory at energies up to 20 MeV. When integrated over the photon emission angle, the bremsstrahlung spectra help to explain the background of the nuclear excitation spectra in 150Nd ( e , e ′ ) reactions which were recently measured on an absolute scale.
The coupling of the giant quadrupole resonance to valence-space configurations is shown to be the origin of the formation of low-lying quadrupole-collective structures in vibrational nuclei with ...symmetric and mixed-symmetric character with respect to the proton-neutron degree of freedom. For the first time experimental evidence for this picture is obtained from electron- and proton scattering experiments on the nucleus ^{92}Zr that are sensitive to the relative phase of valence-space amplitudes by quantum interference.
The phenomenon of fine structure of the Isoscalar Giant Quadrupole Resonance (ISGQR) has been studied with high energy-resolution proton inelastic scattering at iThemba LABS in the chain of stable ...even-mass Nd isotopes covering the transition from spherical to deformed ground states. A wavelet analysis of the background-subtracted spectra in the deformed 146, 148, 150Nd isotopes reveals characteristic scales in correspondence with scales obtained from a Skyrme RPA calculation using the SVmas10 parameterization. A semblance analysis shows that these scales arise from the energy shift between the main fragments of the K=0,1 and K=2 components.
We report here on the first evidence for shape coexistence caused by Type II Shell Evolution which is firmly based on the measurement of absolute E2 transition rates. The data have been obtained in ...high-resolution inelastic electron scattering spectroscopy of the nucleus 96 Zr at the Superconducting Darmstadt Linear electron Accelerator (S-DALINAC). The data are presented and discussed. The neutron sub-shell closure at neutron number N = 56 plays a crucial role for the occurence of shape coexistence in 96,98Zr. We have studied the structure of exotic neutron-rich isotopes near the N = 56 neutron sub-shell closure using γ-ray spectroscopy and radioactive beams. We also present and discuss spectroscopic data on 84,86,88Ge taken recently at RIBF, RIKEN. The new data suggest the hitherto unknown existence of a region of pronounced nuclear triaxiality in neutron-rich Ge isotopes.
High precision electron scattering off 96Zr Kremer, C.; Aslanidou, S.; Bassauer, S. ...
Journal of physics. Conference series,
06/2016, Letnik:
724, Številka:
1
Journal Article
Recenzirano
Odprti dostop
We report on our recent electron scattering experiment off 96Zr. The B (E2; 01+→22+) transition strength is extracted in a relative analysis and allows the determination of all decay strengths of the ...22+ state. The strong collectivity of the 22+ → 02+ transition establishes the 02+ state and the states build on top of it as an isolated deformed band.
The electric dipole strength distribution in 120Sn has been extracted from proton inelastic scattering experiments at Ep=295 MeV and at forward angles including 0°. It differs from the results of a ...Sn120(γ,γ′) experiment and peaks at an excitation energy of 8.3 MeV. The total strength corresponds to 2.3(2)% of the energy-weighted sum rule and is more than three times larger than what is observed with the (γ,γ′) reaction. This implies a strong fragmentation of the E1 strength and/or small ground state branching ratios of the excited 1− states.
Relative and absolute E0 transition strengths ρ2 (E0) on the transitional path between the X(5) solution and the rigid rotor limit have been evaluated 1 within the framework of the Confined β-Soft ...(CBS) rotor model. Relative E0 transition strengths between the β-vibrational band and the ground state band decrease with increasing angular momentum for a given potential stiffness. The Z-independent quantity X ∝ ρ2(E0; 0+2 → 0+1)/B(E2; 0+1 → 2+1) has been traced between X(5) and the rigid rotor. It reaches the value 4β2M at the rigid rotor limit, as previously derived by Rasmussen. A new Inter-Band E0 − E2 correlation observable Y ∝ ρ2(E0; 0+2 → 0+1)/B(E2; 0+2 → 2+1)2 has be en proposed, which is independent on the absolute nuclear deformation and solely depends on the nuclear stiffness. Available data for X and Y are in satisfactory agreement with the CBS model.
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