The photonuclear cross sections of 48Ca

O’Keefe, Graeme; Thompson, M.N.; Assafiri, Y.; Pywell, R. E.; Shoda, K.

doi:10.1016/0375-9474(87)90108-4

Cited by 49 publications

(32 citation statements)

References 24 publications

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“…A possible explanation for the differences with ref. [203] is the unfolding procedure with a not well-known bremsstrahlung spectrum as input necessary for the extraction of σ abs , leading to sizable systematic uncertainties not reflected in the quoted error bars.…”

Section: Unit Cross-section Methodsmentioning

confidence: 99%

Electric and magnetic dipole modes in high-resolution inelastic proton scattering at 0°

Neumann-Cosel

Tamii

2019

Eur. Phys. J. A

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Inelastic proton scattering under extreme forward angles including 0 • and at energies of a few hundred MeV has been established as a new spectroscopic tool for the study of complete dipole strength distributions in nuclei. Such data allow an extraction of the electric dipole polarizability which provides important constraints for parameters of the symmetry energy, which determine the neutron-skin thickness and the equation of state (EOS) of neutron-rich matter. Also, new insight into the much-debated nature of the pygmy dipole resonance (PDR) is obtained. Additionally, the isovector spin-M1 resonance can be studied in heavy nuclei, where only limited experimental information exists so far. Together with much improved results on the isoscalar spin-M1 strength distributions in N = Z nuclei, these data shed new light on the phenomenon of quenching of the nuclear spin response. Using dispersion matching techniques, high energy resolution (∆E/E ≤ 10 −4 full width at half maximum, FWHM) can be achieved in the experiments. In spherical-vibrational nuclei considerable fine structure is observed in the energy region of the isovector giant dipole resonance (IVGDR). A quantitative analysis of the fine structure with wavelet methods provides information on the role of different damping mechanisms contributing to the width of the IVGDR. Furthermore, level densities can be extracted from a fluctuation analysis at excitation energies well above neutron threshold, a region hardly accessible by other means. The combination of the gamma strength function (GSF) extracted from the E1 and M1 strength distributions with the independently derived level density permits novel tests of the Brink-Axel hypothesis underlying all calculations of statistical model reaction cross sections in astrophysical applications in the energy region of the PDR.

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Section: Unit Cross-section Methodsmentioning

confidence: 99%

Electric and magnetic dipole modes in high-resolution inelastic proton scattering at 0°

Neumann-Cosel

Tamii

2019

Eur. Phys. J. A

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“…Measurements for 48 Ca were performed in Ref. [29]. Later, some evaluated data for photoabsorption cross section in the same energy range became available for the chain of even-even Calcium isotopes 40,42,44,48 Ca in [30].…”

Section: Introductionmentioning

confidence: 99%

Electric dipole response of neutron-rich calcium isotopes in relativistic quasiparticle time blocking approximation

Егорова

Литвинова

2016

Phys. Rev. C

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New results for electric dipole strength in the chain of even-even Calcium isotopes with the mass numbers A = 40 -54 are presented. Starting from the covariant Lagrangian of Quantum Hadrodynamics, spectra of collective vibrations (phonons) and phonon-nucleon coupling vertices for J ≤ 6 and natural parity were computed in a self-consistent relativistic quasiparticle random phase approximation (RQRPA). These vibrations coupled to Bogoliubov two-quasiparticle configurations (2q⊗phonon) formed the model space for the calculations of the dipole response function in the relativistic quasiparticle time blocking approximation (RQTBA). The calculations in the latter approach were performed for the giant dipole resonance (GDR) and compared to those obtained in RQRPA and to available data. Evolution of the dipole strength with neutron number is investigated for both high-frequency GDR and low-lying strength. The development of a pygmy resonant structure on the low-energy shoulder of GDR is traced and analyzed in terms of transition densities. A dependence of the pygmy dipole strength on the isospin asymmetry parameter is extracted.

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“…Experimentally, the isovector GDR in 48 Ca is localized around 19.5 MeV with width of 7.0 MeV [44]. We have found about 97% of the EW SR between 10 and 21 MeV by performing our RPA calculation, with two peaks exhausting 47% of the EW SR around 20 MeV .…”

Section: Resultsmentioning

confidence: 83%

“…There are some discussions in the recent literature in relation to its correct location and their widths [22][23][24]26]. Our calculations predict a considerable strength in the energy region above 20 MeV , which is com- [44] posed by the presence of various narrow peaks superposing to exhaust about 82% of the EW SR between 20 − 30 MeV . These peaks are mainly composed by 3hω transitions involving the neutrons and protons of the externals shells.…”

Section: Resultsmentioning

confidence: 96%

The spreading width calculation of giant resonances with a semi-microscopic approach

Leite¹,

Teruya²

2006

Braz. J. Phys.

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We have proposed a semi-microscopic approach to calculate the two particles -two holes (2p − 2h) spreading width of giant resonances. Our proposal has been based in a hybrid method that implements the statistical multistep compound theory of Feshbach, Kerman and Koonin (FKK), widely and successful used in nuclear reactions mechanisms, in order to include relevant informations about the microscopic structure obtained by the Random Phase Approximation (RPA) calculations. This method is an approximative calculation to avoid the intrinsic numerical difficulties of those microscopic calculations that incorporate more complex structure than one particle -one hole (1p − 1h) excitations. Unlike the reaction context, the residual interaction was adjusted in RPA calculation to reproduce the lowest energy levels of the studied nuclei. The feasibility and the efficiency of the approach has been tested in giant dipole resonances in 208 Pb and neutron-rich calcium isotopes, 48 Ca and 60 Ca.

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The photonuclear cross sections of 48Ca

Cited by 49 publications

References 24 publications

Electric and magnetic dipole modes in high-resolution inelastic proton scattering at 0°

Electric and magnetic dipole modes in high-resolution inelastic proton scattering at 0°

Electric dipole response of neutron-rich calcium isotopes in relativistic quasiparticle time blocking approximation

The spreading width calculation of giant resonances with a semi-microscopic approach

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