Nuclear Data Sheets for A = 239

Browne, E.; Tuli, J.K.

doi:10.1016/j.nds.2014.11.003

Cited by 39 publications

(18 citation statements)

References 243 publications

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“…In the calculations the level scheme of 239 U below 1500 keV was taken from the ENSDF data base [54]. For the level density in the continuum, a constant temperature model was assumed with kT = (320 ± 20) keV and an average resonance spacing D 0 = (20.8 ± 0.3) eV at zero energy [55].…”

Section: Normalisationmentioning

confidence: 99%

Neutron capture cross section measurements for 238U in the resonance region at GELINA

et al. 2016

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Abstract. Measurements were performed at the time-of-flight facility GELINA to determine the 238 U(n, γ) cross section in the resonance region. Experiments were carried out at a 12.5 and 60 m measurement station. The total energy detection principle in combination with the pulse height weighting technique was applied using C 6D6 liquid scintillators as prompt γ-ray detectors. The energy dependence of the neutron flux was measured with ionisation chambers based on the 10 B(n, α) reaction. The data were normalised to the isolated and saturated 238 U resonance at 6.67 eV. Special procedures were applied to reduce bias effects due to the weighting function, normalization, dead time and background corrections, and corrections related to the sample properties. The total uncertainty due to the weighting function, normalization, neutron flux and sample characteristics is about 1.5%. Resonance parameters were derived from a simultaneous resonance shape analysis of the GELINA capture data and transmission data obtained previously at a 42 m and 150 m station of ORELA. The parameters of resonances below 500 eV are in good agreement with those resulting from an evaluation that was adopted in the main data libraries. Between 500 eV and 1200 eV a systematic difference in the neutron width is observed. Average capture cross section data were derived from the experimental capture yield in the energy region between 3.5 keV and 90 keV. The results are in good agreement with an evaluated cross section resulting from a least squares fit to experimental data available in the literature prior to this work. The average cross section data derived in this work were parameterised in terms of average resonance parameters and included in a least squares analysis together with other experimental data reported in the literature.

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Section: Normalisationmentioning

confidence: 99%

Neutron capture cross section measurements for 238U in the resonance region at GELINA

et al. 2016

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“…The half-lives obtained from the fits were A measurement of the electron-capture (EC) decay branch in 244,243 Cf was not possible in this work due to the long half-lives and very low α-decay branching ratios of 244 Bk [26] (T 1/2 = 4.35 (15) h, b α = 6(2) · 10 −3 %) and 243 Bk [27] (T 1/2 = 4.6(2) h, b α = 0.1%). Therefore, an α-decay branching ratio of b α = 14.0 % for 243 Cf that has been estimated in the literature [28,29] using data from [19] and [20] was adopted. It should be noted that an estimate of EC/α = 10 is given in [19] because the assignment of the 7.17-MeV α particles to the α decay of 243 Cf is questionable according to systematics [29].…”

Section: A Lifetimes and α-Decay Branching Ratiosmentioning

confidence: 99%

“…Therefore, an α-decay branching ratio of b α = 14.0 % for 243 Cf that has been estimated in the literature [28,29] using data from [19] and [20] was adopted. It should be noted that an estimate of EC/α = 10 is given in [19] because the assignment of the 7.17-MeV α particles to the α decay of 243 Cf is questionable according to systematics [29].…”

Section: A Lifetimes and α-Decay Branching Ratiosmentioning

confidence: 99%

In-beam spectroscopic study of Cf244

Konki¹,

Sulignano²,

Greenlees³

et al. 2018

Phys. Rev. C

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The ground-state rotational band of the neutron-deficient californium (Z = 98) isotope 244 Cf was identified for the first time and measured up to a tentative spin and parity of I π = 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 γ-ray transition energies. The behaviour 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 abouthω = 0.20 MeV. The results were compared to the systematic behaviour of the even-even N = 146 isotones as well as to available theoretical calculations that have been performed for nuclei in the region.

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“…The experimental data are taken from Refs. [62,63]. The fission-isomeric energy defined as the energy difference between the lowest-energy solution in the ground state and the fission-isomeric well is denoted by EII.…”

Section: Fission-isomeric Energiesmentioning

confidence: 99%

Fission barriers of two odd-neutron actinide nuclei taking into account the time-reversal symmetry breaking at the mean-field level

et al. 2017

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Background: Fission barriers of actinide nuclei have been mostly and for long been microscopically calculated for even-even fissioning systems. Calculations in the case of odd nuclei have been performed merely within a so-called equal-filling approximation (EFA) as opposed to an approach taking explicitly into account the time reversal breaking properties at the mean field level-and for only one single-particle configuration. Purpose: We study the dependence of the fission barriers on various relevant configurations (e.g. to evaluate the so-called specialization energy). Besides, we want to assess the relevance as a function of the deformation of the EFA approach which has been already found out at ground state deformation. Methods: Calculations within the Hartree-Fock plus BCS with self-consistent particle blocking have been performed using the SkM* Skyrme effective interaction in the particle-hole channel and a seniority force in the particle-particle channel. Axial symmetry has been imposed throughout the whole fission path while the intrinsic parity symmetry has been allowed to be broken in the outer fission barrier region. Results: Potential energy curves have been determined for six different configurations in 235 U and four in 239 Pu. Inner and outer fission barriers have been calculated along with some spectroscopic properties in the fission isomeric well. These results have been compared with available data. The influence of time-reversal breaking mean fields on the solutions has been investigated. Conclusions: A sizeable configuration dependence of the fission barrier (width and height) has been demonstrated. A reasonable agreement with available systematic evaluations of fission barrier heights has been found. The EFA approach has been validated at the large elongations occurring at the outer barrier region.

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Nuclear Data Sheets for A = 239

Cited by 39 publications

References 243 publications

Neutron capture cross section measurements for 238U in the resonance region at GELINA

Neutron capture cross section measurements for 238U in the resonance region at GELINA

In-beam spectroscopic study of Cf244

Fission barriers of two odd-neutron actinide nuclei taking into account the time-reversal symmetry breaking at the mean-field level

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