Evaluation of the Unresolved Resonance Range of<sup>238</sup>U

Fröhner, F. H.

doi:10.13182/nse89-a28501

Cited by 37 publications

(32 citation statements)

References 12 publications

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“…A similar evaluation was performed by Maslov et al [16] and Courcelle et al [17]. The capture cross section of Fröhner [14,15], which is strongly based on the data of Kazakov et al [18], is in good agreement with the one of Carlson et al [19]. The latter was derived from a least squares adjustment to experimental data available in the literature using the generalised least squares code GMA developed by Poenitz [20] and named after Gauss, Markov, Aitken.…”

Section: Introductionmentioning

confidence: 71%

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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: Introductionmentioning

confidence: 71%

“…They refer to the evaluation of Fröhner, which is described in detail in refs. [14,15]. This evaluation is based on an analysis of experimental data using the Hauser-Feshbach theory with width fluctuations.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2016

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“…7 has been fitted by an average parameter description, also shown in the figure. A different way to describe average cross sections, as a complement to optical model calculations, is to use R-matrix theory, which is usually used for resolved resonances. This procedure corresponds to a Hauser-Feshbach calculation with width fluctuations [51]. In the unresolved resonance region, fictitious resonances can be generated to describe the average cross section.…”

Section: Average Parameter Description Of the Capture Cross Sectionmentioning

confidence: 99%

Neutron capture cross section ofTh232measured at the n_TOF facility at CERN in the unresolved resonance region up to 1 MeV

Aerts¹,

Fujii²,

Vlastou³

et al. 2006

Phys. Rev. C

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We have measured the neutron capture reaction yield of 232 Th at the neutron time-of-flight facility n TOF at CERN in the energy range from 1 eV to 1 MeV. The average capture cross section has been extracted in the energy range from 4 keV up to 1 MeV with an overall accuracy better than 4%. An independent IAEA evaluation shows good agreement with the data. The average cross section has been expressed in terms of average resonance parameters using the partial waves = 0, 1, and 2.

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“…These parameters could also be used in analysis code like CONRAD [6] and FITACS [11]. They allow the modelling of the total, capture, fission and scattering cross sections.…”

Section: E Soukhovitsky Potentialmentioning

confidence: 99%

Generalization of the SPRT method: application to ²⁴²Pu cross sections in the Unresolved Resonance Range

Rich¹,

Noguère²,

Jean³

et al. 2007

Nd2007

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Abstract. The modelling of the neutron cross sections consists in their interpretation in three different energy ranges: the first one is the Resolved Resonance Range (RRR) at low energy, the second is the Unresolved Resonance Range (URR), and the third one concerns the high energies. For this, we generally use the Reich-Moore approximation of the R-Matrix formalism, the average R-Matrix formalism and optical model calculations. One of the main challenges of such a work is to study the consistency of the average parameters obtained by these different calculations. With the ESTIMA and SPRT methods, we provide a set of parameters for partial s and p waves (strength functions, effective potential scattering radius, mean-level spacing and reduced neutron width). But, in order to analyse accurately the URR domain, we need more information than the parameters associated to the orbital moments L = 0 and L = 1. This work describes the link between the average R-Matrix formalism and the optical model, especially concerning the transmission coefficients, total and shape elastic cross sections. Based on these two models, we propose a generalization of the SPRT method for L > 1, and we obtain a new set of parameters for the URR domain in terms of S LJ and R ∞ JL .

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Evaluation of the Unresolved Resonance Range of²³⁸U

Cited by 37 publications

References 12 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

Neutron capture cross section ofTh232measured at the n_TOF facility at CERN in the unresolved resonance region up to 1 MeV

Generalization of the SPRT method: application to ²⁴²Pu cross sections in the Unresolved Resonance Range

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Evaluation of the Unresolved Resonance Range of238U

Cited by 37 publications

References 12 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

Neutron capture cross section ofTh232measured at the n_TOF facility at CERN in the unresolved resonance region up to 1 MeV

Generalization of the SPRT method: application to 242Pu cross sections in the Unresolved Resonance Range

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Evaluation of the Unresolved Resonance Range of²³⁸U

Generalization of the SPRT method: application to ²⁴²Pu cross sections in the Unresolved Resonance Range