Validation of the Characteristic Function Model for the Unresolved Resonance Region

Koyumdjieva, N.; Janeva, N.; Volev, K.

doi:10.13182/nse01-a2185

Cited by 8 publications

(5 citation statements)

References 8 publications

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“…Thereby it is possible to affirm that the composed in this way resonance ladder suits not only for description of resonance averaged cross sections but for receiving as well the average functionals for self-shielding problems. This idea is applied in the code HARFOR for computing in the unresolved range the bothaveraged in energy group cross sections and the corresponding self-shielding coefficients for our functionals [15]. The results of HARFOR agree in general with these obtained by the codes GRUCON [16], NJOY [17] and by resonance sampling Monte Carlo method [8].…”

Section: Generalized Statistical Approachsupporting

confidence: 66%

Resonance data for self-shielding problems

Janeva

Luk'yanov

Koyumdjieva

2007

Nd2007

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Abstract. The investigation of resonance self-shielding effects in macroscopic medium is important for the physics of nuclear reactors and shielding. The degree of consistency of evaluated resonance cross sections data and the requirements to the accurate presentation of self-shielding effects can be estimated by using the simplest benchmark data for resonance averaged functions of neutron transmission and self-indication cross section at arbitrary filter thickness n. We report the developed (for nonfissile nuclei) methods for description of cross sections and their functionals in the unresolved resonance range that aim to estimate properly the self-shielding effects and reveal the resonance structure in averaging intervals (groups).

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Section: Generalized Statistical Approachsupporting

confidence: 66%

Resonance data for self-shielding problems

Janeva

Luk'yanov

Koyumdjieva

2007

Nd2007

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“…These corrections were studied by both analytical expressions [6] and Monte Carlo simulations. For the analytical expressions we used the HARFOR code [7,8] to calculate the self-shielding corrections. This code was primarily developed for the parameterization of cross sections in the URR (see the next section).…”

Section: Th(nγ) Cross-section Measurements At Gelinamentioning

confidence: 99%

“…In the URR average cross sections can be parameterized by statistical models, implemented in e.g., the FITACS [12] and HARFOR [7,8] codes. The former is based on the Hauser-Feshbach statistical reaction theory including width fluctuations following the Moldauer prescription.…”

Section: Evaluation In the Unresolved Resonance Regionmentioning

confidence: 99%

Evaluation of the 232Th Neutron Cross Sections between 4 keV and 140 keV

Volev

Koyumdjieva

Brusegan³

et al. 2005

AIP Conference Proceedings

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An evaluation of the 232 Th neutron total and capture cross sections has been performed in the energy region between 4 keV and 140 keV. The evaluation results from a simultaneous analysis of capture, transmission, and selfindication measurement data, including the most recent capture cross-section data obtained at the GELINA facility of the Institute for Reference Materials and Measurements at Geel (B) and at the n-TOF facility at CERN (CH). The experimental data have been analysed in terms of average resonance parameters exploiting two independent theoretical approaches -the Characteristic Function model and the Hauser-Feshbach-Moldauer theory. The resulting parameters are consistent with the resolved resonance parameters deduced from the transmission measurements of Olsen et al. at the ORELA facility.

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“…The characteristic function method for one channel case is applied in the HARFOR code [8]. The average cross sections and their functionals are computed by the Rnn (ε)-function (equation ( 5)).…”

Section: Numerical Procedures For Calculation Of Cross Sections and T...mentioning

confidence: 99%

Cross section structure of²³²Th in the unresolved resonance region

Koyumdjieva¹,

Janeva²,

Luk'yanov³

2010

J. Phys. G: Nucl. Part. Phys.

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An analysis of the 232Th neutron total and neutron capture cross sections has been performed in the energy region between 4 keV and 140 keV. The experimental data are analysed in terms of average resonance parameters utilizing a new statistical method for modelling of the resonance cross section structure in the region of experimentally unresolved resonances. The method exploits the characteristic function of the R-matrix elements distribution in Wigner's theory of nuclear reactions. To improve the representation of the 232Th cross section, the neutron strength functions for s- and p-waves are fitted to the experimental data in order to reproduce their observable fluctuations in (4–140) keV. Our method offers analytical expressions even for nonlinear functionals (observables) of neutron cross section as a transmission ratio. These functionals are incorporated into the evaluation process as a simple benchmark test for verification of the 232Th resonance parameters.

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Validation of the Characteristic Function Model for the Unresolved Resonance Region

Cited by 8 publications

References 8 publications

Resonance data for self-shielding problems

Resonance data for self-shielding problems

Evaluation of the 232Th Neutron Cross Sections between 4 keV and 140 keV

Cross section structure of²³²Th in the unresolved resonance region

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Validation of the Characteristic Function Model for the Unresolved Resonance Region

Cited by 8 publications

References 8 publications

Resonance data for self-shielding problems

Resonance data for self-shielding problems

Evaluation of the 232Th Neutron Cross Sections between 4 keV and 140 keV

Cross section structure of232Th in the unresolved resonance region

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Product

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Cross section structure of²³²Th in the unresolved resonance region