An Analytic Benchmark for Neutron Boltzmann Transport with Downscattering—Part II: Flux and Eigenvalue Sensitivities to Nuclear Cross Sections and Resonance Parameters

Author(s):  
A. Alhajri ◽  
V. Sobes ◽  
P. Ducru ◽  
B. Ganapol ◽  
B. Forget
2019 ◽  
Vol 211 ◽  
pp. 02001 ◽  
Author(s):  
Aloys Nizigama ◽  
Pierre Tamagno ◽  
Olivier Bouland

The excited compound nucleus 17O* has been studied over (n,α) and (α,n) cross sections modelling, respectively for 16O and 13C targets in their ground states. The modelling is fulfilled within the Reich-Moore formalism. We were able to calculate the (α,n) cross section by two separate ways: the direct kinematic standard route and by inversion of the (n,α) cross section using the compound nucleus hypothesis. Resonance parameters of the resolved resonance range (0 to 6 MeV) were borrowed from the CIELO project. In a first stage, the modelling is carried out in the referential of the incident particle (either way neutron or α) requesting conversion of the CIELO neutron-type resonance parameters to the α-type. In a second stage, the implementation is uniquely designed in the center of mass system of the excited compound nucleus. The resonance parameters are thus converted in that unique reference framework. The present investigation shows the consistency of the kinetic transformation that relies on the compound nucleus hypothesis.


2016 ◽  
Vol 183 (2) ◽  
pp. 286-297 ◽  
Author(s):  
Taofeng Wang ◽  
Guinyun Kim ◽  
Young Do Oh ◽  
Moo-Hyun Cho ◽  
In Soo Ko ◽  
...  

1952 ◽  
Vol 30 (5) ◽  
pp. 565-576 ◽  
Author(s):  
A. D. MacDonald ◽  
D. D. Betts

Electrical breakdown of neon at high frequencies has been treated theoretically on the basis of the Boltzmann transport equation. Exciting and ionizing collisions are accounted for as energy loss terms in the Boltzmann equation and measured values of the ionization efficiency are used in the integral determining the ionization rate. Electrons are lost to the discharge by diffusion. The equations are treated separately for the cases in which the collision frequency is much less than or much greater than the radian frequency of the applied field. The electron energy distribution functions are expressed in terms of Bessel functions, confluent hypergeometric functions, and simple exponentials. The ionization rate and the diffusion coefficient are calculated using these distribution functions in kinetic theory formulas, and combined with the diffusion equation to predict breakdown fields. The theoretically predicted fields are compared with experiment at 3000 Mc. per sec. The breakdown equations, calculated from kinetic theory and using no gas discharge data other than collision cross sections, predict breakdown electric fields within the limits of accuracy determined by these cross sections over a large range of experimental variables.


1978 ◽  
Vol 45 (6) ◽  
pp. 1189-1191 ◽  
Author(s):  
V. A. Anufriev ◽  
T. S. Belanova ◽  
Yu. S. Zamyatnin ◽  
A. G. Kolesov ◽  
S. N. Nikol'skii ◽  
...  

2021 ◽  
Author(s):  
Jie Ren ◽  
xichao ruan ◽  
Wei Jiang ◽  
Jie Bao ◽  
jincheng wang ◽  
...  

Abstract The capture cross sections of the 169Tm(n, γ) reaction were measured at the back streaming white neutron beam line (Back-n) of the China Spallation Neutron Source (CSNS) using four C6D6 liquid scintillation detectors. To obtain accurate cross sections, the background subtraction, normalization, and correction were carefully taken into consideration in the data analysis. For the resonance at 3.9 eV, the R-matrix code SAMMY was used to determine the resonance parameters with internally normalization method. While the average capture cross sections of 169Tm in the energy range between 30 keV and 300 keV were extracted relative to the 197Au(n, γ) reaction. The measured cross sections of the 169Tm(n, γ) reaction were reported in logarithmically equidistant energy bins with 20 bins per energy decade with a total uncertainty of 5.4%-7.0% in this paper, and described in terms of average resonance parameters by means of a Hauser-Feshbach calculation with fluctuations. Both of the point-wise cross sections and the averge resonance parameters showed fair agreement with the evaluated values of ENDF/B-VIII.0 library in the energy region studied.


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