scholarly journals SENSITIVITY OF MONTE CARLO CALCULATIONS TO THE NEUTRON CROSS SECTIONS FOR NEUTRON TRANSPORT IN NITROGEN AND IN AIR.

1971 ◽  
Author(s):  
L.F. Hansen ◽  
J.D. Anderson ◽  
J.L. Kammerdiener ◽  
C. Wong
Keyword(s):  
Monte Carlo ◽  
Cross Sections ◽  
Neutron Transport ◽  
Monte Carlo Calculations ◽  
Neutron Cross Sections

scholarly journals IMPROVEMENT OF SCALE-XSProc MULTIGROUP CROSS SECTION PROCESSING BASED ON THE CENTRM POINTWISE SLOWING DOWN CALCULATION

2021 ◽  
Vol 247 ◽  
pp. 02011
Author(s):  
Seog Kim Kang ◽  
Andrew M. Holcomb ◽  
Friederike Bostelmann ◽  
Dorothea Wiarda ◽  
William Wieselquist
Keyword(s):  
Monte Carlo ◽  
Cross Section ◽  
Cross Sections ◽  
Reaction Rate ◽  
Neutron Transport ◽  
Energy Structure ◽  
Reactor Physics ◽  
Slowing Down ◽  
Monte Carlo Calculations ◽  
Scattering Matrices

The SCALE-XSProc multigroup (MG) cross section processing procedure based on the CENTRM pointwise slowing down calculation is the primary procedure to process problem-dependent self-shielded MG cross sections and scattering matrices for neutron transport calculations. This procedure supports various cell-based geometries including slab, 1-D cylindrical, 1-D spherical and 2-D rectangular configurations and doubly heterogeneous particulate fuels. Recently, this procedure has been significantly improved to be applied to any advanced reactor analysis covering thermal and fast reactor systems, and to be comparable to continuous energy (CE) Monte Carlo calculations. Some reactivity bias and reaction rate differences have been observed compared with CE Monte Carlo calculations, and several areas for improvement have been identified in the SCALE-XSProc MG cross section processing: (1) resonance self-shielding calculations within the unresolved resonance range, (2) 10 eV thermal cut-off energy for the free gas model, (3) on-the-fly adjustments to the thermal scattering matrix, (4) normalization of the pointwise neutron flux, and (5) fine MG energy structure. This procedure ensures very accurate MG cross section processing for high-fidelity deterministic reactor physics analysis for various advanced reactor systems.

Reactions of 88Sr with protons of energies7–85 MeV

1967 ◽  
Vol 45 (10) ◽  
pp. 1149-1160 ◽  
Author(s):  
D. R. Sachdev ◽  
N. T. Porile ◽  
L. Yaffe
Keyword(s):  
Monte Carlo ◽  
Compound Nucleus ◽  
Cross Sections ◽  
Experimental Results ◽  
Excitation Functions ◽  
Monte Carlo Calculations ◽  
High Energies ◽  
The Individual ◽  
Two Peaks ◽  
Evaporation Stage

Excitation functions for the (p,xn) (x = 1–5), (p,p3n), and (p,2pxn) (x = 1, 3, 4) reactions induced in 88Sr by protons of energy from 7 to 85 MeV have been measured by radiochemical methods. Cross sections for the individual isomeric species for the products of (p,2n), (p,3n), (p,4n), and (p,p3n) reactions are also presented.Excitation functions for each of the (p,2p3n) and (p,2p4n) reactions exhibit two peaks, the first of which is assigned to (p,α n) or (p,α 2n) reactions from threshold considerations. The experimental results are compared with Monte Carlo calculations using the codes of Chen et al. for the cascade stage and Dostrovsky et al. for the evaporation stage. The comparison suggests that the calculations of Chen et al. overestimate the extent of compound nucleus contribution at high energies.

scholarly journals Collisions of Nucleons with Atoms: Calculated Cross Sections and Monte Carlo Simulation

2021 ◽  
Vol 9 ◽  
Author(s):  
Francesc Salvat ◽  
José Manuel Quesada
Keyword(s):  
Monte Carlo ◽  
Cross Sections ◽  
Nuclear Reactions ◽  
Impact Ionization ◽  
Neutron Transport ◽  
Emission Spectra ◽  
Monte Carlo Code ◽  
Dose Distributions ◽  
Elastic Collisions ◽  
Proton Impact

After a summary description of the theory of elastic collisions of nucleons with atoms, we present the calculation of a generic database of differential and integrated cross sections for the simulation of multiple elastic collisions of protons and neutrons with kinetic energies larger than 100 keV. The relativistic plane-wave Born approximation, with binding and Coulomb-deflection corrections, has been used to calculate a database of proton-impact ionization of K-shell and L-, M-, and N-subshells of neutral atoms These databases cover the whole energy range of interest for all the elements in the periodic system, from hydrogen to einsteinium (Z = 1–99); they are provided as part of the penh distribution package. The Monte Carlo code system penh for the simulation of coupled electron-photon-proton transport is extended to account for the effect of the transport of neutrons (released in proton-induced nuclear reactions) in calculations of dose distributions from proton beams. A simplified description of neutron transport, in which neutron-induced nuclear reactions are described as a fractionally absorbing process, is shown to give simulated depth-dose distributions in good agreement with those generated by the Geant4 code. The proton-impact ionization database, combined with the description of atomic relaxation data and electron transport in penelope, allows the simulation of proton-induced x-ray emission spectra from targets with complex geometries.

Electron-beam spreading in thin foils at 40keV

1983 ◽  
Vol 41 ◽  
pp. 370-371
Author(s):  
T.A. Stephenson ◽  
M.H. Loretto ◽  
I.P. Jones ◽  
P. Augustus
Keyword(s):  
Monte Carlo ◽  
Single Crystal ◽  
Cross Sections ◽  
Single Crystal Silicon ◽  
Orientation Dependence ◽  
High Angle ◽  
Crystal Silicon ◽  
Beam Spreading ◽  
Monte Carlo Calculations ◽  
Thin Foils

Experiments have been performed to determine the effects of thickness, and crystallinity on beam spreading in thin foils. The experimental technique consists of measuring an incident and exit electron probe size as shown in Fig. 1. Beam spreading is defined as the difference between these two quantities. Results were compared with Monte Carlo calculations.Beam spreading experiments in single crystal silicon oriented positive of a 440 reflection have shown that the experimental measurements are adequately described by Monte Carlo calculations using Doyle and Turner elastic scattering cross-sections (Fig.2). The addition of an inelastic component via the Bethe continuous loss approximation produces an insignificant change. Adjustment for the generation and scattering of fast secondary electrons is reserved for future work.Two experiments were performed to elucidate the effects of crystallinity. The first involved single crystal silicon in which exit grobe size measurgments were performed with diffracting conditions s=+0.0027Å-1 and s=-0.0034Å-1 from 220 (Table 1). Since beam spreading is dependent on high angle scattering, these results are qualitatively consistent with the orientation dependence of high angle diffuse scattering.

Using the Few-Group Approximation for Calculating Some Neutron-Physical Characteristics of VVER-1000 Core by Means of the MCU Monte-Carlo Code

2021 ◽  
Author(s):  
Artem S. Bikeev ◽  
Yulia S. Daichenkova ◽  
Mikhail A. Kalugin ◽  
Denis Shkarovsky ◽  
Vladislav V. Shkityr
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Cross Sections ◽  
Optimal Number ◽  
Physical Characteristics ◽  
Monte Carlo Code ◽  
Special Version ◽  
The Monte Carlo Method ◽  
Scattering Anisotropy ◽  
Neutron Cross Sections

Abstract The main purpose of this work is to study the possibility of using the few-group approximation for calculation of some neutron-physical characteristics of VVER-1000 core by means of special version of MCU code. The Monte-Carlo method for VVER-1000 core neutron-physical characteristics calculation using the few-group approximation with an estimate of neutron cross sections “by location“ was provided and tested in this research. The reduction of calculation time due to the transition from a pointwise model of representation of cross sections to the few-group approximation and methodical error of this approach were evaluated. Optimal number of energy groups was determined. It was found that consideration of the scattering anisotropy leads to a significant decrease in methodical error. Ways of further reduction of methodical error were worked out.

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