scholarly journals The 58Ni(n,p)58Co, 58Ni(n,2n)57Ni, and 58Ni(n,np)57Co Cross Sections at 14·1 MeV

1959 ◽  
Vol 12 (1) ◽  
pp. 103 ◽  
Author(s):  
KH Purser ◽  
EW Titterton
Keyword(s):  
Reaction Mechanism ◽  
Energy Spectrum ◽  
Cross Section ◽  
Cross Sections ◽  
Accurate Estimate ◽  
Experimental Results ◽  
Relative Importance

The energy spectrum of the protons which are emitted when nickel is bombarded with 14 �1 MeV neutrons has been studied recently by several workers-Allan (1957), Colli, Facchini, et al. (1958), and Colli, Pignanelli, et al. (1958). The results of these experiments do not allow an accurate estimate of the relative importance of contributions from the (n,p) reaction and the (n,np) reaction. Such information is necessary when any reaction mechanism is postulated to account for the experimental results. In these experiments, therefore, activation techniques have been used to measure these two cross sections separately for the isotope 58Ni at 14�1 MeV; in addition, the 68Ni(n,2n)57Ni cross section has been remeasured.

scholarly journals Uncertainty Analysis of WWER-1000 Core Macroscopic Cross Sections due to Spectral Effects

2020 ◽  
pp. 39-46
Author(s):  
О. Kukhotska ◽  
I. Ovdiienko ◽  
M. Ieremenko
Keyword(s):  
Energy Spectrum ◽  
Isotopic Composition ◽  
Uncertainty Analysis ◽  
Neutron Flux ◽  
Flux Density ◽  
Cross Section ◽  
Cross Sections ◽  
Fuel Burnup ◽  
Thermophysical Parameters ◽  
Neutron Flux Density

The paper presents the results of uncertainty analysis of WWER‑1000 core macroscopic cross sections due to spectral effects during WWER‑1000 fuel burnup and the analysis of cross section sensitivity from thermophysical parameters of the calculated cell, which affect energy spectrum of neutron flux density. The calculation of changes in the isotopic composition during burnup and the preparation of macroscopic cross sections used the developed HELIOS computer model [1] for TVSA, which is currently operated at most Ukrainian WWER‑1000 units. The GRS approach applying Software for Uncertainty and Sensitivity Analyses (SUSA) [2] was chosen to assess the uncertainty of the macroscopic cross sections due to spectral effects and analysis of cross section sensitivity from thermophysical parameters. The spectral effect on macroscopic cross sections was taken into account by calculating the fuel burnup for variational sets of thermophysical parameters (fuel temperature, coolant temperature and density, boric acid concentration) prepared in advance by the SUSA program, as a result of which fuel isotopic composition vectors were obtained. After that, neutronic constants for the reference state were developed for each of the sets of isotopic composition, which corresponded to a certain set of thermophysical parameters. At the next stage, the uncertainty of macroscopic cross sections of the interaction due to the spectral effects on the isotopic composition of the fuel was analyzed using SUSA 4, followed by the analysis of cross section sensitivity from thermophysical parameters of the calculated cell affecting energy spectrum of neutron flux density. In the future, the uncertainty of two-group macroscopic diffusion constants can be used to estimate the overall uncertainty of neutronic characteristics in large-grid core calculations, in particular, in the safety analysis.

The Scattering of Positrons by Helium: Total Cross Sections up to 270 eV

1975 ◽  
Vol 53 (10) ◽  
pp. 962-967 ◽  
Author(s):  
B. Jaduszliwer ◽  
A. Nakashima ◽  
D. A. L. Paul
Keyword(s):  
Energy Range ◽  
Cross Section ◽  
Cross Sections ◽  
Born Approximation ◽  
Reasonable Agreement ◽  
Experimental Results ◽  
Formation Cross Section ◽  
Sum Rule ◽  
Total Cross Sections ◽  
High Energies

The total cross sections for the scattering of positrons by helium have been measured by the method of transmission in the 16 to 270 eV energy range. The experimental results are higher than those of Canter et al. but are in reasonable agreement with recent results of Griffith et al., and at high energies tend towards Born approximation calculations. The integral of the cross section over positron momentum is smaller than the sum rule estimate made by Bransden et al. A tentative value of (0.034 ± 0.017)πa02 is assigned to the positronium formation cross section at threshold.

scholarly journals Numerical Analysis of Fusion Cross Section of (_^16)O+(_^16)O by Using The Modified Glas-Mosel Formula

2019 ◽  
Vol 8 (2) ◽  
pp. 81
Author(s):  
Yacobus Yulianto ◽  
Zaki Su'ud
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Nuclear Reactions ◽  
Fusion Reaction ◽  
Fusion Cross Section ◽  
Reaction Cross ◽  
Experimental Results ◽  
Light Nuclei ◽  
Study Results ◽  
Numerical Process

<p class="paragrafabstract">One of the interesting topics in nuclear reactions is a study about reaction cross section between the interacting nuclei. For calculating fusion cross section, the Glas-Mosel formula has been proven successfully in explaining the experimental results of fusion cross section. In this study, the fusion cross sections of O16+O16 reaction were calculated by using modified Glas-Mosel formula. The energies were set at 10≤𝐸≤40 MeV. The potential of interacting nuclei was approached by using Woods-Saxon potential. In numerical process, the differential equations were solved by using finite different method and optimization process was performed by using Nelder-Mead method. Good agreement between the experimental and this study results has been achieved successfully. Referring those results above, it can be indicated that the modified Glas-Mosel formula has good capability to explain the experimental results of fusion reaction of light nuclei. It can be a useful tool in explaining the experimental results or in predicting fusion cross section of light nuclei.</p>

Determination of K shell absorption parameters for some lanthanides using the X-ray attenuation method

2015 ◽  
Vol 93 (12) ◽  
pp. 1532-1540 ◽  
Author(s):  
F. Akman ◽  
R. Durak ◽  
M.R. Kaçal
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Experimental Results ◽  
Secondary Source ◽  
X Rays ◽  
Strength Parameters ◽  
X Ray ◽  
Total Attenuation ◽  
First Time

The total attenuation cross section at the K edge, absorption jump ratio, jump factor, Davisson–Kirchner ratio, and oscillator strength parameters for the K shell were determined by measuring the total attenuation cross sections around the K edge for Pr, Nd2O3, and Sm. The measurements were performed in a secondary excitation geometry using the Kα2, Kα1, Kβ1, and Kβ2 X-rays (in the region from 31.817 to 55.293 keV) from different secondary source targets excited by the 59.54 keV γ-photons from an 241Am annular source. It is the first time that the Davisson–Kirchner ratio values have been determined for present samples. The experimental results were compared with the theoretically calculated and other available experimental results.

Cross section for the excitation of helium by He+

1978 ◽  
Vol 56 (9) ◽  
pp. 1232-1234
Author(s):  
S. P. Ojha ◽  
P. Tiwari ◽  
K. P. Srivastava
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Ground State ◽  
Experimental Results

Cross sections for the singlet excitation of helium by He+ impact have been calculated under the Vainshtein, Presnyakov, and Sobelman (VPS) method with peaking approximation. Transitions from the ground state to the n1P(n = 2 and 3) states have been considered. The results are compared with other theoretical and experimental results.

Diffusion and excitation transfer of metastable helium in normal gaseous helium

1952 ◽  
Vol 213 (1115) ◽  
pp. 506-519 ◽  
Keyword(s):  
Diffusion Coefficient ◽  
Elastic Scattering ◽  
Potential Barrier ◽  
Cross Section ◽  
Cross Sections ◽  
Excitation Transfer ◽  
Experimental Results ◽  
Metastable Helium ◽  
Helium Atoms ◽  
Gaseous Helium

The resonance collision of normal and metastable helium atoms has been investigated, and cross-sections calculated for total elastic scattering, diffusion and transfer of excitation. The theoretical diffusion coefficient of metastable atoms in normal helium agrees reasonably well with experimental results of Ebbinghaus and Biondi. As a consequence of a potential barrier in the interaction of the atoms at large separations, the transfer cross-section shows an unusual variation, being small for low collision energies and reaching a maximum of the order of 10 πa 2/0 for collisions about 0.25 eV energy. Comparison is made with experiments by Reynolds.

scholarly journals Cross-section measurements for disintegrations produced by deuterons in the heavy elements

1942 ◽  
Vol 180 (982) ◽  
pp. 321-332 ◽  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Experimental Results ◽  
Heavy Elements ◽  
Nuclear Radius ◽  
The Cross ◽  
Gold Mercury

The cross-sections have been measured for reactions produced by deuterons in platinum, gold, mercury, thallium, lead, bismuth, thorium and uranium, using deuterons of 9 MeV energy from the Cavendish cyclotron. The observed values of σ for the ( d, p ) reaction vary from 30 x 10 -27 cm. 2 for platinum to 5 x 10 -27 cm. 2 for uranium. The values for the ( d, n ) reaction are about one-fifth of those for the ( d, p ) reaction. Calculations of the cross-sections to be expected on theoretical grounds, have been made for two different values of the standard nuclear radius R 0 , namely, 2.0 x 10 -13 and 1.47 x 10 -13 cm. The experimental results are shown to favour the lower of these values.

Cross sections for elastic collisions in cesium–gas interactions

1980 ◽  
Vol 58 (11) ◽  
pp. 1649-1650 ◽  
Author(s):  
E. Bernabeu ◽  
J. M. Alvarez
Keyword(s):  
Total Cross Section ◽  
Cross Section ◽  
Cross Sections ◽  
Noble Gas ◽  
Experimental Results ◽  
Molecular Gas ◽  
Elastic Collisions ◽  
Gas Interactions

The shift and broadening constants for D1, D2 lines of Cs – noble gas and Cs – light molecular gas(H2, N2) systems are reported. The total cross section for elastic collisions is calculated from our experimental results. Some considerations are made on the mixing between 62P1/2 and 62P3/2 for these systems.

scholarly journals GAINS: neutron inelastic cross section measurements of interest for applications and reaction studies

2020 ◽  
Vol 239 ◽  
pp. 01005
Author(s):  
A. Negret ◽  
C Borcea ◽  
M. Boromiza ◽  
Ph. Dessagne ◽  
Gr. Henning ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Nuclear Structure ◽  
Cross Section ◽  
Cross Sections ◽  
Structural Materials ◽  
Reliable Data ◽  
Inelastic Cross Section ◽  
Nuclear Facilities ◽  
Materials Used

The paper represents an overview of the measurements performed using GAINS at GELINA (JRC-Geel, Belgium). While undergoing continuous upgrades, the setup produced highly precise cross sections. Our measurements are primarily driven by technological needs with an emphasis on structural materials used in the development of nuclear facilities. However, most cases offered the opportunity to investigate various reaction mechanism and/or nuclear structure issues. We concentrate on several specific experiments describing the particular difficulties we met and the solutions we adopted to infer reliable data and to draw significant conclusions.

Study of proton induced nuclear reactions on molybdenum: cross section measurements and theoretical calculations

2019 ◽  
Vol 108 (1) ◽  
pp. 1-9
Author(s):  
Alaa Elbinawi ◽  
Mogahed Al-abyad ◽  
Ibrahim Bashter ◽  
Usama Seddik ◽  
Ferenc Ditrói
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Nuclear Reactions ◽  
Theoretical Calculations ◽  
Experimental Results ◽  
Excitation Functions ◽  
Stacked Foil Technique ◽  
Theoretical Results ◽  
Production Conditions ◽  
Foil Technique

Abstract Excitation functions were measured by the activation method using the stacked-foil technique for the natMo(p,x)93(m+g),94m,g,95m,g,96(m+g),99mTc, 92m,95Nb reactions up to 18 MeV. The experimental results were compared with literature data and theoretical results from EMPIRE-3.2.2 code and TENDL. Special attention was paid to the 100Mo(p,2n)99mTc reaction which is very promising for the production of 99mTc at a cyclotron. In order to optimize the production conditions of some medically important Tc isotopes, the integral yields were estimated based on the measured cross sections.

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