Analysis of the reaction Q-value effect using newly evaluated empirical formulas of (n,2n) cross-sections near 14.6MeV

2020 ◽  
Vol 29 (02) ◽  
pp. 2050005 ◽  
Author(s):  
M. Yiğit
Keyword(s):  
Experimental Data ◽  
Cross Section ◽  
Cross Sections ◽  
Nuclear Reactions ◽  
Measured Data ◽  
Q Value ◽  
Present Communication ◽  
Empirical Formulas ◽  
The Cross ◽  
Value Effect

Empirical formulas in determining the cross-sections play an important role at the energies of which there are no experimental data scattered about. The purpose of the present communication is to further improve the formulas of the cross-section of [Formula: see text] reactions at the energies near 14.6[Formula: see text]MeV. A systematics for the evaluation of these cross-sections is studied. We present the empirical formulas based on the statistical theory of nuclear reactions in connection with the compound nucleus. The new empirical formulas are found by using the experimental cross-sections as a function of the reaction [Formula: see text]-value. Thus, the new formulas provide the best description of the existing measured data compared with systematics suggested earlier by other authors.

A new empirical formula for cross-sections of (n,nα) reactions

2020 ◽  
Vol 29 (08) ◽  
pp. 2050062
Author(s):  
Mustafa Yiğit
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Empirical Formula ◽  
Nuclear Reactions ◽  
Measured Cross Section ◽  
Future Studies ◽  
Present Formalism ◽  
The Cross ◽  
Neutron Cross Sections ◽  
Good Agreement

Studies on the cross-sections of (n,n[Formula: see text]) reactions which are energetically possible, about 14 MeV neutrons are quite scarce. In this paper, the cross-sections of (n,n[Formula: see text] nuclear reactions at [Formula: see text]14–15 MeV are analyzed by using a new empirical formula based on the statistical theory. We show that neutron cross-sections are closely related to the [Formula: see text]-value of nuclear reaction, in particular for (n,n[Formula: see text]) channels. Results obtained with this empirical formula show good agreement with the available measured cross-section values. We hope that the estimations on the cross-sections using the present formalism may be helpful in future studies in this field.

scholarly journals Cross sections of electron collisions with noble gases atoms

2021 ◽  
pp. 11-16
Author(s):  
Rusudan Golyatina ◽  
Sergei Maiorov
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Noble Gas ◽  
Empirical Formulas ◽  
Electron Collisions ◽  
Wide Range ◽  
Analytical Formulas ◽  
The Cross ◽  
Approximation Coefficients ◽  
Ionization Cross Sections

Consideration is given to the analysis of data on the cross sections of elastic and inelastic col-lisions of electrons with noble gas atoms. The transport (diffusion) cross section, the excita-tion and ionization cross sections are studied. For the selected sets of experimental and theo-retical data, optimal analytical formulas are found and approximation coefficients are select-ed for them. The obtained semi-empirical formulas allow us to reproduce the cross section values in a wide range of collision energies from 0.001 to 10000 eV with an accuracy of sev-eral percent.

scholarly journals Numerical simulation of the transverse flow over spans of girder bridges

2018 ◽  
Vol 18 (4) ◽  
pp. 362-378
Author(s):  
Yu. A. Gosteev ◽  
A. D. Obukhovskiy ◽  
S. D. Salenko
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Cross Section ◽  
Cross Sections ◽  
Aerodynamic Characteristics ◽  
Transverse Flow ◽  
Single Beam ◽  
Weighted Estimates ◽  
Girder Bridges ◽  
The Cross

Introduction. The technique of numerical modeling of the transverse flow over span structures of bridges on the basis of the two-dimensional URANS (Unsteady Reynolds-averaged Navier-Stokes) approach used in the modern methods and software packages for computational fluid dynamics is verified. The work objective was debugging and experimental substantiation of this technique with the use of the database on the aerodynamic characteristics of the cross-sections of span structures of girder bridges of standard shapes pre-developed by the authors.Materials and Methods. A numerical simulation of the transverse flow of low-turbulent (smooth) and turbulent air flows around the bridge structures in a range of practically interesting attack angles is carried out. SST  k − ω turbulence model was used as the closing one. The technique was preliminarily tested on the check problem for the flow of the rectangular crosssection beams. Calculations were carried out using the licensed ANSYS software.Research Results. The calculated dependences on the attack angle of the aerodynamic coefficients of forces (drag and lift) and the moment of the cross sections of the girder bridges of standard shapes are obtained. These data refer to the span structures at the construction phase (without deck and parapets, without parapets) and operation phase, under the conditions of model smooth and turbulent incoming flow. The latter allows us to outline the boundaries for more weighted estimates of the aerodynamic characteristics of thegirder bridges in a real wind current. The best agreement with the experimental data was obtained from the drag of the cross-section. The magnitude of the lifting force is more sensitive to the presence and extent of the separation regions, so its numerical determination is less accurate. The reproduction of the angle-of-attack effect on the aerodynamic moment of the cross-section is the most challenging for the majority of configurations.Discussion and Conclusions. Comparison of the calculated and experimental data indicates the applicability of the URANS approach to the operational prediction of the aerodynamic characteristics of the single-beam span structures. In the case of multi-beam span structures, where the aerodynamic interference between separate girders plays an important role, the URANS approach must apparently give way to more accurate eddy-resolving methods. The results obtained can be used in the aerodynamic analysis of structures and in practice of the relevant design organizations in the field of transport construction.

scholarly journals Study of the Production Cross-Sections of the Neutron-rich 184Ta and 186Ta

2021 ◽  
Vol 9 (1) ◽  
pp. 25-29
Author(s):  
Susshma Nagarajan ◽  
Deepa Seetharaman ◽  
Gowrishankar Ramadurai
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Cross Section ◽  
Cross Sections ◽  
Good Yield ◽  
Production Cross ◽  
Effective Synthesis ◽  
The Cross

Synthesizing nuclei through reactions that produce a reasonable yield is important for the experimental study of neutron-rich nuclei. In this study, the cross-section values of 184Ta and 186Ta nuclei in various experiments were reviewed and analysed. The experimental data of (n, p), (p, x) and (n, α) reactions were compared to identify the best reaction to produce these nuclei for further study. Our study shows that (n, p) reactions on natural Tungsten targets are the most feasible reactions with a good yield of the neutron-rich Tantalum isotopes. New reactions have been proposed for the effective synthesis of 184Ta and 186Ta using tritium beams on Hafnium targets. The cross-section values of the proposed reactions were calculated by PACE4 software simulations.

scholarly journals A comprehensive analysis of differential cross sections and analyzing powers in the proton–deuteron break-up channel at 135 MeV

2021 ◽  
Vol 57 (2) ◽  
Author(s):  
H. Tavakoli-Zaniani ◽  
M. Eslami-Kalantari ◽  
H. R. Amir-Ahmadi ◽  
M. T. Bayat ◽  
A. Deltuva ◽  
...  
Keyword(s):  
Experimental Data ◽  
Cross Section ◽  
Cross Sections ◽  
Theoretical Calculations ◽  
Nucleon Force ◽  
Satisfactory Description ◽  
Analyzing Powers ◽  
Global Comparison ◽  
Break Up ◽  
The Cross

AbstractA selection of measured cross sections and vector analyzing powers, $$A_{x}$$ A x and $$A_{y}$$ A y , are presented for the $$\vec {p}{d}$$ p → d break-up reaction. The data are taken with a polarized proton beam with a kinetic energy of 135 MeV using the Big Instrument for Nuclear-polarization Analysis (BINA) at KVI, the Netherlands. With this setup, $$A_{x}$$ A x is extracted for the first time for a large range of energies as well as polar and azimuthal angles of the two outgoing protons. For most of the configurations, the results at small and large relative azimuthal angles differ in behavior when comparing experimental data with the theoretical calculations. We also performed a more global comparison of our data with theoretical calculations. The cross-section results show huge values of $$\chi ^{2}$$ χ 2 /d.o.f.. The absolute values of $$\chi ^{2}$$ χ 2 /d.o.f. for the components of vector analyzing powers, $$A_{x}$$ A x and $$A_{y}$$ A y , are smaller than the ones for the cross section, partly due to larger uncertainties for these observables. However, also for these observables no satisfactory agreement is found for all angular combinations. This implies that the present models of a three-nucleon force are not able to provide a satisfactory description of experimental data.

scholarly journals PROMPT PHOTON PRODUCTION IN p-p COLLISIONS

1995 ◽  
Vol 10 (20n21) ◽  
pp. 2941-2960 ◽  
Author(s):  
J. CLEYMANS ◽  
E. QUACK ◽  
K. REDLICH ◽  
D.K. SRIVASTAVA
Keyword(s):  
Experimental Data ◽  
Cross Section ◽  
Cross Sections ◽  
Systematic Study ◽  
Structure Functions ◽  
Photon Production ◽  
Prompt Photon ◽  
Centre Of Mass ◽  
The Cross ◽  
Photon Cross Section

A systematic study of the inclusive photon cross-section in p-p collisions is presented. The dependence of the γ rates on the renormalization and factorization scales is discussed. A comparison is made with experimental data for centre-of-mass energies ranging from 23 GeV to 1.8 TeV. Predictions of the cross-sections are given for two different sets of structure functions for RHIC and LHC energies.

scholarly journals Estimation Pre-Equilibrium Particle and Angular Distribution Spectra for the Neutrons Induce Nuclear Reactions on 90Zr Nuclei by using (FKK) Model

2021 ◽  
Vol 12 (5) ◽  
pp. 2001-2008
Author(s):  
Abd alsatar Khlil Maroof, Et. al.
Keyword(s):  
Angular Distribution ◽  
Cross Section ◽  
Cross Sections ◽  
Nuclear Reactions ◽  
Target Material ◽  
Shell Effects ◽  
Well Depth ◽  
Light Particles ◽  
The Cross

Particles pre - equilibrium spectra and angular distribution are calculated by usingFeshbach-Kerman- Koonin (FKK) model with  PRECO-2006 code. The angular distribution of the nuclei of nuclear reactions between the nucleus of a target (90Zr) and the tapline of light particles wascalculated by using reactions of the multistep compound (MSC) and of multistep direct (MSD).Isospin, the finite well depth, and shell effects are considered. Byusing [(_40^90)〖Zr〗_50 ] as target material the cross section of  [90Zr(n,n)90Zr], [90Zr(n,p)90Y], [90Zr(n,D)89Y], [90Zr(n,T)88Y], [90Zr(n,3He)88Sr] and [90Zr(n,4He)87Sr] reactions were estimated. Values of  cross sections estimated  are 550, 371, 16.3, 4.55, 0.271 and 2.35 mb/MeV respectively. Also the angular  distribution of same nuclear reactions were estimated, and the values of angular  distribution  are 850, 392, 4.55, 4.55,0.27 and 2.35mb/sr.MeV respectively.

The cross sections for different channels in heavy ion nuclear reactions

1971 ◽  
Vol 32 (1) ◽  
pp. 7-9 ◽  
Author(s):  
J. Galin ◽  
D. Guerreau ◽  
M. Lefort ◽  
X. Tarrago
Keyword(s):  
Cross Sections ◽  
Nuclear Reactions ◽  
Heavy Ion ◽  
The Cross

Experimental Studies Of Multilayer Glass Structures On Compression, Compression With Bending And Simple Bending

2019 ◽  
pp. 22-30
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Applied Load ◽  
Experimental Studies ◽  
Strength Properties ◽  
Research Topic ◽  
Normative Values ◽  
Laminated Glass ◽  
The Cross ◽  
Experimental Values

The work of multilayer glass structures for central and eccentric compression and bending are considered. The substantiation of the chosen research topic is made. The description and features of laminated glass for the structures investigated, their characteristics are presented. The analysis of the results obtained when testing for compression, compression with bending, simple bending of models of columns, beams, samples of laminated glass was made. Overview of the types and nature of destruction of the models are presented, diagrams of material operation are constructed, average values of the resistance of the cross-sections of samples are obtained, the table of destructive loads is generated. The need for development of a set of rules and guidelines for the design of glass structures, including laminated glass, for bearing elements, as well as standards for testing, rules for assessing the strength, stiffness, crack resistance and methods for determining the strength of control samples is emphasized. It is established that the strength properties of glass depend on the type of applied load and vary widely, and significantly lower than the corresponding normative values of the strength of heat-strengthened glass. The effect of the connecting polymeric material and manufacturing technology of laminated glass on the strength of the structure is also shown. The experimental values of the elastic modulus are different in different directions of the cross section and in the direction perpendicular to the glass layers are two times less than along the glass layers.

SETTING A DIAGRAM APPROACH TO CALCULATING VIBRATED, CENTRIFUGED AND VIBROCENTRIFUGED REINFORCED CONCRETE COLUMNS WITH A VARIATROPIC STRUCTURE

2020 ◽  
pp. 22-34
Author(s):  
Л. Р. Маилян ◽  
С. А. Стельмах ◽  
Е. М. Щербань ◽  
М. П. Нажуев
Keyword(s):  
Experimental Data ◽  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Cross Section ◽  
Concrete Columns ◽  
Reinforced Concrete Columns ◽  
The Cross ◽  
Concrete Elements ◽  
Diagram Approach

Состояние проблемы. Железобетонные элементы изготавливаются, как правило, по трем основным технологиям - вибрированием, центрифугированием и виброцентрифугированием. Однако все основные расчетные зависимости для определения их несущей способности выведены, исходя из основного постулата - постоянства и равенства характеристик бетона по сечению, что реализуется лишь в вибрированных колоннах. Результаты. В рамках диаграммного подхода предложены итерационный, приближенный и упрощенный способы расчета несущей способности железобетонных вибрированных, центрифугированных и виброцентрифугированных колонн. Выводы. Расчет по диаграммному подходу показал существенно более подходящую сходимость с опытными данными, чем расчет по методике норм, а также дал лучшие результаты при использовании дифференциальных характеристик бетона, чем при использовании интегральных и, тем более, нормативных характеристик бетона. Statement of the problem. Reinforced concrete elements are typically manufactured according to three basic technologies - vibration, centrifugation and vibrocentrifugation. However, all the basic calculated dependencies for determining their bearing capacity were derived using the main postulate, i.e., the constancy and equality of the characteristics of concrete over the cross section, which is implemented only in vibrated columns. Results. Within the framework of the diagrammatic approach, iterative, approximate and simplified methods of calculating the bearing capacity of reinforced concrete vibrated, centrifuged and vibrocentrifuged columns are proposed. Conclusions. The calculation according to the diagrammatic approach showed a significantly better convergence with the experimental data than that using the method of norms, and also performs better when using differential characteristics of concrete than when employing integral and particularly standard characteristics of concrete.

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