Annihilation of positrons in noble gases in the presence of an electric field

1982 ◽  
Vol 60 (12) ◽  
pp. 1717-1719
Author(s):  
P. U. Arifov ◽  
G. I. Zhuravleva
Keyword(s):  
Experimental Data ◽  
Elastic Scattering ◽  
Electric Field ◽  
Cross Sections ◽  
Noble Gases ◽  
Distribution Functions ◽  
Simultaneous Interpretation ◽  
Slowing Down ◽  
Speed Distribution ◽  
Scattering Cross Sections

The present article combines our earlier separate calculations of elastic scattering cross sections, annihilation parameters, and speed distribution functions of positrons slowing down in noble gases for the simultaneous interpretation of experimental data of both beam and drift experiments. Here we present the results on the calculations of phase shifts, annihilation parameter Z(k), speed distribution functions, and Zeff(F).

Microscopic spin-orbit potential for p +6He elastic scattering

2019 ◽  
Vol 28 (09) ◽  
pp. 1950074
Author(s):  
Zakaria M. M. Mahmoud ◽  
Awad A. Ibraheem ◽  
M. A. Hassanain
Keyword(s):  
Experimental Data ◽  
Elastic Scattering ◽  
Cross Sections ◽  
Optical Model ◽  
Spin Orbit ◽  
Current Form ◽  
Density Distributions ◽  
Orbit Potential ◽  
Scattering Cross Sections ◽  
Good Agreement

In this work, we simultaneously reanalyzed the differential elastic scattering cross-sections ([Formula: see text]) and the vector analyzing power ([Formula: see text]) of [Formula: see text]He elastic scattering. This analysis was performed using the folded optical model for both real central and spin-orbit (SO) potentials, respectively. For the imaginary central, we used the usual Woods-Saxon (WS) form. Three different model density distributions are used to calculate the potential. We aimed to examine the applicability of the microscopically derived SO potential and the structure effect of 6He nucleus. The presence of the [Formula: see text] experimental data of [Formula: see text]He makes it interesting for this study. Our calculations showed that the three densities gave similar predictions for the cross-sections data. The three microscopic SO potentials calculations of [Formula: see text] are not in a good agreement with the experimental data. We concluded that the SO formalism in its current form needs more investigations for exotic halo nuclei.

scholarly journals Comparative analysis of proximity potentials to describe scattering of 13C projectile off 12C, 16O, 28Si and 208Pb nuclei

2018 ◽  
Vol 64 (2) ◽  
pp. 149 ◽  
Author(s):  
M. Aygun
Keyword(s):  
Experimental Data ◽  
Comparative Analysis ◽  
Elastic Scattering ◽  
Cross Sections ◽  
Optical Potential ◽  
Saxon Potential ◽  
208Pb Target ◽  
Scattering Cross Sections ◽  
First Time ◽  
Theoretical Results

In this work, we examine the elastic scattering cross sections of 13C on 12C, 16O, 28Si and 208Pb target nuclei at different incident energies. For the first time, we apply six types of proximity potentials such as Broglia andWinther 1991 (BW 91), AageWinther (AW95), Christensen and Winther 1976 (CW 76), Bass 1973 (Bass 73), Bass 1977 (Bass 77) and Bass 1980 (Bass 80) in order to obtain the real part of the optical potential. The imaginary part is taken as the Woods-Saxon potential. Theoretical results are compared with each other as well as the experimental data.

scholarly journals Mott-Schwinger Effect in the Elastic Scattering of Neutrons from 209Bi

1994 ◽  
Vol 47 (6) ◽  
pp. 681 ◽  
Author(s):  
N Alexander ◽  
K Amos ◽  
L Berge
Keyword(s):  
Elastic Scattering ◽  
Electric Field ◽  
Cross Sections ◽  
Magnetic Moment ◽  
Born Approximation ◽  
Exact Results ◽  
Specific Solution ◽  
Scattering Cross ◽  
The Past ◽  
Scattering Cross Sections

The Mott-Schwinger potential arising from the interaction of the magnetic moment of a neutron incident upon an electric field (of 209Bi) is found to have a profound effect upon the elastic scattering cross sections and polarisations at 0�5, 14�5 and 24 MeV. These effects are evaluated by specific solution of the relevant Schrodinger equations (for 100 partial waves) and with the Born approximation used to define the influence upon all higher ones. These 'exact' results agree with the estimations made under approximation in the past, but not Schr6dinger 100 with 'exact' results calculated by a different method.

A comprehensive theoretical analysis of 22Ne nucleus by using different density distributions, different nuclear potentials and different cluster approach

2020 ◽  
Vol 29 (01) ◽  
pp. 1950112
Author(s):  
M. Aygun
Keyword(s):  
Experimental Data ◽  
Elastic Scattering ◽  
Theoretical Analysis ◽  
Cross Sections ◽  
Angular Distributions ◽  
Cluster Approach ◽  
Systematic Analysis ◽  
Density Distributions ◽  
Theoretical Approaches ◽  
Scattering Cross Sections

In this study, a systematic analysis is made on the [Formula: see text]Ne nucleus. First, using different theoretical approaches, we show eight density distributions for the [Formula: see text]Ne nucleus. For there densities, we obtain the elastic scattering angular distributions of [Formula: see text]Ne by [Formula: see text]C and [Formula: see text]C targets. Then, to offer alternative nuclear potentials in explaining nuclear interactions related to [Formula: see text]Ne projectile, we calculate the elastic scattering cross-sections of [Formula: see text]C and [Formula: see text]C reactions by using six different nuclear potentials. Finally, we investigate cluster structures of the [Formula: see text]Ne nucleus via a simple cluster approach. We compare the calculated elastic scattering angular distributions with the experimental data.

scholarly journals A Multilevel Formalism for Neutron Elastic Scattering Cross Sections

1970 ◽  
Vol 23 (5) ◽  
pp. 823
Author(s):  
E Clayton
Keyword(s):  
Experimental Data ◽  
Elastic Scattering ◽  
Cross Sections ◽  
Resonance Region ◽  
R Matrix ◽  
Scattering Cross ◽  
Scattering Cross Sections

An extension of the Feshbach, Porter, and Weisskopf formalism has been developed for neutron elastic scattering. The emphasis in this paper is on resonanceresonance interference and explicit use of the background R matrix. The results of this formulation are compared with experimental data in the resonance region for the nuclides 238U, 197Au, and 23Na.

A ALow-Energy Direct Channel Regge-pole Approach to α-C12Elastic Scattering .I

1981 ◽  
Vol 36 (5) ◽  
pp. 443-446 ◽  
Author(s):  
D. Majumdar ◽  
A. Roy Chowdhury ◽  
T. Roy
Keyword(s):  
Elastic Scattering ◽  
Compound Nucleus ◽  
Cross Sections ◽  
Regge Pole ◽  
Direct Channel ◽  
Scattering Cross ◽  
Scattering Cross Sections ◽  
Background Effect

Abstract Differential scattering cross-sections for the elastic scattering of α by C12 at laboratory bombarding energies from 11.0 to 16.0 MeV have been evaluated in the direct channel Regge-pole formalism, taking into account the contributions from a few nearby dominant excited levels of the compound nucleus O16 and incorporating the background effect. The relevant pole-parameters have also been predicted.

Pseudopotential calculations of elastic scattering of electrons by helium atoms in the range 0–20 eV

1990 ◽  
Vol 68 (1) ◽  
pp. 104-110 ◽  
Author(s):  
B. Plenkiewicz ◽  
P. Plenkiewicz ◽  
J.-P. Jay-Gerin
Keyword(s):  
Experimental Data ◽  
Elastic Scattering ◽  
Momentum Transfer ◽  
Cross Sections ◽  
Theoretical Calculations ◽  
Incident Electron ◽  
Elastic Electron ◽  
Scattering System ◽  
Helium Atoms ◽  
Pseudopotential Calculations

Our earlier pseudopotential calculations on electrons colliding with argon and krypton are extended to consider the elastic electron–helium scattering system. In this paper, we present detailed results for phase shifts, differential, total, and momentum-transfer cross sections for this system for incident electron energies in the range from 0 to 20 eV. These agree very well with existing experimental data and with other theoretical calculations.

scholarly journals Elastic scattering and breakup reactions with light proton- and neutron-rich exotic nuclei

2018 ◽  
Vol 194 ◽  
pp. 07002
Author(s):  
M.K. Gaidarov ◽  
V.K. Lukyanov ◽  
D.N. Kadrev ◽  
E.V. Zemlyanaya ◽  
A.N. Antonov ◽  
...  
Keyword(s):  
Experimental Data ◽  
Elastic Scattering ◽  
Cross Sections ◽  
Cluster Model ◽  
Microscopic Analysis ◽  
High Energy ◽  
The Real ◽  
Optical Potentials ◽  
Generator Coordinate ◽  
Energy Approximation

A microscopic analysis of the optical potentials (OPs) and cross sections of elastic scattering of 8B on 12C, 58Ni, and 208Pb targets at energies 20 < E < 170 MeV and 12,14Be on 12C at 56 MeV/nucleon is carried out. The real part of the OP is calculated by a folding procedure and the imaginary part is obtained on the base of the high-energy approximation (HEA). The density distributions of 8B evaluated within the variational Monte Carlo (VMC) model and the three-cluster model (3CM) are used to construct the potentials. The 14Be densities obtained in the framework of the the generator coordinate method (GCM) are used to calculate the optical potentials, while for the same purpose both the VMC model and GCM densities of 12Be are used. In the hybrid model developed and explored in our previous works, the only free parameters are the depths of the real and imaginary parts of OP obtained by fitting the experimental data. The use of HEA to estimate the imaginary OP at energies just above the Coulomb barrier is discussed. In addition, cluster model, in which 8B consists of a p-halo and the 7Be core, is applied to calculate the breakup cross sections of 8B nucleus on 9Be, 12C, and 197Au targets, as well as momentum distributions of 7Be fragments. A good agreement of the theoretical results with the available experimental data is obtained. It is concluded that the reaction studies performed in this work may provide supplemental information on the internal spatial structure of the proton- and neutron-halo nuclei.

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