scholarly journals Corrigendum: Mott?Schwinger Effect in the Elastic Scattering of Neutrons from 209Bi

1995 ◽  
Vol 48 (4) ◽  
pp. 737 ◽  
Author(s):  
N Alexander ◽  
K Amos ◽  
L Berge
Keyword(s):  
Partial Wave ◽  
Cross Section ◽  
Cross Sections ◽  
Phase Shifts ◽  
Exact Results ◽  
Forward Angle ◽  
Nuclear Scattering ◽  
Wave Phase ◽  
Angle Effect ◽  
Theoretical Developments

The results presented in our recent paper are in error. All of the theoretical developments contained therein are correct but the Mott-Schwinger (MS) interaction was doubly counted for small radii in our computations. That had a significant effect upon the exact values of the small-f partial wave phase shifts. In fact, the correct variation of the first 20 partial wave phase shifts from purely nuclear scattering are much smaller than we presented before. Consequently the variation caused by the MS effect in predictions of the observables is smaller than previously indicated, and particularly so for scattering angles in excess of 20� for the cases of neutrons scattered from bismuth that were considered. At small angles, there are still characteristic and noticeable differences caused by the MS interaction for the scattering of 0�5, 14�5 and 24 MeV neutrons from 209Bi. With the differential cross section, the forward angle effect remains as shown previously; that is, dominated by the cot (~O) element in the scattering amplitudes due to the infinite partial wave sum of MS phase contributions. But the deviations to the higher angle cross sections reported earlier are very much reduced. The major effects of the correction, however, are with the predictions of the spin-dependent measureables and the exact results for P(O) and the two general variables, Xvar(O) and Yvar(O).

Positron–Helium Scattering Cross Sections and Phase Shifts below 19 eV

1973 ◽  
Vol 51 (14) ◽  
pp. 1565-1572 ◽  
Author(s):  
B. Jaduszliwer ◽  
D. A. L. Paul
Keyword(s):  
Energy Range ◽  
Cross Section ◽  
Cross Sections ◽  
Phase Shifts ◽  
S Wave ◽  
Wave Phase ◽  
Entire Energy Range ◽  
Nice Agreement ◽  
Scattering Cross Sections ◽  
D Wave

The total cross sections for elastic scattering of positrons in the energy range from 4 to 19 eV have been measured by the method of transmission. By varying a magnetic field applied along the axis of the scattering chamber the transmitted fraction of the beam is altered, from which individual phase shifts can be extracted. s-, p-, and d-wave phase shifts are given over the entire energy range. The s-wave phase shifts are in agreement with values published by Drachman in 1968, while the p- and d-wave phase shifts are intermediate between values calculated by the same author in 1966 and 1971. The experimental results agree with those of Costello et al., and marginally with our own 1972 results, but are significantly different from those of Canter et al. We compute that the Ramsauer minimum in the diffusion cross section must be 0.04πa02 at 1.6 eV while the minimum in the total cross section is 0.11πa02 at 2.1 eV. The shoulder breadth observed in annihilation experiments is in nice agreement with what one would predict from our phase shifts.

scholarly journals Scattering Cross Sections in Argon from Electron Transport Parameters

1982 ◽  
Vol 35 (1) ◽  
pp. 35 ◽  
Author(s):  
GN Haddad ◽  
TF O'Malley
Keyword(s):  
Phase Shift ◽  
Cross Section ◽  
Cross Sections ◽  
Lateral Diffusion ◽  
Phase Shifts ◽  
P Wave ◽  
Transport Parameters ◽  
S Wave ◽  
Wave Phase ◽  
Range Theory

Previously determined experimental drift velocities Vdr and ratios of lateral diffusion coefficient to mobility DT/µ have been refitted directly with a three parameter modified effective range theory (MER T) representation of the S wave phase shift, a one parameter fit to the P wave phase shift and fixed higher partial wave phase shifts. The MERT representation now extends to 1·0 eV, a threefold extension of the energy range of the MERT fit reported by Milloy et al. (1977). The total cross section derived from the phase shifts is also reported, together with the differential cross section at 1·0 eV which is compared with a previous experimental determination.

STOPPING CROSS SECTIONS IN CARBON FOR LOW-ENERGY ATOMS WITH

1963 ◽  
Vol 41 (9) ◽  
pp. 1424-1442 ◽  
Author(s):  
J. H. Ormrod ◽  
H. E. Duckworth
Keyword(s):  
Monte Carlo ◽  
Cross Section ◽  
Atomic Number ◽  
Cross Sections ◽  
Monte Carlo Calculation ◽  
Low Energy ◽  
Energy Interval ◽  
Nuclear Scattering

The electronic stopping cross sections in carbon for atomic projectiles with [Formula: see text] have been determined in the energy interval from 10 to 140 kev. In doing so a Monte Carlo calculation was used to subtract from each experimentally observed cross section the contribution which arises from nuclear scattering. The trend of the results thus obtained agrees well with theory. In addition, however, a periodic dependence of Sε on the atomic number of the projectile is observed.

Basic Concepts

2020 ◽  
pp. 1-30
Author(s):  
Andrew T. Boothroyd
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Scattering Length ◽  
Neutron Production ◽  
Absorption Cross ◽  
Nuclear Scattering ◽  
Simple Interpretation ◽  
Matter Waves ◽  
Basic Concepts ◽  
Scattering Cross Sections

This chapter introduces the basic properties of the neutron and its interactions with matter. The principal methods for neutron production are described, especially reactor and spallation sources. The kinematics of scattering are explained, and a simple interpretation is given in terms of the interference of matter waves. Nuclear scattering is separated into coherent and incoherent contributions, and the neutron scattering length is defined. The concept of the cross-section is introduced, and the total, differential, and partial differential scattering cross-sections, as well as the absorption cross-section, are defined.

scholarly journals AN APPROACH TO POTENTIAL SCATTERING

2005 ◽  
Vol 20 (26) ◽  
pp. 1983-1989 ◽  
Author(s):  
B. GÖNÜL ◽  
M. KOÇAK
Keyword(s):  
Perturbation Theory ◽  
Partial Wave ◽  
Bound State ◽  
Phase Shifts ◽  
Potential Scattering ◽  
Wave Phase

Recently developed time-independent bound-state perturbation theory is extended to treat the scattering domain. The changes in the partial wave phase shifts are derived explicitly and the results are compared with those of other methods.

Vacuum polarization and D-wave α−α scattering

1969 ◽  
Vol 47 (1) ◽  
pp. 113-115 ◽  
Author(s):  
Mark W. Kermode
Keyword(s):  
Cross Sections ◽  
Differential Cross ◽  
Vacuum Polarization ◽  
Center Of Mass ◽  
Phase Shifts ◽  
Differential Cross Sections ◽  
Wave Phase ◽  
Low Energies ◽  
D Wave

The D-wave phase shifts for α−α scattering at low energies are obtained from (i) new analyses of the differential cross sections and (ii) the effects of vacuum polarization. The results are −0.4° (−0.4°), −0.2° (−0.4°), +0.2° (−0.4°), −0.2° (−0.2°), and 0.3° (0.2°) for the center-of-mass energies 0.3, 0.425, 0.5, 0.75, and 1.0 MeV, respectively. It is felt that these results are significant.

Calculation of Average Collision Cross Sections of Low Energy for Elastic e-Ar Scattering Using MERT4

2014 ◽  
Vol 81 (1) ◽  
Author(s):  
S. Hassanpour ◽  
S. Nguyen-Kuok
Keyword(s):  
Energy Range ◽  
Cross Section ◽  
Electron Scattering ◽  
Cross Sections ◽  
Phase Shifts ◽  
Low Energy ◽  
Effective Range ◽  
Collision Cross Sections ◽  
Range Theory ◽  
Effective Range Theory

Cross sections in the very low energy range are also represented by the modified effective-range theory (MERT) for low-energy electron scattering from the rare gas (argon). Simulations using published (theoretical) phase shifts indicate that extended versions of the standard effective-range theory with four adjustable parameters are required to give an adequate description of the phase shifts for argon. A four-parameter MERT fit gives a good representation of a recent electron–argon (e-Ar) total cross section experiment at energies less than 10.0 eV. Cross section Q(l) (E) for collision in dilute gases is given for any order l. Here Q(l) (E) are presented for l = 1. . .6. We present calculations for the elastic cross sections for electron scattering from argon. The improvement in the agreement between our theoretical calculations and the experimental measurements in the case of argon in scattering calculations are showed. Differential scattering experiments have been performed for the systems e-Ar in the energy range E = 0–10 eV and the angular range θ = 0–20° using a crossed-beam arrangement. Differential and integrated cross sections for the elastic scattering of low- and intermediate-energy (0–50 eV) electrons by argon atoms are calculated. For each impact energy, the phase shifts of the lower partial waves are obtained exactly by numerical integration of the radial equation. Transport coefficients of argon plasma are requested exactly, which is why we calculated the average collision cross sections for s = 1. . .11, l = 1. . .6.

Sign in / Sign up

Export Citation Format

Share Document