Efficient and accurate computation of 0th angular moment of the Doppler-broadened elastic scattering kernel in the resonance domain

2015 ◽  
Vol 295 ◽  
pp. 645-650
Author(s):  
Richard Sanchez ◽  
Claire Hewko ◽  
Simone Santandrea
Keyword(s):  
Elastic Scattering ◽  
Angular Moment ◽  
Accurate Computation ◽  
Resonance Domain ◽  
Scattering Kernel

scholarly journals Neutron Slowing Down with Inelastic Scattering

1978 ◽  
Vol 33 (12) ◽  
pp. 1452-1454
Author(s):  
S. A. El Wakil ◽  
H. M. Machali ◽  
E. A. Saad
Keyword(s):  
Excited State ◽  
Elastic Scattering ◽  
Difference Equation ◽  
Asymptotic Solution ◽  
Homogeneous Medium ◽  
Isotropic Scattering ◽  
Slowing Down ◽  
Differential Difference Equation ◽  
Collision Density ◽  
Scattering Kernel

Abstract The neutron slowing-down equation in an infinite homogeneous medium with isotropic scattering is solved. The slowing-down kernel is separated into an elastic and an inelastic part. The collision density is expressed in terms of Green’s function of the elastic scattering only. The Greuling- Goertzel (G-G) approximation is used for the elastic scattering kernel, while Volkin’s model is used for the inelastic one. A differential-difference equation for a one-level excited state is solved by Laplace transform. Discussion of the poles obtained in the Laplace inverse shows that there are forbidden zones in which there is no solution. Numerical calculations of the collision density in Fes6 at 922 and 865 kev levels are performed, which give the same behaviour as obtained by Corngold. The average slowing-down time calculated with our approach agrees with Williams’s result in the asymptotic solution.

Doppler broadening of neutron elastic scattering kernel in Tripoli-4®

2013 ◽  
Vol 54 ◽  
pp. 218-226 ◽  
Author(s):  
Andrea Zoia ◽  
Emeric Brun ◽  
Cédric Jouanne ◽  
Fausto Malvagi
Keyword(s):  
Elastic Scattering ◽  
Doppler Broadening ◽  
Scattering Kernel

Investigations on the Impact of Heavy Nuclides Resonance Elastic Scattering Models on Resonance Integrals

2010 ◽  
Author(s):  
Sitao Peng ◽  
Shaohong Zhang ◽  
Xiaofeng Jiang
Keyword(s):  
Elastic Scattering ◽  
Cross Section ◽  
Incident Energy ◽  
Cross Section Data ◽  
Section Data ◽  
Slowing Down ◽  
The Monte Carlo Method ◽  
Resonance Cross Section ◽  
Scattering Kernel ◽  
The Impact

In today’s cross section data processing process, asymptotic scattering model is employed by NJOY for the neutron/nucleus elastic scattering interactions in the epithermal energy region, which means that the energy of a scattered neutron is always lower than its incident energy and it falls evenly within the interval of [αE, E]. This model has recently been proved to have non-ignorable errors at some resonances of heavy nuclides. In this study, to investigate the impact of heavy nuclides resonance elastic scattering models to the resonance integrals, exact scattering kernel is employed and a deterministic code Estuary is developed to efficiently solve the neutron slowing down problem. Numerical results demonstrate that with the use of Estuary, results given in the literature obtained by the Monte Carlo method can be reproduced. With the resonance cross section approximately represented by the single-level Breit-Wigner formulation, investigations are made for different resonance parameters for both asymptotic and exact scattering models. Relations between errors and these related parameters are summarized.

scholarly journals Accelerated sampling of the free gas resonance elastic scattering kernel

2014 ◽  
Vol 69 ◽  
pp. 116-124 ◽  
Author(s):  
Jonathan A. Walsh ◽  
Benoit Forget ◽  
Kord S. Smith
Keyword(s):  
Elastic Scattering ◽  
Free Gas ◽  
Scattering Kernel

scholarly journals Transport, Quantum Interference and Localisation in Ultrathin Systems with Randomly Corrugated Walls and Interfaces

2000 ◽  
Vol 53 (1) ◽  
pp. 53 ◽  
Author(s):  
A. E. Meyerovich ◽  
A. Stepaniants
Keyword(s):  
Elastic Scattering ◽  
Quantum Interference ◽  
Collision Operator ◽  
Quantum Resonance ◽  
Random Surface ◽  
Physical Systems ◽  
General Surface ◽  
Analytical Applications ◽  
Resonance Domain ◽  
Surface Collision

Comparative effects of elastic scattering by random surface inhomogeneities and bulk impurities are discussed for ultrathin quantised systems. A simple general surface collision operator is derived outside of the quantum resonance domain. Analytical and semi-analytical applications to corrugation-defined localisation and transport in various types of physical systems are presented.

Elastic Scattering in Electron Microscopy

1973 ◽  
Vol 31 ◽  
pp. 252-253
Author(s):  
J. Langmore ◽  
M. Isaacson ◽  
J. Wall ◽  
A. V. Crewe
Keyword(s):  
Electron Microscopy ◽  
Elastic Scattering ◽  
Cross Section ◽  
Quantum Noise ◽  
Dark Field ◽  
Elastic Cross Section ◽  
Biological Molecules ◽  
Dark Field Microscopy ◽  
Field Systems ◽  
Effects Of Radiation

High resolution dark field microscopy is becoming an important tool for the investigation of unstained and specifically stained biological molecules. Of primary consideration to the microscopist is the interpretation of image Intensities and the effects of radiation damage to the specimen. Ignoring inelastic scattering, the image intensity is directly related to the collected elastic scattering cross section, σɳ, which is the product of the total elastic cross section, σ and the eficiency of the microscope system at imaging these electrons, η. The number of potentially bond damaging events resulting from the beam exposure required to reduce the effect of quantum noise in the image to a given level is proportional to 1/η. We wish to compare η in three dark field systems.

The Resolution and Contrast in Biological Sections Determined by Inelastic and Elastic Scattering

1973 ◽  
Vol 31 ◽  
pp. 224-225
Author(s):  
D. L. Misell
Keyword(s):  
Electron Microscopy ◽  
Adverse Effect ◽  
Elastic Scattering ◽  
Inelastic Scattering ◽  
Amorphous Carbon ◽  
Polymeric Materials ◽  
Chromatic Aberration ◽  
Image Resolution ◽  
Quantitative Estimates ◽  
Elastic Ratio

In the electron microscopy of biological sections the adverse effect of chromatic aberration on image resolution is well known. In this paper calculations are presented for the inelastic and elastic image intensities using a wave-optical formulation. Quantitative estimates of the deterioration in image resolution as a result of chromatic aberration are presented as an alternative to geometric calculations. The predominance of inelastic scattering in the unstained biological and polymeric materials is shown by the inelastic to elastic ratio, I/E, within an objective aperture of 0.005 rad for amorphous carbon of a thickness, t=50nm, typical of biological sections; E=200keV, I/E=16.

A New Image Processing Technique for STEM

1974 ◽  
Vol 32 ◽  
pp. 432-433
Author(s):  
Yasushi Kokubo ◽  
Hirotami Koike ◽  
Teruo Someya
Keyword(s):  
Electron Microscopy ◽  
Image Processing ◽  
Scanning Electron Microscopy ◽  
Elastic Scattering ◽  
Field Emission ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Energy Analyzer ◽  
Scanning Microscope ◽  
Scanning Electron

One of the advantages of scanning electron microscopy is the capability for processing the image contrast, i.e., the image processing technique. Crewe et al were the first to apply this technique to a field emission scanning microscope and show images of individual atoms. They obtained a contrast which depended exclusively on the atomic numbers of specimen elements (Zcontrast), by displaying the images treated with the intensity ratio of elastically scattered to inelastically scattered electrons. The elastic scattering electrons were extracted by a solid detector and inelastic scattering electrons by an energy analyzer. We noted, however, that there is a possibility of the same contrast being obtained only by using an annular-type solid detector consisting of multiple concentric detector elements.

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