THE ABSORPTION OF HIGH-ENERGY RADIATION, A MONTE CARLO STUDY: II. SPHERICAL GEOMETRY

1963 ◽  
Vol 41 (4) ◽  
pp. 651-663
Author(s):  
N. R. Steenberg
Keyword(s):  
Cross Section ◽  
Spherical Geometry ◽  
Monte Carlo Study ◽  
Nuclear Data ◽  
High Energy ◽  
Rare Gas ◽  
Nuclear Radius ◽  
Rigid Spheres ◽  
High Energy Radiation ◽  
The Individual

The absorption of radiation in a spherical obstacle composed of rigid spheres has been studied. The result is the absorption cross section of such an obstacle as a function of the free cross section and the number A of the individual spheres and of packing density. It is found that the usual rare-gas formula represents the cross section adequately. The analysis is applied to nuclear data for the absorption of 25-Bev/c protons by nuclei. It is found that for a nuclear radius R = r0A1/3 + δ, where δ is the radius of the nucleon, r0 = 1.17 fermi, δ = 1.05 fermi, and an average nucleon transparency a2 = 0.30 is consistent with the data.

THE ABSORPTION OF HIGH-ENERGY RADIATION, A MONTE CARLO STUDY: I. RECTANGULAR GEOMETRY

1963 ◽  
Vol 41 (4) ◽  
pp. 632-650 ◽  
Author(s):  
N. R. Steenberg ◽  
W. Van Iterson
Keyword(s):  
Monte Carlo ◽  
Cross Section ◽  
Effective Cross Section ◽  
Monte Carlo Study ◽  
High Energy ◽  
Rare Gas ◽  
High Energy Radiation ◽  
Energy Radiation ◽  
Alternative Formula ◽  
Random Array

As part of an investigation of the scattering of high-energy radiation by nuclei a Monte Carlo study has been made of the attenuation of radiation by a rectangular barrier composed of a moderately dense random array of rigid semiopaque spheres. It is found that the attenuation is much more rapid than that predicted by the rare-gas formula usually assumed and is well described by an alternative formula which is derived on probabilistic grounds. A corollary is that an effective cross section which is substantially larger than the free cross section must be assumed inside such a medium.

THE ABSORPTION OF HIGH-ENERGY RADIATION, A MONTE CARLO STUDY: III. DENSITY AND TRANSPARENCY DISTRIBUTIONS

1963 ◽  
Vol 41 (12) ◽  
pp. 2206-2240
Author(s):  
N. R. Steenberg ◽  
W. P. Crofts
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Study ◽  
High Energy ◽  
Matter Distribution ◽  
Monte Carlo Data ◽  
Rigid Spheres ◽  
High Energy Radiation ◽  
Geometric Origin ◽  
Strong Surface ◽  
Spherical Arrays

Random spherical arrays of rigid spheres are being studied as a model for a nucleus under high-energy bombardment. This paper reports on the distribution of sphere centers, the matter distribution, and the transparency for such arrays. Low (12.5%) and high (42.2%) nominal densities are treated for arrays numbering 27 and 216 spheres. At high densities a strong surface correlation of geometric origin is observed. Analytic formulas are presented which in general adequately represent the Monte Carlo data.

Ultrasmall Gd@Cdots as a Radiosensitizing Agent for Non-Small Cell Lung Cancer

Nanoscale ◽  
2021 ◽  
Author(s):  
Chaebin Lee ◽  
Xiangji Liu ◽  
Weizhong Zhang ◽  
M. A. Duncan ◽  
Fangchao Jiang ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Small Cell Lung Cancer ◽  
Cross Section ◽  
Cell Lung Cancer ◽  
High Energy ◽  
Small Cell ◽  
Small Cell Lung ◽  
High Energy Radiation ◽  
Energy Radiation

High-Z nanoparticles (HZNPs) afford high cross-section for high energy radiation and have attracted wide attention as a novel type of radiosensizers. However, conventional HZNPs are often associated with issues such...

scholarly journals Validated scattering kernels for triphenylmethane at cryogenic temperatures

2020 ◽  
Vol 239 ◽  
pp. 14002
Author(s):  
Florencia Cantargi ◽  
Javier Dawidowski ◽  
Christian Helman ◽  
José Ignacio Márquez Damian ◽  
Rolando Jose Granada ◽  
...  
Keyword(s):  
Cross Section ◽  
Density Functional ◽  
Processing System ◽  
Nuclear Data ◽  
High Energy ◽  
Industrial Applications ◽  
Polymer Science ◽  
Functional Theory ◽  
Scattering Kernel ◽  
Pulsed Neutron

Cold neutrons are widely used in different fields of research such as the study of the structure and dynamics of solids and liquids, the investigation of magnetic materials, biological systems, polymer science, and a rapidly growing area of industrial applications. In a pulsed neutron source where the pulse width is an important parameter to be considered, hydrogenated materials are often used because of their high energy transfer in each collision. The preliminary scattering kernel for triphenylmethane, a material of great potential interest for cold neutron production, had been presented at the ND2016 conference. Here, a new model for the generation of the scattering kernels for this material, together with experimental results on its total cross section measured at the VESUVIO instrument (ISIS Neutron and Muon Source, United Kingdom) is presented. The thermal scattering kernel was generated by means of the NJOY Nuclear Data Processing system, using as input the vibrational modes obtained by density functional theory techniques (DFT). The agreement between measurements and our model validates the scattering kernel construction and the cross section library generated in ENDF and ACE formats.

Cosmogenic Rare Gas Ratios in Iron Meteorites

1961 ◽  
Vol 16 (12) ◽  
pp. 1387-1390
Author(s):  
David E. Fisher
Keyword(s):  
Cross Section ◽  
Energy Flux ◽  
High Energy ◽  
Low Energy ◽  
Rare Gas ◽  
Iron Meteorites

Rare gas abundances in iron meteorites are compared with cross section ratios from high energy bombardments. A meteoritic low-energy flux (below 1 Gev) of about 13 times the high energy flux (above 1 Gev) is found. About half the helium is produced by this low energy flux.

scholarly journals Validation of heavy water cross section using AmBe neutron source

2020 ◽  
Vol 239 ◽  
pp. 18008
Author(s):  
Michal Kostal ◽  
Martin Schulc ◽  
Evzen Novak ◽  
Tomas Czakoj ◽  
Zdenek Matej ◽  
...  
Keyword(s):  
Cross Section ◽  
Neutron Source ◽  
Cross Sections ◽  
Average Energy ◽  
Nuclear Data ◽  
High Energy ◽  
Suitable Candidate ◽  
Neutron Spectra ◽  
Misleading Interpretation ◽  
Neutron Leakage

Physical quantities derived from integral experiments can usually be measured much more accurately than that from differential nuclear data. The accurate knowledge of integral parameters provide excellent grounds for testing and tuning differential data such as, for instance, cross sections. Measurement of neutron leakage spectra with 252Cf neutron source located at sphere center is often used for integral experiments. While this type of experiments provide information for cross section tuning, however, care must be taken to avoid misleading interpretation, namely, at high energies due to the very low portion of high energy neutrons in 252Cf spectrum. This issue can be alleviated by the use of point source with different spectra shape. For that purpose one suitable candidate seems to be the AmBe neutron source which has a relatively high average energy and peak character of emitted neutrons. Indeed, AmBe seems an interesting option because the calculated leakage neutron spectra are not very sensitive to the input shape of the neutron spectra. Thus the neutron leakage spectra calculated using tabulated of International Organization for Standardization spectra is nearly the same as stilbene measured AmBe spectra as an input.

scholarly journals On-the-fly temperature-dependent cross section treatment under extremes in RMC code

2020 ◽  
Vol 239 ◽  
pp. 22009
Author(s):  
Lei Zheng ◽  
Wei Wang ◽  
Kan Wang
Keyword(s):  
Data Storage ◽  
Cross Section ◽  
Inertial Confinement Fusion ◽  
Neutron Transport ◽  
Resonance Region ◽  
Nuclear Data ◽  
High Energy ◽  
Inertial Confinement ◽  
Treatment Technique ◽  
Temperature Dependent

Neutron transport relevant to inertial confinement fusion always involves extremes, in which the physical quantities are extremely high, widely distributed and changes rapidly with space and time. In order to solve the memory and efficiency problems in nuclear data storage and processing, the on-the-fly temperature-dependent cross section treatment technique was investigated and developed under extremes in RMC code. Different strategies were adopted for different energy regions, i.e., the free gas model in the thermal region, the TMS method with 0K basis cross section temperature in the resolved resonance region, and the infinite dilution cross section in the unresolved resonance region, whereas the high energy region above the unresolved resonance region was not treated currently. The test results of Godiva sphere and plutonium sphere show that the on-the-fly technique has high accuracy, but the efficiency of the proposed technique still needs to be improved for some cases, and the optimization work with the elevated basis cross section temperatures is ongoing.

In situ irradiation effects studies in medium- and high-voltage TEM

1995 ◽  
Vol 53 ◽  
pp. 234-235
Author(s):  
Charles W. Allen
Keyword(s):  
Cross Section ◽  
Particle Flux ◽  
Threshold Value ◽  
High Energy ◽  
Irradiation Damage ◽  
Defect Complexes ◽  
Lattice Position ◽  
Electrons And Ions ◽  
The Masses

With respect to structural consequences within a material, energetic electrons, above a threshold value of energy characteristic of a particular material, produce vacancy-interstial pairs (Frenkel pairs) by displacement of individual atoms, as illustrated for several materials in Table 1. Ion projectiles produce cascades of Frenkel pairs. Such displacement cascades result from high energy primary knock-on atoms which produce many secondary defects. These defects rearrange to form a variety of defect complexes on the time scale of tens of picoseconds following the primary displacement. A convenient measure of the extent of irradiation damage, both for electrons and ions, is the number of displacements per atom (dpa). 1 dpa means, on average, each atom in the irradiated region of material has been displaced once from its original lattice position. Displacement rate (dpa/s) is proportional to particle flux (cm-2s-1), the proportionality factor being the “displacement cross-section” σD (cm2). The cross-section σD depends mainly on the masses of target and projectile and on the kinetic energy of the projectile particle.

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