Formation process of dislocation loops in iron under irradiations with low-energy helium, hydrogen ions or high-energy electrons

2002 ◽  
Vol 307-311 ◽  
pp. 272-277 ◽  
Author(s):  
K. Arakawa ◽  
H. Mori ◽  
K. Ono
Keyword(s):  
Formation Process ◽  
High Energy ◽  
Low Energy ◽  
Hydrogen Ions ◽  
Dislocation Loops ◽  
High Energy Electrons

scholarly journals Symmetric and triangle-shaped variability of blazars

2014 ◽  
Vol 10 (S313) ◽  
pp. 97-98
Author(s):  
Kenji Yoshida
Keyword(s):  
Gamma Ray ◽  
High Energy ◽  
Low Energy ◽  
Light Curves ◽  
X Ray ◽  
High Energy Electrons ◽  
Flux Variability ◽  
Low Energy Electrons ◽  
Flux Increase ◽  
Rise Phase

AbstractSymmetric and triangle-shaped flux variability in X-ray and gamma-ray light curves is observed from many blazars. We derived the X-ray spectrum changing in time by using a kinetic equation of high energy electrons. Giving linearly changing the injection of low energy electrons into accelerating and emitting region, we obtained the preliminary results that represent the characteristic X-ray variability of the linear flux increase with hardening in the rise phase and the linear decrease with softening in the decay phase.

On Lensless Imaging of Organics with Neutrons, X-Rays, Helium Atoms and Low Energy Electrons: Damage and Iterative Phase Retrieval

2001 ◽  
Vol 7 (S2) ◽  
pp. 268-269
Author(s):  
J.C.H. Spence ◽  
U. Weierstall ◽  
J. Fries
Keyword(s):  
Phase Retrieval ◽  
Iterative Algorithms ◽  
High Energy ◽  
Low Energy ◽  
X Rays ◽  
Noise Sources ◽  
Helium Atoms ◽  
High Energy Electrons ◽  
Elastic Event ◽  
Low Energy Electrons

Recent experiments with X-rays and high energy electrons have shown that image recovery from diffracted intensities is possible for non-periodic objects using iterative algorithms. Application of these methods to biological molecules raises the crucial problem of radiation damage, which may be quantified by Q = ΔE σi/σe, the amount of energy deposited by inelastic events per elastic event. Neutrons, helium atoms and low energy electrons below most ionization thresholds produce the smallest values of Q (see for TMV imaged at 60 eV). For neutrons (λ = 10-2Å, and deuterated, 15N-abelled molecules) Q is ∼3000 times smaller (∼50 times for λ = 1.8Å) than for electrons (80- 500keV) and about 4x 106 times smaller than for soft X-rays (1.5Å). Since σe for neutrons is about 105 times smaller than for electrons (and about 10 times smaller than for soft X-rays), a 105 times higher neutron dose is required to obtain the same S/N in a phase contrast image compared with electrons, if other noise sources are absent.

scholarly journals Quantum Mechanisms of Electron and Positron Acceleration through Nonlinear Compton Scatterings and Nonlinear Breit-Wheeler Processes in Coherent Photon Dominated Regime

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Bo Zhang ◽  
Zhimeng Zhang ◽  
Zhi-gang Deng ◽  
Jian Teng ◽  
Shu-kai He ◽  
...  
Keyword(s):  
Charged Particles ◽  
High Energy ◽  
Low Energy ◽  
Electric Force ◽  
Quantum Processes ◽  
High Energies ◽  
Large Numbers ◽  
High Energy Electrons ◽  
Electrons And Positrons ◽  
Proof Of Principle

AbstractElectric force is presently the only means in laboratory to accelerate charged particles to high energies, corresponding acceleration processes are classical and continuous. Here we report on how to accelerate electrons and positrons to high energies using ultra intense lasers (UIL) through two quantum processes, nonlinear Compton scattering and nonlinear Breit-Wheeler process. In the coherent photon dominated regime of these two processes, the former can effectively boost electrons/positrons and the latter can produce high energy electrons and positrons with low energy γ photons. The energy needed for such quantum acceleration (QA) is transferred from large numbers of coherent laser photons through the two quantum processes. QA also collimate the generated high energy electrons and positrons along the laser axis and the effective acceleration distance is of microscopic dimensions. Proof of principle QA experiment can be performed on 100 petawatt (PW) scale lasers which are in building or planning.

scholarly journals The Role of Low Energy Electrons in Radiobiology and Cancer Treatment

2021 ◽  
Author(s):  
Sasan Esmaili ◽  
Farzaneh Allaveisi
Keyword(s):  
Cancer Treatment ◽  
Anticancer Agents ◽  
High Energy ◽  
Low Energy ◽  
New Drugs ◽  
Particle Radiation ◽  
Energy Radiation ◽  
Regulatory Pathways ◽  
High Energy Electrons ◽  
Low Energy Electrons

Low energy radiation can be produced by all types of high energy radiation. Studies of low energy particle radiation help us to understand the chemistry induced by high energy radiations. Low energy electrons are capable of chemical selectivity in contrast to high energy electrons due to the large number of open dissociative channels in the former case and their resonant nature. Among different types of radiation, low energy electrons have a higher cross-section to DNA damage and they have an important role in the synergistic effect between radiation and chemotherapy anticancer agents in cancer treatment. Analysis of these combined records helps assign function of cells, identify metabolic and regulatory pathways and suggest targets for diagnostics and therapeutics identify animal models to develop new drugs, among other goals of biomedical interest.

Is the End-of-Range Loops Kinetics Affected by Surface Proximity or Ion Beam Recoils Distribution?

1989 ◽  
Vol 147 ◽  
Author(s):  
E. Ganin ◽  
A. Marwick
Keyword(s):  
Lower Energy ◽  
Depth Distribution ◽  
Ion Beam ◽  
Amorphous Region ◽  
High Energy ◽  
Low Energy ◽  
Dislocation Loops ◽  
Residual Damage ◽  
Effect Of Surface ◽  
Surface Proximity

AbstractWe studied formation and annihilation of dislocation loops formed beyond the amorphous/crystalline interface after indium and boron dual implantation and subsequent annealing in the 800–1 100°C temperature range. The residual damage for low (40 keV) and high (200 keV) energy In implants were compared. The depth of the amorphous region in the sample implanted with the higher energy ions was reduced by using anodic oxidation and etching, to equate it with that of the sample implanted by lower energy ions. This enabled the study of the effect of surface proximity on residual disorder upon annealing. The damage was strongly dependent on the energy of In ions. No end-of-range damage was observed for the low energy implant. High energy implantation resulted in end-of-range dislocation loops, stable below 1050°C. The loops kinetics was neither affected by their proximity to the surface, nor by In precipitation. Monte-Carlo full cascade simulation has been used to estimate the depth distribution of interstitials and vacancies produced by In implant.

Multi-Scale Modeling of Interstitial Dislocation Loop Growth in Irradiated Materials

2012 ◽  
Vol 1444 ◽  
Author(s):  
Bei Ye ◽  
Di Yun ◽  
Zeke Insepov ◽  
Jeffrey Rest
Keyword(s):  
Reaction Rates ◽  
Dose Dependence ◽  
High Energy ◽  
Theory Model ◽  
Rate Theory ◽  
Dislocation Loops ◽  
Multi Scale ◽  
Scale Modeling ◽  
High Energy Electrons ◽  
Multi Scale Modeling

ABSTRACTIn order to reduce the inherent uncertainty in kinetic theory models and promote their transition to become predictive methodologies, a multi-scale modeling approach is proposed and demonstrated in this work. KiValues of key materials properties such as point defect (vacancy and interstitial) migration enthalpies, as well as kinetic factors, such as dimer formation and defect recombination coefficients and self-interstitial atom – interstitial loop reaction rates, were obtained by ab initio/molecular dynamics calculations. A rate theory model was used to interpret the evolution of dislocation loops in irradiated molybdenum. Calculations of the dose dependence of average loop diameter were performed and compared to experimental measurements obtained from irradiations with high-energy electrons. The comparison demonstrates reasonable agreement between model-predicted and experiment-measured data.

Spatial Distribution of Particle Precipitation in Terms of Energy Channels under Different Geomagnetic Conditions

2020 ◽  
Author(s):  
Han-Wen Shen ◽  
Jih-Hong Shue ◽  
John Dombeck ◽  
Hsien-Ming Li
Keyword(s):  
Spatial Distribution ◽  
Wave Scattering ◽  
High Energy ◽  
Low Energy ◽  
Electron Precipitation ◽  
Spatial Distributions ◽  
Static Potential ◽  
Physical Processes ◽  
High Energy Electrons ◽  
Energy Channels

<p>The geomagnetic activity can modulate the number and energy fluxes of precipitation and their spatial distributions. Most previous studies examined precipitation in terms of energy spectrum types associated with quasi-static potential structures (QSPS) acceleration, Alfvénic acceleration, and wave scattering under various geomagnetic conditions. In this study, we instead categorize precipitation according to energy channels of particles. The spatial distribution of the precipitation for various energy channels is also derived under different geomagnetic conditions. Our results indicate that regardless of active and quiet times, low-energy (high-energy) precipitation is mostly distributed on the dayside (nightside). By comparing with past results, we infer that electron precipitation is mainly caused by QSPS and Alfvénic acceleration for most cases; however, the high-energy electrons during quiet times are predominantly created by wave scattering. For high-energy precipitation, the dawn-dusk asymmetry of the spatial distribution during active times is found to be opposite of that during quiet times. Based on their spatial distributions, we suggest that the high-energy precipitation during quiet times is dominated by the curvature and gradient drifts, while that during active times is mainly affected by physical processes related to substorms in the magnetotail.</p>

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