scholarly journals Self-Organized Nanostructures Generated on Metal Surfaces under Electron Irradiation

2021 ◽  
Vol 5 (1) ◽  
pp. 4
Author(s):  
Keisuke Niwase

Irradiation of high-energy electrons can produce surface vacancies on the exit surface of thin foils by the sputtering of atoms. Although the sputtering randomly occurs in the area irradiated with an intense electron beam of several hundred nanometers in diameter, characteristic topographic features can appear under irradiation. This paper reviews a novel phenomenon on a self-organization of nanogrooves and nanoholes generated on the exit surface of thin metal foils irradiated with high doses of 360–1250 keV electrons. The phenomenon was discovered firstly for gold irradiated at temperatures about 100 K, which shows the formation of grooves and holes with widths between 1 and 2 nm. Irradiation along [001] produces grooves extending along [100] and [010], irradiation along [011] gives grooves along [100], whereas no clear grooves have been observed for [111] irradiations. By contrast, nanoholes, which may reach depths exceeding 20 nm, develop mainly along the beam direction. The formation of the nanostructures depends on the irradiation temperatures, exhibiting an existence of a critical temperature at about 240 K, above which the width significantly increases, and the density decreases. Nanostructures formed for silver, copper, nickel, and iron were also investigated. The self-organized process was discussed in terms of irradiation-induced effects.

2009 ◽  
Vol 27 (3) ◽  
pp. 511-520 ◽  
Author(s):  
Limin Li ◽  
Lie Liu ◽  
Guoxin Cheng ◽  
Lei Chang ◽  
Hong Wan ◽  
...  

AbstractThe development of pulsed power technology, particularly for inductive energy storage, promotes the extensive discussions of electrical explosion process in high energy density. This paper presents the electrical-explosion behavior of carbon fibers subjected to about 20 kA, ~5 µs high-density current pulse igniting an intense electron beam accelerator. After electrical explosion, and surface rupture, submicron particles, fibrillar and strip-shaped structures were observed, experimentally supporting the microstructure model (skin-core heterogeneity) of carbon fiber. Interestingly, the start and turn-off of the current were followed by radiation pulses with different intensities. It was found that the radiation was focused on the explosion stage which was characterized by an oscillating current. The instabilities of plasma produced during the explosion process play an important role in the microstructure changes of carbon fibers and the radiation generation.


1996 ◽  
Vol 14 (3) ◽  
pp. 519-528
Author(s):  
Stanley Humphries

High-intensity electron beams could be focused in low-frequency RF accelerators and induction linear accelerators by adding transverse components to the accelerating electric field. Calculations with a 3D code show that quasielectrostatic focusing is sufficient to transport kiloampere electron beams in RF accelerators and the high-energy sections of induction accelerators. The elimination of conventional magnetic focusing systems could lead to reductions in the volume and weight of high-current electron accelerators. Two novel quadrupole geometries are investigated: a periodic array of spherical electrodes with alternating displacements and a set of plate electrodes with elliptical apertures.


2020 ◽  
Vol 34 (34) ◽  
pp. 2050395
Author(s):  
Matlab N. Mirzayev

B4C and B6Si samples have been irradiated by using swift heavy ions and high intense electron beam. Ion irradiation of the samples was carried at the different electron fluences [Formula: see text], [Formula: see text] and [Formula: see text] cm[Formula: see text] ion/cm2, and energy of ions flux 167 MeV. Also, the samples were irradiated with high energy electron beams at the linear electronic accelerator at different electron fluencies up to [Formula: see text] cm[Formula: see text] and energy of electron beams 2.5 MeV and current density of electron beams [Formula: see text]s. The unirradiation and irradiation of the thermodynamic kinetics of samples at low-temperature change with a differential mechanism. In the DSC curves, at the low temperature for unirradiation and irradiation, boron carbide and boron silicide samples do not undergo phase transition. But at the [Formula: see text] K temperature range, the thermodynamic mechanism of ions and electron beam irradiation are very difficult and measuring the temperature of conductivity, thermal conductivity, calibration factor, specific heat capacity becomes more complicated.


2018 ◽  
Vol 3 (6) ◽  
pp. 278-292 ◽  
Author(s):  
Jianhua Yang ◽  
Zicheng Zhang ◽  
Hanwu Yang ◽  
Jun Zhang ◽  
Jinliang Liu ◽  
...  

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