scholarly journals Ultrarelativistic electron beam spatial size estimation from angular distribution emission in thin crystals

Author(s):  
Yu.A. Goponov ◽  
M.A. Sidnin ◽  
K. Sumitani ◽  
Y. Takabayashi ◽  
I.E. Vnukov
2015 ◽  
Vol 22 (2) ◽  
pp. 167-171
Author(s):  
J. Guo ◽  
B. Yu

Abstract. With two-dimensional (2-D) particle-in-cell (PIC) simulations we investigate the evolution of the double layer (DL) driven by magnetic reconnection. Our results show that an electron beam can be generated in the separatrix region as magnetic reconnection proceeds. This electron beam could trigger the ion-acoustic instability; as a result, a DL accompanied with electron holes (EHs) can be found during the nonlinear evolution stage of this instability. The spatial size of the DL is about 10 Debye lengths. This DL propagates along the magnetic field at a velocity of about the ion-acoustic speed, which is consistent with the observation results.


Author(s):  
I. E. Vnukov ◽  
Yu. A. Goponov ◽  
M. A. Sidnin ◽  
R. A. Shatokhin ◽  
K. Sumitani ◽  
...  

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Manish Kumar ◽  
Krishna Kumar Parashar ◽  
Sushil Kumar Tandi ◽  
Tanuj Kumar ◽  
D. C. Agarwal ◽  
...  

Ag:TiO2nanocomposite films have been synthesized by sol-gel method followed by electron beam physical vapour deposition. Targets for this deposition were prepared by a hydraulic press using a powder containing Ag and TiO2prepared by sol-gel technique. Microstructure, surface, and plasmonic properties of nanocomposite films were studied using glancing angle X-ray diffractometer, atomic force microscopy, field emission secondary electron microscopy, and UV-Vis spectroscopy. Microstructural study reveals that Ag nanoparticles are embedded in TiO2matrix consisting of mixed phases of anatase and rutile. Size estimation using Scherrer formula reveals that average crystallite size of Ag nanoparticles is 23 nm. Surface morphological studies indicate that deposited films are uniform and intact to the substrate and have very low value of root mean square roughness. Optical studies exhibit a surface plasmon resonance induced absorption band in visible region, which is the characteristic feature of Ag nanoparticles. The intensity of this absorption band is found to increase with the increase in deposition time. Multiple peaks observed in absorption band were explained using the concepts of extended Mie scattering. Preliminary experiments also suggested that these nanocomposite films exhibit promising photocatalytic properties, which can be used for water treatment.


2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Andrii Sofiienko ◽  
Chad Jarvis ◽  
Ådne Voll

Monte Carlo simulations were used to study photon production in a panoramic X-ray tube with a conical tungsten target to determine the optimal characteristics of the target shape and electron beam configuration. Several simulations were performed for accelerating potentials equal to 250 kV, 300 kV, and 500 kV with electron beams of various radii and anode sizes. The angular distribution of the photon intensity was analysed by numerical calculations for an assembly composed of an X-ray tube and an external collimator with a cylindrical hole to simulate a panoramic scanning system with an X-ray pencil beam.


2007 ◽  
Author(s):  
V. A. Cha ◽  
B. N. Kalinin ◽  
E. A. Monastyrev ◽  
G. A. Naumenko ◽  
A. P. Potylitsyn ◽  
...  

1979 ◽  
Vol 57 (12) ◽  
pp. 2190-2193 ◽  
Author(s):  
G. E. Giakoumakis ◽  
C. D. Nomicos ◽  
P. C. Euthymiou

The angular distribution of the light emitted from a ZnCdS(Ag) phosphor screen excited by an electron beam is measured for different thicknesses of the screen and for two grain sizes. This angular distribution is found to have a divergence from the Lambert law. A theoretical model is proposed leading to an equation fitting to the experimental results. Using this equation the modulation transfer function (MTF) of the screen was calculated.


1979 ◽  
Vol 6 (1) ◽  
pp. 9-12
Author(s):  
Miklós Szilágyi

The experimental data for the anistropic component of the angular distribution of electron-beam evaporation sources are usually described in terms of thecosnθdependence. In this paper a simple model for calculating angular distributions is presented. The generally used dependence appears as a particular case in the model.


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