scholarly journals ACCELERATION OF ELECTRON BUNCHES USING PERIODIC DIELECTRIC STRUCTURES WITH AND WITHOUT COATING

2021 ◽  
pp. 60-64
Author(s):  
A.V. Vasyliev ◽  
A.O. Bolshov ◽  
K.V. Galaydych ◽  
A.I. Povrozin ◽  
G.V. Sotnikov
Keyword(s):  
Laser Excitation ◽  
Geometric Parameters ◽  
Gold Coating ◽  
Electron Bunches ◽  
Numerical Studies ◽  
High Acceleration ◽  
On Chip ◽  
Laser Accelerators ◽  
Dielectric Structures

The numerical studies of high acceleration gradients obtaining for the dielectric laser accelerators (DLA) based on-chip structures with one-sided laser excitation at a wavelength of 800 nm are presented. The electron flight heights of 200 and 400 nm over a structure are presented. The influence of the geometric parameters of the structures on the acceleration gradients was also investigated. A study of changes in the acceleration gradients of structures, when applying a gold coating on these types of structures, has been carried out.

scholarly journals COMPARATIVE ANALYSIS OF ACCELERATION GRADIENTS FOR CHIP STRUCTURES WITH DIFFERENT REFRACTIVE INDICES

2021 ◽  
pp. 75-79
Author(s):  
A.V. Vasyliev ◽  
O.O. Bolshov ◽  
O.O. Svistunov ◽  
A.I. Povrozin ◽  
V.P. Zaitsev ◽  
...  
Keyword(s):  
Refractive Index ◽  
Comparative Analysis ◽  
Laser Pulse ◽  
Sapphire Laser ◽  
Refractive Indices ◽  
Electron Bunches ◽  
Numerical Studies ◽  
Laser Accelerators

The results of numerical studies of accelerating gradients in accelerators based on dielectric chip structures with different refractive indices, excited by a titanium-sapphire laser pulse, are presented. A comparative analysis of the influence of the refractive index on the rate of acceleration of electron bunches is carried out. Promising materials for the manufacture of dielectric laser accelerators are proposed.

scholarly journals Influence of multiple load indentation on the mechanical and material behaviour of steel cone-cylinder under axial compression

2021 ◽  
Author(s):  
Olawale Ifayefunmi ◽  
Sivakumar D. ◽  
Amir Hafiz Sazali
Keyword(s):  
Test Data ◽  
Good Accuracy ◽  
Cone Angle ◽  
Geometric Parameters ◽  
Collapse Load ◽  
Material Behaviour ◽  
Numerical Studies ◽  
Multiple Load ◽  
Welding Technique ◽  
Load Indentation

Abstract The first set of test data on axial collapse of cone-cylinder assembly having multiple load indentation (MLI) and its accompanying numerical studies is presented in this paper. Two perfect and two imperfect steel cone-cylinders were prepared in pairs. The cone-cylinder models have the following geometric parameters: cone radius of 40 mm, cylinder radius of 70 mm,wall thickness of 0.5 mm and cone angle of 16.7°. Cone and cylinder part were combined using Metal Inert Gas (MIG) welding technique. Results show that the repeatability of the experiment was good (3% for the perfect and 7% for the imperfect). Also, numerical prediction tends to reproduce the test data with good accuracy. The error between both approches ranges from 1% to -8%. Furthermore, the influence of geometric parameters are also significant in determining the collapse load of this type of structure. Finally, the worst multiple load indentation (WMLI) was explored for steel cone-cylinders assembly using different number of load indentations. Results indicate that as the number of indents increases, the sensitivity of the cone-cylinder models to imperfection also increases. However, at different imperfection amplitude, A, two regions were observed; (i) the region where cone-cylinder with N = 8 is more sensitive (A < 1.5), and (ii) the region where N = 4 produce the worst imperfection (1.5 < A ≤ 1.68).

scholarly journals ACCELERATING OF THE ELECTRONS OF ELECTRON BUNCHES IN A WAVEGUIDE LOADED DIELECTRIC STRUCTURE

2021 ◽  
pp. 67-71
Author(s):  
A.F. Linnik ◽  
I.N. Onishchenko ◽  
O.L. Omelayenko ◽  
V.I. Pristupa ◽  
G.V. Sotnikov ◽  
...  
Keyword(s):  
Experimental Studies ◽  
Bunch Length ◽  
Dielectric Structure ◽  
Steady State Mode ◽  
Electron Bunches ◽  
Simple Physical Model ◽  
Wake Wave ◽  
The Difference ◽  
Wake Fields ◽  
Dielectric Structures

The paper presents some results of experimental studies of the excitation of wake fields and the acceleration of electrons in waveguide-dielectric structures (DS) upon injection of a sequence of electron bunches into them. Exper-iments have shown an increase in the amplitude of the wake wave and the acceleration of a small fraction of elec-trons when the wavelength of the excited field is equal to the doubled bunch length. A simple physical model of the observed phenomenon is given. Also, the paper proposes a method for accelerating a part of each electron bunch in the steady-state mode of the resonator dielectric structure. Some of the electrons are “cut out” by the collimator and enter the accelerating phase of the previously excited wake wave. The wave is displaced due to the difference in the distances traveled by the wave and the accelerated part of the electrons.

RECENT STRUCTURE BASED HIGH GRADIENT WAKEFIELD EXPERIMENTS AT ARGONNE

2007 ◽  
Vol 21 (03n04) ◽  
pp. 372-377
Author(s):  
W. GAI ◽  
M. E. CONDE ◽  
F. GAO ◽  
C. JING ◽  
R. KONECNY ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Electron Beam ◽  
Output Coupler ◽  
High Field ◽  
Bunch Length ◽  
Accelerator Facility ◽  
Dielectric Tube ◽  
Electron Bunches ◽  
Dielectric Structures ◽  
Wakefield Accelerator

Dielectric structures promise to support high field, especially for short wakefield pulses produced by a high charged electron beam traveling in a dielectric tube. To push the gradient higher, we have tested two structures using recent upgraded Argonne wakefield accelerator facility that capable of producing up to 100 nC charge and bunch length of < 13 ps (FWHM). Here we report on the experiment results that more than 80 nC beam passes through a 14 GHz dielectric loaded wakefield structure that produced an accelerating field of ~ 45 MV/m . The two structures consist of a cylindrical ceramic tube (cordierite) with a dielectric constant of 5, inner and outer radii of 5 mm and 7.49 mm, respectively, and with length of 102 mm and 23 mm long. We present measurements made with single electron bunches and also with two bunches separated by 1.5 ns. As a next step in these experiments, another structure, with an output coupler, has been designed and is presently being fabricated.

Static Strenght of Doubler Plate Reinforced Tubular K-Joints under Bending Load

2012 ◽  
Vol 166-169 ◽  
pp. 645-648
Author(s):  
Wei Ning Sui ◽  
Xin Long Zhang ◽  
Guo Chang Li ◽  
Xue Bai
Keyword(s):  
Ultimate Strength ◽  
Static Strength ◽  
Geometric Parameters ◽  
Hollow Section ◽  
Numerical Studies ◽  
Bending Load ◽  
Circular Hollow Section

Abstract: In order to study static strength of doubler plate reinforced circular hollow section (CHS) K-joints, experimental and numerical studies conducted by the authors. The effects of parameters Δ (the ratio between the length of doubler plate and the diameter of the brace) and α (the width of the doubler plate) on CHS K-joints subjected to bending load have been investigated and reported by the authors. It is found that the ultimate strength of a CHS K-joints reinforced with appropriately proportioned doubler plates can be up to 2 ratio to its un-reinforced counterpart. Reasonable geometric parameters of the doubler plate can make the chord, brace and doubler plate work together to bear the external bending load. The width and length parameter of the doubler plate, however, have no effect on the stiffness of the reinforced K-joints.

scholarly journals Dielectric Laser Accelerators: Designs, Experiments, and Applications

2016 ◽  
Vol 09 ◽  
pp. 105-126 ◽  
Author(s):  
K. P. Wootton ◽  
J. McNeur ◽  
K. J. Leedle
Keyword(s):  
Repetition Rate ◽  
Computational Study ◽  
High Repetition Rate ◽  
Optical Wavelength ◽  
Electron Bunches ◽  
High Repetition ◽  
Recent Developments ◽  
Accelerator Technology ◽  
Laser Accelerators

Novel laser-powered accelerating structures at the miniaturized scale of an optical wavelength [Formula: see text] open a pathway to high repetition rate, attosecond scale electron bunches that can be accelerated with gradients exceeding 1 GeV/m. Although the theoretical and computational study of dielectric laser accelerators dates back many decades, recently the first experimental realizations of this novel class of accelerators have been demonstrated. We review recent developments in fabrication, testing, and demonstration of these micron scale devices. In particular, prospects for applications of this accelerator technology are evaluated.

scholarly journals Silicon nitride waveguide as a power delivery component for on-chip dielectric laser accelerators

2019 ◽  
Vol 44 (2) ◽  
pp. 335 ◽  
Author(s):  
Si Tan ◽  
Zhexin Zhao ◽  
Karel Urbanek ◽  
Tyler Hughes ◽  
Yun Jo Lee ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Power Delivery ◽  
On Chip ◽  
Laser Accelerators

Justification of Non-Dimensional Schemes and Identification of Parameters on Modelling Electrokinetic Transport Phenomena in Microchannels

2010 ◽  
Author(s):  
Zhanjie Shao ◽  
Gerry Schneider ◽  
Carolyn Ren
Keyword(s):  
Initial Conditions ◽  
Transport Phenomena ◽  
Concentration Field ◽  
Electrokinetic Transport ◽  
Dimensional Model ◽  
Applied Potential ◽  
Governing Equations ◽  
Numerical Studies ◽  
Electrokinetic Flows ◽  
On Chip

The electrokinetic transport phenomena are to be numerically studied based on cross-linked microchannel networks, which have been commonly employed for on-chip capillary electrophoresis applications. Applied potential field, flow field and concentration field should be solved to predict the species transport process under electrokinetic flows. Together with the well-designed channel geometry, a detailed physical model was firstly formulated through a series of governing equations and corresponding boundary/initial conditions, which was briefly re-presented from our previous publications. The emphasis of current work was to justify the simplest non-dimensional scheme and identify the most beneficial parameters so that an effective and simplified non-dimensional model was developed for numerical studies.

scholarly journals Numerical Studies of the Aerodynamic Features of Dead-end Entries with Side Junction

2020 ◽  
Vol 174 ◽  
pp. 01057
Author(s):  
Yuri Govorukhin ◽  
Victor Krivolapov ◽  
Dmitry Paleev ◽  
Vyacheslav Portola
Keyword(s):  
Numerical Simulation ◽  
Turbulent Diffusion ◽  
Geometric Parameters ◽  
Simulation Data ◽  
Flow Rates ◽  
Numerical Studies ◽  
Air Movement ◽  
Dead End ◽  
Wide Range ◽  
The Dead

Investigations of aerodynamic processes occurring in dead-end short entriesaired by turbulent diffusion have been performed. The numerical simulation of the processes of air movement through the entry, flow stalling at the junction with the dead-end entry (for side junction), and the formation of vortices at the dead end have been carried out. The study has been done for a wide range of air flows submitted for computation of air consumption and for various geometric parameters of the dead-end entry. The sizes of the vortex structures and the flow rates in the dead endshave been determined. Based on the results of processing the simulation data, we obtained graphs of the dependences between the length of the ventilated zone of the dead end and its height and width.

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