A TRAIN OF MICRO-BUNCHES FOR PWFA EXPERIMENTS PRODUCED BY RF PHOTOINJECTORS

2007 ◽  
Vol 21 (03n04) ◽  
pp. 415-421 ◽  
Author(s):  
M. BOSCOLO ◽  
M. FERRARIO ◽  
C. VACCAREZZA ◽  
I. BOSCOLO ◽  
F. CASTELLI ◽  
...  
Keyword(s):  
Electron Beam ◽  
Energy Distribution ◽  
Pulse Shaping ◽  
Laser System ◽  
Initial Density ◽  
Beam Dynamics ◽  
Electron Bunches ◽  
Energy Modulation ◽  
Accelerating Structure ◽  
Density Modulation

An electron beam generated in a radio-frequency photo-injector illuminated by a laser "comb" pulse evolves towards a homogenous electron beam with an energy modulation. The density modulation in fact is transformed into an energy modulation, with a saw-tooth like shape, by the longitudinal space charge forces. Such an energy distribution can be exploited to restore the initial density profile by means of a RF accelerating structure operating in the velocity bunching mode. It results a train of short electron bunches suitable for advanced PWFA experiments. The initial laser comb can be obtained with a pulse shaping device inserted into the laser system. In this paper we discuss the beam dynamics features of such a beam.

A coherent harmonic generation method for producing femtosecond coherent radiation in a laser plasma accelerator based light source

2021 ◽  
Vol 28 (3) ◽  
pp. 669-680
Author(s):  
Weihang Liu ◽  
Chao Feng ◽  
Yi Jiao ◽  
Sheng Wang
Keyword(s):  
Electron Beam ◽  
Light Source ◽  
Laser Plasma ◽  
Percent Level ◽  
Coherent Radiation ◽  
Level Energy ◽  
Seed Laser ◽  
Energy Modulation ◽  
Density Modulation ◽  
Longitudinal Position

The electron beam generated in laser plasma accelerators (LPAs) has two main initial weaknesses – a large beam divergence (up to a few milliradians) and a few percent level energy spread. They reduce the beam brightness and worsen the coherence of the LPA-based light source. To achieve fully coherent radiation, several methods have been proposed for generating strong microbunching on LPA beams. In these methods, a seed laser is used to induce an angular modulation into the electron beam, and the angular modulation is converted into a strong density modulation through a beamline with nonzero longitudinal position and transverse angle coupling. In this paper, an alternative method to generate microbunching into the LPA beam by using a seed laser that induces an energy modulation and transverse–longitudinal coupling beamlines that convert the energy modulation into strong density modulation is proposed. Compared with the angular modulation methods, the proposed method can use more than one order of magnitude lower seed laser power to achieve similar radiation performance. Simulations show that with the proposed method a coherent pulse of a few microjoules pulse energy and femtosecond duration can be generated with a typical LPA beam.

Energy Distribution in Electron Beams

1972 ◽  
Vol 30 ◽  
pp. 568-569
Author(s):  
Tamotsu Ohno
Keyword(s):  
Electron Beam ◽  
Energy Distribution ◽  
Cross Section ◽  
Integral Curve ◽  
Electron Beams ◽  
Electron Gun ◽  
Angular Divergence ◽  
Apparent Increase ◽  
Integral Width ◽  
The Cross

The energy distribution in an electron; beam from an electron gun provided with a biased Wehnelt cylinder was measured by a retarding potential analyser. All the measurements were carried out with a beam of small angular divergence (<3xl0-4 rad) to eliminate the apparent increase of energy width as pointed out by Ichinokawa.The cross section of the beam from a gun with a tungsten hairpin cathode varies as shown in Fig.1a with the bias voltage Vg. The central part of the beam was analysed. An example of the integral curve as well as the energy spectrum is shown in Fig.2. The integral width of the spectrum ΔEi varies with Vg as shown in Fig.1b The width ΔEi is smaller than the Maxwellian width near the cut-off. As |Vg| is decreased, ΔEi increases beyond the Maxwellian width, reaches a maximum and then decreases. Note that the cross section of the beam enlarges with decreasing |Vg|.

Pulse Shaping a High-Current Relativistic Electron Beam in Vacuum

1990 ◽  
Author(s):  
J. D. Miller ◽  
R. F. Schneider ◽  
H. S. Uhm ◽  
K. T. Nguyen ◽  
K. W. Struve
Keyword(s):  
Electron Beam ◽  
Relativistic Electron ◽  
Relativistic Electron Beam ◽  
Pulse Shaping ◽  
High Current

Electron beam dynamics in an ultrafast transmission electron microscope with Wehnelt electrode

2016 ◽  
Vol 171 ◽  
pp. 8-18 ◽  
Author(s):  
K. Bücker ◽  
M. Picher ◽  
O. Crégut ◽  
T. LaGrange ◽  
B.W. Reed ◽  
...  
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Beam Dynamics ◽  
Transmission Electron ◽  
Electron Beam Dynamics

scholarly journals The use of ANSYS for modelling the energy distribution in steady mode with electron beam welding

2021 ◽  
Vol 1889 (4) ◽  
pp. 042061
Author(s):  
A V Murygin ◽  
S O Kurashkin ◽  
V S Tynchenko ◽  
D V Rogova
Keyword(s):  
Electron Beam ◽  
Energy Distribution ◽  
Electron Beam Welding ◽  
Steady Mode

Estimation of Nanometer-Sized EB Patterning Using Energy Deposition Distribution in Monte Carlo Simulation

2011 ◽  
Vol 497 ◽  
pp. 127-132 ◽  
Author(s):  
Hui Zhang ◽  
Takuro Tamura ◽  
You Yin ◽  
Sumio Hosaka
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Electron Beam ◽  
Energy Distribution ◽  
Electron Energy ◽  
Electron Beam Lithography ◽  
Energy Deposition ◽  
Si Substrate ◽  
Positive Resist

We have studied on theoretical electron energy deposition in thin resist layer on Si substrate for electron beam lithography. We made Monte Carlo simulation to calculate the energy distribution and to consider formation of nanometer sized pattern regarding electron energy, resist thickness and resist type. The energy distribution in 100 nm-thick resist on Si substrate were calculated for small pattern. The calculations show that 4 nm-wide pattern will be formed when resist thickness is less than 30 nm. Furthermore, a negative resist is more suitable than positive resist by the estimation of a shape of the energy distribution.

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