High resolution electron beam measurements on the ALPHA-X laser–plasma wakefield accelerator

2012 ◽  
Vol 78 (4) ◽  
pp. 393-399 ◽  
Author(s):  
G. H. WELSH ◽  
S. M. WIGGINS ◽  
R. C. ISSAC ◽  
E. BRUNETTI ◽  
G. G. MANAHAN ◽  
...  
Keyword(s):  
Electron Beam ◽  
High Resolution ◽  
Laser Plasma ◽  
Electron Bunch ◽  
High Energy ◽  
Energy Spread ◽  
Gas Jet ◽  
X Rays ◽  
Electron Bunches ◽  
Wakefield Accelerator

AbstractThe Advanced Laser–Plasma High-Energy Accelerators towards X-rays (ALPHA-X) programme at the University of Strathclyde is developing laser–plasma accelerators for the production of ultra-short high quality electron bunches. Focussing such LWFA bunches into an undulator, for example, requires particular attention to be paid to the emittance, electron bunch duration and energy spread. On the ALPHA-X wakefield accelerator beam line, a high intensity ultra-short pulse from a 30 TW Ti:Sapphire laser is focussed into a helium gas jet to produce femtosecond duration electron bunches in the range of 90–220 MeV. Measurements of the electron energy spectrum, obtained using a high resolution magnetic dipole spectrometer, show electron bunch r.m.s. energy spreads down to 0.5%. A pepper-pot mask is used to obtain transverse emittance measurements of a 128 ± 3 MeV mono-energetic electron beam. An average normalized emittance of ϵrms,x,y = 2.2 ± 0.7, 2.3 ± 0.6 π-mm-mrad is measured, which is comparable to that of a conventional radio-frequency accelerator. The best measured emittance of ϵrms,x, = 1.1 ± 0.1 π-mm-mrad corresponds to the resolution limit of the detection system. 3D particle-in-cell simulations of the ALPHA-X accelerator partially replicate the generation of low emittance, low energy spread bunches with charge less than 4 pC and gas flow simulations indicate both long density ramps and shock formation in the gas jet nozzle.

scholarly journals Improvement of Properties of Self-Injected and Accelerated Electron Bunch by Laser Pulse in Plasma, Using Pulse Precursor

2019 ◽  
Keyword(s):  
Laser Pulse ◽  
Laser Plasma ◽  
Electron Bunch ◽  
Energy Spread ◽  
Intense Laser ◽  
X Rays ◽  
Laser Wakefield Acceleration ◽  
Small Energy ◽  
Wakefield Acceleration ◽  
Laser Wakefield

The accelerating gradients in conventional linear accelerators are currently limited to ~100 MV/m. Plasma-based accelerators have the ability to sustain accelerating gradients which are several orders of magnitude greater than that obtained in conventional accelerators. Due to the rapid development of laser technology the laser-plasma-based accelerators are of great interest now. Over the past decade, successful experiments on laser wakefield acceleration of electrons in the plasma have confirmed the relevance of this acceleration. Evidently, the large accelerating gradients in the laser plasma accelerators allow to reduce the size and to cut the cost of accelerators. Another important advantage of the laser-plasma accelerators is that they can produce short electron bunches with high energy. The formation of electron bunches with small energy spread was demonstrated at intense laser–plasma interactions. Electron self-injection in the wake-bubble, generated by an intense laser pulse in underdense plasma, has been studied. With newly available compact laser technology one can produce 100 PW-class laser pulses with a single-cycle duration on the femtosecond timescale. With a fs intense laser one can produce a coherent X-ray pulse. Prof. T. Tajima suggested utilizing these coherent X-rays to drive the acceleration of particles. When such X-rays are injected into a crystal they interact with a metallic-density electron plasma and ideally suit for laser wakefield acceleration. In numerical simulation of authors, performed according to idea of Prof. T.Tajima, on wakefield excitation by a X-ray laser pulse in a metallic-density electron plasma the accelerating gradient of several TV/m has been obtained. It is important to form bunch with small energy spread and small size. The purpose of this paper is to show by the numerical simulation that some precursor-laser-pulse, moved before the main laser pulse, controls properties of the self-injected electron bunch and provides at certain conditions small energy spread and small size of self-injected and accelerated electron bunch.

scholarly journals Electron bunch injection at an angle into a laser wakefield

2009 ◽  
Vol 27 (1) ◽  
pp. 69-77 ◽  
Author(s):  
M.J.H. Luttikhof ◽  
A.G. Khachatryan ◽  
F.A. van Goor ◽  
K.-J. Boller ◽  
P. Mora
Keyword(s):  
Laser Pulse ◽  
Electron Bunch ◽  
Extensive Study ◽  
Energy Spread ◽  
Pulse Dynamics ◽  
Electron Bunches ◽  
Vacuum Plasma ◽  
Laser Wakefield ◽  
External Injection ◽  
Wakefield Accelerator

AbstractExternal injection of electron bunches longer than the plasma wavelength in a laser wakefield accelerator can lead to the generation of femtosecond ultra relativistic bunches with a couple of percent energy spread. Extensive study has been done on external electron bunch (e.g., one generated by a photo-cathode RF linac) injection in a laser wakefield for different configurations.In this paper, we investigate a new way of external injection where the electron bunch is injected at a small angle into the wakefield. This way one can avoid the ponderomotive scattering as well as the vacuum-plasma transition region, which tend to destroy the injected bunch. In our simulations, the effect of the laser pulse dynamics is also taken into account. It is shown that injection at an angle can provide compressed and accelerated electron bunches with less than 2% energy spread. Another advantage of this scheme is that it has less stringent requirements in terms of the size of the injected bunch and there is the potential to trap more charge.

scholarly journals Energy Enhancement and Energy Spread Compression of Electron Beams in a Hybrid Laser-Plasma Wakefield Accelerator

2019 ◽  
Vol 9 (12) ◽  
pp. 2561 ◽  
Author(s):  
Ying Wu ◽  
Changhai Yu ◽  
Zhiyong Qin ◽  
Wentao Wang ◽  
Zhijun Zhang ◽  
...  
Keyword(s):  
Laser Plasma ◽  
Electron Beams ◽  
Energy Levels ◽  
High Energy ◽  
Energy Spread ◽  
Particle In Cell ◽  
Wakefield Acceleration ◽  
Plasma Wakefield Accelerator ◽  
Plasma Wakefield ◽  
Wakefield Accelerator

We experimentally demonstrated the generation of narrow energy-spread electron beams with enhanced energy levels using a hybrid laser-plasma wakefield accelerator. An experiment featuring two-color electron beams showed that after the laser pump reached the depletion length, the laser-wakefield acceleration (LWFA) gradually evolved into the plasma-driven wakefield acceleration (PWFA), and thereafter, the PWFA dominated the electron acceleration. The energy spread of the electron beams was further improved by energy chirp compensation. Particle-in-cell simulations were performed to verify the experimental results. The generated monoenergetic high-energy electron beams are promising to upscale future accelerator systems and realize monoenergetic γ -ray sources.

scholarly journals Control of electron beam energy-spread by beam loading effects in a laser-plasma accelerator

2020 ◽  
Vol 62 (5) ◽  
pp. 055004 ◽  
Author(s):  
Guangyu Li ◽  
Quratul Ain ◽  
Song Li ◽  
Muhammad Saeed ◽  
Daniel Papp ◽  
...  
Keyword(s):  
Electron Beam ◽  
Laser Plasma ◽  
Beam Energy ◽  
Plasma Accelerator ◽  
Energy Spread ◽  
Electron Beam Energy ◽  
Beam Loading ◽  
Loading Effects ◽  
Laser Plasma Accelerator

scholarly journals Coupling of longitudinal and transverse motion of accelerated electrons in laser wakefield acceleration

2004 ◽  
Vol 22 (4) ◽  
pp. 407-413 ◽  
Author(s):  
A.J.W. REITSMA ◽  
D.A. JAROSZYNSKI
Keyword(s):  
Laser Pulse ◽  
Group Velocity ◽  
Electron Bunch ◽  
Coupling Effect ◽  
Energy Spread ◽  
Transverse Motion ◽  
Laser Wakefield Acceleration ◽  
Wakefield Acceleration ◽  
Laser Wakefield ◽  
Wakefield Accelerator

The acceleration dynamics of electrons in a laser wakefield accelerator is discussed, in particular the coupling of longitudinal and transverse motion. This coupling effect is important for electrons injected with a velocity below the laser pulse group velocity. It is found that the electron bunch is adiabatically focused during the acceleration and that a finite bunch width contributes to bunch lengthening and growth of energy spread. These results indicate the importance of a small emittance for the injected electron bunch.

Laser wakefield acceleration: the injection issue. Overview and latest results

2006 ◽  
Vol 364 (1840) ◽  
pp. 679-687 ◽  
Author(s):  
M.J van der Wiel ◽  
O.J Luiten ◽  
G.J.H Brussaard ◽  
S.B van der Geer ◽  
W.H Urbanus ◽  
...  
Keyword(s):  
Radio Frequency ◽  
State Of The Art ◽  
Plasma Waves ◽  
Energy Spread ◽  
Laser Wakefield Acceleration ◽  
Electron Bunches ◽  
Wakefield Acceleration ◽  
Laser Wakefield ◽  
External Injection ◽  
Wakefield Accelerator

External injection of electron bunches into laser-driven plasma waves so far has not resulted in ‘controlled’ acceleration, i.e. production of bunches with well-defined energy spread. Recent simulations, however, predict that narrow distributions can be achieved, provided the conditions for properly trapping the injected electrons are met. Under these conditions, injected bunch lengths of one to several plasma wavelengths are acceptable. This paper first describes current efforts to demonstrate this experimentally, using state-of-the-art radio frequency technology. The expected charge accelerated, however, is still low for most applications. In the second part, the paper addresses a number of novel concepts for significant enhancement of photo-injector brightness. Simulations predict that, once these concepts are realized, external injection into a wakefield accelerator will lead to accelerated bunch specs comparable to those of recent ‘laser-into-gasjet’ experiments, without the present irreproducibility of charge and final energy of the latter.

scholarly journals Radioluminescence Response of Ce-, Cu-, and Gd-Doped Silica Glasses for Dosimetry of Pulsed Electron Beams

Sensors ◽  
2021 ◽  
Vol 21 (22) ◽  
pp. 7523
Author(s):  
Daniel Söderström ◽  
Heikki Kettunen ◽  
Adriana Morana ◽  
Arto Javanainen ◽  
Youcef Ouerdane ◽  
...  
Keyword(s):  
Electron Beam ◽  
Electron Bunch ◽  
Sol Gel ◽  
Readout System ◽  
Pulsed Electron Beam ◽  
Silica Glasses ◽  
Electron Bunches ◽  
Pure Silica ◽  
Radiation Induced ◽  
The Individual

Radiation-induced emission of doped sol-gel silica glass samples was investigated under a pulsed 20-MeV electron beam. The studied samples were drawn rods doped with cerium, copper, or gadolinium ions, which were connected to multimode pure-silica core fibers to transport the induced luminescence from the irradiation area to a signal readout system. The luminescence pulses in the samples induced by the electron bunches were studied as a function of deposited dose per electron bunch. All the investigated samples were found to have a linear response in terms of luminescence as a function of electron bunch sizes between 10−5 Gy/bunch and 1.5×10−2 Gy/bunch. The presented results show that these types of doped silica rods can be used for monitoring a pulsed electron beam, as well as to evaluate the dose deposited by the individual electron bunches. The electron accelerator used in the experiment was a medical type used for radiation therapy treatments, and these silica rod samples show high potential for dosimetry in radiotherapy contexts.

High-Energy Inelastic-Scattering Beamline for Electron Momentum Density Study

1998 ◽  
Vol 5 (3) ◽  
pp. 208-214 ◽  
Author(s):  
Y. Sakurai
Keyword(s):  
High Resolution ◽  
Inelastic Scattering ◽  
Compton Scattering ◽  
High Energy ◽  
Momentum Density ◽  
High Resolution Spectroscopy ◽  
X Rays ◽  
Circularly Polarized ◽  
Magnetic Structures ◽  
Momentum Resolution

The advent of synchrotron radiation sources for well polarized and high-energy X-rays offers new opportunities for exploiting Compton scattering spectroscopy as a tool for investigating the electronic and magnetic structures of materials. Recent high-resolution Compton scattering experiments show the unique capability for the study of Fermiology-related issues and electron–electron correlation effects. Intense, high-energy and circularly polarized X-ray sources have improved magnetic Compton scattering spectroscopy from the point of statistical accuracy and momentum resolution. As a next advance, a high-energy inelastic scattering beamline dedicated to Compton scattering spectroscopies is being constructed at SPring-8. The light source is an elliptic multipole wiggler with a periodic length of 12 cm. The beamline includes two experimental stations: one is for high-resolution spectroscopy using 100–150 keV X-rays and the other is for magnetic Compton scattering experiments using circularly polarized 300 keV X-rays. The use of such high-energy X-rays makes it possible to carry out experiments efficiently on samples including heavier elements, such as high-T c superconductors and 4f and 5f magnetic materials.

scholarly journals Numerical analysis of space charge effects in electron bunches at laser-driven plasma accelerators

Open Physics ◽  
2011 ◽  
Vol 9 (4) ◽  
Author(s):  
Anthony Ashmore ◽  
Riccardo Bartolini ◽  
Nicolas Delerue
Keyword(s):  
Space Charge ◽  
Electron Bunch ◽  
Beam Quality ◽  
Experimental Studies ◽  
High Energy ◽  
Space Charge Effects ◽  
Charge Effects ◽  
Electron Bunches ◽  
Plasma Accelerators ◽  
Beam Parameters

AbstractLaser-driven Plasma Accelerators (LPA) have successfully generated high energy, high charge electron bunches which can reach many kA peak current, over short distances. Space charge issues, even in transport lines as simple as a drift section, have to be carefully taken into account since they can degrade the beam quality, preventing any further application of such electron beams. We analyse the space charge effects within an electron bunch with numerical simulations in order to assess their effect on the beam. We use LPA beam parameters published in previous experimental studies. These studies can give an indication of the working point where space charge can dominate the beam dynamics and has to be taken into account in the application of such beams.

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.

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