The successful operation of future e+ e- linear colliders (LC) critically relies on the ability to tightly focus beams at the interaction point to achieve high luminosities. With spot sizes expected to reach the nanometer scale in TeV LC, traditional beam delivery systems face challenges due to chromatic effects and the requirement of small emittance. To overcome these challenges, the concept...
Attosecond bunch generation may play a key role in many scientific applications, such as providing high temporal resolution for ultra-fast electron diffraction and mitigating beam-beam effects in linear colliders. Recently, we have started studying the feasibility of generating an attosecond bunch and its high-resolution measurement using the existing Argonne Wakefield Accelerator(AWA)...
Structure-based wakefield acceleration (SWFA) is a proposed concept to overcome limitations in conventional accelerators. This approach allows for the creation of short-input radiofrequency (rf) pulses, which have been empirically shown to reduce breakdown rates at a given gradient. Metamaterial structures with negative group velocity have shown promise in accelerator applications. A structure...
In wakefield LPA the use of special plasma profiles has a significant effect. Earlier (see [1-2]) it was shown that with a longitudinal growing plasma density due to the compression of the wake bubble, synchronicity of the maximum acceleration field in the region of the rear wall of the bubble and the bunch is achieved. However, in the blowout regime, the radial force is uniform along most of...
Next generation laser drivers for laser plasma acceleration and secondary radiation sources will require 3 to 4 orders of magnitude increase in pulse repetition rates, to produce TW-PW class peak power ultrashort pulses at multi-kilowatt average powers [1]. Coherently combined ultrashort pulse fiber laser systems are recognized as a pathway to such high power technology [1]. However, although...
A major challenge for any experiment involving laser - electron beam interaction such as Compton scattering, dielectric laser accceleration or ponderomotve bunching is spatiotemporal overlap of the pulses. In this paper, we demonstrate how a simple electro-optic sampling setup can be used as a tool to read out the spatiotemporal overlap of an electron bunch and laser pulse. By using an...
EuPRAXIA@SPARC_LAB will be a user-oriented X-ray free-electron laser, based on plasma wakefield acceleration. A 20 pC, 500 MeV witness electron bunch will be injected in plasma with density ~10^16cm-3,accelerated to >1 GeV and delivered to undulators for generating radiation in the water-window region (~4nm).
To preserve beam quality upon acceleration in plasma, the envelope of the witness...
The impediment of collective beam effects, including coherent synchrotron radiation (CSR) is a critical challenge in the generation of high-brightness beams, requiring new theoretical and experimental insight. This work will outline plans for a sequence of upcoming experiments at the Argonne Wakefield Accelerator (AWA) that leverages both the large parameter space for the bunch charge and...
Plasma wakefield accelerators (PWFA) have showcased remarkable acceleration gradients, reaching tens of GeV per meter. Advancements in generating high-quality beams via self-injection schemes and pursuing attosecond electron beams represent the forefront of this field. In this work, we introduce a novel approach to inject a high-quality electron beam using beam-induced ionization injection...
Acceleration by the wakefield provides compact sources of electron bunches of high brightness [1]. Electron–positron colliders and x-ray microscopes require bunches with low energy spread. In the blowout regime, the radial force is uniform along the wakefield bubble $F_r=const$ and $F_r(r)$ is proportional to $r$. These lead to the harmonicity of the radial oscillations of the bunch....
Traditional linear accelerators (LINACS) are effective for accelerating large amounts of ion charge with high efficiency. However, their compactness is limited by the breakdown of the solid accelerating structure, typically on the order of MV/m. On the other hand, laser-target ion accelerators can produce much higher accelerating field, e.g. via a TNSA mechanism, but are limited in the...
Precise control of the temporal shape of ultrashort pulses of terawatt scale peak power is often desirable in experiments. In previous work, we used single, few-cycle 5 fs pulses for 1 kHz rep. rate laser wakefield acceleration (LWFA) to 15 MeV in near-critical density hydrogen plasma [1]. Double pulses are also of interest for LWFA, as prior simulation studies suggest that resonant driving of...
The first demonstrations of fully optical multi-GeV laser wakefield acceleration (LWFA) have been enabled by the advent of low density (~1017 𝑐𝑚−3), meter-scale plasma waveguides generated in supersonic gas jets [1-8]. In this talk, I will present results from our recent LWFA experiments using plasma waveguides up to 30 cm in length, which have produced sub-milliradian divergence electron...
We attempt to combat the quadrupole-mode transverse wakefields inherent in planar-symmetric dielectric structures by periodically rotating the structure 90 degrees about the beam axis so that the beam sees an alternating quadrupole-like field as it progresses through the entire structure. We study this configuration experimentally in a two-period structure where the gap in each transverse...
Coherent synchrotron radiation (CSR) is a limiting effect in linear accelerators with dispersive elements due to its contribution to projected transverse emittance growth. This effect becomes a limitation for highly compressed beams. Even though CSR-induced projected emittance growth has been widely studied, conventional measurement techniques are not detailed enough to resolve the...
Radio frequency (RF) electromagnetic radiation in the form of an electromagnetic pulse (EMP) resulting from high intensity laser plasma experiments can damage essential scientific diagnostics in experiments relevant to advanced accelerator concepts, particularly in the petawatt era of lasers. Here we compare the EMP in three different experiments: a direct laser acceleration (DLA) experiment...
A train of charged particle bunches can resonantly drive large amplitude wakefields in plasma, when spaced by integers of one plasma wavelength, and high-transformer-ratio wakefields, when spaced by integers of half plasma wavelength and with properly ramped bunch density. We show with numerical simulations that the SPARC_LAB linear accelerator can provide a train of compressed electron...
Ultrashort transverse Faraday-rotation probes of laser-driven wakefield accelerators (LWFAs) have measured kilo-T magnetic fields originating from accelerating electrons and bubble sheath currents in plasmas ranging in density from >10^19 [1] to 10^17 cm-3 [2]. Such measurements have revealed e.g. wake size and shape [1,2], bunch duration [3], and longitudinal charge distribution within a...
Betatron radiation produced from a laser-wakefield accelerator (LWFA) is a broadband, hard X-ray (> 1 keV) source that has been used in a variety of applications in medicine, engineering and fundamental science. Recent advances in laser technology has enabled increases in shot-rate and system stability providing improved statistical analysis and detailed parameter scans. However, unique...
Ultra-intense lasers in the long-wavelength infrared (LWIR) spectral region are particularly attractive to the areas of ultrafast and strong-field science, primarily due to favorable quadratic scaling of the ponderomotive potential with the laser wavelength, which benefits accelerator research. However, advancing LWIR lasers peak power faces significant challenges due to intensity-dependent...
Long-wave infrared (LWIR) lasers are well-suited for applications such as laser wakefield acceleration and high harmonic generation due to the favorable wavelength scaling of the ponderomotive force. Using CO2 amplifiers, multi-terawatt peak powers with sub-picosecond pulse durations have been demonstrated. However, a limiting factor for these amplifiers is the current necessity of using...
Compression of amplified laser pulses beyond the limits of a compressor grating-setup has been a fruitful topic of research for decades. Filamentation compression offers a solution which benefits from a higher energy capacity and being easier to couple light into than the the hollow-core fiber compression scheme. Here, 40 fs CPA laser pulses with 40 nm FWHM bandwidth are spectrally-broadened...
“Flying focus” techniques produce laser pulses with dynamic focal points that can travel distances much greater than a Rayleigh length. The implementation of these techniques in laser-based applications requires the design of optical configurations that can both extend the focal range and structure the radial group delay. This work describes a method for designing optical configurations that...
Two-beam acceleration is a powerful method to generate high accelerating fields by utilizing short radiofrequency pulses. The Argonne Wakefield Accelerator facility is applying a two-beam acceleration approach to an X-band radiofrequency gun. This gun has experimentally demonstrated an electric field on the photocathode of ~400 MV/m. The next phase of this experiment will involve adding a...
Longitudinally shaped electron bunches are useful in wakefield acceleration, allowing for transformer ratios greater than 2. Electro-optic sampling can provide an accurate and non-destructive determination of the electron bunch current profile by measuring the transverse terahertz electric field of the electron bunch. Specifically, electro-optic sampling using the phase diversity...
Laser Wakefield Acceleration (LWFA) offers a promising alternative to conventional accelerators, offering superior acceleration gradients. However, the effect of radiation reaction inside the wake-field can be detrimental to their operation. The transverse focusing field in the wakefield can drive betatron oscillations and cause radiation emission, with radiation back-reaction effects on the...
Quasi-static (QS), particle-in-cell (PIC) algorithms are extremely efficient methods for modeling plasma-based acceleration (PBA) driven by an intense laser or particle beam. Compared to conventional PIC methods, QS-PIC codes can speed up simulations by several orders of magnitude due to the larger time-steps permitted. These computational savings permit high-fidelity modeling of intractable...
Laser driven ion acceleration provides a route to achieve high quality ion beams, which could be superior for specific applications. In this talk I will present recent development of a laser driven ion acceleration beam line at Shanghai Institute of Optics and Fine Mechanics (SIOM). Meanwhile I will also give an update on the current status of the 10 PW and 100 PW Laser systems at SIOM.
Fully relativistic particle-in-cell (PIC) simulations continue to be a critical pillar in plasma-based advanced accelerator concepts research. Modern state-of-the-art GPU supercomputers offer the potential to perform PIC simulations of unprecedented scale, but require robust and feature-rich codes which can fully leverage the computational resources. We have addressed this demand by adding GPU...
We have performed periodic, one-dimensional particle-in-cell (PIC) simulations to test the numerical stability of a variety of explicit energy-conserving PIC algorithms. When an optical-field-ionized (OFI) plasma column expands, it can create a radially propagating shock in the surrounding gas. Ionization of this shocked gas has enabled recent experiments to achieve low density (~$10^{17}...
The ongoing Plasma-driven Attosecond X-ray source experiment (PAX) at FACET-II aims to produce coherent soft X-ray pulses of attosecond duration using a Plasma Wakefield Accelerator [1]. These kinds of X-ray pulses can be used to study chemical processes where attosecond-scale electron motion is important. For this first stage of the experiment, PAX plans to demonstrate that <100 nm bunch...
FLASHForward is a beam-driven plasma-wakefield accelerator (PWFA) experiment at DESY, acting as a test bench to develop technologies to accelerate electron beams with high quality and high average power. By enhancing conventional acceleration methods with plasma acceleration, the cost and footprint of future accelerators could be significantly reduced. To achieve this, it is crucial to have...
Recent advances in multi-GeV laser wakefield acceleration (LWFA) depend on plasma waveguides initiated by intense Bessel beam pulses [1,2]. We demonstrate for the first time the generation and characterization of Bessel-like beams using highly customizable eight-level diffractive logarithmic axicons. The high degree of tunability achievable with these optics enables controllable axial laser...
The recent development of advanced black box optimization algorithms has promised order of magnitude improvements in optimization speed when solving accelerator physics problems. These algorithms have been implemented in the python package Xopt, which has been used to solve online and offline accelerator optimization problems at a wide number of facilities, including at SLAC, Argonne, BNL,...
Beam-driven plasma wakefield acceleration(PWFA) has shown great potential to be the basis for future linear colliders(LCs).PWFA can achieve high acceleration gradients with high energy transfer efficiency while maintaining low energy spread.For linear collider applications and designs,the witness beam transverse spot sizes and emittances are on the order of hundreds of nanometers with charges...
Laser ionized plasma sources for plasma wakefield accelerators (PWFA) offer numerous advantages, including the ability to shape the transverse and longitudinal density profile of the plasma source to create a controlled density ramp for emittance preservation or a plasma column with a prescribed width. One of the experimental challenges of this scheme is aligning the plasma source to the...
The Advanced WAKefield Experiment (AWAKE) relies on the self-modulation of a long proton bunch in plasma to resonantly excite wakefields. We use a relativistic ionization front to provide initial transverse wakefields for the self-modulation to grow from. It was shown that when the amplitude of the initial transverse wakefields exceeds a given value, a transition between two regimes,...
RF breakdown limits the attainable acceleration gradient in normal conducting RF structures, challenging high-gradient operations. Recent experiments at the Argonne Wakefield Accelerator (AWA) suggest short RF pulses (a few nanoseconds) can mitigate this breakdown. We simulated dark current emission in the short-pulse regime to study breakdown initiators including field emission and...
During a laser wakefield acceleration experiment, accelerated electrons produce betatron X-rays which contain information about the evolution of electron energy as they propagate through the plasma. As the electrons are accelerated, the critical energies of their synchrotron-like X-ray emission spectra change with time. In the case of a transverse density gradient, the wakefield curves towards...
Anthony Lu, Hailang Pan, Deepak Sapkota, Aodhan McIlvenny, Alexander Picksley, Adrian Woodley, Vassilia Zorba, Eric Esarey, Cameron Geddes, Anthony Gonsalves, Tong Zhou, Jeroen van Tilborg
Lawrence Berkeley National Laboratory, Berkeley, CA 94720
Many kilohertz repetition rate, ultrashort-pulse lasers generate Gaussian-profile beams. Nonlinear post-laser compression using near-field...
Multi-kHz laser plasma accelerators (LPA) have the potential for high impact applications in scientific, medical, industrial and security fields. Today’s >100MeV LPAs are limited to a few Hertz repetition rates since they are driven by Ti:Sapphire lasers that have limited power handling capability and wall-plug efficiency. To address this, we propose coherently combining short pulse fiber...
In reducing the Low Lagrangian to a finite system for numerical computation it is generally the case that basic physical properties such as momentum and charge conservation are lost. Using a macro-particle reduction of the charge distribution function we explore the connection between the non-canonical treatment and a fully-canonical treatment recognizing that the use of electromagnetic...
At UCLA, a plasma source using capillary discharge has been developed and studied for its potential use in plasma wakefield experiments at MITHRA and AWA facilities. This compact source, measuring 8 cm in length, can generate plasmas with a wide range of densities, making it suitable for various plasma wakefield acceleration (PWFA) experiments. With a 4-mm aperture, it can accommodate...
We present experimental results from Helmholtz-Zentrum Dresden-Rossendorf of a THz Smith-Purcell Radiation source generated using Laser Wakefield Accelerator electron bunches. Affordable and small, aluminum-coated gratings were placed near accelerated electron bunches with an average energy and charge of 405 MeV and 467 pC to produce strong, coherent emission. The generated shots of radiation...
Laser-driven ion accelerators (LDIAs) generate high-intensity beams, offering immense potential across various applications, including investigating ultra-high dose rate radiobiological research. The significant beam divergence of laser-driven proton beams at the source requires capture and transport of these beams to maintain a high particle intensity at the sample site located outside the...
The development of plasma channels is of great interest for many applications, including Laser Wakefield Acceleration (LWFA). However, the creation of meter-scale plasma channels that allow precise spatial and temporal control remains a complex challenge. Designing a plasma channel involves determining an optical phase that can generate the required intensity profile at the focus. In this...
Generating multi-GeV electron beams with Laser-Plasma Accelerators is accessible with PW class lasers [1] but requires an accelerator many Raleigh lengths long. A plasma waveguide is often used in LWFA experiments to combat drive laser beam diffraction and increase the electron energy gain. Hydrodynamic Optically Field Ionized (HOFI) plasma channels are particularly suitable for LWFA...
The generation of meter-scale, low density (≤10^17 cm^(-3)) plasma waveguides [1,2] in long supersonic gas jets has enabled the consistent production of multi-GeV electron beams in laser wakefield acceleration (LWFA), using drive pulses of just a few hundred TW [3,4,5]. The customizability of these waveguides has opened a wide parameter space for LWFA performance since the electron injection...
We pay homage to previous work using multiple laser pulses shown to yield widespread benefits in laser driven particle acceleration and radiation generation - and here explore the consequences of scaling the interaction to an “infinite” number of co-propagating beamlets which couple together and form large-gradient, periodic accelerating structures capable of elevated injection for high-charge...
The APS linear accelerator produces electron beams with energies on the order of 425 MeV. Using a low emittance photocathode electron gun as a source, we will be able to test compact accelerator structures and other advanced accelerator components in the Linac Extension Area (LEA). LEA includes a 270 mm inner diameter vacuum chamber equipped with two vacuum shutters for easy installation of...
This study presents a Dielectric Laser Accelerator (DLA) tailored for single-electron acceleration, optimised for particle survival and minimal beam energy spread. Leveraging a genetic algorithm, we strategically design the dielectric structure to achieve efficiency in both computational runtime and structure performance.
The study focuses on three key aspects: the selection of a suitable...
Over the past decade, the development of compact and cost-effective laser plasma accelerators (LPAs) operating at kHz repletion rates has opened attractive possibilities for practical applications, such as ultrafast electron probing and photon sources. In addition to high-flux, the high repetition rate enables active feedback stabilization in these accelerators, as mechanical instabilities...
Laser wakefield accelerators (LWFAs) have been successful in experimentally producing sustained gradients of tens of GeV/m over tens of centimeters. While the strength of these fields has been demonstrated, a direct measurement of the field configurations inside an LWFA especially at low densities is a huge challenge. Here, we report on the results of transverse electron beam probing of the...
Laser wakefield accelerator-driven betatron x-rays are bright, broadband synchrotron-like emission with micrometer-scale source size and sub-picosecond duration. Betatron x-rays provide a new avenue for high-resolution, high-throughput imaging of additively manufactured (AM) materials. AM alloys are commonly used in aerospace and automotive industries due to high strength and stiffness to...
Plasma-based acceleration (PBA) has emerged as a promising candidate for the accelerator technology used to build a future linear collider and/or an advanced light source. In PBA, the witness beam needs to be matched to the focusing forces of the wakefield (WF) to reduce the emittance growth. In some linear collider designs, the matched spot size of the witness beam can be 2 to 3 orders of...
The Hundred Terawatt Thomson (HTT) laser system at the LBNL BELLA Center operates a laser-plasma accelerator to produce high energy (~100s MeV) electron beams. A second high-intensity laser beam is scattered off of these electrons, boosting the photon energies from the eV to MeV range, in order to produce a tunable source of gamma rays for applications in security and the probing of high-Z or...
Laser plasma accelerators (LPAs) have emerged as a promising alternative to classical accelerators for a variety of applications, due to their ability to produce high brightness beams and significantly higher accelerating gradients, allowing more compact designs for future light sources and colliders. However, the LPA mechanism comes with a unique set of challenges based on the nature of the...
Structured solid-density or foam Ion Source Targets (ISTs) driven by PW-class lasers can generate ion beams with desirable characteristics via Hole-Boring Radiation Pressure Acceleration (HB-RPA) mechanism. Since HB-RPA accelerates ions perpendicular to the front surface of the IST, judicious target front surface fabrication translates to engineered velocity distribution. Ion beams with exotic...
The high accelerating gradients of plasma-based acceleration can lead to beams with large projected energy spread, which necessitates schemes for energy spread reduction. Here we present a ‘direct beam-loading’ scheme that uses the Trojan Horse injection method [1] to produce ultrahigh brightness beams in a single stage with a single bunch. Witness charge is optimised in simulation for...
Beam-driven plasma wakefield acceleration can sustain accelerating fields on the GV/m scale, making it well-suited for linear collider applications. However, in recent years, an efficiency-instability relation has been proposed, which limits the energy transfer efficiency from the wake to the trailing bunch that can be achieved without inducing transverse instabilities detrimental to the...
It is well known that high (105 to over 1010) temporal laser pulse contrasts are necessary to mitigate undesirable prepulse effects in laser-plasma acceleration (LPA) and other high-field applications. Many pulse contrast enhancement schemes have been devised to meet this requirement, but tend to suffer from low efficiency, inadequate prepulse suppression, beam distortion, or a combination...
At AWAKE, self-modulation of a long relativistic proton bunch is used to drive high-amplitude wakefields. As the proton bunch self-modulates while propagating through the 10 m long plasma, the amplitude of the wakefields grows. Measuring the wakefield amplitude directly has not been possible so far. However, as the energy stored in the wakefields is dissipated, some fraction of it is emitted...
Plasma-based particle accelerators maintain accelerating fields that are several orders of magnitude higher than conventional accelerators. This allows for more compact accelerator footprints that can deliver particle beams of very high charge (> 100 pC) and large current (> kA) for various applications. For instance, plasma-wakefield accelerators are promising candidates for next-generation...
We investigate the production and subsequent confinement of an electron-positron pair plasma when a laser pulse of ultra-relativistic intensity collides with a beam of incoherent gamma-rays. The secondary fermions tend to be confined when the radial ponderomotive force due to the laser intensity profile is balanced by the radiation damping (recoil) that they experience due to energetic photon...
The next-generation precision laser-plasma accelerators (LPA) require kHz repetition-rates and higher to enable feedback control, and to meet application rep-rate needs. Coherently combined fiber lasers, efficient and high-power, are considered one of the most promising laser technologies to drive kHz LPAs. Since LPAs need short laser pulse durations at tens-of-fs, the pulse stretcher,...
We explore the possibility of using a CO2-laser driven, self-guided wakefield accelerator as a stage for the acceleration of externally injected electron beams.
Optimal conditions for acceleration were explored through 2d and quasi-3D PIC simulations with FBPIC and WarpX. Parameters and regimes are specified by linear accelerator and CO2 laser at ATF facility in Brookhaven National Lab...
The ERC project SPARTA (Staging of Plasma Accelerators for Realizing Timely Applications) [1] started in 2024 at the University of Oslo. With the ultimate goal of reaching electron energies beyond what is available in a single plasma-accelerator stage, it aims to solve two key challenges of plasma accelerators: beam-quality preservation between accelerating stages and stability. The project...
A Dielectric Disk Accelerator (DDA) is a metallic accelerating structure loaded with dielectric disks to increase coupling between cells, thus high group velocity, while still maintaining a high shunt impedance. This is crucial for achieving high efficiency high gradient acceleration in the short rf pulse acceleration regime. Recent research of these structures has produced traveling wave...
This paper presents the final physics design of the THz wakefield acceleration experiment using three dielectric structure cross-sections at the Argonne Wakefield Accelerator (AWA) facility. The experiment will focus on multi-bunch excitation of wakefields, exploration of the wakefield transverse-force topology, and possibly support an experiment on energy recovery. This contribution discusses...
We are utilizing a sub-ps, sub-10 micron X-ray source for X-ray phase contrast imaging (XPCI) tomography of Inertial Confinement Fusion (ICF) fuel capsules). We will present results from an experiment in April 2024 at the Advanced Laser Light Source in Montreal, Canada. Radiography data was captured with Laser Wakefield Acceleration blowout regime betatron X-rays with a critical energy of...
Because of their ability to produce high gradients, radiofrequency (RF) structures in the sub-terahertz (sub-THz) regime are of considerable interest in structure wakefield acceleration. These structures can be used to generate a high gradient and high efficiency wakefield, allowing for a low physical footprint. In the pursuit of a structure with these properties, we have designed and built a...
QuickPIC is a parallel 3D PIC code that applies the quasi-static approximation. QuickPIC can simulate both beam driven and laser driven plasma wake field accelerators with a speed that is 1000 times faster than the conventional PIC code without losing accuracy. QuickPIC is developed based on the frame work UPIC, which has a hybrid parallelism algorithm that uses both OpenMP and MPI. Such an...
Laser plasma accelerators (LPAs) have promise to be the next generation accelerator for colliders, as well as drive a number of basic science, industry, security and medical applications. Many applications require high brightness electron beams enabled by low emittance. One proposal to achieve ultra-low emittance from an LPA is a two color laser configuration, where a long wavelength laser,...
The Argonne Wakefield Accelerator (AWA) supports research on advanced acceleration, beam manipulation, and beam production with the goal of enabling the next generation of accelerators for the energy frontier. Additionally, this research is synergistic with R&D on compact X-ray light sources. We discuss near-term upgrade plans to improve beam brightness and stability. Furthermore, we describe...
UT3 Accelerator Applications Development Facility
P. Franke 1,2*, E. W. McCary 1,2, T. Ha 1,2, D. Phan2, T. Borger1, J. Brooks2, J. F. Altamirano2, C. Hojbota2, H. L. Smith1,2, R. van Mourik1, G. R. Plateau1, O. Z. Labun2, L. Labun1,2, R. Kumar1, M. Gracia1, S. Dale1, M. Connolly1, M. C. Downer2, S. V. Milton1 and B. M. Hegelich1,2
1Tau Systems Inc.
2U. Texas at...
Advanced laser-driven ion acceleration mechanisms offer a promising route to high-quality proton beams and offer advantages over thermal-based Target Normal Sheath Acceleration (TNSA) [1]. Magnetic Vortex Acceleration, in principle, can produce lower divergence beams with a more favorable ion energy scaling with laser intensity. This regime can be accessed with thin (10’s 𝜇m) near-critical...