Advanced accelerator concepts have potential to enable future colliders. Recent progress includes multi-GeV acceleration, positron acceleration, strong structure loading and focusing, staging of two modules, beam shaping for efficiency, high gradient structures and greatly improved beam quality which recently enabled wakefield-based FELs.
The recent 2023 Particle Physics Project...
European research groups and institutions, often working in close collaboration with others from around the world, work on all aspects of advanced accelerator research.
In this talk I will give an overview of research efforts in Europe, highlight recent key results, and indicate anticipated future directions.
The first demonstrations of fully optical multi-GeV laser wakefield acceleration (LWFA) have been enabled by the advent of low density (~$10^{17}$ $cm^{-3}$), meter-scale plasma waveguides generated in supersonic gas jets [1-7]. 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...
Laser-accelerated electron beams have been the subject of intense research in the last few decades. The general direction in the field is the development towards ultralow beam emittance, necessitating controlled injection methods to ensure electron trapping in the laser-driven plasma wave. Due to its simplicity, one of the more popular injection mechanisms relies on a downward step in gas...
Future applications of laser-plasma accelerators will require one or more stages providing multi-GeV energy gain. Preformed plasma channels can increase the maximum energy gain of a laser-plasma accelerator. Recently, hydrodynamic optical-field-ionized (HOFI) plasma channels [1-3] have gained attention because i) they produce tightly confined channels at densities required for multi-GeV...
Structure wakefield accelerators (SWFAs) offer a path to high accelerating gradient using either collinear wakefield acceleration or two-beam acceleration (TBA). In the past five years, significant progress has been made in operating accelerating structures powered externally by short radiofrequency pulses generated from thew wakefield of decelerating bunches. Such a TBA approach has...
Accelerator-based x-ray free-electron lasers (XFELs) are the latest addition to the revolutionary tools of discovery for the 21st century. The two major components of an XFEL are an accelerator-produced electron beam and a magnetic undulator, which tend to be kilometer-scale long and expensive. A proof-of-principle demonstration of free-electron lasing at 27 nm using beams from compact laser...
Laser-plasma acceleration has enormous potential to provide compact sources of ultra-short ion beams. However, several factors hamper their wider adoption, such as the low shot-to-shot stability, large beam divergence and the difficulty of high-repetition rate operation. In this talk I will outline an approach for overcoming these challenges by a novel liquid sheet target, developed at the...
Currently, the Extreme Light Infrastructure – Nuclear Physics (ELI-NP) facility is running the most powerful laser in the world. The commissioning of the 10 PW laser system began at the end of 2022 and continued until recently. The first ever 10 PW shot focused on target was fired on April 2023 and since then a constant effort has been made to improve the laser performance and the experimental...
Laser-driven (LD) proton sources are of interest for various applications due to their ability to produce short proton bunches with high charge. These sources can be used in biological studies investigating improvements to radiation cancer therapy. Recently, the differential sparing effect on normal tissues versus tumors using the delivery of high radiation doses >10 Gy at extremely high dose...
Laser-plasma accelerators (LPAs) have great potential to be compact and economic, and can enable many applications in science, industry, and medicine, from wakefield colliders (e.g. 10TeV) and precision LPA facilities (e.g. kBELLA) to photon and particle sources. These applications need new kHz rep-rate laser driver technologies producing Joules of pulse energy, up to 100’s kW average power,...
The space-charge field of a relativistic bunch is screened in plasma due to the presence of mobile charge carriers. We experimentally investigate such screening by measuring the effect of dielectric wakefields driven by an electron bunch in an uncoated dielectric capillary where the plasma is confined [1]. We show that the plasma screens the space-charge field and therefore suppresses the...
Beam test facilities have been an integral part of accelerator science research, education, and applications development. However, awareness of their capabilities is limited, and potential new researchers typically face a multitude of barriers in accessing their capabilities, such as a lack of centralized information on facility capabilities or how to engage with them. BeamNetUS is a network...
The United States government high energy physics community develops state-of-the-art particle accelerator technologies, which later must be purchased from abroad to support domestic projects, because US-based firms are not consistently prioritized for government programs of record. In contrast, the high energy physics communities in Europe and Asia work to nurture their domestic industrial...
ALEGRO, the Advanced LinEar collider study GROup, is an international study group created in 2017 to promote Advanced and Novel Accelerators (ANAs) for High-Energy Physics applications. It is driven by the ICFA-ANA panel. ALEGRO organizes workshops (CERN 2017, Oxford 2018, CERN 2019, DESY 2023, IST 2024) to energize the ANA community around applications to particle and high-energy physics. The...
I will give an overview of the 2023 P5 recommendations for accelerators as well as rollout plans, processes, recent HEP organizational changes and possibly share some personal perspectives and thoughts.
This discussion focuses on the planning for R&D toward a linear collider based on advanced acceleration concepts.
The ion channel laser (ICL) is similar to the free electron laser (FEL) but utilizes the electric field from a blowout regime plasma wake rather than the magnetic field from an undulator to oscillate particles. Compared to the FEL, the ICL can lase with much larger energy spread beams and in much shorter distances, making it an attractive candidate for a future compact plasma accelerator...
We demonstrate through high-fidelity particle-in-cell simulations a simple approach for efficiently generating 20+ GeV electron beams with the necessary charge, energy spread, and emittance for use as the injector for an electron arm of a future linear collider or a next generation XFEL. The self-focusing of an unmatched, relatively low quality, drive beam results in self-injection by...
Recent high repetition rate lasers capable to produce TW peak power, few-cycle laser pulses with 100 W average power at industrial standards. Hence, they may offer an alternative to the PW peak power lasers for applications that need a quasi-continuous source of neutrons.
The SEA laser of ELI-ALPS delivered 21 mJ, 12 fs laser pulses at 10 Hz repetition rate on the target. Deuterons were...
Plasma based acceleration is considered a promising concept for the next generation of linear electron-positron colliders. Despite the great progress achieved over the last twenty years in laser technology, laser- and beam-driven particle acceleration, and special target availability, positron acceleration remains significantly underdeveloped if compared to electron acceleration. This is due...
Free-electron laser facilities demand versatile and inexpensive THz sources for pump-probe experiments. Smith-Purcell radiation provides a compact method to generate resonant and narrowband terahertz sources when relativistic electrons go through periodic dielectric grating structures, which are cost-efficient when fabricated by 3D printing. It has certain advantages over other available...
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...
High-energy, spin-polarized particles are of great interest for a variety of applications like deep-inelastic scattering for the investigation of the proton nuclear structure or fusion, where the use of polarized reactants can increase the fusion cross-section. Acceleration of such particles via laser-plasma interaction can prove to be difficult, as the target needs to be pre-polarized. This...
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...
The Facility for Advanced Accelerator Experimental Tests II (FACET-II) has successfully completed its first plasma wakefield acceleration (PWFA) experiments using the two-bunch beam delivery configuration. In these initial studies, a drive and witness pair of bunches were produced at the photocathode injector, co-accelerated, and transported to the experimental area. Two plasma sources were...
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) suggests 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...
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...
Hydrodynamic plasma waveguides initiated by optical field ionization (OFI) have recently become a key component of multi-GeV laser wakefield accelerators [1–4], We present comprehensive experimental and simulation-based characterization, applicable both to current multi-GeV experiments and future 100 GeV-scale laser plasma accelerators. Crucial to the simulations is the correct modeling of...
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...
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 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...
Ion acceleration via compact laser-plasma sources presents great potential for applications ranging from medical treatments to fusion research. Achieving the desired beam quality parameters necessitates an in-depth understanding and precise control of the laser-plasma interaction process. Our ongoing collaborative research at the DRACO PW (HZDR) and J-KAREN-P (KPSI) laser systems is focused on...
The characterization and mitigation of collective beam effects, particular coherent synchrotron radiation (CSR), represents an important challenge in facilitating the development of particle accelerators with higher beam brightness. Among the mitigation strategies proposed in the literature, the use of appropriately configured shielding walls to curb CSR remains an promising area of research...
The generation of high spectral brilliance radiation with electron beam sources relies heavily on the qualities of the electron transverse emittance and its longitudinal compression which significantly affect X-ray generation efficiency in Inverse Compton Scattering. Designing and building such a system in a compact formfactor requires non-trivial solutions starting from electrons generation...
Designs for linear colliders based on laser wakefield acceleration (LWFA) must address dephasing, which occurs when trapped particles outpace the accelerating phase of the wakefield. To address dephasing, current designs employ many stages, each operating at a low plasma density, which limits the acceleration gradient and elongates both the individual stages and total collider length. Here, we...
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...
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...
Kinetic simulations of relativistic, charged particle beams and advanced plasma accelerator elements are often performed with high-fidelity particle-in-cell simulations, some of which fill the largest GPU supercomputers. Self-consistent modeling of wakefield accelerators for colliders includes many elements beyond plasma acceleration. The integrated Beam, Plasma & Accelerator Simulation...
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...
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...
Laser-plasma accelerators (LPAs) offer an attractive alternative to conventional accelerators, enabling the acceleration of high-brightness electron beams to ultra-relativistic energies using compact, table-top setups. However, LPAs and their applications are plagued by intrinsic shot-to-shot instability largely attributed to fast fluctuations (>1 Hz) and long-term drifts (<1 Hz) in the...
The interaction of an ultra-intense laser pulse with a near critical density target can result in the formation of a plasma channel, a strong azimuthal magnetic field and moving vortices. An application of this is the generation of energetic and collimated ion beams via Magnetic Vortex Acceleration (MVA). The optimized regime of MVA is becoming experimentally accessible with new high intensity...
A laser pulse composed of a fundamental and an appropriately phased second harmonic can drive a time-dependent current of photoionized electrons that generates broadband THz radiation. Over the propagation distances relevant to many experiments, dispersion causes the relative phase between the harmonics to evolve. This “dephasing” slows the accumulation of THz energy and results in a...
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 high-energy photons is a useful diagnostic tool in many different contexts. In laser-solid target experiments, the total yield and energy distribution can be compared for different target types to determine the optimal set-up for photon generation, to be used in radiography and computed tomography of dense objects. In colliding experiments between a laser pulse and an...
We report on the ongoing commissioning of a prototype Electro-Optic Sampling Beam Position Monitor (EOS-BPM) at the FACET-II Facility at SLAC National Accelerator Laboratory. In EOS-BPM, a birefringence is induced in two electro-optic crystals on either side of the electron beam's trajectory as it passes by. Laser pulses traveling through each crystal pick up a spacially encoded polarization...
The advanced accelerator community increasingly recognizes the importance of extending high peak- and average-power laser facilities to longer wavelengths. This recognition is driven by the lambda-squared scaling of the ponderomotive force, inverse-lambda-squared scaling of critical plasma density, and linear-lambda scaling of the number of photons per joule of energy. A significant potential...
In this talk we will consider possible pathways for the upgrade of a linear Higgs factory to High Energy.
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...
Target normal sheath acceleration (TNSA) is one of the best-known laser-plasma interaction mechanism of ion acceleration, capable of generating multi-MeV collimated ion beams. The conventional TNSA (flat-foil target) has a few inherent limitations, such as poor coupling efficiency of the laser energy into hot electrons and short ion acceleration distance at the back of the target. By means of...
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 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...
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...
The thin, underdense, passive plasma lens promises compact, strong, tunable, axisymmetric focusing of intense electron beams. It is ideally suited for matching beams into and out of plasma wakefield accelerator stages, and for reducing divergence of high-brightness plasma-injected beams as they exit the plasma source. The plasma lens comprises a sub-millimeter scale, laser-ionized plasma in...
While the well-known transition radiation usually has negligible impact on high-energy beams, high-current beams such as those from the FACET-II facility can be strongly self-focused by the near field of transition radiation when passing through multiple closely spaced foils. This extreme focusing of high-energy beams opens a new physics frontier with unprecedented densities, potentially...
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...
Filamentation instability can occur in plasma wakefield accelerators as well as in astrophysical media. This instability takes place when a charged particle bunch streams through a plasma with skin depth smaller than the bunch transverse size, so that the plasma return current flows within the bunch. Repulsion between opposite currents tends to reinforce any initial transverse perturbation or...
A wakefield experiment that will utilize electron beams with highly asymmetric transverse emittances, or flat beams, to drive plasma wakefields is underway at the Argonne Wakefield Accelerator (AWA) facility . In the underdense regime, the flat beams create an elliptical blowout structure, resulting in asymmetric focusing forces in the transverse planes. The beam evolution and matching...
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...
Research is in progress to develop high efficiency RF sources for driving accelerators and colliders. These include a 350-450 MHz multiple beam triode, a single beam klystron at L-Band, and a multiple beam klystron at C-Band. The goal efficiency for these devices is 80% or better.
A single beam klystron estimated to operate at 80% has been built and is awaiting testing. The klystron uses a...
In a series of experiments at OMEGA EP facility, we explore potential of petawatt 1-um laser-driven ion acceleration in two-photon polymerization 3D laser printed microstructures. We tested two types of accelerators made of acrylic log-pile organized wire and stochastic non-periodic wire microstructures. We find that enhanced target normal sheath acceleration mechanism is responsible for...
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...
Laser plasma-based ion accelerators have not reached their full potential in producing high-radiation doses at high energies. The most stringent limitation is the lack of a suitable high-repetition rate target that also provides a high degree of control of the plasma conditions. For high-intensity laser-solid interactions, the absolute density and surface gradients of the target at the arrival...
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...
FACET-II is an accelerator test beam facility that delivers high-charge, ultra-short bunches with nC-level charge. FACET also supports a multi-TW laser system that is used to ionize plasmas or collide with electron beams for strong-field QED experiments. Because FACET-II is a test beam facility, both the beam parameters and experimental area can be configured to meet the needs of the...
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...
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...
High intensity laser facilities are expanding their scope from laser and particle-acceleration test beds to user facilities and nuclear physics experiments. A basic goal is to confirm long-standing predictions of strong-field quantum electrodynamics, but with the advent of high-repetition rate laser experiments producing GeV-scale electrons and photons, novel searches for new high-energy...
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...
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...
Reducing the size of free-electron laser (FEL) light sources relies on producing bright electron beams and preserving the beam brightness during acceleration and beam manipulation. The laser-assisted bunch compression (LABC) scheme is a promising technique to significantly enhance the beam current for a very low emittance beam. We explore the application of the LABC scheme to a compact FEL...
An electron source is a crucial component of any accelerator facility, as it defines the scientific reach and capabilities of accelerator applications. Therefore, detailed modeling of electron emission along with advanced growth and characterization of cathode materials are required to enhance emission capabilities of cathodes. This presentation will review the practices being developed at...
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...
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...
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...
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...
Given a very short and intense plane-wave laser pulse travelling in the positive $z$ direction, we propose a multi-step preliminary analytical procedure to tailor the initial density profile $\widetilde{n_0}(z)$ of a cold diluted collisionless plasma to the pulse, so as to control the formation of the plasma wave (PW), its wave-breaking (WB) at density inhomogeneities, the self-injection of...
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...
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...
Compact laser plasma accelerators running at repetition rates >1 kHz promise a wide range of applications in science research, medicine, and security. Commercially available laser systems operating at kHz repetition rates offer mJ pulses with pulse duration as low as tens fs. To fulfill the resonant condition for the laser wakefield acceleration, temporal compression of these pulses is...
This talk will cover proposals for beam driven, plasma-based (PWFA) colliders both past and present. It will cover the proposed systems and future work as written. It will also review community feedback and challenges, some unique to PWFA. The goal is a high degree of audience discussion of the status of PWFA and the road to a collider.
A new paradigm based on oscillations of quantum gas of conduction band electrons known as plasmons has opened unprecedented PetaVolts per meter fields [1,2,3,4]. PV/m fields can be attained using a class of non-perturbative plasmons uncovered in our work. This class of plasmons is excited by particle beams launched inside a conductive tube which makes it possible to control the excitation of...
Free electron lasers (FEL) are powerful scientific tools for a wide variety of applications which require bright, coherent X-ray light. FELs require electron beams with high requirements on brightness, as well as alignment and matching into the undulators. At the Hundred Terawatt Undulator (HTU) system at the BELLA Center, we are aiming to demonstrate a compact Laser-Plasma Accelerator...
Extreme ultraviolet (XUV) light sources allow for the probing of bound electron dynamics on attosecond scales, interrogation of high-energy-density and warm dense matter, photolithography of nanometer-scale features, and access to novel regimes of strong-field quantum electrodynamics. Despite the importance of these applications, coherent XUV light sources remain relatively rare, and those...
We report self-injecting LWFA driven by CPA-CO2 laser pulses of wavelength ~10 micrometers at Brookhaven's Accelerator Test Facility [1]. Long-wave IR pulses open opportunities to drive large wakes in low-density plasma more efficiently than near-IR pulses, potentially enabling higher-quality accelerated bunches. In experiments, 0.5-TW, 4-ps laser pulses generated no electrons, but drove...
The acceleration of positron beams in plasma wakefield accelerators (PWFA) has gained significant interest in recent years due to its potential applications in colliders. One promising scheme for achieving positron acceleration in PWFA is to create an electron-driven blowout wake within a finite-radius, pre-ionized plasma column (narrow plasma column). This approach allows for the formation of...
Muons and their applications in tomography of large objects have recently gained significant interest within the accelerator physics community. However, the lack of portable muon sources has limited muon tomography to relying on cosmic rays, which have a typical flux of $F~1 s^-1 cm^-2$ at ground level for muon energies above 1 GeV. This low flux restricts muon tomography to objects that...
“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...
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 plasma accelerators are poised to reach electron energies of 10-100 GeV and this new regime will open novel applications such as the production of heavy particles including muons. Electrons with energies exceeding twice the rest mass of a muon (211 MeV/c2) can initiate muon generation through the Bethe-Heitler pair production process. This talk will present work on behalf of a...
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...
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...
In this talk we will present results from high gradient structure testing of single, multi-cell and meter-scale accelerating structures. Structures were tested with a variety of fabrication techniques including brazing, diffusion bonding and clamped plated structures. Target gradients of 120 MeV/m were achieved and exceeded. Designs and performance of rf components (loads, windows, etc.) for...
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 report on electron-beam collimation using a passive plasma lens[1], integrated directly into a laser wakefield-accelerator stage operating in the high-charge regime. The lens is created by the reshaping of the gas-density profile of a supersonic jet at the beam’s exit side. It reduces the beam’s divergence by a factor of 2 to below 1 mrad (rms), while preserving the total charge of 170 pC...
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...
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...
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...
The global collaboration between PAL, NIU, ANL, and KU is ongoing to develop an electron beam-driven THz power generation and two-beam acceleration in SWFA. We successfully demonstrated the fabrication of a 0.2 THz structure and the characteristic of wakefield using the beam-based experimental measurement. of a 0.2 THz structure a few years ago. The success of a new fabrication method led us...
Laser wakefield acceleration (LWFA) using laser-ablated metallic plasma targets has been developed for high-vacuum and high-repetition rate operations. The metallic plasma density (called the pre-plasma) generated by laser-ablation is increased via the optical ionization process due to intense fs laser pulse (called the main laser). The optical guiding of main laser in the plasma is influenced...
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...
Direct laser acceleration (DLA) can generate superponderomotive energy electrons to hundreds of MeV, along with secondary particles and radiation, through the interaction of high-intensity picosecond laser pulses with underdense plasma. As a complex and dynamic process, the DLA electron acceleration can be affected by a number of factors, such as the laser focusing geometries [H Tang et al. ...
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...
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...
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,...
Recently developed techniques for optical generation of low density (≤10^17 cm^(-3)), meter-scale hydrodynamic plasma waveguides in extended supersonic gas jets [1-3] have already enabled a new class of fully-optical multi-GeV laser wakefield accelerators [4,5]. Optimization of the laser wakefield acceleration (LWFA) process in these types of waveguides and plans for future, single-stage 100...
Recent progress in plasma-based accelerators has sparked intense interest in developing plasma-driven free-electron lasers [1]. However, operating free-electron lasers at soft and hard X-ray wavelengths necessitates electron beams with significantly enhanced 6D brightness. The author outlines comprehensive strategies for producing ultrahigh 6D brightness electron beams in beam-driven plasma...
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...
A tunable laser positron source as originally described in [1] is being prototyped using the collocated LWIR CO2 laser and electron beam at BNL-ATF. Unlike LPA, this work deals with interaction of three distinct entities, a laser, a pair-plasma, and laser-driven electron density structures.
This work relies on the advantages of larger size of electron density structures excited by the CO2...
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,...
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...
Laser-driven free-electron lasers (LDFELs) replace magnetic undulators with the electromagnetic field of a laser pulse. Because the undulator period is half the wavelength of the laser pulse, LDFELs can amplify x rays to saturation using lower electron energies and over shorter interaction lengths than a conventional free-electron laser. Here we show that a flying-focus pulse substantially...
An x-ray excitation in a medium can cause localized heating (<mK) and thermoelastic expansion, inducing a detectable ultrasonic emission which potentially enables low-dose, 3D imaging [1]. For effective ultrasonic emission, the dose should be deposited faster than the stress confinement time of the medium, ~ns for many applications. This modality has been studied in medical linear...