Electron beams of very high energy (50–250 MeV) can potentially produce a more favourable radiotherapy dose distribution compared to state-of-the-art photon-based radiotherapy techniques. To produce an electron beam of sufficiently high energy to allow for a long penetration depth (several cm), very large accelerating structures are needed when using conventional radio-frequency technology,...
We describe a simple scheme, truncated-channel injection, to inject electrons directly into the wakefield driven by a drive pulse guided by an all-optical plasma channel. We use this approach to generate dark-current-free 1.2 GeV, 4.5% relative energy spread electron bunches with 120 TW laser pulses guided in a 110 mm-long hydrodynamic optical-field-ionized (HOFI) plasma channel. Our...
High-brightness RF photo-injectors are crucial for generating high peak current and low transverse emittance electron beams, which are necessary for driving plasma Wake-field acceleration in advanced accelerator concepts and novel radiation sources. To enhance the EuPRAXIA@SPARC_LAB photo-injector for future upgrades, it is essential to investigate and assess the feasibility of achieving...
Electron and X-ray beam instrumentation will be a core component of the EuPRAXIA X-ray free electron laser. It will be used to set up the accelerator, to demonstrate and optimize the beam parameters, to stabilize the beam using feedback and adaptive feed-forward loops, and to diagnose errors.
We present here an overview of the requirements and outline a comprehensive suite of instruments.
Dielectric Assist Accelerating (DAA) structures based on ultralow-loss ceramic are being studied as an alternative to conventional disk-loaded copper cavities. This accelerating structure consists of dielectric disks with irises arranged periodically in metallic structures working under the TM02−𝜋 mode.
Here, the numerical design of an S-band DAA structure for low beta particles, such as...
High-voltage pulsed discharges can produce suitable plasma for wakefield particle acceleration experiments, such as the AWAKE. Using two successive voltage pulses, the first for plasma ignition (up to 60kV of ignition voltage with around 20A of plasma current) followed by a second pulse (currents up to 600A) for plasma heating, it is possible, by taking advantage of the low impedance state...
Recent theoretical advancements propose multiple positron acceleration schemes in plasma wakefield acceleration (PWFA). One of the most promising ideas involves the creation of an electron-driven blowout wake within a finite-radius pre-ionized plasma column. This leads to the formation of an elongated region of sheath electrons at the closing of the first wake period capable of accelerating...
The Free-Electron Laser facility of the EuPRAXIA@SPARC_LAB infrastructure is driven by an electron beam with 1 GeV energy, produced by an X-band normal conducting LINAC followed by a plasma wakefield acceleration stage.
The AQUA beamline aims at delivering variable polarization photons in the 3-4 nm wavelength range by means of out-of-vacuum APPLE-X permanent magnet undulators with 18 mm...
Ultrashort high-peak current electron beams generated from laser wakefield acceleration (LWFA) are capable to drive high accelerating gradient plasma wakefield accelerators (PWFAs) operating in high plasma density regime. Implementation of advanced cold-injection schemes in this hybrid platform promises the generation of high brightness electron beams with unprecedented low emittance and...
The goal of this work is to use Laser Wakefield Acceleration (LWFA) based X-ray sources to develop a diagnostic capable of improved target metrology for Inertial Confinement Fusion (ICF) fuel capsules. We aim to develop a sub-ps, sub-10 micron X-ray source, which is capable not only of imaging ICF fuel capsules with high resolution, but could additionally be deployed for dynamic radiography of...
Transition to practical laser wakefield accelerator (LWFA) facilities with users, especially for multi-stage LWFAs, requires significantly improving the electron beam quality. An integrated study of the beam dynamics is presented, from the electron beam creation in the plasma to the target, including magnetic elements of the transport line. The focus is made on high-charge (more than one...
Plasma wakefield acceleration is nowadays very attractive in terms of accelerating gradient, able to overcome conventional accelerators by orders of magnitude. However, this poses very demanding requirements on the accelerator stability to avoid large instabilities on the final beam energy. In this study we analyze the correlation between the driver-witness distance jitter (due to the RF...
We present a preliminary analytical procedure [1,2] in 4 steps to tailor the initial density of an inhomogenous cold diluted plasma to the laser pulse (both assumed plane-symmetrical) so as to control wave-breakings of the plasma wave and maximize the acceleration of small bunches of electrons self-injected by the first wave-breaking at the density down-ramp. We use an improved fully...
Beam-driven plasma-wakefield acceleration is a promising avenue for the future design of compact linear accelerators with applications in high-energy physics and photon science. Meeting the luminosity and brilliance demands of current users requires the delivery of thousands of bunches per second: many orders of magnitude beyond the current state-of-the-art of plasma-wakefield accelerators,...
The Advanced Proton Driven Plasma Wakefield Acceleration Experiment (AWAKE) explores plasma wakefield acceleration of electrons, using a proton bunches as driver. AWAKE requires plasma sources capable of reaching densities of 1 to 10x10^14 cm^-3, and that allow extending the acceleration length from tens to hundreds of meters, beyond the achievable length with the present laser-ionised,...
Many impressive experimental results in electron acceleration have been achieved using wakefields excited in a plasma. Plasma-wakefield acceleration provides high accelerating gradients and promises compact accelerators of high brightness and high-energy electron beams. Future applications of plasma-wakefield accelerators, in particular, particle colliders and free-electron lasers strongly...
Free-electron lasers (FELs) are powerful tools for studying matter at the atomic level and its dynamics on the femtosecond scale. Plasma accelerators hold the promise of drastically reducing the size and costs of future accelerators, which could also help make FELs more widely applicable and perhaps even viable for industry. While a truly compact, fully plasma-based FEL still faces several...
Polarised beams are indispensable for many experiments in particle, atomic
and nuclear physics where spin-dependent processes are to be studied. Unlike
RF accelerators, Laser-Plasma-Accelerators (LPA) are not limited by material
breakdown and can therefore support thousand times higher accelerating fields,
which make them a promising alternative to conventional accelerators.
The LEAP...
The capability to sustain high accelerating gradients ($\sim$ 100s GV/m) in plasmas leads to electron bunches at GeV-scale energies in short distances, making Laser-Plasma Acceleration (LPA) a promising approach to high gradient particle accelerators. Among injection schemes, ionization injection is one of the most practical with outstanding numerical results (see ReMPI acceleration).
An...
The AWAKE experiment at CERN makes use of a high-energy proton beam to drive plasma wakefields. The long drive bunch self-modulates in the plasma, resulting in a train of microbunches. However, nonlinear effects shift the plasma resonance, causing the wakefield amplitude to saturate after only a fraction of the microbunch train. In this work, we use particle-in-cell simulations to show that...
The Advanced Wakefield Experiment (AWAKE) relies on proton-driven wakefields created in a laser-ionized plasma to accelerate electrons. Accurate measurement and control of the optics, trajectory and timing of the three beams—proton, laser and electron—is a fundamental requirement for successful operation of the facility. Continuous advances in both instrumentation and methods are necessary to...
Laser-plasma accelerators (LPAs) are on the cusp of becoming instrumental in real-world scientific applications. Nevertheless, to be seriously considered as viable alternatives to traditional machines, LPAs must offer competitive quality and flexibility in their electron beam parameters, meeting the diverse requirements of potential applications.
While previous experiments have demonstrated...
We study the stability of plasma wakes and the properties of density-downramp injection in an electron-driven plasma accelerator in the blowout regime. As shown by particle-in-cell (PIC) simulations, the accelerating structure remains highly stable until the moment some electrons of the driver reach almost zero energy, which corresponds to the best interaction length for optimal...
The high-intensity iP2 beamline at the BELLA PW laser enables frontier capabilities in High Energy Density Science, including accessing new regimes of ion acceleration. This system provides a focal spot of ~3 μm diameter, resulting in peak intensities of >5×1021 W/cm2. The 1 Hz pulse repetition rate, if paired with replenishable target systems, can increase the particle...
In laser-driven particle acceleration the choice of the target material can have a large impact on the acceleration process. Therefore, a laser-driven proton acceleration experiment was conducted at the POLARIS laser system, where liquid micro-droplets made of water or ethylene glycole were used as targets.
Droplet chains were created by a pressurized capillary nozzle, which was made to...
High peak current electron beams from laser wakefield accelerators (LWFAs) can excite a high amplitude plasma wave in a subsequent plasma wakefield acceleration (PWFA) stage. The intrinsic short duration of these driver beams enables a new operational regime of PWFAs at plasma densities above $10^{18}$cm$^{-3}$ which is important for the acceleration of ultra-short and ultra-low emittance...
The EuAPS project (EuPRAXIA Advanced Photon Source) aims at realizing an X-ray photon source for users applications. The photons will be produced by betatron radiation mechanism inside a laser plasma accelerator, exploiting an internal injection scheme. The source will produce short pulses of photons in the spectral range 1 - 10 keV for a wide set of applications ranging from imaging to...
We summarize and explain plans for witness particle beam injection into wakefields for the AWAKE Run 2b experiments. In AWAKE, the plasma wakefields are driven by a self-modulating relativistic proton bunch. For Run 2b, we use a novel Rubidium vapor source that allows for a plasma density step. To demonstrate that the density step can stabilize the wakefield amplitude and to probe the...
Beam-driven plasma-wakefield acceleration has the potential to produce accelerating fields up to three orders of magnitude stronger than those in traditional accelerators using RF cavities. However, in recent years, an efficiency-instability relation has been proposed, which limits the energy transfer from the wake to the trailing bunch that can be achieved without causing detrimental...
The Extreme Photonics Applications Centre (EPAC) is an ultra-short pulse, petawatt laser facility under construction on the Rutherford Appleton Laboratory Site in the UK. In Experimental Area 1, it will deliver stable electron beams at a rep rate of 10 Hz for industrial and academic users via laser plasma wakefield acceleration. Simulation studies have been performed in order to understand the...
While multiple works demonstrated the importance of using realistic laser profiles for simulations of laser-plasma accelerators to accurately reproduce experimental measurements, the handshake between experiments and simulations can be challenging.
Similarly, transferring a laser pulse from one code to another, as needed for start-to-end simulations, may require some error-prone...
Recently, free electron lasing at UV wavelength has been demonstrated by deploying the COXINEL beamline driven by HZDR plasma accelerator in a seeded configuration[1]. Further control and optimization of such an FEL radiation require full knowledge of strongly-coupled multivariate parameters involved in laser plasma acceleration, electron beam transport and radiation generation. For this...
High-charge energetic positron beams are a useful tool for probing the Standard Model of particle physics, however, the large scale and cost of accelerators used to conventionally produce such beams (e.g., LEP) have led to the search for smaller and cheaper alternatives. One candidate for $e^--e^+$ pair creation is to collide an ultra-relativistic electron beam with a high-intensity laser...
The level of maturity of laser-based ion accelerators is opening the path for their use in real-life applications. Particularly promising is the in-situ production of short-lived radionuclides for medical imaging, with techniques such as Positron-Emission-Tomography (PET). However, the large activities required (>10MBq for pre-clinical, >200MBq for clinical) are well-above those achievable...
Typically, target normal sheath accelerated protons have a high divergence, often greater than 10s of degrees. However, a lower divergence beam is beneficial for many applications and for beam capture by a transport system. An experiment in at the Gemini TA2 laser facility (Central Laser Facility), using a water sheet target, observed proton beams with a divergence in the order of 1 degree;...
The Compact Linear Accelerator for Research and Applications (CLARA) is an ultra-bright 250 MeV electron beam test facility under development at STFC Daresbury Laboratory. Originally conceived to test advanced Free Electron Laser schemes, CLARA has become a unique facility for user-led experiments in a wide range of disciplines, including advanced accelerator concepts.
Here we report on the...
For more than 5 years, superconducting undulators (SCUs) have been successfully delivering X-rays in storage rings. The European XFEL (EuXFEL) plans to demonstrate the operation of SCUs in XFELs. For the same geometry, SCUs can reach a higher peak field on the axis with respect to all other available technologies, offering a larger photon energy tunability range. The application of...
When a high intensity electron beam passes through a structured nano target, the created solid-state density plasma can support ultra-high accelerating gradients on the order of 1 TeV/m to 10 TeV/m with similarly strong focusing fields. This process may thus lead to an acceleration method with extremely high single-stage energy gains for electron or muon beams. Additionally, simulations...
An overview is presented of the Oxford Plasma Accelerator Laboratory (OPAL), which houses a 600mJ (shortly to be upgraded to 1 J), 10Hz, 45fs Ti:Sapphire laser, and a suite of diagnostics tailored to the development of channel-guided laser-plasma accelerators. A channel is formed with a ~100mJ “channel-forming” beam, focused by an axicon. This channel guides the "drive" beam, thereby...
Laser-driven plasma wakefields accelerators (LWFA) in the past few years have shown rapid progress towards the realization of compact and stable electron sources. Many efforts are devoted to increase the repetition rate of these sources, which is mandatory for their future applications. This requires diagnostics that can work in real-time without losing their precision. This is particularly...
We present first results for a parameter study including transverse instability in the acceleration stages of HALHF, a novel electron positron collider concept combining plasma wakefield acceleration and mature RF acceleration to reach centre of mass energies of 250 GeV. This study is a preliminary extension of the previous studies that indicated promising performance, by including transverse...
The SPARC-LAB test facility at LNF (Frascati) is equipped with a high-brightness photo injector used to explore and develop advanced beam manipulation techniques. This photo-injector can generate high brightness two electron bunches (witness and driver) needed for plasma acceleration. To obtain these, the cathode of the photo-injector at SPARC-LAB is illuminated by a train of laser pulses,...
The last decades have seen a growing interest in plasma-based accelerator technology, leading to establishing these techniques in the particle accelerator community [1, 2]. Nonetheless, they are still only effective on particles already traveling close to the speed of light. Unfortunately, this excludes heavier particles (e.g. muons), naturally produced at lower velocities due to the higher...
Since they have been proposed, laser-plasma accelerators have interested the scientific community for their ability to generate electric fields exceeding the ones of Linacs and RF cavities. Several efforts have been made in order to produce monochromatic electron beams and to increase their maximum energy, often at the expense of the charge. However, some applications like femtosecond...
X-rays production through betatron radiation emission from electron bunches is a valuable resource for several research fields. The EuAPS (EuPRAXIA Advanced Photon Sources) project, within the framework of the EuPRAXIA project, aims to provide 1-10 keV photons (soft X-rays) using a compact plasma based system designed to exploit self-injection processes that occur in highly nonlinear...
Ultrafast shadowgraphy with transverse few-cycle probe pulses has enabled the snapshot of the underdense laser-plasma interactions with unprecedented temporal (~ 4 fs) and spatial (< 10 µm) resolution. However, in laser-plasma experiments, the shot-to-shot fluctuation of high-power laser systems is not negligible. This limits the application of snapshot imaging techniques, especially in...
PALLAS is a laser-plasma injector test facility at IJCLab developed in the framework of the preparatory phase of EuPRAXIA. It aims to achieve reliability, stability and control closer to conventional RF accelerator standards while using Laser Wakefield Acceleration (LWFA) in a plasma target with electron bunches produced by localized ionization injection.
One of the purposes is to correlate...
In laser wakefield acceleration (LWFA) experiments at major facilities, emphasis is typically placed on standard laser and gas parameters such as pulse duration, spot size, normalised vector potential, gas constituents and gas density in order to produce the most stable, high charge, high energy, narrow spread electron beams. While these parameters are certainly of unquestionable importance,...
Numerical simulations of laser-plasma acceleration in the non-linear regime require an accurate modelling of the laser driving the plasma waves. To reconstruct the transverse laser field distribution from fluence measurements, a fast and flexible field reconstruction method based on the Gerchberg-Saxton Algorithm with Hermite-Gauss Modes Decomposition (GSA-MD) has been developped [2].
The...
Plasma temperature is a critical parameter in the physics of discharge capillary plasma sources. It determines their ability to form guiding channels in LWFA, can influence the gas refill time and therefore the maximum repetition rate and confound density measurements taken via optical emission spectroscopy; to name but a few effects. Accurately determining the temperature of these plasmas is...
Efforts towards the next generation of compact accelerators based on plasma wakefield acceleration (PWFA) are aimed at enabling their application in various fields, including basic research, medicine, and industrial uses. To achieve this goal, significant focus is directed towards controlling the plasma creation process, ensuring the development of a time-jitter free channel, and maintaining...
Lattice Boltzmann Method (LBM) is a novel numerical approach for simulating of Plasma WakeField Acceleration (PWFA) processes. In this talk, we employ the LBM to investigate the influence of temperature on plasma waves. Thermal effects can be relevant, for example, in PWFA processes with a high repetition rate, which holds significant importance for various PWFA applications. By utilizing LBM,...
Particle acceleration in wakefields excited in a plasma medium is one of the prime candidates to complement or even replace conventional radiofrequency accelerators in future accelerator facilities due to the far superior acceleration gradients achievable in plasma. In contrast to conventional acceleration techniques, which routinely supply experiments with up to 100’s of thousands of bunches...
The charge of an electron bunch is one of the most fundamental parameters in accelerator physics. Therefore, several techniques to measure the electron bunch charge exist. However, many conventional charge diagnostics face serious drawbacks when applied to plasma accelerators. For example, integrating current transformers (ICTs or toroids) have shown to be sensitive to the EMP originating from...
The relativistic interaction of short pulsed lasers or electrons with plasma has recently led to the birth of a new generation of femtosecond X-ray sources. Radiations with properties similar to those that can be observed from a wiggler or undulator, can be generated by the oscillations induced in the excited plasma by electrons (PWFA) or by lasers (LWFA), making plasma an interesting medium...
Betatron radiation from laser wakefield accelerators is a powerful X-ray source, proven useful in several applications, e.g. in medical imaging and tomography, X-ray absorption spectroscopy for warm dense matter among others. However, due to the large X-ray divergence typically on the order of tens of mrad, an effective beam transport to the sample and subsequent detection becomes challenging...
Lasers with femtosecond pulse durations have become readily available and are used in numerous applications from material processing to plasma-based accelerators. Often, the lasers are focused to small spot sizes, exceeding intensities of $10^{13}$ W/cm2 and thus the ionization threshold in most materials. As this can lead to the production of x-rays, national law in Germany made it mandatory...
The Draco laboratory at HZDR is a versatile, multi-arm and multi-target-area facility, consisting of several, independent subsystems. The lack of an overarching DAQ is balanced by interfaces of the subsystems and custom inter-linking agents. We present recent progress of implementing such software agents, connecting to the center’s electronic lab documentation system. First, manual logging of...
We present the results of an experiment at the POLARIS laser system (at $1030\,$nm) using an off-harmonic optical probe, in which the laser-plasma interaction with water micro-droplets was investigated. In contrast to experiments with thin foils, the spherical symmetry of droplets facilitates a direct imaging of the plasma expansion process using shadowgraphy. In the experimental setup, a jet...
The propagation of particle beams through plasma can give rise to instabilities, relevant for astrophysical and laboratory systems. For ultrarelativistic beams, the oblique two-stream instability (OTSI) generally prevails the early beam-plasma interaction. For conditions relevant to the E305 experiment, which is devoted to study such beam-plasma instabilities with the FACET-II facility at...
We investigate the operation regime and performance of the Plasma-Modulated Plasma Accelerator (P-MoPA), a new approach offering the potential for high-repetition-rate, GeV-scale laser plasma accelerators (LPA) driven by picosecond-duration laser pulses [Phys. Rev. Lett. 127, 184801 (2021)]. P-MoPA uses a plasma modulator stage, which introduces a spectral modulation to a picosecond pulse from...
Plasma targetry design for PALLAS experiment relies on numerical PIC parametric studies, computational fluid dynamic studies and an experimental test bench equipped with plasma density profile diagnostics, density measurement and plasma species spatial distribution for target charecterisation.
We discuss construction of surrogate model of PALLAS, based on 15000 simulations performed for...
We present the conceptual design of an alternative injector system based on laser-plasma accelerator technology, to deliver high-quality electron bunches to PETRA IV – the future 4th generation synchrotron light source at DESY. The design consists of a laser-plasma accelerator to produce electron bunches at 6 GeV with state-of-the-art energy spread and stability, and a X-band energy compressor...
High average power, kHz laser-plasma acceleration is an emerging technique which could supply few MeV, few femtosecond electron bunches with high average current. Here we present exciting experimental results, drawing the path towards the first electron acceleration driven by an industrial Yb:YAG laser at multi-kHz repetition rate.
KHz lasers usually deliver few mJ pulses and, hence,...
Laser WakeField Accelerators (LWFA) are a promising alternative for many industrial and medical applications. Despite significant progress, the use of LWFAs for real-world applications requires improvements in beam and transport quality. LWFAs beams differ from those studied in conventional accelerators. This calls for a dedicated study of transport lines for laser plasma acceleration. The aim...
With the direct laser acceleration (DLA) method, the leading part of an intense laser pulse ionizes the target material and forms a positively charged ion plasma channel into which electrons are injected and accelerated. DLA has been realized over a wide range of laser parameters, using low-atomic-number target materials. The electron beam energy has been confirmed to scale with the normalized...
