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A. Zigler

Publications and source records attributed to A. Zigler.

17 recordsLinked to original sources

Experimental Demonstration of Beam-Driven Wakefield Acceleration in Laser-Plasma Filament

Self-guided femtosecond laser pulses propagating in low-pressure gas can generate plasma filaments, establishing a new framework for plasma wakefield acceleration. Unlike conventional schemes relying on mechanically confined or preformed plasma channels, this method exploits the intrinsic non-linear light-matter interaction, greatly reducing the energy required to generate plasma. This, in turn, allows to realise tunable stages, potentially operating above kHz repetition rate and with meter-scale interaction lengths and transverse sizes down to a few tens of micrometres. Moreover, the laser-plasma filament reproducibility is intrinsically higher than state-of-the-art discharge-plasmas, where the breakdown process is initiated in a stochastic and uncontrolled manner. As a result, laser-based plasma formation offers improved reliability and control over plasma parameters. Here we report a proof-of-principle experimental demonstration of beam-driven wakefield acceleration of electron bunches with an accelerating field exceeding 250 MV/m in a laser-generated plasma filament. The results are cross-checked with numerical simulation, showing an excellent agreement and providing a complete picture of the physical process. Beyond particle acceleration, the concept bridges laser filamentation physics, advanced plasma photonics and compact accelerator technologies, offering a promising route towards sustainable, high-repetition-rate plasma-based facilities.

physics.plasm-ph

Recovery of hydrogen plasma at the sub-nanosecond timescale in a plasma-wakefield accelerator

Plasma wakefield acceleration revolutionized the field of particle accelerators by generating gigavolt-per-centimeter fields. To compete with conventional radio-frequency (RF) accelerators, plasma technology must demonstrate operation at high repetition rates, with a recent research showing feasibility at megahertz levels using an Argon source that recovered after about 60 ns. Here we report about a proof-of-principle experiment that demonstrates the recovery of a Hydrogen plasma at the sub-nanosecond timescale. The result is obtained with a pump-and-probe setup and has been characterized for a wide range of plasma densities. We observed that large plasma densities reestablish their initial state soon after the injection of the pump beam (< 0.7 ns). Conversely, at lower densities we observe the formation of a local dense plasma channel affecting the probe beam dynamics even at long delay times (> 13 ns). The results are supported with numerical simulations and represent a step forward for the next-generation of compact high-repetition rate accelerators.

physics.acc-ph

Sinusoidal Transmission Grating Spectrometer for EUV Measure

Spectral measurements play a vital role in understanding laser-plasma interactions. The ability to accurately measure the spectrum of radiation sources is crucial for unraveling the underlying physics. In this article, we introduce a novel approach that significantly enhances the efficiency of binary Sinusoidal Transmission Grating Spectrometers (STGS). The grating was tailored especially for Extreme Ultraviolet (EUV) measurements. The new design, High Contrast Sinusoidal Transmission Grating (HCSTG), not only suppresses high diffraction orders and retains the advantageous properties of previous designs but also exhibits a fourfold improvement in first-order efficiency. In addition, the HCSTG offers exceptional purity in the first order due to effectively eliminating half-order contributions from the diffraction pattern. The HCSTG spectrometer was employed to measure the emission of laser-produced Sn plasma in the 1-50 nm spectral range, achieving spectral resolution of $λ/Δλ=60$. We provide a comprehensive analysis comparing the diffraction patterns of different STGs, highlighting the advantages offered by the HCSTG design. This novel, enhanced efficiency HCSTG spectrometer, opens new possibilities for accurate and sensitive EUV spectral measurements.

physics.optics

First emittance measurement of the beam-driven plasma wakefield accelerated electron beam

Next-generation plasma-based accelerators can push electron beams to GeV energies within centimetre distances. The plasma, excited by a driver pulse, is indeed able to sustain huge electric fields that can efficiently accelerate a trailing witness bunch, which was experimentally demonstrated on multiple occasions. Thus, the main focus of the current research is being shifted towards achieving a high quality of the beam after the plasma acceleration. In this letter we present beam-driven plasma wakefield acceleration experiment, where initially preformed high-quality witness beam was accelerated inside the plasma and characterized. In this experiment the witness beam quality after the acceleration was maintained on high level, with $0.2\%$ final energy spread and $3.8~μm$ resulting normalized transverse emittance after the acceleration. In this article, for the first time to our knowledge, the emittance of the PWFA beam was directly measured.

physics.acc-ph

Energy spread minimization in a beam-driven plasma wakefield accelerator

Next-generation plasma-based accelerators can push electron bunches to gigaelectronvolt energies within centimetre distances. The plasma, excited by a driver pulse, generates large electric fields that can efficiently accelerate a trailing witness bunch making possible the realization of laboratory-scale applications ranging from high-energy colliders to ultra-bright light sources. So far several experiments have demonstrated a significant acceleration but the resulting beam quality, especially the energy spread, is still far from state of the art conventional accelerators. Here we show the results of a beam-driven plasma acceleration experiment where we used an electron bunch as a driver followed by an ultra-short witness. The experiment demonstrates, for the first time, an innovative method to achieve an ultra-low energy spread of the accelerated witness of about 0.1%. This is an order of magnitude smaller than what has been obtained so far. The result can lead to a major breakthrough toward the optimization of the plasma acceleration process and its implementation in forthcoming compact machines for user-oriented applications.

physics.acc-ph

Accurate spectra for high energy ions by advanced time-of-flight diamond-detector schemes in experiments with high energy and intensity lasers

Time-Of-Flight (TOF) methods are very effective to detect particles accelerated in laser-plasma interactions, but they shows significant limitations when used in experiments with high energy and intensity lasers, where both high-energy ions and remarkable levels of ElectroMagnetic Pulses (EMPs) in the radiofrequency-microwave range are generated. Here we describe a novel advanced diagnostic method for the characterization of protons accelerated by intense matter interactions with high-energy and high-intensity ultra-short laser pulses up to the femtosecond and even future attosecond range. The method employs a stacked diamond detector structure and the TOF technique, featuring high sensitivity, high resolution, high radiation hardness and high signal-to-noise ratio in environments heavily affected by remarkable EMP fields. A detailed study on the use, the optimization and the properties of a single module of the stack is here also described for an experiment where a fast diamond detector is employed in an highly EMP-polluted environment. Accurate calibrated spectra of accelerated protons are presented from an experiment with the femtosecond Flame laser (beyond 100 TW power and ~$10^{19}$ W/cm$^2$ intensity) interacting with thin foil targets. The results that can be readily applied to the case of complex stack configurations and to more general experimental conditions.

physics.ins-det

Longitudinal phase-space manipulation with beam-driven plasma wakefields

The development of compact accelerator facilities providing high-brightness beams is one of the most challenging tasks in field of next-generation compact and cost affordable particle accelerators, to be used in many fields for industrial, medical and research applications. The ability to shape the beam longitudinal phase-space, in particular, plays a key role to achieve high-peak brightness. Here we present a new approach that allows to tune the longitudinal phase-space of a high-brightness beam by means of a plasma wakefields. The electron beam passing through the plasma drives large wakefields that are used to manipulate the time-energy correlation of particles along the beam itself. We experimentally demonstrate that such solution is highly tunable by simply adjusting the density of the plasma and can be used to imprint or remove any correlation onto the beam. This is a fundamental requirement when dealing with largely time-energy correlated beams coming from future plasma accelerators.

physics.acc-ph

Evolution of the electric fields induced in high intensity laser-matter interactions

Multi MeV protons \cite{snavely2000intense} and heavier ions are emitted by thin foils irradiated by high-intensity lasers, due to the huge accelerating fields, up to several teraelectronvolt per meter, at sub-picosecond timescale \cite{dubois2014target}. The evolution of these huge fields is not well understood till today. Here we report, for the first time, direct and temporally resolved measurements of the electric fields produced by the interaction of a short-pulse high-intensity laser with solid targets. The results, obtained with a sub-$100$ fs temporal diagnostics, show that such fields build-up in few hundreds of femtoseconds and lasts after several picoseconds.

physics.plasm-ph

Plasma ramps caused by outflow in gas-filled capillaries

Plasma confinement inside capillaries has been developed in the past years for plasma-based acceleration to ensure a stable and repeatable plasma density distribution during the interaction with either particles or laser beams. In particular, gas-filled capillaries allow a stable and almost predictable plasma distribution along the interaction with the particles. However, the plasma ejected through the ends of the capillary interacts with the beam before the inner plasma, affecting the quality of the beam. In this article we report the measurements on the evolution of the plasma flow at the two ends of a 1 cm long, 1 mm diameter capillary filled with hydrogen. In particular, we measured the longitudinal density distribution and the expansion velocity of the plasma outside the capillary. This study will allow a better understanding of the beam-plasma interaction for future plasma-based experiments.

physics.acc-ph

Recent studies on single-shot diagnostics for plasma accelerators at SPARC_LAB

Plasma wakefield acceleration is the most promising acceleration technique for compact and cheap accelerators, thanks to the high accelerating gradients achievable. Nevertheless, this approach still suffers of shot-to-shot instabilities, mostly related to experimental parameters fluctuations. Therefore, the use of single shot diagnostics is needed to properly understand the acceleration mechanism. In this work, we present two diagnostics to probe electron beams from laser-plasma interactions, one relying on Electro Optical Sampling (EOS) for laser-solid matter interactions, the other one based on Optical Transition Radiation (OTR) for single shot measurements of the transverse emittance of plasma accelerated electron beams, both developed at the SPARC_LAB Test Facility.

physics.plasm-ph

Characterization of self-injected electron beams from LWFA experiments at SPARC_LAB

The plasma-based acceleration is an encouraging technique to overcome the limits of the accelerating gradient in the conventional RF acceleration. A plasma accelerator is able to provide accelerating fields up to hundreds of $GeV/m$, paving the way to accelerate particles to several MeV over a short distance (below the millimetre range). Here the characteristics of preliminary electron beams obtained with the self-injection mechanism produced with the FLAME high-power laser at the SPARC_LAB test facility are shown. In detail, with an energy laser on focus of $1.5\ J$ and a pulse temporal length (FWHM) of $40\ fs$, we obtained an electron plasma density due to laser ionization of about $6 \times 10^{18}\ cm^{-3}$, electron energy up to $350\ MeV$ and beam charge in the range $(50 - 100)\ pC$.

physics.acc-ph

Overview of Plasma Lens Experiments and Recent Results at SPARC_LAB

Beam injection and extraction from a plasma module is still one of the crucial aspects to solve in order to produce high quality electron beams with a plasma accelerator. Proper matching conditions require to focus the incoming high brightness beam down to few microns size and to capture a high divergent beam at the exit without loss of beam quality. Plasma-based lenses have proven to provide focusing gradients of the order of kT/m with radially symmetric focusing thus promising compact and affordable alternative to permanent magnets in the design of transport lines. In this paper an overview of recent experiments and future perspectives of plasma lenses is reported.

physics.acc-ph

The FLAME laser at SPARC_LAB

FLAME is a high power laser system installed at the SPARC_LAB Test Facility in Frascati (Italy). The ultra-intense laser pulses are employed to study the interaction with matter for many purposes: electron acceleration through LWFA, ion and proton generation exploiting the TNSA mechanism, study of new radiation sources and development of new electron diagnostics. In this work, an overview of the FLAME laser system will be given, together with recent experimental results

physics.acc-ph

Recent results at SPARC_LAB

The current activity of the SPARC_LAB test-facility is focused on the realization of plasma-based acceleration experiments with the aim to provide accelerating field of the order of several GV/m while maintaining the overall quality (in terms of energy spread and emittance) of the accelerated electron bunch. In the following, the current status of such an activity is presented. We also show results related to the usability of plasmas as focusing lenses in view of a complete plasma-based focusing and accelerating system.

physics.acc-ph

Wake fields effects in dielectric capillary

Plasma wake-field acceleration experiments are performed at the SPARC LAB test facility by using a gas-filled capillary plasma source composed of a dielectric capillary. The electron can reach GeV energy in a few centimeters, with an accelerating gradient orders of magnitude larger than provided by conventional techniques. In this acceleration scheme, wake fields produced by passing electron beams through dielectric structures can determine a strong beam instability that represents an important hurdle towards the capability to focus high-current electron beams in the transverse plane. For these reasons, the estimation of the transverse wakefield amplitudes assumes a fundamental role in the implementation of the plasma wake-field acceleration. In this work, it presented a study to investigate which parameters affect the wake-field formation inside a cylindrical dielectric structure, both the capillary dimensions and the beam parameters, and it is introduced a quantitative evaluation of the longitudinal and transverse electric fields.

physics.acc-ph

Enhanced Proton Acceleration by an Ultrashort Laser Interaction with Structured Dynamic Plasma Targets

We experimentally demonstrate a notably enhanced acceleration of protons to high energy by relatively modest ultrashort laser pulses and structured dynamical plasma targets. Realized by special deposition of snow targets on sapphire substrates and using carefully planned pre-pulses, high proton yield emitted in a narrow solid angle with energy above 21MeV were detected from a 5TW laser. Our simulations predict that using the proposed scheme protons can be accelerated to energies above 150MeV by 100TW laser systems.

physics.plasm-ph

5.5-7.5 MeV Proton generation by a moderate intensity ultra-short laser interaction with H2O nano-wire targets

We report on the first generation of 5.5-7.5 MeV protons by a moderate intensity short-pulse laser (4.5 \times 1017 W/cm^2, 50 fsec) interacting with H2O nano-wires (snow) deposited on a Sapphire substrate. In this setup, the laser intensity is locally enhanced by the tip of the snow nano-wire, leading to high spatial gradients. Accordingly, the plasma near the tip is subject to enhanced ponderomotive potential, and confined charge separation is obtained. Electrostatic fields of extremely high intensities are produced over the short scale length, and protons are accelerated to MeV-level energies.

physics.plasm-ph