arXiv subjects

G. Grittani

Publications and source records attributed to G. Grittani.

6 recordsLinked to original sources

arXiv2024

Technical Status Report on Plasma Components and Systems in the context of EuPRAXIA

The EuPRAXIA project aims to construct two state-of-the-art accelerator facilities based on plasma accelerator technology. Plasma-based accelerators offer the possibility of a significant reduction in facility size and cost savings over current radio frequency (RF) accelerators. The two facilities - one laser-driven one a beam-driven - are envisioned to provide electron beams with an energy in the range of 1-5 GeV and beam quality comparable to existing RF machines. This will enable a versatile portfolio of applications from compact free-electron laser (FEL) drivers to sources for medical and industrial imaging. At the heart of both facilities is the use of plasma-based accelerator components and systems which encompass not only the accelerating medium itself, but also a range of auxiliary systems such as plasma-based electron beam optics and plasma-based mirrors for high-intensity lasers. From a technical standpoint, a high-degree of control over these plasma devices will be essential for EuPRAXIA to achieve its target performance goals. The ability to diagnose and characterize these plasma devices and to simulate their operation will be further essential success factors. Additionally, compatibility with extended operation at high-repetition rates and integration into the accelerator beamline will also prove crucial. In this work, we aim to review the current status of plasma components and related systems for both laser-driven and beam-driven plasma accelerators and to assess challenges to be addressed regarding implementation at future EuPRAXIA facilities.

physics.plasm-ph↗

arXiv2024

Demonstration of The Brightest Nano-size Gamma Source

Gamma rays selectively interact with nuclei, induce and mediate nuclear reactions and elementary particle interactions, and exceed x-rays in penetrating power and thus are indispensable for analysis and modification of dense objects. Yet, the available gamma sources lack sufficient power and brightness. The predicted and highly desirable laser-driven gamma flash, from here on termed "Gamma Flash", based on inverse Compton scattering from solid targets at extreme irradiances (>$10^{23}W/cm^2$), would be the highest-power and the brightest terrestrial gamma source with a 30-40% laser-to-gamma energy conversion. However, Gamma Flash remains inaccessible experimentally due to the Bremsstrahlung background. Here we experimentally demonstrate a new interaction regime at the highest effective irradiance where Gamma Flash scaled quickly with the laser power and produced several times the number of Bremsstrahlung photons. Simulations revealed an attosecond, Terawatt Gamma Flash with a nanometre source size achieving a record brightness exceeding $~10^{23}photons/mm^2mrad^2s$ per 0.1% bandwidth at tens of MeV photon energies, surpassing astrophysical Gamma Ray Bursts. These findings could revolutionize inertial fusion energy by enabling unprecedented sub-micrometre/femtosecond resolution radiography of fuel mixing instabilities in extremely-compressed targets. The new gamma source could facilitate significant advances in time-resolved nuclear physics, homeland security, nuclear waste management and non-proliferation, while opening possibilities for spatially-coherent gamma rays.

physics.plasm-ph↗

arXiv2023

On the capillary discharge in the high repetition rate regime

We investigate the main physical processes that limit the repetition rate of capillary discharges used in laser accelerators of electrons theoretically and with computer simulations. We consider processes in the capillary. We assume that a cooling system independently maintains temperature balance of the capillary, as well as a gas supply system and a vacuum system maintain conditions outside the capillary. The most important factor, determining the highest repetition rates in this case, is the capillary length, which governs a refilling time of the capillary by the gas. For a short capillary, used for acceleration of sub-GeV electron beams, the repetition rate approximately equal to 10 kHz, which is inversely proportional to the square of the capillary length. The effects of the capillary diameter, gas type and the gas density are weaker.

physics.plasm-ph↗

arXiv2015

Generation of a neutral, high-density electron-positron plasma in the laboratory

We report on the laser-driven generation of purely neutral, relativistic electron-positron pair plasmas. The overall charge neutrality, high average Lorentz factor ($γ_{e/p} \approx 15$), small divergence ($θ_{e/p} \approx 10 - 20$ mrad), and high density ($n_{e/p}\simeq 10^{15}$cm$^{-3}$) of these plasmas open the pathway for the experimental study of the dynamics of this exotic state of matter, in regimes that are of relevance to electron-positron astrophysical plasmas.

physics.plasm-ph↗

arXiv2014

Optimisation of the pointing stability of laser-wakefield accelerated electron beams

Laser-wakefield acceleration is a promising technique for the next generation of ultra-compact, high-energy particle accelerators. However, for a meaningful use of laser-driven particle beams it is necessary that they present a high degree of pointing stability in order to be injected into transport lines and further acceleration stages. Here we show a comprehensive experimental study of the main factors limiting the pointing stability of laser-wakefield accelerated electron beams. It is shown that gas-cells provide a much more stable electron generation axis, if compared to gas-jet targets, virtually regardless of the gas density used. A sub-mrad shot-to-shot fluctuation in pointing is measured and a consistent non-zero offset of the electron axis in respect to the laser propagation axis is found to be solely related to a residual angular dispersion introduced by the laser compression system and can be used as a precise diagnostic tool for compression oprtimisation in chirped pulse amplified lasers.

physics.plasm-ph↗

arXiv2012

Acceleration with Self-Injection for an All-Optical Radiation Source at LNF

We discuss a new compact gamma-ray source aiming at high spectral density, up to two orders of magnitude higher than currently available bremsstrahlung sources, and conceptually similar to Compton Sources based on conventional linear accelerators. This new source exploits electron bunches from laser-driven electron acceleration in the so-called self-injection scheme and uses a counter-propagating laser pulse to obtain X and gamma-ray emission via Thomson/Compton scattering. The proposed experimental configuration inherently provides a unique test-bed for studies of fundamental open issues of electrodynamics. In view of this, a preliminary discussion of recent results on self-injection with the FLAME laser is also given.

physics.plasm-ph↗