Plasma spectroscopy is a versatile tool for diagnosing key properties of plasmas, including those generated by discharges. It provides critical parameters-such as electron density and temperature-needed to optimize plasma sources for laser wakefield acceleration (LWFA). Stable, uniform plasma channels are essential to sustain GV/m wakefield and generate high-quality electron beams for advanced applications like radiation therapy (RT). Accurate spectral measurements require reliable wavelength calibration, as optical components can drift with environmental changes. In this study, atomic emission (AE) lamps-specifically mercury (Hg) and neon-argon (Ne-Ar) were utilized as reference light sources for wavelength calibration of a spectrometer system coupled to an intensified charge-coupled device (ICCD) camera. The known emission lines from these lamps ensured high-precision calibration across the relevant spectral range, facilitating accurate extraction of plasma parameters. This precise calibration enabled the determination of electron density and temperature through spectroscopic diagnostics, which are critical for understanding plasma behaviour. These measurements contribute to the development of gas-filled capillary discharge systems for LWFA and support the experimental objectives of the I-LUCE facility, dedicated to exploring laser-plasma interactions and advancing very high-energy electron beam (VHEE) applications. Monte Carlo (MC) simulations were conducted to assess the dose distribution of VHEE beams for RT applications.

We present an interferometry setup and the detailed fringe analysis method for intense short pulse (SP) laser experiments. The interferometry scheme was refined through multiple campaigns to investigate the effects of pre-plasmas on energetic electrons at the Jupiter Laser Facility at Lawrence Livermore National Laboratory. The interferometer used a frequency doubled ($\unicode[STIX]{x1D706}=0.527~\unicode[STIX]{x03BC}\text{m}$) 0.5 ps long optical probe beam to measure the pre-plasma density, an invaluable parameter to better understand how varying pre-plasma conditions affect the characteristics of the energetic electrons. The hardware of the diagnostic, data analysis and example data are presented. The diagnostic setup and the analysis procedure can be employed for any other SP laser experiments and interferograms, respectively.

Self-focusing effects, induced by ASTERIX pulsed laser at PALS Laboratory of Prague, have been investigated. Laser was employed at the third harmonics (438 nm) and intensities of the order of 1016 W/cm2. Pure Au was used as thin target and irradiated with 30° incidence angle. An ion energy analyzer was employed to detect the energy-to-mass ratio of emitted ions from plasma. Measurements were performed by changing the focal point position with a high spatial resolution step-motor. Results demonstrated that non linear processes, due to self-focusing effects, occurs when the laser beam is focused at about 200 µm in front of the target surface. In such conditions, a new ion group, having high charge state and kinetic energy, is produced because of the increment in temperature of the laser-generated plasma.