POLYMERS CONTAINING Cu NANOPARTICLES IRRADIATED BY LASER TO ENHANCE THE ION ACCELERATION

Mariapompea Cutroneo,Lorenzo Torrisi,Andriy Velyhan,Anna Mackova

doi:10.14311/ap.2015.55.0150

Abstract

Target Normal Sheath Acceleration method was employed at PALS to accelerate ions from laser-generated plasma at intensities above 1015 W/cm2. Laser parameters, irradiation conditions and target geometry and composition control the plasma properties and the electric field driving the ion acceleration. Cu nanoparticles deposited on the polymer promote resonant absorption effects increasing the plasma electron density and enhancing the proton acceleration. Protons can be accelerated in forward direction at kinetic energies up to about 3.5 MeV. The optimal target thickness, the maximum acceleration energy and the angular distribution of emitted particles have been measured using ion collectors, X-ray CCD streak camera, SiC detectors and Thomson Parabola Spectrometer.

Highlights

In a laser-matter interaction, the electromagnetic energy of the laser radiation is converted initially into electronic excitation and later into thermal, chemical and kinetic energy [1]
Using the target normal sheath acceleration (TNSA) regime, in which a double layer of charges generated in the rear side of the foil drives the ion acceleration in the forward direction, along the normal to the target surface, charge states may reach 60+ and ion acceleration values may be higher than 1 MeV per charge state [6]
This result is due to two causes: enhancement of the plasma electron density responsible for the electric field driving the proton acceleration, and enhancement of the laser absorption in the thin target obtained using the Cu metal

Summary

Introduction

In a laser-matter interaction, the electromagnetic energy of the laser radiation is converted initially into electronic excitation and later into thermal, chemical and kinetic energy [1]. The characteristics of the lasergenerated plasma, the amount of emitted ions and their distribution into energy, charge states and angle emission depend on many important factors. At laser intensity higher than 1015 W/cm, plasma may be full ionized, and non-linear effects, ponderomotive forces, relativistic electrons and magnetic self-focusing effects promote high charge states and accelerate the emitted ions [5]. The composition and the geometry of the target absorb high laser energy and generate hot plasmas and high charge separation, inducing high ion acceleration, as will be reported. In this context, investigations into optimal laser parameters and irradiation conditions will be aimed at maximizing the ion kinetic energy

Methods

Results

Conclusion