Study of the X-ray emission from Ta plasma obtained by ns laser ablation

Abstract

In this work, the continuum spectrum of X-rays originated from the interaction of a moderate intensity ns Nd:YAG laser (1064 nm, 9 ns, 30 Hz, 900 mJ, 1011 W/cm2) with Ta target producing plasma is investigated. Plasma expands unisotropically with a velocity, depending on the pressure of the residual gas in the vacuum chamber. The X-ray intensity is a function of the laser energy and of the gas pressure inside the chamber. The X-ray energy is measured with an X-ray filter positioned in front of the Si(Li) solid-state detector. A temperature of about ∼1–2 keV of the hot electrons, responsible for the continuum spectrum emission from the plasma, is calculated from the fit of the X-ray spectrum, applying a Maxwellian distribution.