An intensive source of soft x-ray radiation based on laser produced plasma of sulfur

Abstract

An intense source of soft x-ray radiation in the range of the water window and less intense in the range 1.2–15 Å based on sulfur laser plasma is demonstrated at a laser radiation power density on a target in the range of 1.2 × 1013–1014 W/cm2. A comparison with the radiation of nickel plasma showed that for the radiation of sulfur plasma, there is a sevenfold excess in the maximum value of the spectral energy density in the range of the water window. Nevertheless, experiments on recording the spatial distribution of plasma radiation on a streak camera in the spectral range of 1.2–15 Å in both the time-integral and time-scan modes demonstrated a more intense and widespread emission of nickel plasma compared to sulfur plasma emission. It has also been found that the size of the emitting area of the nickel plasma and the duration of the emission in the range mentioned above depend almost linearly on the power density of the laser radiation. A comparison of the experimental emission spectra of sulfur plasma with those calculated using the collisional–radiative model showed that their satisfactory correspondence occurs at an electron temperature of 160 eV and an electron concentration of (1.2–1.3) × 1020 cm−3. The results obtained and the presence of a large amount of sulfur on the planet together can simplify the task of widespread creation of a cheap and effective source of soft x-ray radiation in the spectral range of the water window.