Study of the emission spectra of Cl-, Br-, I-containing targets in the spectral range of 3–6.5 nm when excited by pulsed laser radiation

Abstract: The results of studying the emission spectra of Cl-, Br-, and I-containing liquid-jet targets in the wavelength range of 3 – 6.5 nm when excited by pulsed laser radiation are described. A number of emission lines of Cl, Br, I ions were registered, including those in the range of the “water transparency window” 2.3 – 4.4 nm. A specially developed system based on the industrial impulse valve was used to form a liquid-jet target. The targets were excited by a Nd:YAG laser (λ 1064 nm, τ = 5.2 ns, E_pulse = 0.8 J). Using a Bragg spectrometer based on a multilayer Cr/Sc X-ray mirror and Ti/Be absorption filters, we measured the absolute intensities of some of the most intense lines. The high emissivity of liquid targets was demonstrated. Thus, for a bromine-containing target in the 6.12 ± 0.05 nm band, the resulting radiation intensity into the half-space was 1.3 × 10¹³ photon/pulse.

Keywords: gas jets, soft x-rays, extreme ultraviolet radiation, emission spectra, laser spark.