Spectroscopic Studies of Soft X-Ray Emission from Gadolinium Plasmas

Abstract

The temporal behavior of gadolinium (Gd) laser-produced plasmas has been studied using a modified grazing incidence spectrometer which allows to capture the evolution of the plasma with spectral and temporal resolution of 0.1 nm and 1 ns, respectively. Experimental results indicate that the soft X-ray emission follows the temporal behavior of the laser pulse at high laser power density of Ф = 4.4×10¹² W/cm² in which the soft X-ray emission lasts for 7.5 ns (at FWHM) whereas at Ф = 5.4×10¹¹ W/cm² and Ф = 7.6×10¹⁰ W/cm² the emission lasts for only 4 ns and 2.5 ns respectively,these are shorter than laser pulse duration due to lower electron temperatures achieved in the plasma generation. Lower Gd ion stages ranging from Gd¹¹⁺ – Gd¹⁴⁺ are also found to contribute to the spectral emission over time.

Received: 08 November 2013; Revised: 09 May 2014; Accepted: 09 May 2014