SPARTUVIX II: An improved x-ray ultraviolet spectrograph with temporal and spatial capabilities for indirect drive inertial confinement fusion experiments (abstract)

Abstract

An improved version of the initial x-ray ultraviolet spectrograph SPARTUVIX1 has been developed to record the time evolution of spatially resolved spectra in the soft x-ray range (from 30 to 300 Å). This diagnostic can be applied to the new class of laser produced plasma experiments now performed in order to better understand the physical evolution of x-ray indirect drive plasmas. Instead of a one-dimensional streak camera used for the first version, a new widely used 2-D soft x-ray time gated imager allows us to follow the time evolution of the spatially resolved soft x-ray spectra. This instrument was designed for plastic foam soft x-ray opacity measurements. The soft x-rays, emitted by an auxiliary radiography laser plasma source, are transmitted through the foam and dispersed into two parts (+1 and −1 order of the transmission grating). Each dispersed spectrum is placed on two different gated striplines of the soft x-ray imager and thus recorded at two different times (exposure time 300 ps, adjustable interframe 600 ps). The spatial resolution is obtained with a slit added in front of the spectrograph, that images the plasma onto the detector with a magnification ratio of 15 and a spatial resolution of 50 μm. A detailed description of this instrument and the main results obtained for two different plastic foam opacity measurements (undoped and doped with chlorine) will be presented. This work is supported by European Community Contract No. CEE/CHGF-CT-92-0016.