RESUMEN
A new approach for the spectral reconstruction of time-dependent emission of soft x-ray sources based on the measurement of filtered x-ray diode array systems is suggested. Two reconstruction methods, based on this approach, are demonstrated using both simulated and measured data. The methods use the filtered x-ray diode measurement together with a co-aligned, time-integrated, spectrally resolved measurement, such as transmission grating spectroscopy. The additional experimental information allows for high accuracy spectral reconstruction, even for plasmas far from local thermodynamic equilibrium where the traditional reconstruction methods may miss some important source spectral features. For the demonstrated cases, the accuracy of the new reconstruction methods is better than 10% for the energy dependent flux and 1% of the total flux, which is higher than the accuracy of previous methods and better than the accuracy of the measurement itself.
RESUMEN
Calibration of soft x-ray diagnostics is a challenge due to the lack of laboratory-size calibrated sources. An in situ calibration method for newly developed x-ray mirrors, is presented. The x-ray source is produced by laser-matter interaction, and twin transmission gratings which create two identical dispersion lines. The gratings have a sinusoidal transmission function, which produces a highly precise high-orders free spectrum. An x-ray mirror interacts with one of the dispersion lines, and the mirror efficiency curve as a function of wavelength is extracted. Mirror efficiency shows good agreement with the literature, and evidence of water layer may justify the need of in situ calibration.
RESUMEN
A novel fabrication method for soft x-ray transmission grating and other optical elements is presented. The method uses focused-ion-beam technology to fabricate high-quality free standing grating bars on transmission electron microscopy grids. High quality transmission gratings are obtained with superb accuracy and versatility. Using these gratings and back-illuminated CCD camera, absolutely calibrated x-ray spectra can be acquired for soft x-ray source diagnostics in the 100-3000 eV spectral range. Double grating combinations of identical or different parameters are easily fabricated, allowing advanced one-shot application of transmission grating spectroscopy. These applications include spectroscopy with different spectral resolutions, bandwidths, dynamic ranges, and may serve for identification of high-order contribution, and spectral calibrations of various x-ray optical elements.