The determination of absolutely calibrated spectra from laser produced plasmas using a transmission grating spectrometer at the Nike laser facility

A transmission grating spectrometer has been developed that is capable of recording time-resolved spectra from laser-irradiated target foils in the wavelength range from 10 to 150 Å. Since the primary goal is to quantify the radiation flux from the resulting plasma, a detailed investigation has been conducted to evaluate the estimation of the absolute radiation intensity. Time-integrated spectra were observed on photographic film using a 5000 l/mm grating and clearly show the superposition of four diffraction orders. The deconvolution of the observed spectrum is based on a quantitative description of the spectrometer’s performance using the calibrated transmission efficiencies of the grating’s diffraction orders. This deconvolution procedure can provide an estimate of the absolute spectral intensity with a residual error of ∼20%. Results from a high spectral resolution grazing-incidence spectrometer have been used in the development of this method. A streak camera (not absolutely calibrated) was also used with the transmission grating spectrometer to record the time-resolved spectra.