SOURCE SIZE LINE BROADENING IN CONVEX CURVED CRYSTAL X-RAY SPECTROGRAPHS.

Ray tracing techniques are used to derive an analytic approximation for the resolving power, lambda / DELTA lambda , of convex curved crystal spectrographs as a function of the linear source size parallel to the plane of dispersion and as a function of the Bragg angle. Using the derived expression, source size broadening in spectra from spatially and temporally integrated imploding-wire plasmas were investigated. The level spacing between the last discrete spectral line and the spectral line succeeding it is compared to various line broadening processes; line broadening due to the finite size of the plasma source (source size line broadening), Doppler broadening, and line broadening due to the crystal rocking curve. It is shown that, in some cases, source size line broadening is comparable to the level spacing.