Determination of wavelengths and line shifts based on X-ray spectra from diogeness

Diogeness is the uncollimated scanning flat crystal spectrometer observing flare X-ray spectra in four narrow wavelength bands in the vicinity of Ca XIX, S XV and Si XIII He-like "tiplets" around 3.18 Angstrom, 5.04 Angstrom and 6.65 Angstrom. In two spectral channels, the same emission lines (around Ca XIX omega resonance line, lambda = 3.177 Angstrom) are scanned in opposite directions. The X-rays are reflected from precisely adjusted identical Quartz monocrystals mounted on the common shaft in so-called Dopplerometer configuration. This novel spectrometer design allows for highly accurate determinations of wavelengths and precise determination of line Doppler shifts. We explain the concept of the X-ray Dopplerometer and present results of analysis of the Doppler line shifts for the spectra collected during 25 August 2001 X5.3 flare. We compare derived line of sight plasma velocities with those measured by Yohkoh BCS.