Broad-Band EUV Multilayer Coatings for Solar Physics

We propose to develop and commercialize a new class of aperiodic multilayer coating that is designed to provide high normal-incidence reflectance over a wide spectral band-pass in the extreme ultraviolet (EUV) region, specifically from 9 to 14 nm. A broad-band reflective coating working at these wavelengths will enable, for the first time, the construction of high-resolution imaging spectrometers for solar physics utilizing diffraction gratings operating near normal incidence in this range, akin to previous instruments utilizing normal-incidence optics working at longer EUV wavelengths (i.e., lambda>17 nm) such as the Hinode/EIS satellite instrument and the EUNIS sounding rocket instrument. The development of high-resolution, normal-incidence grating spectrometers operating in the 9?14 nm range will in turn allow for detailed investigations of important solar emission lines, such as those from Fe XVIII?XXIII, that can provide unique diagnostics of high temperature plasma associated with solar flares and active regions. The successful development of efficient, broad-band EUV multilayers for the 9?14 nm region as we propose will thus enable future flights of the EUNIS rocket to target this band, and will also enable the development of high resolution spectrometers that can meet the science requirements of future NASA satellite missions, such as RAM, Solar-C and others that are currently being contemplated.