Fabrication and analysis of Mo-Si multilayers

Mo-Si multilayers have been fabricated in our laboratory for reflecting various soft X-ray wavelengths. Several normal incidence mirrors have been produced for a solar sounding rocket flight. Using properly shaped masks on 3-inch diameter dc magnetrons, we can produce multilayers of a similar size having a uniformity of better than +/- 3 percent over their entire surface area. Peak reflectance of the multilayers are as high as 42 percent at 171 A. Efforts are underway to deposit several layers of different period on top of the multilayers in order to attenuate the reflection of 304 A, a very bright line of He II in the solar spectrum. In the interim, we have made a Mo-Si mirror that reflects at 304 A. In addition to obtaining information on the solar corona at this wavelength, this will greatly reduce the effects of the He II line when its image is appropriately subtracted from others.