<title>18- to 20-nm broadband multilayer at normal incidence</title>

Abstract

A better random method used for improving light throughput of a soft X-ray multilayer has been developed in the 18 - 20 nm spectral region, it bases on the traditional theory of periodic multilayer, a 8% gain in integrated reflectance is obtained. We present ensemble calculation at the same time, and the multilayer is fabricated by magnetron sputtering. Finally low-angle X-ray diffraction and reflectance comparative measurement are used for testing the multilayer. The results demonstrate that layer thickness disorder yields band broadening (for both wavelength and angle) and increased integrated reflectance in the spectral range with respect to periodic multilayer, but accompanied with a reduction in reflectance peak. Layer thickness disorder makes it more difficult to fabricate broadband multilayer, raising the techniques of control layer thickness is the keystone of experiments.