Angle alignment method for soft x-ray using double-periodic multilayer

A double-periodic multilayer method was proposed to test KBA system of 4.75keV using 8keV source. Alignment of angle is the key for most of grazing incidence systems in x-ray range. But for soft x-ray, strong absorption makes the alignment have to be operated in vacuum, which is difficult enough. A double-periodic multilayer was used to experiment at 8keV in air replacing 4.75keV in vacuum. This multilayer includes two parts, the top and the bottom. The top is W/B 4 C multilayer with four bilayers and 6.93nm periods. The bottom is W/B 4 C multilayer with 10 bilayers and 3.95nm periods. For 8keV energy, x-ray will penetrate through the top and reflected by the bottom. While for 4.75keV, x-ray will be reflected by the top directly. The full width of half maximum is 0.1° at 8keV and 0.3° at 4.75keV, so it is accurate enough for 4.75keV to experiment at 8keV, which was also verified by the 1-D KBA experiment. This double-periodic multilayer provides a valid solution for alignment in soft x-ray range.