A Soft X-ray Spectrometer using a Highly Dispersive Multilayer Grating

There is a need for higher resolution spectrometers as a tool for inelastic x-ray scattering. Currently, resolving power around R=10,000 is advertised. Measured RIXS spectra are often limited by this instrumental resolution and higher resolution spectrometers using conventional gratings would be prohibitively large. We are engaged in a development program to build blazed multilayer grating structures for diffracting soft x-rays in high order. This leads to spectrometers with dispersion much higher than is possible using metal coated-gratings. The higher dispersion then provides higher resolution and the multilayer gratings are capable of operating away from grazing incidence as required. A spectrometer design is presented with a total length 3.8m and capable of 10(5) resolving power.