A soft X-ray grating monochromator for undulator radiation

One of the new insertion devices to be installed in the expansion of the DORIS storage ring consists of three undulators designed to cover with the first harmonic the photon energy range between 70 and 2000 eV. The concepts for a high resolution and high throughput monochromator that will take full advantage of this powerful new beam line are discussed. The final design is a modified SX-700 type monochromator in which the focusing elliptical mirror is replaced by a spherical one. The aberrations due to the new mirror are minimized by elongating the exit slit arm of the conventional SX-700. The ultimate resolution expected is 0.03 eV at 152 eV and 0.6 eV at 1086 eV with a photon flux up to 5x1011 photons/(sec 100 mA) at the sample. The spot size at the sample position is less than 0.4x1.0 mm2. (orig.)