SPECTROSCOPY BEAMLINE AT THE ADVANCED PHOTON SOURCE FOR THE PHOTON ENERGY REGION FROM 0.5 TO 3 KEV

Interest in the 0.5 to 3 keV, intermediate x-ray, energy region has re cently intensified as this spectral region covers, among others, the i mportant L and M edges of transition-metal and rare-earth magnetic mat erials, respectively. Third-generation synchrotron facilities with the ir inherent high brightness have the unique potential to cover this en ergy region with high-resolution, high-flux x-ray beams ideal for spec troscopic studies. A 5.5-cm-period, planar undulator to be installed o n the 7-GeV Advanced Photon Source will produce a high brightness sour ce of intermediate-energy x rays. The 0.5- to 3-keV spectroscopy beaml ine is based on the spherical grating monochromator design that has al ready been shown to yield high resolution and throughput in the soft-x -ray region, below 1 keV. The beamline has been designed to cover the entire region with a peak resolving power of 6000-10 000. Photon flux at the sample is calculated to be in the range from 10(11) to 10(13) p hotons/s into a spot size of 1 mm(2). A refocusing mirror will be used to further demagnify the image size at a second experimental station. As a second phase to the spectroscopy program, an elliptically polari zed insertion device will be used. The polarization preserving nature of the grazing incidence optical elements in the SGM is crucial to obt ain x rays of well-defined polarization. The beamline layout, together with calculations of resolution, throughput, power loading, and high harmonic suppression, will be presented. The photoemission experimenta l end stations for the spectroscopy station will also be briefly descr ibed. (C) 1995 American Institute of Physics.