Soft x‐ray spectroscopy beamline 6 m high energy spherical grating monochromator at SRRC: Optical design and first performance tests

The layout and first data on the performance of the soft x‐ray bending magnet beamline 6 m high energy spherical grating monochromator (6m‐HSGM) at SRRC are described. The 6m‐HSGM beamline, which covers photon energies from 110 to 1500 eV, is based on the Dragon concept with spherical gratings, and a movable exit slit. During the first performance tests, core‐excitation thresholds of Ar and Ne, and K thresholds of N and O for gas phase CO, N2, and O2 have been recorded with resolutions which rank among the best reached so far in the soft x‐ray region.