A SOFT-X-RAY (80-1500 EV) GRAZING-INCIDENCE MONOCHROMATOR WITH VARIED-LINE-SPACING PLANE GRATINGS AT PF-BL-11A

The design and performance of a new soft X-ray beamline BL-11A at the Photon Factory (PF) are presented. A Hettrick-type grazing-incidence m onochromator equipped with three varied-line-spacing plane gratings wa s designed and constructed at a bending-magnet source of the PF 2.5 Ge V storage ring. An 800 lines mm(-1) laminar grating produced by aspher ic-wavefront holographic recording optics, as well as a mechanically r uled blazed one, were tested. A resolving power of more than 4500 was achieved at 400 eV with either grating, and similar to 10(10) photons s(-1) are available at a resolving power of 2000. High photon flux ena bles low-concentration samples, such as surface adsorbates, to be stud ied. A simple scanning mechanism for a wide energy range is quite usef ul for EXAFS measurements on light elements such as C, N and O.