J. Phys. IV France 7 (1997) C2-297-C2-301
Micro-XAS Using Tapered Capillary Concentrating OpticsS.M. Heald1, D.L. Brewe2, B. Barg2, K.H. Kim2, F.C. Brown3 and E. A. Stern2
1 APS Bldg. 435E, Argonne National Laboratory, 9700 S. Cass Ave., Argonne IL 60439, U.S.A.,
2 Physics Dept., University of Washington, Seattle WA 98195, U.S.A.
3 Physics Dept., University of Washington, Seattle WA 98195 U.S.A.
Tapered capillary optics are a promising choice for producing micro-beams at third generation sources. The reproducible energy dependence of their X-ray transmission, and fixed output beam position make them well suited for micro-XAS applications. Fiber optics techniques have been developed to produce long (1 m) capillaries which provide a good match to the low divergence undulator beams at third generation sources. The results of X-ray tests made at the NSLS indicate the performance of many of the capillaries closely match theoretical values. Currently these provide a monochromatic beam of about 106 ph/sec/μm² at an unfocused bending magnet beamline. High quality X-ray images and micro-XAFS have been obtained at the NSLS with better than 3 μm resolution. The same capillaries should provide more than 1010 ph/sec/μm² at an APS undulator, indicating that sub-μm XAS is possible.
© EDP Sciences 1997