The Fluorescence X-Ray Microprobe at the Advanced Light Source

Abstract

AbstractThe fluorescence x-ray microprobe beamline at the Advanced Light Source (ALS) provides a technique to study almost any sample with excellent trace element sensitivity, high spatial resolution and minimal sample damage. During the last two years, the focused spot size has been improved from 2 μm × 4 μm to 1.6 μm × 1 μm using a pair of elliptically-bent multilayer mirrors. Two sets of mirrors have been produced for operation at 8.5 keV and 12.5 keV with a bandpass (ΔE/E) of 4 %. The intensity has also increased by a factor of 20 to over 1 × 1010 photons/sec by linearly grading the multilayer coating on the mirrors and by operation of the ALS at 1.9 GeV rather than 1.5 GeV.A wide variety of samples have been studied. Some of the materials science samples that have been studied include gallium nitride samples, polycrystalline silicon solar cells, the liner material of a rocket motor and the central germanium core of an optical fiber.