A soft x-ray reflectivity beamline for 100-1500 eV energy range at Indus-2 synchrotron radiation source

Abstract

A soft x-ray reflectivity beamline covering 100 eV – 1500 eV photon energy range is designed, fabricated and commissioned at bending magnet port of Indian synchrotron radiation facility Indus-2 to cater thin film/ multilayer users to analyze structural and optical behavior. The experimental station is designed to test x-ray mirrors upto ∼300 mm length in the soft x-ray region. The beamline provides monochromatic photons using a constant deviation angle variable line spacing plane grating monochromator with Hettrick type optics. Pre and post focusing toroidal mirrors are used to collect and deliver the beam from source to the experimental station. A reflectometer system comprising of a θ-2θ goniometer capable to hold big size samples upto 300 mm length and 5 kg weight is employed for performing various scans for reflectivity experiments. The goniometer is set in a vertical reflection geometry. The sample stage is electrically isolated from the rest of the system to enable one to record total electron yield signal for soft x-ray absorption measurements. This paper describes the beamline and its capabilities with examples of measured results.