Transmission of x-ray polarization through glass capillary fibers

Synchrotron radiation beams at energies of 7, 8, and 11.5 keV were transmitted through straight and bent capillary fibers of the type used to focus or collimate x rays. The purpose was to learn if the multiple wall collisions during transmission would attenuate the polarization of the incident beam. The emergent polarization was determined using 90° Rayleigh–Thomson scattering by a carbon foil into a proportional counter. The results clearly showed that polarized x rays incident on a capillary fiber retained their polarization after transmission. Hence, focusing or collimating optics can be used with polarized x rays for background reduction in x-ray fluorescence measurements.