Guiding hard X rays with glass polycapillary fiber

Abstract X rays can be guided through a polycapillary fiber by multiple total reflections from the smooth channel walls of the fiber. Using monochromatic synchrotron radiation at energies of 22 and 44 keV, we measured the efficiency of transmission of X rays through polycapillary fibers with channel diameters of about 13 μm. Efficiencies of 57.3 and 54.5% for 22 and 44 keV X rays, respectively, were obtained with a 120-mm-long straight polycapillary fiber aligned with the incident beam. These values are close to the open fraction of the fiber, which is about 60%. In addition, transmission efficiency was measured as a function of the tilt angle between the incident beam and the axis of the fiber. We also measured the transmission efficiency as a function of the deflection angle for a 114-mm-long curved polycapillary fiber. The measurements are compared with a ray-tracing simulation.