Measurement and analysis of leaded glass polycapillary optic performance for hard x rays

The properties of borosilicate glass polycapillary x-ray optics have been e xtensively studied. Small-area scatter rejection borosilicate glass polycap illary optics have been demonstrated with good results. Many medical imagin g and industrial radiographic applications for x rays would require large-a rea optics with good scatter rejection. Since shorter optics are easier to manufacture, optics with a shorter length would provide a faster route to b ringing the benefit of polycapillary x-ray optics to these applications. Le aded glass would allow the optic to be much shorter and still give good con trast enhancement, because of the superior absorption of lead glass. In ord er to investigate the feasibility of using leaded glass polycapillary x-ray optics for these applications, measurements and simulations have been perf ormed on the behavior of leaded glass polycapillary fibers in the 9-80 keV energy range. The transmission efficiencies of these fibers of different ty pes and lengths were measured as a function of source location and x-ray en ergy. The measurements were analyzed using a geometrical optics simulation program, which included roughness, waviness, bending effects, and a leaded glass filter layer. Despite low transmission at low energies, leaded glass polycapillary x-ray optics with a length of 30-60 mm seem promising for man y high-energy (> 20 keV) x-ray applications. The longer fibers have transmi ssion efficiency of up to 50% in the 35-40 keV, and very low scatter transm ission of less than 0.06% up to 80 keV. (C) 2001 American Institute of Phys ics.