Book Description

Polycapillary x-ray optics, arrays of hollow capillary tubes used to guide x-rays by total reflectance, are now being used in increasing numbers of applications, such as materials analysis, microelectronics manufacturing, x-ray astronomy and medical imaging. Because each optic contains hundreds of thousands of precisely shaped and located hollow channels, it is desirable to assess the feasibility of a variety of capillary geometries for a new application without physically constructing the optic. This assessment requires increasingly sophisticated modeling capability as new applications with more stringent requirements are developed. Previous analysis has shown that high-energy applications such as hard x-ray astronomy and medical imaging are particularly sensitive to optic profile errors such as channel waviness. A more physical model for surface waviness has been developed and included in optics simulations. The results are compared to measured data and to the results of other numerical simulation programs. Directed digital mammography can avail itself the advantages of digital processing, including tolerance to under- and over-exposure and image enhancement. In addition, a new technology, polycapillary optics, has been shown to produce clearer image by increasing contrast and resolution. Capillary optics, consisting a array of hollow glass tubes, is a relatively new technology for controlling x-ray beams. Thousands of individual capillary fiber can be strung together to form a multifiber optic. These arrays of curve polycapillary fiber can be used to focus, collimate, and filter x-ray radiation. A number of borrosilicate glass capillary fibers have been measured and simulated in the energy range 10-80 keV. The result shown potential for mammography applications, with transmission of 70% at 20 keV.