Polycapillary x-ray optic spectral gain and transmission

Polycapillary x-ray optics are gaining increased attention as their transmission characteristics and manufacturing difficulties are better understood. This paper reports experimental results obtained with an optic that was designed for use with both Mo K alpha (17.5 keV) and Cu K alpha (8 keV), The spectral gain function from 4 to 30 keV was determined from measurements made with an Si(Li) detector, and the results were compared with Monte Carlo simulations. The spatial variation in the spectral transmission was examined with both an Si(Li) detector and a magnifying x-ray CCD camera. The results show that even though the individual capillaries are tapered, their performance is well described by a simple parabolic relationship between the radius of curvature and the maximum energy transmitted derived for capillaries of constant diameter. Copyright (C) 1999 John Wiley & Sons, Ltd.