X-ray propagation through hollow channel: PolyCAD – a ray tracing code

‘‘PolyCAD’’, a CAD program designed for X-ray photon tracing in polycapillary optics, is described. To understand the PolyCAD code and its results, the theoretical bases of X-ray transmission by a single cylindrical channel (monocapillary) are discussed first. Then cases of cylindrical, lens and semi-lens shaped polycapillary optics are examined. PolyCAD allows any type of X-ray source to be used: an X-ray tube of finite beam dimensions or an astrophysical object can be simulated in combination with the polycapillary optics. The radiation density distribution images formed on a screen located at various focal distances are discussed. The good agreement of the PolyCAD results with experimental and previous theoretical calculations validate the code. 2005 Elsevier B.V. All rights reserved. PACS: 02.60.Cb; 02.70. c; 41.50.+h; 42.15. i; 42.15.Dp; 42.30. d