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.