MCP optics

• Main Author: Brunton, Adam North
• Published: University of Leicester 1994
• Subjects: 530.0724
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.547935

This thesis is an account of research into a novel type of X-ray optic - the microchannel plate (MCP). Experiments to determine the point to point focusing properties of square pore MCPs manufactured by Galileo Electro-Optics and Philips Photonics are reported. These were performed both in a test chamber at Leicester with an electron-bombardment X-ray source and with a laser-plasma X-ray source at the Rutherford Appleton Laboratory. A resolution of 6 arcmin and an intensity gain of 20 were recorded using a Galileo focusing MCP. An invesigation into the focusing action of MCPs which have been curved to a spherical figure is detailed. Such curved MCPs may, in a manner reminiscent of a conventional refractive lens, be used to focus a parallel X-ray beam to a point forming the basis of an X-ray telescope, or conversely to convert the diverging beam from a point-like X-ray source to a quasi-parallel one. The curving experiments were performed by Philips Photonics on standard circular pore MCPs. Tests on these plates were performed at Leicester; the results appear favourable. The technique has been applied to MCPs of up to 4mm thickness, curving them to a radius of 1.4m (0.7m focal length). A comprehensive Monte Carlo ray-tracing model is presented. This was initially developed to facilitate an understanding of the geometry of MCP focusing and to produce idealised images corresponding to a given experimental set up. These perfect images may be compared with, or used to predict experimental results. Comparison with experimental results led to incorporation of MCP distortions into the code. These distortions have been found by a programme of metrology which is also described. The model has led to a clear insight into the causes of poor image quality and their relative importance.