NAM logo, by David Le Conte

Microchannel plate optics for X-ray astronomy missions

Adrian Martin (Leicester)

Slumped square pore microchannel plates (MCPs) in which the long axes of many channels point to a common centre of curvature, are being developed as low mass, wide-field-of-view, soft (0.1-3 keV) X-ray optics for astronomy. MCPs provide an attractive means of realising Angel's "lobster eye" all-sky telescope (LOBSTER) as proposed to the 1997 Small Explorer AO by a consortium led by Los Alamos and including NASA Goddard and the Universities of Wisconsin, Leicester and Melbourne.

We describe the current development status of lead silicate MCP optics with respect to a number of key performance parameters. In particular, we report recent synchrotron results on the overcoating of microchannels with nickel to enhance X-ray reflectivity and on the reduction, by thermal annealing, of channel surface roughness to a level of 11 Angstroms rms - a factor of two better than previously measured for microchannel plates and approaching the level of roughness observed in conventional (macroscopic) X-ray mirrors.

Finally, we describe the concept of a "dual purpose" Imaging X-ray Spectrometer (IXS) based on MCP optics which combines astrophysical observations during the cruise phase of an asteroid rendezvous mission with encounter phase X-ray fluorescence mapping of the asteroid surface. The design of the IXS proposed, accepted and finally rejected for the European Space Agency SMART-1 small mission is outlined.

Maintained by Ian Howarth