Large area focusing collector for the observation of cosmic x rays

A large area focusing x-ray collector constructed for a sounding rocket is described. The instrument consists of nested reflecting plates that are curved slightly in one dimension to form a set of parabolas with a common focus. An array of plates such as the one in the sounding rocket focuses a parallel beam of x-rays to a line. The reflecting surfaces are commercial float glass with an evaporated metallic coating such as gold or nickel. With a gold coating the effective area of the rocket collector is about 250 cm2 for 0.3 keV x rays and about 150 cm2 at 1.2 keV. Its angular resolution is a few arc minutes and field of view is about ±0.75° (full width at half maximum). The collector performed successfully during a sounding rocket flight.