Spiral conical approximations to double reflection Wolter optics

The design of a grazing incidence focusing optic obtained from a spiral approximation to multiple nested conesproduces an annular image of a point source. The angular size of the annulus depends mainly on the pitch of the windingand the focal length. For a spiral conical approximation to Wolter optics, the effect is magnified by the double reflection.However, if the two conical spirals are wound one clock-wise and the other counter-clock-wise, then the aberration ispartially compensated. We use a ray tracing code to evaluate advantages and disadvantages of this optical design forpotential applications of a light weight optics technology based on plastic foils that we are currently investigating.