Abstract: A concentrating solar collector includes a radiation reflective surface having the configuration of a paraboloid of translation, the axial extent of the paraboloid being the portion between the apex and the plane perpendicular to the axis and passing through the focus. A receiver of reflected radiant energy is located along the focal line of the paraboloid, and includes a receiver entrance aperture whose plane is oriented at an angle to the axis, preferably at an angle of 29.degree..+-.10.degree.. The width of the entrance aperture is a function of the distance between the lip and axis of the parabola and the angular radius of the sun.

Abstract: An X-ray lithography system for the production of micro-electronic circuits, of the type comprising a mask having detailed circuit patterns thereon which are irradiated by soft X-rays onto a wafer covered with a photosensitive material to replicate the mask patterns, includes an X-ray source spaced from the mask and operative to produce a plurality of input beams of X-rays which are substantially collimated by an array of grazing incidence mirrors to produce a plurality of output X-ray beams which are spaced from one another at the output of the collimator and which are projected in substantially parallel relation to one another toward the mask. Each output beam exhibits a small divergence which causes the several output beams to merge into a single, comparatively large cross-sectional area, composite beam of X-rays at a plane spaced from the collimator. The mask is positioned substantially in said plane for illumination by the composite beam of X-rays.