Concentrating solar collector cross section

A solar concentrator cross-section arrangement comprised of a concave reflective boundary comprising a circular base section having straight sides extending therefrom, and

• a first flattened, hollow receiver-converter extending outward from the base of the concavity toward an aperture of said boundary and
• said second receiver-converter is well removed from said first, being removed as far as at least partly within the major portion of the distance from said base to said aperture up to as far as said aperture and at least as far as one and one-half times the distance from said base at the point from which extension of said first receiver-converter begins to the termination of said first receiver-converter nearest said aperture,
• of at least a second flattened, hollow receiver-converter following outward after said first, the multiple receiver-converters being able to communicate with each other and positioned such that the first and second receiver-converters have their flattened cross-sections extending in a common plane bisecting said concave reflective boundary.