Hyperbolic Trumpet Geometry

A geometry for reflective concentrators is the trumpet concentrator [128], Fig. 2.11. This is actually a hyperboloid of revolution. Besides the CPC it is denoted as one of the maximum collection efficiency nonimaging concentrators. It is characterized by multitudinous reflections near the exit aperture. 

Trumpet concentrators are ideal concentrators both in 2D and 3D case. They also offer the advantage of concentrating not only internal but also external rays (those latter are concentrated to an annular shape around the exit aperture). Trumpet concentrators are characterized by a small material expenditure. External rays are not usable for detector matrices. 

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