Development and Investigation of Linear Fresnel Lens for Concentrator Space Solar Arrays

Highly efficient ultra-lightweight doubled linear Fresnel-lens concentrators of solar light, which operate in tandem with multijunction InGaP/GaAs/Ge solar cells, have been developed and fabricated. The concentrators have a total photoactive area of (50 x 100) mm(2), with the total thickness of <= 0.35 mm and optical focus of 32 mm. The Fresnel profile of each linear lens in the concentrator is formed from silicone rubber on <= 100 mu m radiation-hard glass. The efficiency of the linear lens concentrators was 90% for the AM0 spectrum (1367 W/m(2)). The efficiency of the concentrators was examined before and after the irradiation and thermal-cycling tests. A 10% decrease in the efficiency of the linear lens concentrators is observed upon irradiation with 1 MeV electrons at a fluence of 3x10(15) cm-(2) and a <10% decrease upon thermal-cycling after the radiation treatment. The optical efficiency of the linear lens concentrators decreased by 13% after crush-testing with the total damage area being 2.5%.