Two source simulator for improved solar simulation

A solar simulator has been constructed which combines the light from two sources-a xenon arc source and a tungsten-halogen source-in order to improve solar simulation compared to that possible with a xenon source alone. The system is a standard Oriel simulator to which an incandescent source has been added. The light from the two sources is filtered and combined by means of a cold mirror. This makes it possible to simulate the solar spectrum with good accuracy over the wavelength range 350-1000 nm, which is more than sufficient for purposes of measuring solar cells based on amorphous silicon and its alloys. The major advantage of this simulator is its simplicity. Calibration is carried out simply by adjusting the two sources until the secondary reference cells generate the proper current