The design and construction of a sunlight integrator of wide intensity range

Abstract

It was stated in the introduction that the purpose of this project was to design and construct a sunlight integrator which would have wide intensity range, reliability under normal operating conditions, and moderate cost. If the minimum sensitivity for the first filter is arbitrarily chosen as one-tenth the dark counting period, which is in excess of three hundred seconds, the minimum detectable light intensity would be: .00858/30 = .000286 lumen per cm². This is equivalent to an intensity of .256 foot-candle for a 30 second counting period.