The effective-area method is a new way to measure aperture area. It defines aperture area by directly using the beam-limiting effect of the aperture in radiometric measurement. Due to the special structure of the measurement device, it is necessary to find a suitable method to design the detection system. In this paper, the measurement system model is constructed in the TracePro program. The real circumstances of light propagation for the measurement beam are simulated, and the responses of the detector are given. It is proved that the relative change in the detector response is the lowest when the detector is at the position of 132°. And this is the best structure design of the detection system. The experimental results are designed to verify the feasibility of the structure design of the detection system.
Keywords: absolute solar irradiance radiometer; design of detection system; effective-area method; measurement device.