Modeling of spectroradiometric error due to unoptimized choiсe of array photodetector for integrated photosynthetically active radiation spectroradiometer

Measuring accuracy of Photosynthetically Active Radiation (PAR) and Plant Biology Active Radiation (PBAR) in plant growth facilities influences its commercial efficiency. Integrated measuring systems based on spectrophotometry are more accurate than systems with sensors with broadband spectral sensitivity. Optical scheme and elements parameters of spectroradiometer have an effect on measurement accuracy. The primary objective is to model error of spectroradiometer for measuring photosynthetically active radiation, investigate error introduced by unoptimized choice of array photodetector and influence of residual defocus of spectra image on photodetector for that spectroradiometric error. Theoretical investigation is carried out with computer software. Modelling is done for optical scheme with different aperture angle, which has an effect on focus surface curvature radius. Measurement error dependence on SRF for full width at half max (FWHM) and residual defocus is calculated numerically. It is demonstrated, that decreasing focal surface radius and increasing aperture angle increases inhomogeneity of spectroradiometric error.