Integral light detectors are composed of photodiodes with optical edge and bandpass filter combinations used to correct or shape spectral sensitivity.
However, the complete detector’s spectral sensitivity, e.g. UV-A, PAR, UV-Erythema, can never perfectly match the intended spectral sensitivity of the ideal actinic function plus tolerance limits in the filter batch processes exist. As such the measurement uncertainty of an integral detector may vary in applications involving light sources with emission spectra different than that of the reference lamp used in the detector calibration.
The a(z) method developed by Gigahertz-Optik makes it possible to calculate calibration correction factors if the emission spectrum of the calibration reference source, spectral sensitivity of the light detector and the application light source emission spectrum is known.
Background information on the a(Z) correction method is available in the knowledge base section.