Combined Out of Range and in Band Stray Light Correction for Array Spectroradiometers

Abstract

Insufficient stray light rejection of array spectroradiometers, in especially the UV spectral range, limits the application of these devices. One important example would be UV hazard measurements. This study shows that a combination of different stray light corrections methods can improve the stray light reduction performance of UV array spectroradiometers significantly, to meet these requirements. The ACGIH Eeff (identical ICNIRP) values measured with an uncorrected array spectroradiometer showed expected large deviations of 73% for a sunbed tanning lamp and 105% for a halogen lamp, relative to a double monochromator reference. With the applied combined Out-of-Range and In-Band stray light correction method, these measurements were within 3% of the reference double monochromator based system. Furthermore, the measurements showed a detection limit of 2E-5 W/m²/nm for the double monochromator and comparable 3E-5 W/m²/nm for the stray light corrected array spectroradiometer. This was in contrast to 5E-4 W/m²/nm for the uncorrected array spectroradiometer. The results suggest that photobiological safety measurements according to IEC / DIN EN 62471 are possible with the applied combined stray light correction method for the used spectroradiometer.