The design and development of a tuneable and portable radiation source for in situ spectrometer characterisation

Abstract. For spectroradiometers the characterisation of their wavelength scale and spectral bandwidth underpins substantially the quality of measured data. This characterisation can be performed using metrology-grade tuneable monochromatic sources, which are currently available only in a few laboratories world-wide. Yet in numerous applications only the in-field calibration is a feasible solution. We have designed and developed a Tuneable and Portable radiation Source (TuPS) in the wavelength range from 300 nm to 350 nm for the in-field characterization of Dobson and Brewer spectrometers wavelength scale and slit-function with uncertainties better than 0.02 nm in wavelength and with the bandwidth of emitted radiation smaller than 0.1 nm FWHM. The TuPS is designed such that only minor modifications of its optical system extends/shifts its spectral range towards visible and near-infrared spectral regions and thus expand its application for characterisation of any spectroradiometers in the relevant spectral region of interest.