Innovative spectrometer system for determining the scattering and absorption coefficients of turbid media
With the new and unique SphereSpectro 150H spectrometer system, from our partner, Gigahertz-Optik offers a solution for simultaneously determining the spectral absorption and scattering coefficients for scattering samples. Conventional spectrophotometers (also called transmission spectrometers or absorption spectrometers) are used to determine the absorption coefficient of clear or colored media. In a similar way to these conventional systems, the SphereSpectro 150H is used to determine the spectral absorption coefficient of scattering media. To do this, the sample is illuminated and the transmitted as well as the reflected light is measured and evaluated in a differentiated manner using radiative transfer theory. For clear samples the absorption coefficient is determined based on Beer-Lambert’s law. However, if the sample exhibits scattering (i.e turbid or translucent samples), the entire physical process must be taken into account, i.e. a combination of scattering and absorption properties.
With the innovative SphereSpectro 150H spectrometer system from Gigahertz-Optik the absolute absorption coefficient can now also be determined for scattering media independent of the scattering properties of the turbid medium. At the same time, the effective scattering coefficient of the sample is determined, which provides additional information about the microstructure of the sample. This is a unique feature, which is not otherwise available on the market. The determined absorption coefficient is identical with the absorption coefficient determined conventionally for clear media and can be used for content determinations, for example. The SphereSpectro 150H uses an integrating sphere to measure the total reflected and transmitted light of an illuminated sample. From these two quantities, the absorption coefficient and the effective scattering coefficient are calculated based on the radiative transfer equation.
The SphereSpectro 150H covers the wavelength range between 200 nm and 2150 nm. Modular versions are also available for sub-ranges within this entire spectral range. The unique measuring system is also characterized by simple operation, short measurement times and a large sample chamber with optimized sample holder whilst keeping overall size to a minimum.