defr Glossar

Transmittance, internal spectral τi(λ)

Spectral internal transmittance τi (λ) is the ratio of the light intensities at the outlet Φout (λ) and inlet Φin (λ) of the flow cell.

$\tau_{i} \left( \lambda \right) = \frac{\phi_{\text{out}} \left( \lambda \right) }{\phi_{\text{in}} \left( \lambda \right) }$

Internal spectral transmittance
Fig. 51: Internal spectral transmittance

Unlike the transmittance, in this case the reflection losses occurring at the flow cell windows have to be eliminated. In practice, this is done by running a comparative measurement of the carrier medium without the absorbent product.


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