- A computercontrolled turbidity apparatus
- I_t = I_0e^{-(α+τ)l}
- We're looking for τ.
- Aparatus for measuring turbidity as function of temperature; includes oven to place sample in. Claims 0.001/mm accuracy and 0.5% precision.
- They measure transmitted light and assume no absorbtion; use a laser of polarized light with beam splitter.
- Use chopper to measure ac instead of dc, claim order of magnitude better long-term stability from it.
- Much improvement from simultaneous reference and measurement beam.