A novel instrument has been developed and optimised for industrial use. Housed in a small table top unit NANOPHOX contains light source, detectors, the correlator, and the sample containing vial and is ready for routine measurements in the laboratory.
PCCS has several advantages:
1. With PCCS the multiple scattering is completely suppressed. This enables PCCS to extend the evaluation method of PCS to opaque suspensions and emulsion.
2. High particle concentrations can be used, resulting in high count rates and short measuring times.
3. In addition the amplitude of the cross correlation function represents the amount of the single scattered light. This information can be used for the analysis of the stability of the sample. It is extremely sensitive as an increase in size by a factor of 10 raises the intensity of the scattered light by 106.
4. As multiple scattering is eliminated, the results are usually independent of the concentration.
Possible remaining changes with increasing concentration are due to changes of the particle-to-particle interactions. Now they can be directly investigated with a dilution series as any contribution of multiple scattering is avoided.
Measurements can be performed at any concentrations. If the concentration is too high only multiple scattered light remains and single scattered light cannot be detected. A result is not presented under these conditions.
5. The results are independent of the position of the measuring volume within the sample vial.
The position of the measuring volume can be chosen to get the highest count rates and thus the shortest measuring times.
6. High particle concentrations reduce the sensitivity of this method to impurities. So standard liquids and laboratory environments can be used, which simplifies the application.
7. The PCCS set-up can be simply switched by software into the PCS mode, by using one detector only and calculating the auto-correlation function. This enables a direct use of former experiences with PCS.