Dynamic Light Scattering
Brookhaven Instruments Corp.,
- A beam of laser light is focussed in the sample.
- Particles in the scattering volume scatter light in all directions.
- The scattered photons are measured by a photomultiplier tube
- The Intensity appears to fluctuate randomly.
- A digital correlator is used to compute the autocorrelation function.
- The autocorrelation function is an exponential decay:
- Each monodisperse population of particle sizes produces its own unique autocorrelation function - a single exponential decay.
- Mixtures of more than one size population produce sums of exponentials.
- Available algorithms can be used to extract "true" size distributions from complex samples - NNLS, CONTIN.
With kind permission of Brookhaven Instruments Corp.