The instrument is used for simultaneous dynamic and static light scattering at ultra-small angles using a CCD camera. The scattered light is detected from 0.3º to 6º, corresponding to length scales from a few microns to a fraction of a millimetre. Time resolved static measurements with a time resolution of approx. 100 msec. Multispeckle correlation functions are processed in real-time, thereby allowing measurements of a set of intensity autocorrelation functions at different q-values using measurement times that are comparable to the longest correlation time. A multitau correlation scheme is adopted (delay time space quasi-lograrithmically), requiring thereby less data storage and processing time. This allows one to calculate time- and pixel-averaged correlation functions in real time. Multiple exposure times are used in order to optimize the mean intensity level for all scattering vectors. The instrument is equipped with a HeNe laser light source with a wavelength of 632.8nm and a maximum power of 35 mW. The sample is filled into squared glass cells with path lengths ranging from 10 mm to 1 mm and placed in a temperature-controlled sample environment. The instrument is designed to study both ergodic and non-ergodic samples.
The apparatus is typically used for:
- Particle sizing via hydrodynamic radius.
- Particle form factor determination.
- Structure factor and dynamic structure factor measurements for strongly interacting dilute and concentrated systems.
- Phase separation kinetics and structural evolution of large length scales