Photon Correlation Spectroscopy (PCS) Set-up
Photon Correlation Spectroscopy (PCS) Set-up
Contact: Lucia Comez
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The photoncorrelation device (Photon correlator Brookhaven BI 9000 AT) consists of a laser source (Coherent: 532nm, 400mW), a goniometer with a special accommodation for samples and a correlator board installed in a computer. The digital correlator works using three sections of channels (low, mid and high speed with different sampling time range) and is able to cover a dynamic range over ten decades (25ns-1310s). |
The apparatus consents to calculate, in the time domain, the autocorrelation functions of the intensity of the electric field scattered by the selected sample. The spectra can be recorded using either a fixed geometry or varying the scattering angle, thus allowing access to several exchanged vectors (q=0.01-0.035nm -1 ). Photoncorrelation Spectroscopy (PCS) can be successfully applied to study of the slow dynamics of a large variety of disordered systems: aqueous solutions, molecular liquids, polymers and glues. For biosystems in solution, this technique allows to determine the hydrodynamic radius (simple particle sizing calculation) and the diffusion constant of the solute by varying temperature and/or concentration. For molecular liquids, polymers and glues, it represents a unique tool to detect the structural relaxation during the vitrification and/or gelation of the system, under the action of chemical or physical agents.
Part of the research activity is dedicated to the study of Glass transition and structural arrest in molecular liquids, polymers, glues.
