Device and method for determining characteristic parameters of the dimensions of nanoparticles

A device for determining characteristic parameters of the dimensions of nanoparticles in suspension in a liquid medium, comprising:

• light-emitting means configured to emit an incident light beam that is linearly polarized along a polarization axis;
• a detecting unit comprising a measurement arm that is rotatable with respect to an axis of rotation, wherein said detecting unit is configured for optical detection of a plurality of beams scattered at a plurality of scattering angles, when the sample is illuminated by the incident beam, and comprises:
• a first detection channel with a first optical axis and
• a second detection channel with a second optical axis, the first and second detection channels being separated by a polarization-splitting element arranged in said measurement arm;
• a fixed sample holder, configured to receive a container of cylindrical symmetry, inside of which is located a sample of said nanoparticles in suspension, the sample holder being arranged such that, in operation, an axis of symmetry of the container is coincident with the axis of rotation of the measurement arm;
• a control unit;
• wherein:
• the polarization-splitting element of the measurement arm is configured to simultaneously send, for each scattering angle of said plurality of scattering angles:
• in the first detection channel, a first polarized component of the beam scattered by the sample at said scattering angle, said first component being linearly polarized with a polarization axis collinear with said polarization axis of the incident beam;
• in the second detection channel, a second polarized component of the beam scattered by the sample at said scattering angle, said second component being linearly polarized with a polarization axis perpendicular to said polarization axis of the incident beam;
• and
• the control unit is configured to determine, from signals corresponding to the polarized components detected in each of the detection channels as a function of time, and for said plurality of scattering angles, at least two characteristic parameters of the dimensions of the nanoparticles.