Courtesy of  LDC Analytical, Thermo Instruments Corporation.

Figure 51  Optical Diagram of a Low Angle Laser Light Scattering Detector

Between the forward detector lens and the rear detector lens is A filter holder and an analyzer/polarizer. Finally the light is focused through a sensor aperture to an opal diffuser that spreads the scattered light through a red filter  and onto the photo- multiplier.

The device is frequently used with a refractive index detector in series to coincidentally measure the refractive index of the eluent. This is necessary to calculate (K) from the refractive index. As discussed, the molecular weight of a solute is determined from the intercept of the graph relating () to the solute concentration (c) as shown in figure 52. The concentration calculated from the refractive index detector employing the data from prior calibration.