This vertical scan macroscopic analyser consists of a reading head that moves along a flat-bottomed cylindrical cell to scan the entire sample length. The reading head consists of a pulsed near infrared light source and two synchronous detectors:

- The transmission detector monitors light transmitted through the product;

- The backscattering detector receives light backscattered by the product (135°).

The reading head acquires transmission and backscattering data every 40 microns along the sample tube for a maximum length of 80 millimeters. This fingerprint of the product characterizes its homogeneity,  particle concentration, and mean particle diameter. Results are represented on the software screen by a curve showing the percentage of backscattered or transmitted light as a function of the sample tube length (in mm).
The acquisition scan is then repeated over and over with a programmable frequency and results are superimposed on a time scan graph. The stability or instability of the product can then be determined by analysing the time graph.  If the scans at different times overlap, the product is stable.