Water molecules contain O-H bonds which absorb light energy in a specific region of the NIR spectrum. The more water that is present, the greater the energy that is absorbed.
The MCT460-WP houses a quartz halogen lamp which channels energy through a rotating wheel containing NIR filters, one positioned at a wavelength where water absorbs and others positioned at reference wavelengths where there’s no absorption by water.
Pulses of light illuminate the product and the diffused reflected light is collected by a concave mirror and focused onto a single temperature controlled detector. Detector signals are processed to give a read-out proportional to the concentration of water. Resin measurements are based upon the O-H and C-H bonds.