Classification of particles according to their Raman response

摘要

A method for sorting particles in which the particles are irradiated with pulsed laser radiation at an intensity and wavelength chosen to cause selected particles to emit a stimulated Raman signal. The particles are sorted into those that emit a stimulated Raman response characteristic of the selected particles and those that do not. In an embodiment, a conveyor belt 10 transports diamond 14 and non-diamond 16 particles to an irradiation zone 22. Radiation scattered from the particles is focused on a detector 26 by a lens system 28 and a monochromatic filter 30 which has a pass band centred at a characteristic Raman wavelength for diamond. An electronic processor 32 controls an ejector apparatus 34 which directs puffs of compressed air at diamond particles which have been detected diverting them into a concentrate collection bin 36.