SCRAP DETECTOR

In order to analyse metal particles for their chemical composition and to obtain a sorting signal, a method and device are proposed in which the particles (1) are subjected to a pulsed laser beam (6, 8, 9, 10) and partially vaporised to form a plasma, purified thereby and subsequently the purified location is partially vaporised by means of a pulsed laser beam to form a plasma and the spectral lines of the plasma are used to identify (11, 14) the metal particles. The required measuring frequency of 30 particles per second can easily be attained and exceeded when a specific narrow waveband or a specific wavelength is filtered (11) out of the total radiation emitted by the plasma, and when the ratios of the intensities of the filtered-out component beams are formed and from the values of these ratios a sorting signal is obtained by comparison with adjustable limiting values. Moreover, the rate of measurement can be improved owing to the fact that the component beam is used for comparison only during a specific time interval.