Bulk material sampling and laser targeting system

摘要

A method is described for providing a continuous flow of a target material past a laser to enable repeated firings of the laser beam at the material in a controlled and uniform fashion. The objective is to provide a means to characterize the target material using laser induced breakdown spectroscopy. The method can be employed in a laboratory or field environment providing improved methods for characterizing in real time the properties of bulk materials.

主权项

1. A bulk sampling and laser-targeting system to provide for continuous or semicontinuous monitoring of a bulk stream of material comprising:
a material flow system comprising a vertically extending flow chute for permitting gravitational flow of said material, said material comprising fine or coarse grained solid granular material including powder-like materials; a laser optics system for directing a pulsed laser beam into said material flowing through said flow chute through a target orifice in said flow chute for ablating a microgram-sized portion of said material so that a light emission over a wide spectral range is released as electrons interact and recombine with ions; a dust and moisture suppression system for preventing dust and moisture build-up from interfering with said laser beam traveling from said laser optics system to said flow chute; and means for delivering light emission from ablated material within said flow chute to a spectrometer for analyzing said light emission; said laser optics system delivering pulsed laser beams to said flowing material through a laser target orifice in said flow chute on a continuous or semi-continuous schedule, while said flow chute minimizes focal length variability of said flowing material including solid particles that are compacted in the flow chute and pressed tightly against a wall of said flow chute by the resistance provided by a flow control means that simultaneously facilitates flow and prevents clogging associated with said flow chute, thereby providing a nearly uniform focal distance from the laser outlet to the migrating material particles; said means to facilitate flow and prevent clogging comprises a rotating disk rod and a mixing tool attached to said rotating disk rod, said mixing tool further having a normally closed, rotational flow control disk at an outlet of said flow chute for opening and rotating to permit flow, and to regulate flow through said flow chute.