In-Situ, Real-Time Measurement of Melt Constituents (Sensors & Controls)
The goal of this project is to develop and test a LIBS-based probe in a laboratory crucible furnace to demonstrate in-situ, real-time measurement of melt constituents with an accuracy and minimum detection limit of 5% and 0.01%, respectively.
The LIBS technology employs a laser and a spectrometer to measure, in situ and in real time, the constituents of the melt in a process furnace. A pulsed (5-10 ns duration) Nd:YAG laser at 532 nm is focused, through a fiber-optic cable, into a molten aluminum sample, generating high-temperature plasma consisting of excited neutral atoms, ions, and electrons. Any chemical compounds that are present in the sample are rapidly dissociated into their constituent elements. The laser-generated plasma is allowed to equilibrate several microseconds after the laser pulse, and optical emission from neutral and ionized atoms is collected and then dispersed by a spectrograph fitted with an intensified charge-coupled array detector. The line radiation signal amplitude can be calibrated quantitatively, thus providing the concentration of each element present.