A COMPACT TEA CO2 LASER FOR FIELD-BASED SPECTROCHEMICAL ANALYSIS OF GEOLOGICAL SAMPLES

Abstract

A compact capacitor-transfer TEA CO2 laser of 180 mJ output energi and 50 ns pulse duration in half width has been designed and constructed for field use. This laser is suitable for laser microprobe spectrochemical analysis on geological and mining samples. Experiments show that the use of helium as a surrouding gas suppresses the continous emission spectrum of the plasma, thus increasing the S/N ratio. Using glass as standard samples, the minimum detectable concentrations are estimated with Zn neutral line and F ionic line to be 60 ppm and 500 ppm, respectively.

Keywords : lasers ( Compact TEA CO2 ), field-based analysis, laser microprobe analysis