Title: Analysis of Laser Ablation Plumes by Laser-Induced Breakdown Spectroscopy and Quadrupole Mass Spectrometry: a Preliminary Study

Plasma plumes resulting from Nd:YAG laser ablation of copper and Fecralloy (Fe 72.8%, Cr 22%, Al 5%, Zr trace, Y trace) have been analysed simultaneously with Laser-Induced Breakdown Spectroscopy (LIBS) and Laser Ablation Mass Spectrometry (LAMS). A commercially available Residual Gas Analyser (RGA) was employed to perform mass spectrometric analysis of the neutral and ionic species created during the laser ablation process. Investigations of laser repetition rate have shown that increasing the frequency of the laser pulse rate is detrimental to the mass spectra produced; the average detectable partial pressure drops and the relative standard deviation of the signal increases. The RGA has been shown to be susceptible to corruption of measurement due to pump oil contamination when recording the partial pressure of neutral species created by the ablation event. Lack of 1 synchronisation between the transient laser pulse and the RGA mass scan results in variable partial pressure readings when analysing both neutral and ionic species. LAMS is able to detect small trace amounts of Zirconium and Yttrium in Fecralloy; LIBS is unable to resolve these trace amounts, but is shown to be unaffected by chamber pump oil contamination.