An optimal configuration for spark-induced breakdown spectroscopy of bulk minerals aimed at planetary analysis

Abstract

Spark-induced breakdown spectroscopy (SIBS) utilizes an electric spark to induce a strong plasma for collecting atomic emissions. The spark is an electric discharge characterized by a high voltage and low current, which occurs when the applied voltage between electrodes is higher than the breakdown voltage of the ambient surroundings of the electrodes. This study analyses the potential for using a compact SIBS instead of conventional laser-induced breakdown spectroscopy (LIBS) in discriminating rocks and soils for planetary missions. Targeting bulky solids using SIBS has not been successful in the past, and therefore a series of optimizations of electrode positioning and electrode materials were performed in this work. The limit of detection (LOD) was enhanced up to four times compared to when LIBS was used, showing a change from 78 to 20 ppm from LIBS to SIBS. Within the same CCD gate delay time and width, the signal intensity for SIBS was substantially higher than for LIBS by three orders of magnitude, due to the higher energy of plasma generated. Changing the electrode material and locating the optimum position of the electrodes were considered for optimizing the current SIBS setup being tested for samples of planetary origin.