Student: Jennifer Thines, Graduate Student in Geoscience, University of Iowa
Faculty Advisor: Dr. Ingrid Ukstins
The effects of surface roughness and composition on Laser Induced Breakdown Spectroscopy (LIBS) laser energy coupling
LIBS has moved to the forefront of emerging analytical techniques with the development of the Mars Curiosity rover though the effect of surface roughness on laser energy coupling remains ambiguous. LIBS is a type of atomic emission spectroscopy that was first introduced in the mid-1960s and has recently gained popularity in extraterrestrial geology. A focused and highly energetic laser beam is directed at a sample and generates a high-temperature plasma at the surface. The resulting emission is resolved to produce an intensity versus wavelength spectrum characteristic of the elemental composition of the sample. The rapid non-destructive in-situ analysis of a variety of mediums with low detection limits for light elements makes LIBS very desirable for extraterrestrial applications. The Curiosity rover includes two remote instruments: LIBS and a Remote Micro-Imager (RMI) which provides texture and morphology data.It is vital to carefully consider the type of sample being analyzed by utilizing the RMI and selecting those with the surface roughness for optimal laser coupling. Though the effect of surface roughness on LIBS laser energy coupling was documented in the past, to date no study has been conducted to further elaborate on the issue. My project aims to quantify the differences in laser energy coupling due to surface roughness by analyzing a suite of rocks with variable texture and composition ground to different grits. Surface roughness will be imposed on different sections of the samples and measured to evaluate this relationship. The goal of the project is to provide insight into the viability of LIBS analysis of Martian soils and rocks by evaluating data quality based solely on differing surface texture.