Examining Rock Coatings with LIBS Spectral and Acoustic Data

Research Period
May 2023 – August 2023

Research Guidance
Guidance under Dr. Nina Lanza, Los Alamos National Laboratory (LANL), New Mexico

Hypothesis
My hypothesis is that while the Laser-Induced Breakdown Spectroscopy (LIBS) instrument effectively detects transitions between coatings and rock when their compositions differ, integrating acoustic data from the microphone can enhance the detection of transitions even when their chemical compositions are similar.

Motivation
My fascination with planetary geology and the potential habitability of Mars drove my interest in this research. Understanding the composition and structure of Martian surfaces is critical for exploring the planet’s history and assessing its capacity to support life. This project offered an opportunity to integrate advanced data analysis techniques and contribute to the growing knowledge of Mars’ geology. The innovative use of Laser-Induced Breakdown Spectroscopy (LIBS) and SuperCam microphone data aligned with my passion for leveraging technology to address fundamental questions about extraterrestrial environments. By focusing on transitions between rock coatings and bedrock, this research highlighted the importance of combining diverse data sources to uncover subtle but meaningful geological insights, reinforcing my long-term goal of exploring planetary surfaces through interdisciplinary approaches.

Problem Breakdown
1. Spectral Analysis: Analyzed LIBS spectra to measure manganese (Mn) peak areas, using the Mn doublet (~403 nm) as a key indicator of composition. The peak areas were plotted against shot count to observe trends across the coating and bedrock transition.
2. Acoustic Analysis: Plotted the microphone amplitude for each shot to assess variations in sound that may correspond to material transitions.
3. Correlation Study: Observed that both the Mn peak area graph and the microphone amplitude graph showed similar patterns, suggesting a correlation between the two variables. This indicates that microphone amplitude could help detect the transition between coating and rock. Additionally, a graph of Mn peak area versus microphone amplitude showed a positive slope, further supporting a direct correlation.
4. Validation: The hypothesis was confirmed, as the microphone amplitude decreased in a manner similar to the Mn peak area during the transition. This demonstrates that microphone amplitude can effectively detect transitions from coating to rock, even when the compositions are similar.

Quantifiable Outcomes
1. Hypothesis Confirmation: The hypothesis was confirmed, demonstrating that acoustic data from the microphone can be used to detect transitions between coating and rock, even when their compositions are similar. This was achieved by identifying a strong positive correlation between the LIBS data and microphone amplitude on a basalt rock (N6B) with a manganese-rich coating. Future testing is required on another rock, known as BaSaJa, which has a coating with a composition similar to its bedrock.
2. Presentation and Knowledge sharing: Presented the findings through a poster titled Examining Rock Coatings with LIBS Spectral and Acoustic Data at Los Alamos National Laboratory and MIT, engaging with researchers for feedback on the methodology and implications.

Skills Acquired

1. Multi-Modal Data Analysis: Gained expertise in integrating and analyzing LIBS spectral data and SuperCam acoustic signals to identify material transitions on Martian surfaces.
2. Data Preprocessing: Acquired skills in normalizing and processing noisy datasets, using statistical techniques like best-fit lines to approximate trends and separate relevant signals.
3. Experimental Simulation: Learned to replicate Martian surface conditions, including low-pressure environments, to conduct LIBS and acoustic experiments effectively.
4. Communication Skills: Developed the ability to effectively present complex scientific concepts by creating and presenting a poster, fostering constructive feedback and engagement.

Key Learnings

1. Complementary Data Integration: Recognized the value of integrating acoustic and spectral data to overcome limitations in single-mode analyses, particularly in distinguishing chemically similar materials.
2. Rock Coating Dynamics: Gained insights into how transitions between rock coatings and bedrock can be identified through variations in acoustic signals and LIBS spectra.
3. Plasma Physics Understanding: Explored how plasma expansion during laser ablation generates shockwaves, deepening understanding of the physical processes underlying LIBS and acoustic measurements.
4. Research Adaptability: Learned to adapt methodologies to address challenges in analyzing mixed datasets, ensuring the reliability of results despite data complexity.
5. Application to Planetary Exploration: Developed an appreciation for how multi-modal data analysis techniques can advance the interpretation of Martian surface compositions and inform future exploration missions.

Graphs and Visualization

Presentation Poster at Los Alamos National Laboratory