scholarly journals Acoustic monitoring of laser-induced phase transitions in minerals: implication for Mars exploration with SuperCam

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Baptiste Chide ◽  
Olivier Beyssac ◽  
Michel Gauthier ◽  
Karim Benzerara ◽  
Imène Estève ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Physical Properties ◽  
Acoustic Signal ◽  
Signal Amplitude ◽  
Acoustic Data ◽  
Breakdown Spectroscopy ◽  
Root Cause ◽  
Mineral Phases ◽  
Surface Exploration ◽  
Laser Induced Breakdown

AbstractThe SuperCam instrument suite onboard the Mars 2020 Perseverance rover uses the laser-induced breakdown spectroscopy (LIBS) technique to determine the elemental composition of rocks and soils of the Mars surface. It is associated with a microphone to retrieve the physical properties of the ablated targets when listening to the laser-induced acoustic signal. In this study, we report the monitoring of laser-induced mineral phase transitions in acoustic data. Sound data recorded during the laser ablation of hematite, goethite and diamond showed a sharp increase of the acoustic signal amplitude over the first laser shots. Analyses of the laser-induced craters with Raman spectroscopy and scanning electron microscopy indicate that both hematite and goethite have been transformed into magnetite and that diamond has been transformed into amorphous-like carbon over the first laser shots. It is shown that these transitions are the root cause of the increase in acoustic signal, likely due to a change in target’s physical properties as the material is transformed. These results give insights into the influence of the target’s optical and thermal properties over the acoustic signal. But most importantly, in the context of the Mars surface exploration with SuperCam, as this behavior occurs only for specific phases, it demonstrates that the microphone data may help discriminating mineral phases whereas LIBS data only have limited capabilities.

Expected first results from the SuperCam microphone onboard the NASA Perseverance rover

2021 ◽  
Author(s):  
Nina Lanza ◽  
Baptiste Chide ◽  
David Mimoun ◽  
Cesar Alvarez ◽  
Stanley Angel ◽  
...  
Keyword(s):  
Acoustic Signal ◽  
Analytical Techniques ◽  
Landing Site ◽  
Thin Layers ◽  
Dust Devils ◽  
Breakdown Spectroscopy ◽  
Analytical Instruments ◽  
Laser Induced Breakdown ◽  
First Results ◽  
Attenuation Models

<p>The NASA Perseverance rover will land on Mars in February 2021, bringing with it a new suite of analytical instruments with which to explore its landing site in Jezero crater. The primary goal of this new mission is to assess the geology and past habitability in order to identify and cache samples with a high likelihood of preserving biosignatures, in preparation for a future sample return mission [1]. As part of its instrument payload, Perseverance will carry the SuperCam instrument [2-3]. SuperCam combines a number of analytical techniques, notably a laser-induced breakdown spectroscopy (LIBS) instrument for chemical analysis that is coupled with a microphone for acoustic studies. The SuperCam microphone is a commercial of-the-shelf electret (based on Knowles EK-23132) and is designed to record sounds in the audible range, from 100 Hz to 10 kHz, during the surface mission. There are three main science investigations of interest for the SuperCam microphone: 1) Analysis of the LIBS acoustic signal; 2) study of atmospheric phenomena; and 3) examination of rover mechanical sounds. Since the atmosphere will be the source of acoustic signals, the microphone may be used to better understand the nature of the atmosphere and related phenomena such as thermal gradient and convective behavior in the rover’s vicinity [4], the behavior of dust devils [5], and to refine current atmospheric attenuation models for Mars [6]. Under atmosphere, LIBS analysis produces an acoustic signal due to the creation of a shock wave during laser ablation of a target. This acoustic signal can provide critical information about a target’s hardness and ablation depth [7-8] and whether there are coatings or thin layers present [9]. Mechanisms on the rover itself will also provide a source of acoustic signal that may be examined by the SuperCam microphone, notably sounds produced by the Mars Oxygen ISRU Experiment (MOXIE, [10]) instrument pumps during oxygen production. By the time of the conference, the SuperCam microphone should have acquired the first sounds on Mars; we will report on these exciting initial results and compare them to our prelanding expectations.</p><p>[1] Farley K.A. et al. (2020) SSR 216, 142. [2] Wiens R.C. et al. (2021) SSR 217(4). [3] Maurice, S. et al. (in revision) SSR. [4] Chide, B. et al. (2020) 52<sup>nd</sup> LPSC. [5] Murdoch, N. et al. (2021) 52<sup>nd</sup> LPSC. [6] Chide, B. et al. (2020) AGU Fall meeting, S007-02. [7] Chide, B. et al. (2019) SAB 153, 50-60. [8] Chide, B. et al. (2020) SAB 174, 106000. [9] Lanza, N.L. et al (2020) 51<sup>st</sup> LPSC, no. 2807. [10] Hecht, M. H. et al. (2015) 46<sup>th</sup> LPSC, no. 2774.</p>

Nanosecond laser-induced breakdown assisted by femtosecond laser pre-ionization in air: the effect on spatial resolution and continuous radiation

2020 ◽  
Vol 92 (2) ◽  
pp. 20701
Author(s):  
Bo Li ◽  
Xiaofeng Li ◽  
Zhifeng Zhu ◽  
Qiang Gao
Keyword(s):  
Femtosecond Laser ◽  
Spatial Resolution ◽  
Laser Induced Breakdown Spectroscopy ◽  
Nanosecond Laser ◽  
Breakdown Threshold ◽  
Powerful Technique ◽  
Breakdown Spectroscopy ◽  
Continuous Radiation ◽  
Laser Induced Breakdown

Laser-induced breakdown spectroscopy (LIBS) is a powerful technique for quantitative diagnostics of gases. The spatial resolution of LIBS, however, is limited by the volume of plasma. Here femtosecond-nanosecond dual-pulsed LIBS was demonstrated. Using this method, the breakdown threshold was reduced by 80%, and decay of continuous radiation was shortened. In addition, the volume of the plasma was shrunk by 85% and hence, the spatial resolution of LIBS was significantly improved.

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