Abstract:Laser-Induced Breakdown Spectroscopy (LIBS) and Raman spectroscopy are complementary techniques providing respectively chemical and structural information on the sample target. These techniques are increasingly used together in Earth and Planetary sciences, and often together. LIBS is locally destructive for the target, and the laser-induced effects due to LIBS laser shots on the structure and on the Raman fingerprint of a set of geological samples relevant to Mars are here investigated by Raman spectroscopy a… Show more
“…Difficulty in detection is mostly due to the high value of a mineral’s optical absorption coefficient that prevents volumetric analysis and/or due to poor Raman efficiency (e.g., Fau et al. 2019 ); this is consistent with laboratory instruments. Fig.…”
Section: Resultsmentioning
confidence: 82%
“…Because of this, the damage caused by the laser is expected to have negligible impact on the other observations (Fau et al. 2019 ). Instrument commands prepare the laser and spectrometers.…”
Section: Details Of Operationmentioning
confidence: 99%
“…At a target distance of 2.5 m, the area of the LIBS laser pit represents ∼ 2.5% of the FOV for Raman and VIS observations, and ∼ 1% of the FOV of the IR observations. Because of this, the damage caused by the laser is expected to have negligible impact on the other observations (Fau et al 2019). Instrument commands prepare the laser and spectrometers.…”
The SuperCam instrument suite provides the Mars 2020 rover, Perseverance, with a number of versatile remote-sensing techniques that can be used at long distance as well as within the robotic-arm workspace. These include laser-induced breakdown spectroscopy (LIBS), remote time-resolved Raman and luminescence spectroscopies, and visible and infrared (VISIR; separately referred to as VIS and IR) reflectance spectroscopy. A remote micro-imager (RMI) provides high-resolution color context imaging, and a microphone can be used as a stand-alone tool for environmental studies or to determine physical properties of rocks and soils from shock waves of laser-produced plasmas. SuperCam is built in three parts: The mast unit (MU), consisting of the laser, telescope, RMI, IR spectrometer, and associated electronics, is described in a companion paper. The on-board calibration targets are described in another companion paper. Here we describe SuperCam’s body unit (BU) and testing of the integrated instrument.The BU, mounted inside the rover body, receives light from the MU via a 5.8 m optical fiber. The light is split into three wavelength bands by a demultiplexer, and is routed via fiber bundles to three optical spectrometers, two of which (UV and violet; 245–340 and 385–465 nm) are crossed Czerny-Turner reflection spectrometers, nearly identical to their counterparts on ChemCam. The third is a high-efficiency transmission spectrometer containing an optical intensifier capable of gating exposures to 100 ns or longer, with variable delay times relative to the laser pulse. This spectrometer covers 535–853 nm ($105\text{--}7070~\text{cm}^{-1}$
105
–
7070
cm
−
1
Raman shift relative to the 532 nm green laser beam) with $12~\text{cm}^{-1}$
12
cm
−
1
full-width at half-maximum peak resolution in the Raman fingerprint region. The BU electronics boards interface with the rover and control the instrument, returning data to the rover. Thermal systems maintain a warm temperature during cruise to Mars to avoid contamination on the optics, and cool the detectors during operations on Mars.Results obtained with the integrated instrument demonstrate its capabilities for LIBS, for which a library of 332 standards was developed. Examples of Raman and VISIR spectroscopy are shown, demonstrating clear mineral identification with both techniques. Luminescence spectra demonstrate the utility of having both spectral and temporal dimensions. Finally, RMI and microphone tests on the rover demonstrate the capabilities of these subsystems as well.
“…Difficulty in detection is mostly due to the high value of a mineral’s optical absorption coefficient that prevents volumetric analysis and/or due to poor Raman efficiency (e.g., Fau et al. 2019 ); this is consistent with laboratory instruments. Fig.…”
Section: Resultsmentioning
confidence: 82%
“…Because of this, the damage caused by the laser is expected to have negligible impact on the other observations (Fau et al. 2019 ). Instrument commands prepare the laser and spectrometers.…”
Section: Details Of Operationmentioning
confidence: 99%
“…At a target distance of 2.5 m, the area of the LIBS laser pit represents ∼ 2.5% of the FOV for Raman and VIS observations, and ∼ 1% of the FOV of the IR observations. Because of this, the damage caused by the laser is expected to have negligible impact on the other observations (Fau et al 2019). Instrument commands prepare the laser and spectrometers.…”
The SuperCam instrument suite provides the Mars 2020 rover, Perseverance, with a number of versatile remote-sensing techniques that can be used at long distance as well as within the robotic-arm workspace. These include laser-induced breakdown spectroscopy (LIBS), remote time-resolved Raman and luminescence spectroscopies, and visible and infrared (VISIR; separately referred to as VIS and IR) reflectance spectroscopy. A remote micro-imager (RMI) provides high-resolution color context imaging, and a microphone can be used as a stand-alone tool for environmental studies or to determine physical properties of rocks and soils from shock waves of laser-produced plasmas. SuperCam is built in three parts: The mast unit (MU), consisting of the laser, telescope, RMI, IR spectrometer, and associated electronics, is described in a companion paper. The on-board calibration targets are described in another companion paper. Here we describe SuperCam’s body unit (BU) and testing of the integrated instrument.The BU, mounted inside the rover body, receives light from the MU via a 5.8 m optical fiber. The light is split into three wavelength bands by a demultiplexer, and is routed via fiber bundles to three optical spectrometers, two of which (UV and violet; 245–340 and 385–465 nm) are crossed Czerny-Turner reflection spectrometers, nearly identical to their counterparts on ChemCam. The third is a high-efficiency transmission spectrometer containing an optical intensifier capable of gating exposures to 100 ns or longer, with variable delay times relative to the laser pulse. This spectrometer covers 535–853 nm ($105\text{--}7070~\text{cm}^{-1}$
105
–
7070
cm
−
1
Raman shift relative to the 532 nm green laser beam) with $12~\text{cm}^{-1}$
12
cm
−
1
full-width at half-maximum peak resolution in the Raman fingerprint region. The BU electronics boards interface with the rover and control the instrument, returning data to the rover. Thermal systems maintain a warm temperature during cruise to Mars to avoid contamination on the optics, and cool the detectors during operations on Mars.Results obtained with the integrated instrument demonstrate its capabilities for LIBS, for which a library of 332 standards was developed. Examples of Raman and VISIR spectroscopy are shown, demonstrating clear mineral identification with both techniques. Luminescence spectra demonstrate the utility of having both spectral and temporal dimensions. Finally, RMI and microphone tests on the rover demonstrate the capabilities of these subsystems as well.
“…The remote configuration of a customized time-resolved Raman and luminescence spectrometer built at IMPMC was used for the present study (Fau et al, 2019). Relying on a conventional Schmidt-Cassegrain telescope (Celestron-C8 * 202 mm diameter Schmidt plate), this instrument allows for Raman signal collection of pristine and irradiated samples without removing them from the chamber in which the irradiation experiments are conducted.…”
Traces of life may have been preserved in ancient martian rocks in the form of molecular fossils. Yet the surface of Mars is continuously exposed to intense UV radiation detrimental to the preservation of organics. Because the payload of the next rovers going to Mars to seek traces of life will comprise Raman spectroscopy tools, laboratory simulations that document the effect of UV radiation on the Raman signal of organics appear critically needed. The experiments conducted here evidence that UV radiation is directly responsible for the increase of disorder and for the creation of electronic defects and radicals within the molecular structure of S-rich organics such as cystine, enhancing the contribution of light diffusion processes to the Raman signal. The present results suggest that long exposure to UV radiation would ultimately be responsible for the total degradation of the Raman signal of cystine. Yet because the degradation induced by UV is not instantaneous, it should be possible to detect freshly excavated S-rich organics with the Raman instruments on board the rovers. Alternatively, given the very short lifetime of organic fluorescence (nanoseconds) compared to most mineral luminescence (micro-to milliseconds), exploiting fluorescence signals might allow the detection of S-rich organics on Mars. In any case, as illustrated here, we should not expect to detect pristine S-rich organic compounds on Mars, but rather by-products of their degradation.
“…These evidences give us a valuable hint about the possible mechanisms of the sodium intake and release. On the one hand, the broadness of the ilmenite peak is directly related to its amorphousness while its position strongly depends on the Ti−O bond length as confirmed by high‐pressure Raman experiments and spectral modification upon cation substitution . On the other hand, the Raman activity of the A g mode is very sensitive to the local symmetry of the TiO 6 octahedra.…”
Ilmenite, general formula FeTiO 3 , has been proposed as possible conversion anode material for lithium-and sodium-ion batteries, with theoretical capacity of 530 mAhg À 1 . Experimentally, the observed specific capacity for pristine ilmenite is far away from the theoretical value; for this reason, the control of morphology via alkaline hydrothermal treatment has been proposed as possible strategy to improve the electrochemical performance. At the same time FeTiO 3 is prone to react with sodium and potassium hydroxide, as already demonstrated by studies on the degradation of ilmenite for the extraction of TiO 2 . In this paper we demonstrate that the alkaline treatment does not induce a morphological modification of the FeTiO 3 powders but involved the degradation of the precursor material with the formation of different phases. A complete physicochemical and electrochemical characterization is performed with the aim of correlating structural and functional properties of the obtained products.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
