Hawaii Institute of Geophysics and Planetology, SOEST, University of Hawaii, Honolulu, HI 96822, USA.
Spectrochim Acta A Mol Biomol Spectrosc. 2011 Oct;80(1):75-81. doi: 10.1016/j.saa.2011.01.033. Epub 2011 Feb 1.
The authors have utilized a recently developed compact Raman spectrometer equipped with an 85 mm focal length (f/1.8) Nikon camera lens and a custom mini-ICCD detector at the University of Hawaii for measuring remote Raman spectra of minerals under supercritical CO(2) (Venus chamber, ∼102 atm pressure and 423 K) excited with a pulsed 532 nm laser beam of 6 mJ/pulse and 10 Hz. These experiments demonstrate that by focusing a frequency-doubled 532 nm Nd:YAG pulsed laser beam with a 10× beam expander to a 1mm spot on minerals located at 2m inside a Venus chamber, it is possible to measure the remote Raman spectra of anhydrous sulfates, carbonates, and silicate minerals relevant to Venus exploration during daytime or nighttime with 10s integration time. The remote Raman spectra of gypsum, anhydrite, barite, dolomite and siderite contain fingerprint Raman lines along with the Fermi resonance doublet of CO(2). Raman spectra of gypsum revealed dehydration of the mineral with time under supercritical CO(2) at 423 K. Fingerprint Raman lines of olivine, diopside, wollastonite and α-quartz can easily be identified in the spectra of these respective minerals under supercritical CO(2). The results of the present study show that time-resolved remote Raman spectroscopy with a compact Raman spectrometer of moderate resolution equipped with a gated intensified CCD detector and low power laser source could be a potential tool for exploring Venus surface mineralogy both during daytime and nighttime from a lander.
作者利用了一种新开发的紧凑型拉曼光谱仪，该光谱仪配备了一个 85 毫米焦距（f/1.8）的尼康相机镜头和一个定制的小型 ICCD 探测器，用于测量在夏威夷大学超临界 CO2（金星腔，约 102 大气压和 423 K）下用脉冲 532nm 激光激发的矿物的远程拉曼光谱，激光脉冲能量为 6mJ/脉冲，重复频率为 10Hz。这些实验表明，通过将倍频 532nm Nd:YAG 脉冲激光束聚焦在距离金星腔 2 米处的矿物上的 1mm 光斑上，用 10×扩束器将其聚焦，可以在白天或夜间用 10 秒积分时间测量与金星探测相关的无水硫酸盐、碳酸盐和硅酸盐矿物的远程拉曼光谱。石膏、硬石膏、重晶石、白云石和菱铁矿的远程拉曼光谱包含指纹拉曼线以及 CO2 的费米共振双峰。在 423 K 的超临界 CO2 下，随着时间的推移，石膏矿物发生了脱水。在超临界 CO2 下，橄榄石、透辉石、硅灰石和α-石英的指纹拉曼线很容易在各自矿物的光谱中识别出来。本研究的结果表明，配备门控增强型 CCD 探测器和低功率激光源的中等分辨率紧凑型拉曼光谱仪进行时间分辨远程拉曼光谱学可能是一种有潜力的工具，可用于从着陆器上在白天和夜间探索金星表面的矿物学。
