Identification of minerals and meteoritic materials via Raman techniques after capture in hypervelocity impacts on aerogel
Identification of minerals and meteoritic materials via Raman techniques after capture in hypervelocity impacts on aerogel
复制标题
在气凝胶超高速撞击中捕获后，通过拉曼技术识别矿物和陨石材料
DOI：
10.1111/j.1945-5100.2006.tb00205.x
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发表时间：
2006
影响因子：
2.2
通讯作者：
I. Franchi
中科院分区：
文献类型：
--
作者：
M. Burchell;J. Mann;J. A. Creighton;A. Kearsley;G. Graham;I. Franchi
摘要-测试了类似宇宙尘埃成分的矿物颗粒，以确定它们在气凝胶中超高速捕获后是否可以识别拉曼特征。通过光-气-枪射击将矿物颗粒加速到二氧化硅气凝胶上。发现气凝胶中捕获的所有单个矿物都可以用拉曼（或荧光）光谱进行识别。激光束光斑尺寸为~ 5微米，在某些情况下捕获的颗粒具有类似的小尺寸。在气凝胶中的一些样品中，观察到一些拉曼带的波数变宽和移动，这是由于被捕获的粒子由于激光加热而处于高温的结果。样品的温度也可以通过Stokes和反Stokes拉曼带的相对强度来估计，或者在刚玉粒子的情况下，通过激光激发的荧光带的波数来估计。温度的变化很大，这取决于激光功率和粒子的性质。当激光功率约为3毫瓦时，大多数被检测的矿物颗粒的温度低于200°C。这个温度足够低，不会破坏大多数在太空中被气凝胶捕获的物质。在最坏的情况下，一些颗粒的温度达到500-700°C。此外，对选定的陨石样本进行了检查，以获得其组成矿物的拉曼特征，然后将其射入气凝胶中。在气凝胶中捕获后，可以找到拉曼特征，并在气凝胶中获得全谷物的原位拉曼图。结论是，拉曼分析确实非常适合于气凝胶中捕获的微米级材料的原位分析。
Abstract— Mineral particles analogous to components of cosmic dust were tested to determine if their Raman signatures can be recognized after hypervelocity capture in aerogel. The mineral particles were accelerated onto the silica aerogel by light‐gas‐gun shots. It was found that all the individual minerals captured in aerogel could be identified using Raman (or fluorescence) spectra. The laser beam spot size was ˜5 micrometers, and in some cases the captured particles were of a similar small size. In some samples fired into aerogel, a broadening and a shift in the wave numbers of some of the Raman bands was observed, a result of the trapped particles being at elevated temperatures due to laser heating. Temperatures of samples were also estimated from the relative intensities of Stokes and anti‐Stokes Raman bands, or, in the case of corundum particles, from the wave number of fluorescence bands excited by the laser. The temperature varied greatly, dependent upon laser power and the nature of the particle. Most of the mineral particles examined had temperatures below 200 °C at a laser power of about 3 mW at the sample. This temperature is sufficiently low enough not to damage most materials expected to be found captured in aerogel in space. In the worst case, some particles were shown to have temperatures of 500–700 °C. In addition, selected meteorite samples were examined to obtain Raman signatures of their constituent minerals and were then shot into aerogel. It was possible to find Raman signatures after capture in aerogel and obtain a Raman map of a whole grain in situ in the aerogel. It is concluded that Raman analysis is indeed well suited for an in situ analysis of micrometer‐sized materials captured in aerogel.