TEM preparation methods and influence of radiation damage on the beam sensitive CaCO3 shell of Emiliania huxleyi
TEM preparation methods and influence of radiation damage on the beam sensitive CaCO3 shell of Emiliania huxleyi
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DOI：
10.1016/j.micron.2014.03.004
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发表时间：
2014-07-01
期刊：
影响因子：
2.4
通讯作者：
Scheu, Christina
中科院分区：
文献类型：
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作者：
Hoffmann, Ramona;Wochnik, Angela S.;Scheu, Christina
生物形成的碳酸钙晶体的超微结构取决于环境条件，如pH值，温度和盐度。因此，它们可以作为气候变化的指标。然而，为此需要详细了解它们的晶体结构和化学组成。高分辨率的方法，如透射电子显微镜，可以提供这些信息的纳米尺度，考虑到足够薄的样品可以制备。在我们的研究中，我们开发了样品制备技术的横截面和平面图的调查，并研究了电子轰击下的样品稳定性。除了生物材料（Emiliania huxleyi），我们还准备了矿物样品（冰洲石）进行比较。高分辨率透射电子显微镜成像，电子衍射和电子能量损失谱的研究表明，所有制备的样品是相对稳定的电子轰击下，在300千伏的加速电压时，使用平行照明。超过类似于10（5）e/nm（2）的累积剂量，材料（无论其来源是生物的还是地质的）转化为多晶氧化钙。(c)2014爱思唯尔有限公司版权所有。
The ultrastructure of biologically formed calcium carbonate crystals like the shell of Emiliania huxleyi depends on the environmental conditions such as pH value, temperature and salinity. Therefore, they can be used as indicator for climate changes. However, for this a detailed understanding of their crystal structure and chemical composition is required. High resolution methods like transmission electron microscopy can provide those information on the nanoscale, given that sufficiently thin samples can be prepared. In our study, we developed sample preparation techniques for cross-section and plan-view investigations and studied the sample stability under electron bombardment. In addition to the biological material (Emiliania huxleyi) we also prepared mineralogical samples (Iceland spar) for comparison. High resolution transmission electron microscopy imaging, electron diffraction and electron energy-loss spectroscopy studies revealed that all prepared samples are relatively stable under electron bombardment at an acceleration voltage of 300 kV when using a parallel illumination. Above an accumulated dose of similar to 10(5) e/nm(2) the material - independent whether its origin is biological or geological - transformed to poly-crystalline calcium oxide. (c) 2014 Elsevier Ltd. All rights reserved.