A Mineral X-ray Linear Attenuation Coefficient Tool (MXLAC) to Assess Mineralogical Differentiation for X-ray Computed Tomography Scanning
A Mineral X-ray Linear Attenuation Coefficient Tool (MXLAC) to Assess Mineralogical Differentiation for X-ray Computed Tomography Scanning
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DOI：
10.3390/min10050441
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发表时间：
2020-05-01
期刊：
影响因子：
2.5
通讯作者：
Becker, Megan
中科院分区：
文献类型：
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作者：
Bam, Lunga C.;Miller, Jodie A.;Becker, Megan
x射线计算机断层扫描（XCT）正在成为地球科学中最重要的技术之一。该技术依靠线性衰减系数差来揭示岩石的内部结构。在这项工作中，我们提出了一个新的excel宏工具，称为MXLAC，这是一个具有excel界面的数据库，它使用密度，x射线能量和矿物化学公式来允许用户计算矿物线性衰减系数，然后可用于确定矿物对之间的区分。矿物中由化学式指定的元素决定了x射线的衰减方式。对密度和衰减系数相近的多种扫描矿物对的分析表明，在45.5 keV有效x射线能量下，XCT单能量扫描要有效区分两种矿物，需要衰减系数差大于等于6%。这意味着目前的XCT仪器无法区分石英和叶蜡石等矿物对，因为在45.5 keV有效x射线能量下，衰减系数差小于1.9%。以石榴石和其他各种矿物为例，说明了解矿物的实际化学式的重要性，以证明它们是否可以部分或完全相互区分。
X-ray computed tomography (XCT) is becoming one of the most important techniques in the geosciences. The technique relies on linear attenuation coefficient differences in order to reveal the internal structure of the rocks. In this work, we present a new excel macro tool, called MXLAC, which is a data bank with an excel interface that uses density, X-ray energy and the mineral chemical formula to allow users to calculate mineral linear attenuation coefficients that can then be used to determine discrimination between mineral pairs. Elements within a mineral and specified by the chemical formula, determine how the X-ray beam is attenuated. Analysis of a variety of scanned mineral pairs with similar densities and attenuation coefficients indicates that an attenuation coefficient difference of greater than or equal to 6% at 45.5 keV effective X-ray energy is required for effective discrimination between two minerals using XCT with single energy scanning. This means that mineral pairs, such as quartz and pyrophyllite cannot be discriminated using the current XCT instruments due to the fact that the attenuation coefficient difference is less than 1.9% at 45.5 keV effective X-ray energy. Garnets and a variety of other minerals were used as examples to illustrate the importance of knowing the actual chemical formula of the mineral to demonstrate whether they can be partially or fully discriminated from each other.