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首页> 外文期刊>Applied radiation and isotopes: including data, instrumentation and methods for use in agriculture, industry and medicine >Low-magnesium uranium-calcite with high degree of crystallinity and gigantic luminescence emission
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Low-magnesium uranium-calcite with high degree of crystallinity and gigantic luminescence emission

机译：具有高结晶度和巨大发光的低镁铀方解石

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摘要

Cabrera (Madrid) low-Mg calcites exhibit: (i) an unusual twofold elevation in X-ray diffraction pattern intensity; (ii) a 60-fold elevation of luminescence emission, compared to six common natural calcites selected for comparison purposes; (iii) a natural relatively high radiation level of circa 200 nSv h(-1) not detected in 1300 other calcites from the Natural History Museum of Madrid. Calcites were analysed by the X-ray diffraction powder method (XRD), cathodo-luminescence spectroscopy in scanning electron microscopy (CL-SEM), thermoluminescence (TL), differential thermal analysis (DTA), X-ray fluorescence spectrometry (XRF) and particle size distribution (PSD). The Cabrera calcite study shows: (i) helicoidally distributed steps along the (0001) orientation; (ii) protuberance defects onto the (0001) surface, observed by SEM; (iii) XRF chemical contents of 0.03% MgO, 0.013% of Y2O3, and 0.022% of U3O8, with accessory amounts of rare earth elements (REE); (iv) DTA dissociation temperature of 879 degrees C; (v) TL maxima peaks at 233 and 297 degrees C whose areas are 60 times compared to other calcites; (vi) spectra CL-SEM bands at 2.0 and 3.4 eV in the classic structure of Mn2+ activators; (vii) a twofold XRD pattern explained given that sample is a low-Mg calcite. The huge TL and CL emissions of the Cabrera calcite sample must be linked with the uranyl group presence. This intense XRD pattern in low-Mg calcites could bring into being analytical errors. (c) 2006 Elsevier Ltd. All rights reserved.
机译：卡夫雷拉（马德里）低镁方解石表现出：（i）X射线衍射图强度异常高的两倍; （ii）与选择用于比较目的的六种普通天然方解石相比，发光发射高度提高了60倍; （iii）马德里自然历史博物馆的1300个其他方解石中未检测到大约200 nSv h（-1）的自然较高辐射水平。方解石通过X射线衍射粉末法（XRD），扫描电子显微镜中的阴极发光光谱（CL-SEM），热发光（TL），差热分析（​​DTA），X射线荧光光谱（XRF）和粒度分布（PSD）。 Cabrera方解石研究表明：（i）沿（0001）方向呈螺旋状分布的台阶; （ii）通过SEM观察到（0001）表面上的突起缺陷; （iii）XRF化学含量为0.03％的MgO，0.013％的Y2O3和0.022％的U3O8，并带有少量的稀土元素（REE）; （iv）DTA解离温度为879摄氏度; （v）TL最高峰出现在233和297摄氏度，面积是其他方解石的60倍; （vi）在经典结构的Mn2 +活化剂中，在2.0和3.4 eV处的CL-SEM谱带光谱; （vii）考虑到样品是低镁方解石，解释了双重XRD图谱。 Cabrera方解石样品的大量TL和CL排放必须与铀基团的存在有关。低镁方解石中强烈的XRD图谱可能导致分析误差。 （c）2006 Elsevier Ltd.保留所有权利。

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