含超轻元素Be矿物的电子探针定量分析——测试条件的约束

铍（Be）是战略性资源，属于关键金属。Be在电子探针（EMPA）可分析的元素范围内属于最难测准的一个元素。难测准的原因在于Be属于超轻元素，其特征X-射线不但信号弱、能量低，而且易受其他元素强烈吸收效应的影响，因此硬件上需要EMPA配置大面网间距的特殊分光晶体。而不同厂家不同大面网间距分光晶体配置的EMPA在铍矿物的测试条件存在明显差异，即使同一EMPA测试不同Be矿物分析条件也不一致。尤其是占据国内市场主流的JEOL电子探针目前也只尝试分析过绿柱石一种Be的矿物。本文利用配置LDE3H分光晶体的JXA-8100（JEOL）电子探针，对除绿柱石之外的金绿宝石、硅铍石、硼铍石和锌日光榴石四种Be矿物开展了Be等元素最佳定量分析方法的研发。通过不同铍矿物的全元素扫描，发现与CAMECA电子探针不同，JEOL电子探针不存在Be_Kα峰被Si_L2，3，M1峰干扰问题。同时发现每种含Be矿物Be_Kα峰位存在不同程度的漂移现象，并结合原子轨道杂化及吸收效应等理论对该现象进行了合理的解释。在此基础上，建立起配置LDE3H分光晶体的JEOL电子探针定量分析金绿宝石、硅铍石、硼铍石和锌日光榴石不同Be矿物中Be等元素含量的有效方法。该Be矿物原位分析方法的探索，不仅为JEOL EMPA用户提供Be矿物分析的成熟经验，也必将为铍资源的相关研究和找矿勘查提供有力的技术支撑。

Quantitative analysis of ultra-light elements beryllium by electron microprobe: Constraints of analysis conditions

Beryllium (Be) is a strategic resource and a critical metal. Beryllium is one of the most difficult elements to be measured in the range of elements that can be analyzed by electron probe microanalysis (EPMA). The reason is that Be is an ultra-light element, and its characteristic X-ray is not only weak signal and low energy, but also vulnerable to the strong absorption effect of other elements. Therefore, EPMA needs to be equipped with special spectroscopic crystals with large mesh spacing. However, there are obvious differences in the analysis conditions of beryllium minerals for EPMA equipped with various large-mesh-spacing spectroscopic crystals from different manufactures. Even if different beryllium minerals are analyzed by the same kind of EPMA, the analysis conditions are also inconsistent. In particular, JEOL EPMA, which occupies the mainstream of the domestic market, has only tried to analyze beryl at present. In this work, JEOL JXA-8100 EPMA with LDE3H crystal is used to develop the best quantitative analysis method of Be and other elements for four kinds of beryllium minerals, namely, chrysoberyl, phenakite, hambergite and genthelvite, except beryl. Through the whole element scanning of these beryllium minerals, it is found that unlike CAMECA EPMA, JEOL EPMA do not have the problem that Kα peak of Be is disturbed by L2, 3 and M1 peaks of Silicon. Meanwhile, it is found that Kα peak of Be of each beryllium mineral has different degreed of drift, and the phenomenon is reasonably explained in combination with theories of atomic orbital hybridization and absorption effect. With that, effective methods for quantitative analysis of Be and other elements in different beryllium minerals, such as chrysoberyl, phenakite, hambergite and genthelvite, were established with JEOL EPMA with LDE3H crystal. The exploration of in situ analysis method of beryllium minerals will not only offer JEOL EPMA users with mature experience, but also provide strong technical support for related research and prospecting of beryllium resources.