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纯的立方氟化铅晶体（βＰｂＦ２）具有密度高（７．７７ｇ／ｃｍ３）、辐射长度短（ｘ０＝９．３ｍｍ）和能量分辨率高等优点，因此可以作为一种超致密的Ｃｈｅｒｅｎｋｏｖ辐射体应用于电磁量能器上。以前生长的纯氟化铅晶体由于存在许多缺陷，如颜色发黄、透光率太低、晶体尺寸小或含有包裹体等而使其应用受到很大限制。一直到９０年代，由于采用了脱氧剂非真空坩埚下降法，才生长出了大尺寸、高质量的氟化铅晶体，从而为该晶体的应用研究创造了有利条件。但是，在氟化铅晶体的生长过程中，由于受内外因素的影响，有时生长出的晶体仍然会或多或少地含有一些针状包裹体。它们的分布特征是：（１）呈针状或芒刺状沿氟化铅晶体中的［１１１］方向延伸，并在空间交叉成网络状；（２）用显微镜观察发现，这些针状分布的包裹体实际上是一系列尺寸为１０～５０μｍ的圆形、椭圆形或其它不规则形状的固体包裹物沿一定方向排列成一条条的长线所致；（３）显微分析表明，这些包裹物的组成为氧化铅和氟氧化铅。氟氧化铅中的氟∶氧原子个数比为３４∶１～１∶５；（４）在晶体生长的初期阶段，这种包裹体的含量少，甚至根本没有，而在晶体生长的后期，它不仅含量多，分布密，而且个体粗大。当晶体中含有这种针?
The pure cubic PbF2 crystal has the advantages of high density (7.77g / cm3), short radiation length (x0 = 9.3mm) and high energy resolution, so it can be used as an ultra-dense Cherenkov radiation Body applied to the electromagnetic energy device. Previously grown pure lead perchlorate crystals have been severely limited in their application due to their many drawbacks, such as yellowing of color, low light transmittance, small crystal size or inclusions. Until the 1990s, large-size and high-quality lead fluoride crystals were grown due to the adoption of the deoxidizer non-vacuum crucible descent method, thus creating favorable conditions for the application of the crystal. However, during the growth of PbF4 crystals, the crystals sometimes grow may contain more or less acicular inclusions due to internal and external factors. Their distribution is characterized by: (1) acicular or prick-like extension along the [111] direction in the crystals of lead fluoride and cross-networked in space; (2) microscopic observation shows that these acicular The inclusions are actually caused by a series of long lines of solid, round, oval or other irregularly shaped solid inclusions with a size of 10 ~ 50μm arranged in a certain direction. (3) The microscopic analysis shows that these inclusions The composition of lead oxide and lead oxyfluoride. The ratio of fluorine to oxygen in the lead oxyfluoride is in the range of 34: 1 to 1: 5; (4) In the early stage of crystal growth, the content of such inclusions is small or none at all, whereas in the late stage of crystal growth, It is not only content, distribution, but also individual. When the crystal contains such a needle?