黑云母中α反冲径迹蚀刻模型研究  

A study of etching model of alpha-recoil tracks in biotite

作　　者：董金泉[1] 袁万明[1] 王世成[1] 樊祺诚[2] 

机构地区：[1]中国科学院高能物理研究所核分析技术重点实验室,北京100049 [2]中国地震局地质研究所,北京100029

出　　处：《核技术》2005年第12期957-961,共5页Nuclear Techniques

基　　金：国家自然科学基金资助项目(10475093;10175076);国家重点基础研究发展规划项目(2001CB409804)

摘　　要：同裂变径迹定年方法一样,α反冲径迹(Alpha-recoiltracks)定年方法也是天然放射性释放的核粒子在固体中积累产生的可蚀刻径迹。自然界中的黑云母含有微量元素铀和钍,当它们发生α衰变时,每射出一个α粒子就有一个较重的子体核素反冲,在晶体内形成30—40nm的辐射损失,经过连续反冲就会形成在干涉相差显微镜下可观测的蚀刻径迹,如果自样品形成以来的全部径迹被保存,测得这些径迹数(即α反冲径迹的体密度)就可以得到样品的年龄。对蚀刻模型的研究就是要准确得到α反冲径迹的体密度。应用该蚀刻模型可以在一个样品上多层面、多点位地测定体密度,进而减小误差、提高准确性。Like fission-track dating, alpha-recoil track （ART） dating is based on the accumulation of nuclear particles that are released from natural radioactivity and produce etchable tracks in solids. ARTs are formed during the alpha-decay of uranium and thorium as well as of their daughter nuclei. When emitting an alpha-particle, the heavy remaining nucleus recoils 30-40 nm, leaving behind a trail of radiation damage. Through etching the ART tracks become visible with the aid of an interference phase-contrast microscope. Under the presupposition that all tracks are preserved since the formation of a sample their total number is a measure of the sample＇s age. The research for etching model is to accurately determine ART volume density, i.e., the number of ARTs per unit volume. The volume density of many dots in many layers may be determined on a sample using this etching model, and as decreasing the error and increasing the accuracy.

关 键 词：α反冲径迹 定年 蚀刻模型 黑云母 

分 类 号：P578.959[天文地球—矿物学] O571.321[天文地球—地质学]