Argon isotope analysis by a newly developed mass spectrometric system for K-Ar dating.
Argon isotope analysis by a newly developed mass spectrometric system for K-Ar dating.
复制标题
通过新开发的 K-Ar 定年质谱系统进行氩同位素分析。
DOI：
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发表时间：
1991
期刊：
影响因子：
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通讯作者：
Atsumi Ogata
中科院分区：
文献类型：
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作者：
T. Itaya;K. Nagao;K. Inoue;Y. Honjou;T. Okada;Atsumi Ogata
设计和建造了一台新的质谱仪和相关的分析系统，称为HIRU，用于年轻火山岩以及变质和花岗岩类矿物的氩同位素分析。HIRU由样品保持器、萃取炉、净化管线、标准气体管线、质谱仪和超高真空抽气系统组成。除样品保持器外，所有部件均由不锈钢制成，并使用Cu垫圈或超高真空金属阀与ICF法兰连接。该质谱仪为15cm扇形斜入射单聚焦系统，采用电子轰击离子源和三个收集器，分别包括8级（36Ar）、6级（38Ar）和4级（40Ar）二次电子倍增器，本文综述了HIRU用于氩同位素分析的情况，并讨论了新质谱系统的精度和可靠性。本文介绍了一种利用计算机控制的氩同位素分析系统，包括获取一组谱图、计算同位素比值、计算氩含量、计算年龄等一系列的氩同位素分析。HIRU使高灵敏度的地质材料定年成为可能。白垩纪时代的云母的几十毫克），高精度（约。1%的误差氩含量），可靠性（可能为岩石年龄超过0.1 Ma），和方便（如。5-6样品可以每天注明日期）。
A new mass spectrometer and the associated analytical systems, called HIRU, was designed and constructed for the argon isotope analysis of minerals from young volcanic rocks as well as metamorphics and granitoids. HIRU is composed of a sample holder, an extraction oven, purification lines, standard gas lines, a mass spectrometer, and an ultra high vacuum pumping system. All the parts, except for the sample holder, were made of stainless steel and connected with ICF flanges using Cu gaskets or ultra high vacuum metal valves. The mass spectrometer is a 15cm sector type with an oblique incidence-single focusing system using an electron bombard ion source and three collectors which contain 8 (for 36Ar), 6 (38Ar) and 4 (40Ar) stage secondary electron multipliers respectively.Argon isotope analysis by HIRU is summarized and the precision and reliability of the new mass spectrometric system are discussed in this paper. A series of analysis for argon isotopes, such as taking a set of spectrum, the calculation of isotopic ratios, argon content, and ages is carried out with a computer-controlled system. HIRU has mde it possible to date geological materials with high sensitivity (eg. tens mg of mica of Cretaceous age), high precision (ca. 1% of error for argon content), reliability (possible for rocks older than 0.1 Ma), and convenience (eg. 5–6 samples can be dated per day).