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Simultaneous measurement of argon isotopes using microchannel plates

使用微通道板同时测量氩同位素

基本信息

批准号：
13354007
负责人：
ITAYA Tetsumaru
金额：
$ 17.72万
依托单位：
Okayama University of Science
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13354007/
关键词：
Ar-Ar dating method multi-detector microchannel plates position sensitive detector Backgammon method ion counting method neutron irradiation single mineral age 単結晶鉱物年代

项目摘要

In 40Ar/39Ar stepwise heating experiments, the fast measurements need to be carried out to obtain time-independent data sets, in particular for small samples. In this study, microchannel plates are used for ion detection, and simultaneous measurement of five argon isotopes from 36Ar to 40Ar was attempted.Simple combination of microchannel plates and a position sensitive detector is not suitable in an ultrahigh vacuum system because it needs baking at temperature over 100℃. Thus, we adopted the two dimensional Modified Backgammon method with Weighted coupling Capacitors(MBWC) designed by Drs Mizokawa at Wakayama College of Technology and Shiromaru at Tokyo Metropolitan University.36Ar,38Ar and 40Ar from atmosphere were detected simultaneously, but the system was not enough for quantitative measurements. The large volume of 40Ar disturbs the simultaneous measurement of 36Ar and 38AT signals which is approximately one three hundredth and one sixteen hundredth, respectively. The system allows two dimensional ion detection, and it is effective to adjust ion optics of each isotope in a mass spectrometer.Designing an one-dimensional chain of linear channeltron was considered to make quantitative measurements, and it became possible with coorperation with Dune Inc. Combining the two dimensional system and a small mass spectrometer with one dimensional system allow easy tuning of ion optics and highly sensitive quantitative argon mass spectrometry. Independent developments of two different types of mass spectromenters is now resulting in a new ultra small highly sensitive mass spectrometer.Signals from the position sensitive detector is measured by the ion counting method. The interface and program were developed as well as the automatic control for the measurement. The control and measurement units are connected via LAN cable. The extraction and purification system to separate ultra low volumes of the standard air and high purity gases were completed.

在40Ar/39Ar分步加热实验中，需要进行快速测量以获得与时间无关的数据集，特别是对于小样本。本研究采用微通道板进行离子检测，并尝试同时测量36~40Ar范围内的5种Ar同位素。微通道板和位置灵敏探测器的简单组合不适合超高真空系统，因为它需要在100℃以上的温度下烘烤。为此，我们采用了和歌山理工学院的Mizokawa博士和东京市立大学的Shiromaru设计的带加权耦合电容的二维改进的双子棋方法，同时检测了大气中的36Ar、38Ar和40Ar，但该系统不足以进行定量测量。40Ar的大体积干扰了36Ar和38at信号的同时测量，分别约为百分之一和十六分之一。该系统支持二维离子检测，可以有效地调节质谱仪中每个同位素的离子光学。设计一维线性沟道加速器链进行定量测量，并与Dune公司合作使其成为可能。将二维系统与小型质谱仪与一维系统相结合，可以轻松地调节离子光学和高灵敏度的定量Ar质谱仪。两种不同类型的质谱计的独立发展正在产生一种新的超小型高灵敏度质谱仪。位置灵敏探测器的信号是用离子计数法测量的。开发了测量界面和程序，实现了测量的自动控制。控制单元和测量单元通过局域网电缆连接。完成了分离超低量标准空气和高纯度气体的萃取净化系统。