Accelerator mass spectrometry analysis of ultra-low-level (129)I in carrier-free AgI-AgCl sputter targets.
Accelerator mass spectrometry analysis of ultra-low-level (129)I in carrier-free AgI-AgCl sputter targets.
复制标题
无载流子 AgI-AgCl 溅射靶材中超低水平 (129)I 的加速器质谱分析。
DOI：
10.1007/s13361-015-1086-1
复制
发表时间：
2015
影响因子：
3.2
通讯作者：
Fu Yunchong
中科院分区：
文献类型：
--
作者：
Liu Qi;Hou Xiaolin;Zhou Weijian;Fu Yunchong
从低碘样品中分离出无载体碘，精确测量微克级碘靶中的超低水平129 I，是利用天然129 I进行地质环境研究的关键，也是制约研究的瓶颈。本文介绍了一种精确测定无载体AgI-AgCl溅射靶中超低水平~（129）I的加速器质谱检测技术。为了避免AgI-AgCl粉末与铝反应，选择铜代替铝作为合适的样品保持器材料。选择铌粉作为导热导电基体，与AgI-AgCl粉末混合，以获得并保持稳定的高碘离子电流强度，以及较小的记忆效应和较低的129 I本底水平。Nb基体与AgI-AgCl粉末的最佳质量比为5：1。用碘含量为5 ~ 80 μg的AgI-AgCl靶，测得~（127）I ~（5+）的典型电流为5 ~ 100 nA。AMS连续4年对低碘标准品和机器空白样品中129 I/127 I比值的测量结果具有良好的重复性和稳定性。
Separation of carrier-free iodine from low-level iodine samples and accurate measurement of ultra-low-level129I in microgram iodine target are essential but a bottleneck in geology and environment research using naturally produced129I. This article presents a detection technique of accelerator mass spectrometry (AMS) for accurate determination of ultra-low-level129I in carrier-free AgI-AgCl sputter targets. Copper instead of aluminum was selected as the suitable sample holder material to avoid the reaction of AgI-AgCl powder with aluminum. Niobium powder was selected as thermally and electrically conductive matrix to be mixed with AgI-AgCl powder, in order to obtain and maintain a stable and high iodine ion current intensity, as well as less memory effect and low background level of129I. The most optimal ratio of the Nb matrix to the AgI-AgCl powder was found to be 5:1 by mass. The typical current of127I5+using AgI-AgCl targets with iodine content from 5 to 80 μg was measured to be 5 to 100 nA. Four-year AMS measurements of the129I/127I ratios in standards of low iodine content and the machine blanks showed a good repeatability and stability.