Advanced instrumentation for accelerator mass spectrometry

用于加速器质谱分析的先进仪器

• 批准号: 327359-2011
• 负责人: Kieser, William
• 金额: $ 2.04万
• 依托单位: University of Ottawa
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=571997
• 关键词: Advanced; instrumentation; accelerator; mass; spectrometry

The advantages of accelerator mass spectrometry (AMS), in which isotopes and rare atoms can be measured in sub-milligram samples with sensitivities approaching 1 part in a thousand million million, have been largely confined to elements which readily make negative ions and which have isobars that do not, such as Carbon-14 and Iodine-129. For elements that do not meet one or both of these conditions, the development of analytical strategies has been limited and often been confined to the use of larger accelerators (>5 MV). Two innovations begun recently at the IsoTrace Laboratory have demonstrated that the use of AMS can be extended to a much larger fraction of the periodic table. These are: (i) the use of fluoride molecular anions to enhance the production of the negative ions required for AMS and (ii) the use of radio-frequency quadrupole ion guides in cooling and reaction cells to eliminate both atomic and molecular isobars at very low energies - collectively known as the Isobar Separator for Anion (ISA). These techniques are both at a very early stage in their development; much further work is needed to understand the physical processes involved (i) in the formation of the fluoride molecular anions in the complex chemical environment of the ion source and (ii) in the behaviour of the ions as they traverse the intricate electric fields and cooling and reaction gas regions of the ISA. This knowledge is essential for the application of these techniques to different elements and for their use in reliable analytical procedures and equipment. The establishing of the new AMS facility at the University of Ottawa and, while this facility is in preparation, the continued operation of the IsoTrace equipment provide a unique opportunity to carry out this research and to involve in it the participation of graduate students and post-doctoral fellows both in the generation of this knowledge and the implementation of new applications in a multi-disciplinary setting.

加速器质谱法（AMS）的优点是可以在低于毫克的样品中测量同位素和稀有原子，灵敏度接近十亿分之一，但主要局限于容易产生负离子的元素和具有不产生负离子的同量异位素的元素，如碳14和碘129。 对于不满足这些条件中的一个或两个的元素，分析策略的开发受到限制，并且通常限于使用较大的加速器（>5 MV）。 IsoTrace实验室最近开始的两项创新表明，AMS的使用可以扩展到周期表中更大的部分。 这些是：（i）使用氟化物分子阴离子来增强AMS所需的负离子的产生，以及（ii）在冷却和反应池中使用射频四极离子导向器来消除极低能量下的原子和分子同量异位素-统称为阴离子同量异位素分离器（伊萨）。 这些技术都处于发展的早期阶段;需要进一步的工作来了解（i）在离子源的复杂化学环境中形成氟化物分子阴离子的物理过程，以及（ii）当离子穿过伊萨的复杂电场以及冷却和反应气体区域时离子的行为。这些知识对于将这些技术应用于不同的元素及其在可靠的分析程序和设备中的使用至关重要。 在渥太华大学建立新的AMS设施，并在该设施筹备期间继续运行IsoTrace设备，这为开展这项研究提供了一个独特的机会，并使研究生和博士后研究员参与这一知识的产生和在多学科环境中实施新的应用。