A Compact System for Continuous-flow Accelerator Mass Spectrometry

0321045 Hayes该主要研究仪器奖授予马萨诸塞州的伍兹霍尔海洋研究所（WHOI），为开发紧凑、连续流动、加速器质谱仪提供资金，该质谱仪专门设计用于监测连续流动气流中14 C（放射性碳）相对于其他碳同位素的水平。 该仪器将对小至1微克碳的样品中的放射性碳浓度作出显著响应（信号/噪声= 3），该浓度比现代大气中的浓度低10倍。 它将能够连续分析色谱流出物，并确定单个色谱峰中14 C的丰度。 以前的工作已经证明，对天然样品中单个有机化合物的放射性碳分布的调查可以揭示这些化合物的来源，而这种新仪器将使这些结果扩展到不同样品中的各种化合物成为可能，解决了有关自然环境中碳循环的重要问题。 初步计划的具体应用包括研究二氧化碳向大气的释放和重建古代气候。 对烃循环的研究将利用化石烃中缺乏放射性碳的优势，从而为自然环境中的石油和其他污染物提供强有力的负示踪剂。 该仪器将由两个大型磁铁、一个粒子加速器、一个静电偏转系统和一个粒子计数探测器以及一个微波离子源构成，微波离子源是一个关键的子系统，它使用微波能量产生等离子体，从中可以提取正碳离子。 微波离子源的原型已经建成，并在WHOI的国家海洋科学加速器质谱（NOSAMS）设施进行了测试。 新仪器将安置在一个正在建造的新实验室内，以便扩大NOSAMS，并作为该设施的一部分进行管理。 一旦建成，它将作为合格的联邦资助的研究人员和其他人的共享使用设施运行，类似于NOSAMS现有的加速器质谱仪。该仪器奖由NSF海洋科学部支持。 伍兹霍尔海洋研究所提供非联邦基金的费用分摊支助。

0321045 Hayes This Major Research Instrumentation award to Woods Hole Oceanographic Institution (WHOI) in Massachusetts provides funds for development of a compact, continuous-flow, accelerator mass spectrometer, designed specifically for monitoring levels of 14C (radiocarbon) relative to other carbon isotopes in a continuously flowing gas stream. The instrument will respond significantly (signal/noise = 3) to concentrations of radiocarbon ten-fold lower than those in the modern atmosphere in samples as small as one microgram carbon. It will be capable of continuously analyzing chromatographic effluents and of determining the abundance of 14C in individual chromatographic peaks. Previous work has demonstrated that surveys of radiocarbon distribution within individual organic compounds from natural samples can reveal the sources of those compounds, and this new instrument will make it possible to extend those results to a wide variety of compounds in diverse samples, addressing important questions about carbon cycling in natural environments. Specific initial planned applications include study of releases of carbon dioxide to the atmosphere and the reconstruction of ancient climates. Research on hydrocarbon cycling will take advantage of the lack of radiocarbon in fossil hydrocarbons, thus providing a strong negative tracer for petroleum and other pollutants in natural environments. The instrument will be constructed from two large magnets, a particle accelerator, an electrostatic deflecting system and a particle-counting detector in addition to a microwave ion source, a key subsystem that uses microwave energy to create a plasma from which positive carbon ions can be extracted. A prototype of the microwave ion source has been built and tested previously at the National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) facility at WHOI. The new instrument will be housed in a new laboratory being constructed to allow expansion of NOSAMS, and managed as part of that facility. Once built, it will be operated as a shared-use facility for qualified, federally-funded researchers and others, similar to the existing accelerator mass spectrometer at NOSAMS. This instrumentation award is supported by the Division of Ocean Sciences at NSF. Woods Hole Oceanographic Institution provides cost sharing support from non-federal funds.***