NSF Arizona Accelerator Mass Spectrometry Facility: Operations and Research Applications

9508413自1981年以来，亚利桑那大学一直在使用加速器质谱仪(AMS)，该质谱仪使用的是2 mV通用离子串联粒子加速器。这个AMS实验室的主要任务是双重的。它既是一个服务实验室，向整个科学界提供具有地球物理和考古重要性的样品的放射性碳(14C)测定，也支持广泛的内部科学研究。目前，该实验室每年为来自世界各地的许多科学家分析3000多个样本中的14C含量。目前不到一半的实验室分析是用于内部研究或与外部研究人员合作进行的研究。这样的内部研究集中在一系列不同的主题上。这项研究的一些方向是在样品的化学制备、仪器改进以及数据简化和解释方面改进AMS技术。实验室的努力使他们能够在14C分析中获得前所未有的精确度。对于最近的材料，他们目前能够在每个样品大约30分钟的计数时间内产生14C/L3C比率，测量精度为+0.5%。据报道，该设备使用多个靶标进行了高精度测量，精确度为+0.25%。其他内部研究项目面向更基本的科学目标，包括在岩石和冰中原位产生14C的研究，以及利用树木年轮或珊瑚14Cu-Th测量改进14C校准曲线。这笔赠款支持亚利桑那州加速器质谱仪(AMS)实验室的运营和维护成本，并将使他们能够保持和改进科学界对该设施所期望的AMS测量的高标准，并开发AMS的新应用，然后供科学界使用。作为这笔赠款的一部分，亚利桑那州将升级其现有的AMS系统，配备一个静电分析器、一个高分辨率注入磁铁、一个快速同位素脉冲系统、一个带有静电四极透镜的高能分析系统、一个90度磁分析器和一个圆柱形静电分析器。还包括对将于1996年3月在图森举行的下一次加速器质谱学国际会议的支助。***

9508413 Donahue An Accelerator Mass Spectrometer (AMS) using a 2 MV General Ionex tandem particle accelerator has been operated at the University of Arizona since 1981. The primary mission of this AMS laboratory is twofold. It operates as both a service laboratory to provide radiocarbon (l4C) determinations of samples of geophysical and archaeological importance to the scientific community at large, but also supports a wide range of in-house scientific research. The laboratory presently analyzes the l4C content of over 3,000 samples a year for many scientists from many parts of the world. Just under half of the current laboratory analyses are for in-house research, or for research undertaken in collaboration with external researchers. Such in-house research has focused on a diverse set of topics. Some of this research has been oriented toward improving AMS technology in terms of chemical preparation of samples, improvements to instrumentation and data reduction and interpretation. The labs efforts have enabled them to obtain unprecedented precision in l4C analyses. They currently are able to produce l4C/l3C ratios with measurement precisions of +0.5% in a counting time of about 30 minutes per sample, for recent material. High-precision measurements as accurate as +0.25% have been reported by this facility using multiple target determinations. Other in-house research projects are oriented towards more basic science goals including studies of in-situ production of 14C in rocks and ice and improvements to the l4C calibration curve using tree rings or coral l4CU-Th measurements. This grant supports operating and maintenance costs of the Arizona Accelerator Mass Spectrometer (AMS) laboratory and will allow them to maintain and improve the high standards of AMS measurements that the scientific community has come to expect from this facility, and to develop new applications of AMS, which will then be available to the scientific community. As part of this grant, Arizona will upgrade their existing AMS system with an injection system with an electrostatic analyzer, a high-resolution injection magnet, a fast isotope pulsing system, a high-energy analysis system with an electrostatic quadrupole lens, a 90 magnetic analyzer, and a cylindrical electrostatic analyzer. Support for the next International Conference on Accelerator Mass Spectrometry, to be held in Tucson in March 1996 is also included. ***