Acquisition of Low Background High-Resolution Gamma Spectrometers for Research and Undergraduate Student Training

这笔赠款将用于购买两台高分辨率伽马能谱仪，用于威廉玛丽大学地质学系和环境科学项目的教职员工研究和本科生培训。这些光谱仪将能够精确测量世界各地岩石和沉积物中存在的铀、钍、钾和镭的同位素，以及空气、土壤和核燃料和武器过程中产生的沉积物中的人造铯和钚的同位素，从而精确测量自然产生的伽马放射性核素。重要的是，这些仪器将使我们能够确定沉积层的年代，从而有助于重建区域污染历史和更好地了解北极气候变化。由于伽马光谱分析的样品制备简单，仪器具有长期稳定性，这些光谱仪将用于支持本科生的研究培训，增加本科课程和实验室练习，并将为当地两年制社区大学托马斯·纳尔逊社区学院的教职员工和学生提供教育推广机会。购买的伽马光谱仪将通过提供环境样品中放射性核素浓度的精确超痕量测量，支持威廉和玛丽大学以及弗吉尼亚海洋科学研究所正在进行的一系列研究项目。仪器的设计允许使用探测器和定时测量来记录重合和反重合脉冲，以选择性地分析来自相反两侧的单个样本，这一配置将大大提高对宇宙成因22NA的探测极限，以及沉积物岩心研究所需的小样本质量的放射性核素测量。威廉玛丽研究中心现有研究的一个主要目标是利用湖泊沉积岩心对格陵兰、挪威、斯瓦尔巴特群岛和法罗群岛的更新世和全新世的过去气候变化进行高分辨率重建。这项设备采购将支持的第二个项目旨在更好地了解大西洋沿岸平原的氡源，该地区以前被认为铀和氡潜力较低。该仪器将支持这两个项目，并为威廉和玛丽大学和弗吉尼亚海洋科学研究所的研究人员提供广泛的装备，研究大陆边缘环境中的盐沼开发和沉积。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This grant will support the acquisition of two high-resolution gamma spectrometers for faculty research and undergraduate student training in the Geology Department and Environmental Science Program at William & Mary. The spectrometers will enable precise measurements of naturally occurring gamma-emitting radionuclides from isotopes of uranium, thorium, potassium, and radium present in rocks and sediments worldwide, along with artificial isotopes of cesium and plutonium in air, soil, and sediment generated by the nuclear fuel and weapons processes. Importantly, these instruments will give us the capability to date sedimentary layers and thus be used to help reconstruct regional pollution histories and better understand Arctic climate change. Because sample preparation is simple for gamma spectrometry and the instruments have long-term stability, the spectrometers will be used to support undergraduate research training, augment undergraduate courses and laboratory exercises, and will provide educational outreach opportunities to faculty and students at Thomas Nelson Community College, a local two-year community college.The gamma spectrometers acquired will support a wide range of ongoing research projects at William & Mary and the Virginia Institute of Marine Sciences by providing precise ultra-trace measurements of radionuclide concentrations in environmental samples. The design of the instrumentation allows for optionally analyzing a single sample from opposing sides using both detectors and timed measurements to record coincident and anti-coincident pulses, a configuration that that will enable greatly improved detection limits for cosmogenic 22Na and for radionuclide measurements on small sample masses required by sediment core research. A major goal of existing research at William & Mary is to generate high-resolution reconstructions of past climate changes in the Pleistocene and Holocene at sites in Greenland, Norway, Svalbard, and the Faroe Islands from lake sediment cores. A second project that will be supported by this equipment acquisition aims to better understand radon sources in the Atlantic Coastal Plain, an area previously believed to have low uranium and radon potential. This instrumentation will support these two projects, and broadly equip researchers at William & Mary and the Virginia Institute of Marine Sciences studying salt marsh development and sedimentation in continental margin environments.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.