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

这笔赠款将支持在威廉玛丽地质系和环境科学计划的教师研究和本科生培训的两个高分辨率伽马光谱仪的收购。 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、钾和镭的同位素中自然产生的伽马放射性核素，沿着核燃料和武器过程产生的空气、土壤和沉积物中的铯和钚的人工同位素。 重要的是，这些仪器将使我们能够确定沉积层的日期，从而有助于重建区域污染历史，更好地了解北极气候变化。由于伽马光谱法的样品制备简单，仪器具有长期稳定性，光谱仪将用于支持本科生研究培训，增加本科生课程和实验室练习，并将为托马斯纳尔逊社区学院的教师和学生提供教育推广机会，收购的伽马光谱仪将通过提供以下服务，支持WilliamMary和弗吉尼亚海洋科学研究所正在进行的广泛研究项目&环境样品中放射性核素浓度的精确超痕量测量。 仪器的设计允许选择性地分析一个单一的样品从相对的两侧使用两个检测器和定时测量记录重合和反重合脉冲，配置，这将能够大大提高宇宙成因22钠和沉积物芯研究所需的小样品质量的放射性核素测量的检测极限。威廉玛丽现有研究的一个主要目标是在格陵兰岛，挪威，斯瓦尔巴特群岛和法罗群岛的湖泊沉积物岩心中生成更新世和全新世过去气候变化的高分辨率重建。第二个项目将得到此次设备采购的支持，旨在更好地了解大西洋沿海平原的氡源，该地区以前被认为具有低铀和氡潜力。 该仪器将支持这两个项目，并广泛装备研究人员在威廉玛丽和弗吉尼亚海洋科学研究所研究盐沼的发展和沉积在大陆边缘环境。这一奖项反映了NSF的法定使命，并已被认为是值得通过评估使用基金会的智力价值和更广泛的影响审查标准的支持。

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.