Acquisition of a multicollector mass spectrometer for 40Ar/39Ar geochronology

该项目为岩石、矿物等地质材料的40 Ar/39 Ar定年提供了一种新的质谱计。这一工具将用于提供地球及其生物群（包括人类）演变的基本时间限制。除其他应用外，要处理的具体专题包括气候变化的克里思和历史，这是评估人为影响程度所必需的;地质记录中显示的大规模喷发的原因;以及火山活动的时间尺度，这对评估火山灾害至关重要。该仪器将被学生广泛使用，他们将获得宝贵的实践经验，以促进维持STEM教育管道。伯克利地质年代学中心实验室是培养下一代40 Ar/39 Ar地质年代学家的重要基地，他们将受益于使用最现代化仪器的经验。新仪器取代了过时和失败的质谱仪，具有多收集器，高灵敏度，高分辨率的功能，有助于提高40 Ar/39 Ar年代的精度和准确性。多收集功能使吞吐量增加了五倍。该仪器采用新型的电容放电离子束检测，使高度稳定的法拉第收集器的使用，从而降低了精度和准确度的离子计数倍增器的相互校准牺牲。离子Ar束是由一种新型的阴极源，其工作温度大大低于传统的灯丝源，使更高的灵敏度和更长的源寿命。新仪器将与高度灵活的全自动提取线配合使用，该提取线带有双样品室，以利用增加的吞吐量，并带有参考气体储层，以监测质量鉴别和灵敏度。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This project provides a new mass spectrometer for 40Ar/39Ar dating of geologic materials such as rocks and minerals. This instrument will be used to provide fundamental time constraints on the evolution of Earth and its biota, including humans. Among other applications, specific topics to be addressed include the tempo and history of climate change, which is needed to evaluate the extent of anthropogenic effects; the causes of mass extinctions manifest in the geologic record; and the timescales of volcanism, which is critical to evaluating volcanic hazards. The instrument will be extensively used by students who will gain invaluable hands-on experience in furtherance of sustaining the STEM educational pipeline. The Berkeley Geochronology Center laboratory is an important training ground for the next generations of 40Ar/39Ar geochronologists, who will benefit from experience using the most modern available instrument.The new instrument replaces obsolete and failing mass spectrometers with multi-collector, high sensitivity, high resolution capabilities which serve to improve the precision and accuracy of 40Ar/39Ar dates. The multicollection feature enables a five-fold increase in throughput. The instrument uses novel capacitive discharge ion beam detection, enabling the use of highly stable Faraday collectors, thus reducing the precision and accuracy sacrificed by the intercalibration of ion-counting multipliers. The ion Ar beam is produced by a novel cathode source that operates at substantially lower temperatures than conventional filament sources, enabling higher sensitivity and greater source lifetime. The new instrument will be mated to a highly flexible, fully automated extraction line with dual sample chambers to exploit the increased throughput, and reference gas reservoirs to monitor mass discrimination and sensitivity.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.