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

该项目为岩石和矿物等地质物质的40Ar/39Ar定年提供了一种新的质谱仪。该仪器将用于提供地球及其生物群（包括人类）进化的基本时间限制。在其他应用中，需要解决的具体主题包括气候变化的速度和历史，这需要评估人为影响的程度；地质记录显示了大规模物种灭绝的原因；以及火山活动的时间尺度，这对评估火山危害至关重要。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下一代40Ar/39Ar地质年代学家的重要培训基地，他们将受益于使用最现代仪器的经验。新仪器以多收集器、高灵敏度、高分辨率功能取代了过时和失效的质谱仪，有助于提高40Ar/39Ar日期的精度和准确性。多收集特性使吞吐量提高了5倍。该仪器采用新颖的电容放电离子束检测，能够使用高度稳定的法拉第集热器，从而降低了离子计数倍增器间校准所牺牲的精度和准确性。离子氩束是由一种新型阴极源产生的，其工作温度比传统的灯丝源低得多，具有更高的灵敏度和更长的源寿命。新仪器将配备一条高度灵活的全自动提取线，配备双样品室，以提高通量，并配备参考气藏，以监测质量判别和灵敏度。该奖项反映了美国国家科学基金会的法定使命，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.