Fitzgerald Ryan P, Alpert Bradley K, Becker Daniel T, Bergeron Denis E, Essex Richard M, Morgan Kelsey, Nour Svetlana, O'Neil Galen, Schmidt Dan R, Shaw Gordon A, Swetz Daniel, Verkouteren R Michael, Yan Daikang
National Institute of Standards and Technology, Gaithersburg, MD 20899, USA.
National Institute of Standards and Technology, Boulder, CO 80305, USA.
J Res Natl Inst Stand Technol. 2022 Feb 24;126:126048. doi: 10.6028/jres.126.048. eCollection 2021.
We present a new paradigm for the primary standardization of radionuclide activity per mass of solution (Bq/g). Two key enabling capabilities are 4π decay-energy spectrometry using chip-scale sub-Kelvin microcalorimeters and direct realization of mass by gravimetric inkjet dispensing using an electrostatic force balance. In contrast to traditional traceability, which typically relies on chemical separation of single-radionuclide samples, 4π integral counting, and additional spectrometry methods to verify purity, the system described here has both 4π counting efficiency and spectroscopic resolution sufficient to identify multiple radionuclides in the same sample at once. This enables primary standardization of activity concentrations of mixed-radionuclide samples. A major benefit of this capability, beyond metrology, is in assay of environmental and forensics samples, for which the quantification of multiplenuclide samples can be achieved where presently inhibited by interferences. This can be achieved without the need for chemical separations or efficiency tracers, thereby vastly reducing time, radioactive waste, and resulting measurement uncertainty.
我们提出了一种用于每单位质量溶液中放射性核素活度（Bq/g）一级标准化的新范例。两项关键的赋能能力是使用芯片级亚开尔文微热量计进行4π衰变能谱测定，以及通过使用静电力平衡的重力喷墨分配直接实现质量测定。与传统的溯源方法不同，传统方法通常依赖于单放射性核素样品的化学分离、4π积分计数以及用于验证纯度的其他能谱方法，这里描述的系统具有足够的4π计数效率和光谱分辨率，能够一次识别同一样品中的多种放射性核素。这使得混合放射性核素样品的活度浓度一级标准化成为可能。这种能力除了在计量学方面的主要优势外，还体现在环境和法医样品的分析中，对于这些样品，目前由于干扰而无法实现的多核素样品定量测定可以得以实现。这可以在无需化学分离或效率示踪剂的情况下实现，从而极大地减少时间、放射性废物以及由此产生的测量不确定度。
