The international reference system for radioactivity relies on stable instrumentation for comparing primary standards of radioactivity; these instruments enable national metrology institutes to demonstrate the equivalence of their primary standards. The international bureau of weights and measures (BIPM) holds two such instruments for gamma-ray emitting radionuclides, and is working with the POLATOM, LNE/LNHB, NIM, NPL and PTB to develop a new system called the ‘extended international reference system’ (ESIR). The ESIR will address pure beta-particle emitting radionuclides as well as other radionuclides (such as 55 Fe) which cannot be measured in the established international systems. The ESIR will be a liquid scintillation system based on three photon-counting channels operating in coincidence. This article reports the results from validation studies carried out using solutions of 3 H, 55 Fe, 63 Ni and 14 C to assess the reprodu...

中文翻译：

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纯β粒子发射放射性核素的国际参考系统：对结果可重复性的研究

国际放射性参考系统依靠稳定的仪器来比较放射性的主要标准；这些仪器使国家计量机构能够证明其主要标准的等效性。国际度量衡局（BIPM）拥有两种用于伽马射线发射放射性核素的仪器，并且正在与POLATOM，LNE / LNHB，NIM，NPL和PTB合作开发一种称为“扩展的国际参考系统”的新系统。 （ESIR）。ESIR将处理纯β粒子发射放射性核素以及其他在现有国际体系中无法测量的放射性核素（例如55 Fe）。ESIR将是基于三个同时运行的光子计数通道的液体闪烁系统。