Fitzgerald R, Zimmerman B E, Bergeron D E, Cessna J C, Pibida L, Moreira D S
Physical Measurement Laboratory, National Institute of Standards and Technology (NIST), 100 Bureau Drive, Gaithersburg, MD 20899, USA.
Physical Measurement Laboratory, National Institute of Standards and Technology (NIST), 100 Bureau Drive, Gaithersburg, MD 20899, USA.
Appl Radiat Isot. 2014 Feb;85:77-84. doi: 10.1016/j.apradiso.2013.11.116. Epub 2013 Dec 4.
A new primary standardization of (18)F by NIST is reported. The standard is based on live-timed beta-gamma anticoincidence counting with confirmatory measurements by three other methods: (i) liquid scintillation (LS) counting using CIEMAT/NIST (3)H efficiency tracing; (ii) triple-to-double coincidence ratio (TDCR) counting; and (iii) NaI integral counting and HPGe γ-ray spectrometry. The results are reported as calibration factors for NIST-maintained ionization chambers (including some "dose calibrators"). The LS-based methods reveal evidence for cocktail instability for one LS cocktail. Using an ionization chamber to link this work with previous NIST results, the new value differs from the previous reports by about 4%, but appears to be in good agreement with the key comparison reference value (KCRV) of 2005.
美国国家标准与技术研究院（NIST）报告了一种新的¹⁸F初级标准。该标准基于实时β-γ反符合计数，并通过其他三种方法进行验证测量：（i）使用CIEMAT/NIST³H效率追踪的液体闪烁（LS）计数；（ii）三对双符合比（TDCR）计数；以及（iii）NaI积分计数和HPGeγ射线光谱分析。结果报告为NIST维护的电离室（包括一些“剂量校准仪”）的校准因子。基于LS的方法揭示了一种LS鸡尾酒存在鸡尾酒不稳定性的证据。使用电离室将这项工作与NIST以前的结果联系起来，新值与以前的报告相差约4%，但似乎与2005年的关键比对参考值（KCRV）高度一致。
