O'Brien Michelle, Bueermann Ludwig
National Institute of Standards and Technology, Gaithersburg, MD 20899.
Physikalisch-Technische Bundesanstalt, Braunschweig, Germany.
J Res Natl Inst Stand Technol. 2009 Dec 1;114(6):321-31. doi: 10.6028/jres.114.023. Print 2009 Nov-Dec.
A comparison has been made of the air-kerma standards for low-energy x rays at the National Institute of Standards and Technology (NIST) and the Physikalisch-Technische Bundesanstalt (PTB). The comparison involved a series of measurements at the PTB and the NIST using the air-kerma standards and two NIST reference-class transfer ionization chamber standards. Results are presented for the reference radiation beam qualities in the range from 25 kV to 50 kV for low energy x rays, including the techniques used for mammography dose traceability. The tungsten generated reference radiation qualities, between 25 kV and 50 kV used for this comparison, are new to NIST; therefore this comparison will serve as the preliminary comparison for NIST and a verification of the primary standard correction factors. The mammography comparison will repeat two previously unpublished comparisons between PTB and NIST. The results show the standards to be in reasonable agreement within the standard uncertainty of the comparison of about 0.4 %.
已对美国国家标准与技术研究院（NIST）和德国物理技术研究院（PTB）的低能X射线空气比释动能标准进行了比较。该比较涉及在PTB和NIST使用空气比释动能标准以及两个NIST参考级传递电离室标准进行的一系列测量。给出了低能X射线在25 kV至50 kV范围内参考辐射束质的结果，包括用于乳腺摄影剂量溯源的技术。用于此次比较的25 kV至50 kV之间的钨产生的参考辐射质对NIST来说是新的；因此，此次比较将作为NIST的初步比较以及对初级标准校正因子的验证。乳腺摄影比较将重复PTB和NIST之间之前两次未发表的比较。结果表明，在约0.4%的比较标准不确定度范围内，这些标准具有合理的一致性。
