Determination of the Avogadro constant by the XRCD method using a²⁸Si-enriched sphere

Abstract

The revision of the SI-the result of three decades of progress in metrology Michael Stock et al

High-Precision Atomic Mass Measurements for Fundamental Constants

“…Also notable was the use of the high axial frequency of 3.5 MHz, which reduces some anharmonic shifts and leads to a lower cyclotron temperature after cyclotron-to-axial coupling. The third is a measurement by the SMILETRAP group [75] using their time-of-flight detection technique to measure the CFRs of H 2 + relative to several charge states of 12 C, but also of 28 Si, 14 N, 20 Ne, and 40 Ar, making use of measurements of these atoms at the 10 −10 level by MIT [41]. The fourth is another measurement by the SMILETRAP group [38], but making use of the Ramsey variant of their TOF method, and measuring H 2 + against D + as a reference.…”

Single‐Electron Pumps and Quantum Current Metrology in the Revised SI

“…[] and references herein) and silicon‐sphere (aka XRCD or Avogadro; see refs. [] and references herein) experiments, which helped to remove inconsistencies that had been revealed in the intermediate CODATA adjustments from 2010 . With respect to future QMT experiments, the new benchmark figures from the latest CODATA adjustment need to be discussed: these impose that significant impact on the Josephson and quantum Hall relations (in the sense of an increase of confidence) now requires closing the QMT with an uncertainty of one part in 10 8 or better.…”

Progress in Reducing the Uncertainty of Measurement of Planck’s Constant in Terms of the Information Approach

“…The noted scientific articles belong to CoP SI ≡ LMТF [32][33][34][35][36][37][38]. The values of absolute and relative uncertainties differ by more than a factor of three.…”