Momentum ratios of some of the more intense internal conversion lines from sources of thorium radioactive deposit have been determined with accuracies of 1 to 4 parts in 105 using an iron-free β spectrometer. Accurate absolute values of the momenta were obtained from intercomparisons of these line momenta with that of the K-412 internal conversion line in 198Hg. The X-ray self-calibration method of Siegbahn is discussed in some detail and is shown to be less accurate at this time. The results are analyzed on both the 1955 and 1963 least-squares adjusted values of the fundamental constants.
A Vision-Based Self-Calibration Method for Robotic Visual Inspection Systems