Crystallite Size Measurements on Thoria Gel

As part of a detailed study of the sintering behavior of thoria gel, the crystallite size distribution in the gel was measured by electron microscopy. The distribution is in quantitative agreement with BET surface area and X‐ray crystallite size measurement, and X‐ray diffraction line profiles calculated using the measured size distribution agree with experiment. The relative accuracies of the integral and half‐maximum intensity breadth techniques, and the relation between the size distribution and the crystallite size measured by each technique are discussed. Some implications of this work to the sintering study are mentioned.