Accession Number : AD0631382

Title :   X-RAY DIFFRACTION STUDIES OF THERMAL MOTIONS IN CRYSTALS.

Descriptive Note : Quarterly progress rept. no. 26, 1 Sep-31 Dec 65,

Corporate Author : GEORGIA INST OF TECH ATLANTA ENGINEERING EXPERIMENT STATION

Personal Author(s) : Young,R. A.

Report Date : 11 MAR 1966

Pagination or Media Count : 6

Abstract : Measurements were made on germanium and silicon samples to determine the temperature dependence of X-ray diffracted intensity without changing the temperature. The expected results were calculated by the method of Demarco and Weiss (Acta Cryst. 19:68 (1965)); to eliminate uncertainties in the measurements of incident intensity, the results for each crystal were normalized to the predicted value at one point. The measurements on silicon demonstrate a much larger variation from the predictions than do those of germanium. The 777 of germanium continues to show an anomaly relative to the other hhh planes but that this anomaly is not present in the silicon measurements. This method of measurement does not show a significant difference due to variations in dislocation density. Three of the silicon samples which were measured are to be submitted for fast neutron radiation damage. Sample no. 5 will be exposed to determine the damage versus integrated flux with x-ray integrated intensity measurements being made periodically during the exposure. It appears probable that the total exposure may be about 5 x 10 to the 21st power nvt. The two larger ('monochromator') crystals will eventually be exposed to a degree dependent on the results of the no. 5 sample.

Descriptors :   (*CRYSTALS, *X RAY DIFFRACTION), (*THERMAL STRESSES, CRYSTALS), SILICON, GERMANIUM, TEMPERATURE, CRYSTAL DEFECTS, CRYSTAL STRUCTURE

Subject Categories : Physical Chemistry
      Crystallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE