Accession Number : AD0734171

Title :   Phonon Scattering by Isolated Isotopic Impurities in Single Crystals of Helium.

Descriptive Note : Doctoral thesis,

Corporate Author : DUKE UNIV DURHAM N C DEPT OF PHYSICS

Personal Author(s) : Lawson,Dewey Tull

Report Date : NOV 1971

Pagination or Media Count : 156

Abstract : Thermal conductivity measurements of oriented single crystals of hexagonal close-packed He4 have been made in order to study the scattering of phonons by isotopic impurities. Apparatus and techniques have been developed which allow the growth of crystals at preferred orientations: c-axis orientations of 0 and 90 degrees with respect to the direction of heat flow were chosen for this study. Quality and orientation of the sample crystals were determined from the thermal conductivity measurements themselves. (Author)

Descriptors :   (*SOLIDIFIED GASES, THERMAL CONDUCTIVITY), (*PHONONS, SCATTERING), HELIUM, SINGLE CRYSTALS, CRYSTAL GROWTH, CRYOGENICS, IMPURITIES, TEST EQUIPMENT, EXPERIMENTAL DESIGN, THESES

Subject Categories : Solid State Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE