Accession Number : AD0759552

Title :   An Apparatus for Measuring Thermal Conductivities to 2 degrees K. Measurements in Single Crystal Halides as a Function of Dislocation Density.

Descriptive Note : Technical rept. Nov 68-Mar 71,

Corporate Author : AIR FORCE MATERIALS LAB WRIGHT-PATTERSON AFB OHIO

Personal Author(s) : Haury,George L.

Report Date : DEC 1972

Pagination or Media Count : 36

Abstract : A thermal conductivity apparatus was constructed and used to measure the thermal conductivity of a single crystal of sodium chloride as a function of dislocation density, N. The temperature range of the measurements was 2.5 to 40K. The temperatures were measured with gold (.02 atomic % iron) vs. chromel thermocouples, and germanium resistance thermometers. A well defined maximum was observed in the thermal conductivity at around 10K, the value of which was three times greater in an annealed crystal (minimum number of dislocations) than it was in the unannealed crystal. A relationship of K = 0.049(T to the 2.7 power)/(N to the 0.8 power) was observed between T equal to 7 and 2K for the thermal conductivity vs. temperature. (Author)

Descriptors :   (*THERMOMETERS, CRYOGENICS), (*THERMAL CONDUCTIVITY, CRYOGENICS), CALIBRATION, SINGLE CRYSTALS, DISLOCATIONS, SODIUM CHLORIDE, MEASUREMENT

Subject Categories : Test Facilities, Equipment and Methods

Distribution Statement : APPROVED FOR PUBLIC RELEASE