Accession Number : AD0430020

Title :   (NO TITLE).

Descriptive Note : Quarterly rept. no. 6, 1 Oct-1 Dec 63.

Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE LAB FOR INSULATION RESEARCH

Report Date : 01 DEC 1963

Pagination or Media Count : 13

Abstract : Crystals of alkaline earth fluorides grown by the Bridgman or to a lesser extent by the pull ing technique are frequently colored (yellow, green, or violet). The coloration can be removed by annealing the colored crystals in a graphite crucible above 1000 C, under a neutral atmosphere such as argon. Absorption spectra of colored alkaline earth fluorides are similar to those obtained by coloration with high-energy quanta or particles. The chemical preparation and purification of lead halides has proven more complicated than expected; the impurities which cause the darkening of crystals are especially elusive. Sulfur seems to be the impurity causing darkening. Dielectric measurements of CaF2, SrF2, and BaF2, are reported. (Author)

Descriptors :   (*DIELECTRICS, HALIDES), (*ALKALINE EARTH COMPOUNDS, DIELECTRICS), (*FLUORIDES, DIELECTRICS), (*LEAD COMPOUNDS, HALIDES), DIELECTRIC PROPERTIES, COLOR CENTERS, IMPURITIES, OXYGEN, SULFUR, CALCIUM COMPOUNDS, STRONTIUM COMPOUNDS, BARIUM COMPOUNDS, PURIFICATION, ZONE MELTING, CRYSTAL GROWTH, PHASE STUDIES, BROMIDES, CHLORIDES, SOLID SOLUTIONS

Distribution Statement : APPROVED FOR PUBLIC RELEASE