Computer-operated quartz differential dilatometer

Abstract

From international symposium on thermal expansion of solids; Lake of the Czarks, Missouri, USA (7 Nov 1973). A quartz differential dilatometer was interfaced with a Digital Equipment Corporation PDP-8 computer to automatically measure the thermal expansion of solids from 300 to 1000 K. A Carson-Dice Electronic-Mechanicai Micrometer, readable to 2.5 x 10/sup -6/ cm, was employed for length-change measurements accurate to 2.5 x 10/sup -5/ cm. Calibrated Pt/Pt/ sub 90/Rh/sub 10/ thermocouples were used to measure temperature changes to plus or minus 0.22 K. The software and hardware necessary to completely automate the measurements are described. Measurements on National Bureau of Standards certified quartz, tungsten, and copper specimens demonstrated an accuracy of plus or minus 1.5% in determination of the coefficient of thermal expansion. (auth