Thermal stabilization for accurate dimensional measurement using gallium

Abstract

A new method of thermal stabilization that uses gallium as an isothermal heat exchanger is presented. Gallium maintains a fixed temperature near 29 degreesC when it melts, and the resultant temperature sustains extremely good stability against ambient change of temperature and pressure. This thermo-physical property allows gallium to be utilized as an isothermal medium that is capable of performing precise thermal stabilization at near room temperature without intensive care on temperature sensing and heat control. In this investigation, an isothermal gallium chamber is designed and an ultraprecision level of temperature stabilization to +/-1 mK is demonstrated with the aid of Fabry-Perot interferometry. (C) 2004 Elsevier Ltd. All rights reserved.