ACCURATE LINEAR THERMAL EXPANSION COEFFICIENT DETERMINATION BY INTERFEROMETRY

In precision length measurements the accurate and traceable value of the linear thermal expansion coefficient (LTEC) is needed. A device for interferometric determination of the LTEC of gauge blocks has been constructed. Minimum temperature gradients in a gauge block with 500 mm maximum length and relatively fast operation were the objectives of this project. Based on uncertainty analysis LTEC can be measured with a standard uncertainty of 0,02×10 -6 1/K for 100 mm gauge blocks.