Abstract
Length measurement was conducted on ultra low expansion ceramics, NEXCERA™, and synthetic quartz for 13 months. One line scale made of each of the two materials was manufactured and their changes in length were measured using a high-precision line scale calibration system. NEXCERA was used to evaluate its long-term dimensional stability. Synthetic quartz was used to ensure the stability of the long-term measurement including the line scale calibration system and the procedure for the measurement. The long-term stability of the NEXCERA line scale of 550 mm length over 13 month was 4.6 nm (2σ), which was within the estimated measurement error. No significant creep was observed for the NEXCERA line scale.
