高湿度の計測と標準に関する調査研究

Abstract

The importance of the measurement of high humidity at dew points in excess of 100 C has been increasing in industrial fields such as reliability tests for electronic devices. Although the traceability to primary measurement standards is essential to ensure the reliability of measurement, no primary humidity standard in the dewpoint range above 100 C has been established yet. This article reviews the principles and characteristics of methods that have been developed to generate high humidity at dew-point temperatures below 100 C , in addition to some theoretical aspects and measuring methods of high humidity. It also describes various refinements adopted to primary high-humidity generators in the world and their components for reducing uncertainties. As a result of this inspection, the potential difficulties of high-precision humidity generation in the dew-point range above 100 C with traditional generators are revealed. This article discusses the new techniques of humidity generation and possible improvements applied to some components of generators that may solve those problems and presents a basic conception of a primary humidity generator in order to replace the present one and extend the operating range to dew-point temperatures above 100 C.