Over forty years ago, Thornton designed and manufactured the original analog resistivity meters for high purity water. Thornton later pioneered microprocessor-based resistivity instrumentation with the first computed high purity temperature compensation in this new, demanding and innovative industry. Over the years, Thornton has become the resistivity measurement standard in the semiconductor manufacturing industry. Thornton instruments are specified in the majority of semiconductor manufacturing facilities worldwide to monitor and control ultrapure water systems. Thornton has intimate knowledge of critical measurements needed for ultrapure water production. Our expansive measurement capabilities mean Thornton products are used throughout a plant’s complete water cycle in areas such as wafer processing tools, recycle/reclaim, waste treatment and various facility operations. Today Thornton continues to provide innovative solutions, offering expanded measurement capabilities and a greater array of products to meet global microelectronics industry requirements. As part of the Mettler-Toledo Process Analytics Group, Thornton has gained worldclass technology in the areas of pH, ORP, dissolved oxygen and ozone measurement.