Isotech Slim Fixed Point Cells are primary temperature standards used to realize the International Temperature Scale of 1990 (ITS-90) at the water triple point—one of the most fundamental fixed points in thermometry. At precisely 0.01°C, the triple point of water provides the defining reference for calibrating Standard Platinum Resistance Thermometers (SPRTs) and other precision temperature sensors.

The cells are available in two construction types: quartz-clad for the highest purity and stability, and metal-clad for enhanced durability in industrial calibration environments. Both types contain water with 99.9999% (6N) purity, hermetically sealed to maintain long-term stability. Measurement uncertainty is rated at ±0.5mk for standard cells and ±0.1mk for premium-grade cells, making them suitable for national metrology institutes, accredited calibration laboratories, and precision thermometer manufacturing.

These slim-format cells are compatible with Isotech maintenance baths and fixed point apparatus, allowing straightforward realization of the water triple point for thermometer calibration at the highest level of accuracy. Each cell is supplied with an individual calibration certificate traceable to national standards.

Features

• ITS-90 defining fixed point: water triple point at 0.01°C
• Purity: 99.9999% (6N) water fill
• Uncertainty: ±0.5mk (standard) or ±0.1mk (premium)
• Construction options: quartz-clad or metal-clad
• Slim format — compatible with Isotech baths and fixed point apparatus
• Hermetically sealed for long-term stability
• Individual calibration certificate traceable to national standards
• Applications: SPRT calibration, ITS-90 realization, primary lab standards