Isotech Fixed Point Cells – Sealed and Open

Isotech Fixed Point Cells are designed for the highest possible accuracy in temperature calibration, for both primary and secondary laboratories. These cells enable the liquid-solid phase transitions of pure metals to be achieved, providing a stable reference temperature in accordance with the ITS-90 (International Temperature Scale of 1990). Isotech offers both sealed and open fixed point cells, each with specific advantages. The sealed cells offer protection against contamination and external pressure changes, while the open cells offer flexibility for pressure settings and gas flow control.

Ultra-pure metals and minimal uncertainties

The cells contain metals with a purity of >99.9999% (6N), guaranteeing an extremely stable melting and freezing curve. Thanks to advanced production techniques and more than 40 years of experience in metrological standardisation, these cells are among the most accurate on the market. Depending on the calibration requirement, there are two UKAS-certified calibration levels:

• > Premium Calibration Service: Realisation of three melting plateaus, three freezing plateaus and two interlaboratory comparisons. Minimum uncertainties from ±0,07mK bij 0,01°C at ±2mK bij 961,78°C.
• > Standard Calibration Service: A single melting, freezing and interlaboratory comparison with uncertainties from ±1mK to ±10mK, suitable for most secondary laboratories.

Available Temperature Points and Uncertainties

The following fixed points are available for sealed and open configurations:

Other fixed points, such as lead and antimony, are available on request.

Different Designs: Sealed and Open Cells

Isotech Fixed Point Cells are available in four variants, depending on the application and conditions of use:

Sealed Cells – Metal or Quartz Housing

These cells are permanently sealed with 6N pure argon at the freezing/melting temperature, which protects them from contamination and pressure fluctuations. This keeps them stable and easy to transport without having to be reset.

• > Sealed Metal Clad: Extra robust and resistant to mechanical impact.
• > Sealed Quartz Clad: Optimal thermal stability with minimal interference.
  Resealable and Open Cells.

Resealable and Open Cells

For laboratories that want more control over pressure and gas flows, Isotech also offers open and reopenable configurations.

• > Resealable Metal Clad: Allows manual adjustment of internal pressure via a vacuum and gas flow system.
• > Open Quartz Clad: Can be disassembled for in-depth examination and validation of thermometers.

Physical Specifications

Cells are supplied with a carrying case, heat conductors and reflectors, and comply with CCT/2000-13 international guidelines.

Applications

Isotech Fixed Point Cells are used worldwide in primary and secondary calibration laboratories, national measurement institutes and research centres. Some applications are:

• > Calibration of standard platinum resistance thermometers (SPRTs) and industrial PRTs
• > Phase transition analysis of ultra-pure metals
• > Laboratory ring comparisons and accreditation audits
• > Validation of temperature sensors in the aerospace, medical and semiconductor industries
• > Automatic calibration cycles for continuous temperature standardisation

Isotech Fixed Point Cells offer unrivalled stability, accuracy and reliability for ITS-90 Fixed Point calibrations. Their high metrological performance and robustness make them the perfect choice for laboratories that require the highest standard in temperature calibration.