Description
The eXacal precision thermometers are used for precise temperature measurements or as calibration standards.
NEW design: gas-tight handle with inert gas filling
Temperature range: -200 °C to 250 °C
small measurement uncertainties: 11 mK to 13 mK
robust alternative to ITS-90 standard thermometers
high stability and good calibration capability
low hysteresis and drift through inert gas
New design: gas-tight handle with inert gas filling
The new design of the gas-tight handle allows the thermometer’s protection tube to be filled with a protective gas. This improves the properties of the thermometer and ensures less drift and hysteresis at the extremely low temperatures down to the argon point (-189 °C).
Calibration
eXacal thermometers are calibrated in our own DAkkS calibration laboratory. The DAkkS accreditation ensures that all calibrations are traceable to national and international standards.
The precision thermometers have been designed so that they can be calibrated very well at temperature fixed points up to the argon triple point. However, calibration can also be done by using the comparison method. Small measurement uncertainties are achieved with the temperature fixed points used. A comparison calibration is done by with ITS-90 standard thermometers as calibration standards in calibration baths and calibration furnaces. The measurement uncertainty is calculated from many components. The largest component are reproducibility, ITS-90 characteristic, selfheating an hysteresis.
Measurement uncertainties
Small measurement uncertainties with DAkkS calibration certificate
Temperature fixed points from argon triple point -189,3442 °C to tin melting point 231,928 °C
ITS-90 Standard thermometer during comparison calibration
| Temperature range | Method | Measurement uncertainty |
|---|---|---|
| -189,3442 °C – 0,01 °C | Argon to water | 12 mK |
| -38,8344 °C – 0,01 °C | Mercury to water | 10 mK |
| 0,01 °C – 29,7646 °C | Water to gallium | 12 mK |
| 0,01 °C – 156,5985 °C | Water to indium | 11 mK |
| 0,01 °C – 231,928 °C | Water to tin | 11 mK |
