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Absolute temperature radiation thermometer

Low uncertainty, high temperature measurement

Introduction of high temperature reference standards opens the door to low cost radiation thermometers for establishing a traceable temperature scale above 1000 °C. The Absolute Temperature-Kelvin (AT-K) radiation thermometer provides a stable base for calibration using high temperature fixed-points from 1000 °C to 2750 °C.

Key features:

  • The optics are mounted to a precision machined titanium framework.
  • Aluminium lens tubes hold the optics so that the thermal expansion is balanced to give a fixed optical path from the field stop to the Lyot stop that defines the aperture of the instrument.
  • The field stop which defines the measurement spot is low thermal expansion molybdenum.
  • Temperature sensitive components are thermally stabilised.
  • The detector is an 18 mm by 18 mm silicon photodiode with only the central 10 mm diameter used as this improves stability and linearity.
  • The amplifier is NPL designed and manufactured specifically for the detector and is based on a high quality op-amp and stable resistor pack.

High temperature blackbody sources: 1153°C to 2748°C

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