Medium Temperature Blackbody Source, 30 °C to 550 °C E >0.995 Cavity 65 x 160mm

• 30°C to 550°C
• Emissivity > 0.995 Cavity 65 x 160mm
• Controller Resolution 0.1°C

The Gemini R comprises a blackbody with which radiation pyrometers (infrared thermometers) can be calibrated.

The temperature of the cavity can be set to ±0.1°C over the temperature range 30°C to 550°C. The temperature of the furnace is set on a controller, whilst an independent indicator, whose sensor fits into the cavity, indicates the actual radiance temperature. The sensor can be removed for external calibration or the complete system can be calibrated.

The cavity temperature reaches 550°C approximately 45 minutes from switch on. The variation seen on the controller's temperature indication over a 5 minute period was ±0.2°C. Similar variations were detected by a radiation thermometer looking into the cavity. Using a portable radiation thermometer having a target diameter of 13mm, the 65mm target was surveyed. Maximum temperature differences of ±1°C were found for set temperatures in the range 100°C to 500°C. Temperatures along the inner 100mm of the 160mm long cavity were measured at 400°C and 500°C, using a hand held fibre-optic radiation probe. Maximum temperature differences of ±4°C were found. The temperature, as shown on the controller, agrees with the cavity temperature as measured by a radiation thermometer, where calibration is traceable to National Standards, to within ±2°C.

Traceability may be established with a UKAS certificate for the in-built indicator and supplied probe (935- 14-72).