| 摘要 |
PURPOSE:To make an accurate calibration possible even for a radiation thermometer having a measuring diameter larger than the target diameter of a radiator by using the magnified virtual image of the radiator for calibration generated by a concave mirror. CONSTITUTION:Black body furnace 10 is arranged with a slight inclination for the center axis of concave mirror 16, and mirror 16 is provided in the light path between standard thermometer 12 and calibrated thermometer 14 which are arranged in both sides of furnace 10. Various conditions of furnace 10 are so set that an isotropic black body radiation can be obtained sufficiently in the solid for all the surface of the concave mirror, and the reflection factor of mirror 16 is enhanced by subjecting the concave sphere of metal or glass to gold plating, and the hollow target part of furnace 10 is placed in the focal distance of mirror 16, and 1 to 10 magnifications can be obtained by adjusting the distance between them. In case of calibration, mirror 16 is rotated to measure the temperature of magnified virtual image 24 in the hollow of furnace 10 by thermometers 12 and 14, thereby calibratting thermometer 14. |
