Long Term Drift of Radiation Thermometers Due to Interference Filters
The long term stability of a radiation thermometer is critical when it is calibrated in terms of its output signal for the realisation or approximation of ITS-90 above or below the silver point respectively. Very large drifts have been observed in several radiation thermometers at NMC due to abnormal deterioration of interference filters. The measurement results (in terms of thermometer fixed point output signal, relative spectral responsivity and filter transmittance),collected over a period of 16 years indicate that the abnormal deterioration is likely to be caused by high environmental humidity in Singapore. This is further confirmed by monitoring the stability of a new interference filter, which has been always kept in a dryer cabinet, over a 7 year period. It concludes that the interference filters with hard and durable coatings are essential for stable radiation thermometers especially in tropical countries.
Metrology Long term drift Radiation thermometer Relative spectral responsivity Effective wavelength Interference filter Transmittance Central wavelength
Wang Li
National Metrology Centre, Singapore
国际会议
2008年国际温度与热物性测量会议(TEMP BEIJING 2008)
北京
英文
188-193
2008-10-20（万方平台首次上网日期，不代表论文的发表时间）