This paper mainly discusses the measuring and traceable methods of spectral irradiance and ultraviolet irradiance in
order to advance the accuracy of the two quantities. The contents include: 1.The working principal of the primary
standard apparatus of spectral irradiance and spectral radiance and the value transferring methods of spectral irradiance.
2. The traceable methods of ultraviolet irradiance to spectral irradiance primary standard apparatus. 3. Introduce the
international comparison of spectral irradiance and the comparison of irradiance responsivity of UV detectors. 4. The
influence factors that decrees measuring accuracy of UV radiometer and the capability evaluated methods. We put forward a fitting function of spectral irradiance of standard lamp and an optimizing method for parameters. The relative deviation of the fitting function is acceptable comparing to the uncertainty of national primary standard of spectral irradiance lamp. We also defined evaluated capabilities of UV radiometers to reflect the instrument condition and promote measuring accuracy.
The widely use of UV radiation led to the demand for improved understanding of the properties of instrumentation
used to measure this radiation. The UV radiometers are mainly influenced by the factors as operating conditions,
environmental conditions and the UV sources to be calibrated and measured. In addition, large errors can occur due to
out-of-band, non-linear, and non-ideal cosine or spatial response of the UV meters. Through a new designed
measurement system for cosine response property, we do some measuring experiments to 21 kinds of UV radiometers
and calculate the relative deviation of each UV meters. The cosine errors are existed universally. It is recommended that
keeping the UV source closing to a point source and perpendicular to UV detector when it is measured is very important.
We also design and fulfill an experimental system to reflect the measuring errors of UV radiometers when measuring
sources and calibrated sources are mismatched. The results show that if the measurement is of a broadband source, it is
wise to unify the measuring and calibrated source or the two sources have similar spectral distribution. If that is not
possible, we can calculate the spectral mismatch correction factor and spectral matching characteristic factor to correct
the measuring data. All the works above are to let the users in appropriate usage of UV Radiometers in a standardized
and comparable way and make the measurement quantities more accurate.
KEYWORDS: Black bodies, Temperature metrology, Metrology, Radiometry, Ultraviolet radiation, Pyrometry, Lamps, Calibration, Sensors, Standards development
High temperature blackbody BB3500M is used as the primary standard of spectral irradiance at the National Institute of Metrology (NIM). In order to find out whether BB3500M is suitable or not in the realization of the spectral irradiance
scale, we investigated the temperature property of blackbody. On the other hand, a full description of the property of BB3500M can help us to evaluate the uncertainty due to BB3500M. In the experiment, feedback control mode was used to guarantee the temperature stability during the whole process. We measured the temperature drift in an hour, which is needed in transferring the spectral value to the standard lamp. Results show that the temperature change is less than 0.6
K when the temperature is near 3020 K. Also, we measured the uniformity of the bottom of the radiator of BB3500M,
the result showed that the non-uniformity is less than 0.5 K in the effective area around 2870 K.
The aim of this paper is to promote the accuracy of the quantity for spectral irradiance of standard lamps at transferring,
optimize the calibration uncertainty of ultraviolet irradiance, analyze and solve the problem which will effect the
measuring course of ultraviolet irradiance, and provide reliable calibration standard for application areas. The main
contents include: 1. Put forward a new three segment fitting function of spectral irradiance of standard lamp and an
optimizing method for non-linear parameter. Compare relative errors of different curve fitting methods by a new
successive error analysis method. The relative deviation of the new curve fitting function is: 0.27% between 250nm and
2500nm which is acceptable comparing to the uncertainty of national primary standard of spectral irradiance lamp. 2.
Through a new designed measurement system for cosine response property of UV radiometers, we do some measuring
experiments to 21 kinds of UV radiometers and calculate the relative deviation of each UV meters. By measuring
experiments we can understand the cosine response property of UV radiometers exactly and do cosine compensation
accordingly. 3. Design and fulfill an experimental system to reflect the measuring errors of UV radiometers when
measuring sources and calibrated sources are mismatched. Calculate the spectral mismatch correction factor and spectral
matching characteristic factor to modify the measuring data.
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