We present an experimental realization of differential spectral responsivity measurement by using a light-emitting diode (LED)-based integrating sphere source. The spectral irradiance responsivity is measured by a Lambertian-like radiation field with a diameter of 40 mm at the peak wavelengths of the 35 selectable LEDs covering a range from 280 to 1550 nm. The systematic errors and uncertainties due to lock-in detection, spatial irradiance distribution, and reflection from the test detector are experimentally corrected or considered. In addition, we implemented a numerical procedure to correct the error due to the broad spectral bandwidth of the LEDs. The overall uncertainty of the DSR measurement is evaluated to be 2.2% (k = 2) for Si detectors. To demonstrate its application, we present the measurement results of two Si photovoltaic detectors at different bias irradiance levels up to 120 mW/cm(2).
The thermoelectric inhomogeneity as a function of position along wires is one the significant uncertainty of measurement using thermocouples. Here we report development of an electrical annealing system for thermoelectric inhomogeneity treatment. Two inhomogeneous type-S thermocouples, which had the inhomogeneity greater than 0.04%emf, are successfully recovered using the system. An improvement on thermocouple performance as large as 0.28 °C (at temperature of 1000 °C) can be obtained using the system. This article provides detailed information and may help the reader to obtain a quick grasp about the system.
This paper explainsan enthalpy uncertainty ofnatural gas energy measurement (custody transfer) using orifice meter in non adiabatic condition. The method of uncertainty analysis used in this paper was developed based on theuncertainty analysis of natural gas flow measurement using orifice meter at adiabatic condition based on AGA 3, 1992 (which reference by No 10.). In addition of non adiabatic condition includes: critical pressure, critical temperature, realtime pressure, realtime temperature and generalized correlation constanta. The measurement of enthalpy uncertaintyis referring to the Guide to the Eexpression of Uncertainty Measurementof the Guide in MetrologyWorking Group 1 of Joint Committee for Guide In Metrology, 2011. Based on the energy flow in orifice meter is 1000 Mmbtud, The combined uncertainty of f enthalpy is 3.86 x 10-7 Mmbtud (3.86 x 10-8 %) while the expandeduncertainty analysis results 7.73 x 10-7 Mmbtud (7.73 x 10-8 %)with confidence level 95%. This number of uncertaintyis smaller than the Measurement Permissive Error specified by legal metrology organization 0.1667%.
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