The traceable calibration of an Imaging Luminance Measurement Device (ILMD) requires a detailed characterization as well as an estimation of uncertainty contributions. Both are related to the spatial and angular characteristic, therefore a variable but precisely known positioning of the ILMD in front of a light source is needed. This is realized by extending a photometric bench facility by an articulated industrial robot dedicated for absolute positioning of an ILMD. Emphasis is given to make also the robot cell itself capable for photometric measurements. The working space of the installed system, aspects regarding differences to the common use of such industrial robots, and issues of an ILDM as a tool are discussed.
A radiance camera was used to investigate the radiation field emitted by high-temperature blackbodies and fixed-point cavities up to temperatures of 3000 K. In a first step the applicability of the camera to measure the spectral radiance at such high temperatures was investigated. In a second step the radiation characteristics of several sources were studied using the camera system, in particular, large area fixed-point blackbodies of Cu, Pt–C and ZrC–C. Especially for the ZrC–C fixed points the radiation field at the cavity opening was found to be non-uniform. This observation explains systematic differences in the plateau shape of large aperture eutectic fixed-point cells for radiometers with different fields of view. Using the two-dimensional radiance distribution measured with the camera system the deviation of the temperatures measured with interference filter radiometers and radiation thermometers was studied.
A modular photometric trap detector system has recently been developed at Physikalisch-Technische Bundesanstalt (PTB). All parts of the detector are now completely calibrated. The new planned traceability chain for the realisation of luminous intensity unit can therefore be established for the first time. This contribution shows the results of the individual calibration steps including the associated measurement uncertainties and correlations. A major part of the calibrations along the traceability chain is done at the upgraded measurement setup TULIP (TUnable Lasers In Photometry). The improvements of the TULIP setup are presented and the effects on the measurement uncertainty are shown. The result of the first complete calibration according to the new traceability chain is compared to previous calibration results both in terms of spectral irradiance responsivity and luminous responsivity. The further steps required towards implementing the new traceability chain and the possible implications are discussed.
Main text The metrological equivalence of national measurement standards in the field of photometry and radiometry is determined by a set of key comparisons chosen and organised by the Consultative Committee of Photometry and Radiometry (CCPR) of the Comité international des poids et mesures (CIPM), working closely with the Regional Metrology Organisations (RMOs). In September 2009 the CCPR decided that a second round of the key comparison K3 Luminous Intensity be commenced. The National Research Council of Canada (NRC) was chosen to pilot this comparison. A total of 12 participants were selected from the three RMO group members: EURAMET&COOMET (6: IO-CSIC, LNE-CNAM, METAS, NPL, PTB, VNIIOFI), APMP&AFRIMETS (4: NMISA, NIM, NMIA, NMIJ), and SIM (2: NIST, NRC). The comparison was organised as a star comparison (NMI-Pilot-NMI) using incandescent standard lamps supplied by each NMI (National Metrology Institute) as the travelling comparison artifact. This report describes the comparison organisation (Section 2), the measurement methods and uncertainties achieved at all the participants and at the pilot (Sections 3 and 4), and the method for analysis and the results of the comparison according to this method (Section 4). It includes a comparison of the results of this comparison with the 1999 first round key comparison (Section 5). Section 6 presents a summary of the comparison. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/. The final report has been peer-reviewed and approved for publication by the CCPR, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
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