Reflectance of diffusing materials

Project Description

The facilities of the PTB for the calibration of reflection standards are used to provide the partner NMIs with absolutely calibrated transfer standards traceable to the absolute scale of the radiance factor for standardized geometries at the PTB.In 2003, no calibration of one of these reflection standards has been carried out at the PTB. For reflection measurements in practice, reference standards with known properties are needed.

Therefore it is intended to maintain facilities for absolute calibration of diffuse reflectance standards at PTB only and to provide NPL with reference standards for practial measurements. NPL will then use the diffuse reflectance standards for its disseminated scales.


Progress Report of 12.01.2016

The facilities of PTB for the calibration of diffuse reflection standards are used to provide the partner NMIs with absolute calibrated transfer standards traceable to the scale of the spectral radiance factor in standardized geometries. These are the so-called hemispherical-directional and bi-directional geometries. For diffuse reflection measurements in practice as done in industry, such reference standards with known properties are needed.

The final report for the CCPR-K5: "Key-Comparison of Spectral Diffuse Reflectance" was approved on September 9, 2013.

The EURAMET PR-K5: Key-Comparison of Spectral Diffuse Reflectance is piloted by MKEH of Hungary. In 2013 a Draft A3 version was handled, the Draft B version was not provided yet.

In the European Research project “xD-Reflect” financed under EMRP a major part of the measurements have been performed and first results were published. The current status and results may be found under http://www.xdreflect.eu.


Progress Report of 25.03.2014

The facilities of PTB for the calibration of diffuse reflection standards are used to provide the partner NMIs with absolute calibrated transfer standards traceable to the scale of the spectral radiance factor in standardized geometries. These are the so-called hemispherical-directional and bi-directional geometries. For diffuse reflection measurements in practice as done in industry, such reference standards with known properties are needed.

For the CCPR-K5: "Key-Comparison of Spectral Diffuse Reflectance" the final report was approved last year on September 9, 2013. This report is available from the BIPM web page under: http://kcdb.bipm.org/mwg-internal/de5fs23hu73ds/progress?id=Rkw1zRaiw3.

This circumstance is the basis for the preparation of a Draft B version for the EURAMET PR-K5: Key-Comparison of Spectral Diffuse Reflectance piloted by MKEH of Hungary. In 2013 a Draft A3 version was already handled. Besides MKEH as the pilot, PTB serves in this comparison as an additional link laboratory to the CCPR-K5 comparison.

Within the EMRP (European Metrology Research Program) of the European Commission a project with the title "Multidimensional Reflectometry for Industry", short name xD-Reflect was successfully sought by 7 European NMIs (FR, DE, IT, CZ, SE, FI, SP). This project started in September 2013. PTB serves here as the leader of the work package "Goniochromatism". Within this package an important task is the improvement of the traceability for standard goniometric geometries. For this purpose a round robin comparison of the involved institutes started in March 2014, measuring grey scale and coloured diffuse reflection standards, in the goniometric geometries of 0:45 and 45:0.


Progress Report of 20.03.2014

The facilities of the PTB for the calibration of diffuse reflection standards are used to provide the partner NMIs with absolutely calibrated transfer standards traceable to the absolute scale of the radiance factor for standardized geometries at the PTB. This are hemispherical/directed and directed/directed geometries. For reflection measurements in practice, reference standards with known properties are needed.
For the CCPR-K5 : Key-Comparison of Spectral Diffuse Reflectance in the last year a Draft B was approved. This circumstance is the basis in order to prepare a Draft A version for the EURAMET PR-K5: Key-Comparison of Spectral Diffuse Reflectance piloted by MKEH of Hungary. Besides MKEH as the pilot, PTB serves here as an additional link laboratory to the CCPR-K5 comparison.
Within the EMRP (European Metrology Research Program) of the European Commission a project with the title “Multidimensional Reflectometry for Industry” was successfully sought by 7 European NMI´s (FR, DE, IT, CZ, SE, FI, SP). PTB will serve as work package leader for a partial aspect named “Goniochromatism”. Within this package it is planned to implement a task dealing with the improvement of the traceability for standard goniometric geometries. For this purpose a round robin comparison of reflection standards in such goniometric geometries will be performed.    


Progress Report of 09.02.2012

The facilities of the PTB for the calibration of diffuse reflection standards are used to provide the partner NMIs with absolutely calibrated transfer standards traceable to the absolute scale of the radiance factor for standardized geometries at the PTB. This are hemispherical/directed and directed/directed geometries. For reflection measurements in practice, reference standards with known properties are needed. PTB and Aalto (formerly MIKES-TKK) Finland have performed a bilateral comparison of their diffuse reflection scales in 2008. The results of this comparison are published in Applied Optics, Vol. 48, No. 15, p. 2946-2956 (2009).

PTB performed measurements on the three-dimensional appearance characterisation of diffuse standard reflection materials with their robot-based gonioreflectometer. Within this investigation, different widely used diffuse reflection materials, were measured for the first time in multi-geometry configurations in order to characterise their angle-resolved reflection behaviour. For a set of four distinct incident angles the full hemispherical reflection indicatrix was determined. The results are published in Metrologia 47, p. 295-304 (2010). The data will be available shortly as animated graphics via the PTB internet presence.

Currently the EURAMET PR-K5: Key-Comparison of Spectral Diffuse Reflectance piloted by MKEH of Hungary makes good progress towards to finish Draft A. Besides MKEH as the pilot, PTB serves here as an additional link laboratory to the CCPR-K5 comparison.


Progress Report of 20.02.2009

The facilities of the PTB for the calibration of diffuse reflection standards are used to provide the partner NMIs with absolutely calibrated transfer standards traceable to the absolute scale of the radiance factor for standardized geometries at the PTB. For reflection measurements in practice, reference standards with known properties are needed. Last calibration in this connection was for NPL in 2006. PTB and MIKES-TKK Finland have performed a bilateral comparison of their diffuse reflection scales within the last one and a half years. The results of this comparison have been submitted to a journal and are currently (spring 2009) in the review process.


Progress Report of 07.03.2007

The facilities of the PTB for the calibration of reflection standards are used to provide the partner NMIs with absolutely calibrated transfer standards traceable to the absolute scale of the radiance factor for standardized geometries at the PTB. For reflection measurements in practice, reference standards with known properties are needed. Last calibration in this connection was for NPL in 2006. Currently (spring 2007) PTB and MIKES/TKK Finland (formerly named as HUT) are performing a bilaberal comparison of their diffuse reflection scales.

Subjects
Photometry and Radiometry (PR)
Coordinator
Alfred Schirmacher, PTB (Germany)
Coordinating Institute
PTB (Germany)