Requirements for reflection standards and the measurement of their reflection values

Area of Science:

• Metrology
• Optical Engineering
• Materials Science

Background:

• Accurate reflection standards are crucial for optical measurements.
• Existing materials may not fully meet the stringent requirements for reflection scale transfer.
• The Physikalisch-Technische Bundesanstalt (PTB) has developed advanced instrumentation for this purpose.

Purpose of the Study:

• To assess the suitability of current materials for reflection standards.
• To describe the PTB's instrumentation for measuring spectral radiance factor.
• To explain the methodology for relating material standards to primary standards.

Main Methods:

• Evaluation of material properties against established requirements for reflection standards.
• Description of specialized instrumentation for spectral radiance factor (beta(lambda)) measurements.
• Methodology for calibrating material standards against a perfect reflecting diffuser.

Main Results:

• The paper discusses how well current materials meet the necessary requirements for reflection standards.
• Detailed description of the developed instrumentation for spectral radiance factor measurements.
• Explanation of the measurement process linking material standards to the primary standard.

Conclusions:

• Current materials' suitability for reflection standards requires careful evaluation.
• The developed instrumentation enables precise spectral radiance factor measurements.
• A clear methodology exists for transferring reflection scale values to primary standards.