Infrared Spectrometry forms part of the Optical Radiation Measurement (ORM) group. This work began in the 1980s in response to a lack of traceable standards in the mid-infrared spectral region. The main driver has always been the needs of industry to measure infrared optical properties accurately. In recent years Quality Assurance systems in industry have also underlined the need for traceable measurement.

Infrared optical properties are important across a range of applications including spectroscopic analysis in pharmaceutical and chemical industries, thermal control in buildings, infrared tracking and guidance systems and both instrumentation and thermal control in satelites.

All measurement is subject to some degree of uncertainty or error. The measurements and provision of standards from NPL are currently based on the use of grating spectrophotometers, the sources of error of which are well understood and can be evaluated. The newer breed of Fourier Transform Infrared (FTIR) spectrometers are now dominant amongst users of IR spectrometry. Whilst conveying many advantages to most users, the many possible intrinsic sources of error are not as easily separable^[1]. However, original research is under way to allow use of this instrumentation at NPL, firstly for measurment services, and eventually for the underpinning basic standards work.

More information can be found on the following Technical Information Pages:

• Wavenumber Calibration QA Standard
• NPL Branded Polystyrene Wavenumber Standard
• Mid-Infrared Transmittance Transfer and QA Standard
• Infrared Reflectance Standards from NPL
• Near-normal and Large Angle Regular Reflectance Calibrations
• Absolute Calibration of Regular Reflectance Standards for the Thermal Infrared Spectral Region
• Measurement of Hemispherical Reflectance and Transmittance over the Thermal Infrared Spectrum
• Hemispherical Reflectance Measured by the NPL Relative Technique, with Diffuse and Regular Components Separated
• Hemispherical Reflectance Measured by the NPL Direct Absolute Technique
• Spectral and Total Emissivity at Near Ambient Temperatures

Reference

1. J.R. Birch and F.J.J. Clarke, "Fifty categories of ordinate error in Fourier Transform spectroscopy", Spectroscopy Europe, (7/4), 16-22 (1995)

Contact

Customer Service tel: +44 20 8943 6151
E-mail: optical_enquiries@npl.co.uk