SRS12 Spectral Radiance and Radiant Intensity StandardCL3 UV spectral irradiance standard

The SRS12 is a uniform source calibrated in spectral radiance for routine calibration of spectroradiometers, telephotometers and luminance meters.

It is based on BaSO4 coated integrating spheres fitted with a baffled quartz halogen lamp to provide excellent illumination uniformity, and is easily mountable on all optical bench systems or flat surfaces.

Whilst the standard calibration range is 380nm-800nm, this can be extended as defined in the options table below. This calibration is performed with respect to National Physical Laboratory (NPL, Teddington, UK) calibrated lamps held by Bentham. Alternatively, direct NPL calibration can be offered.

The 300mm diameter SRS12, fitted with a baffled 100W quartz halogen lamp provides an output of 100mm diameter. The SRS12 requires a precision constant current DC power supply at 8.5A and recommends the Bentham 610 Power supply.

The SRS12 has been designed to complement the Bentham TEL309 for the measurement of the Photobiological Safety of Lamps according to EN/IEC62471, where, in certain instances, the convolution of a relatively wide field of view and a measurement distance of several metres can lead to the requirement of a large uniform source for the purposes of calibration.


Luminance 35000 cd.m-2
Colour temperature 3276K
Chromaticity x = 0.4197, y = 0.3996

SRS8 ans SRS12 spectra


Standard calibration 380-800nm
EX-1 Extension of calibration from 300-1400nm