SRS8 / SRS8RI Spectral Radiance and Radiant Intensity StandardsCL3 UV spectral irradiance standard

The SRS8 and SRS8RI are uniform sources calibrated in spectral radiance for routine calibration of spectroradiometers, telephotometers and luminance meters.

Both sources are based on BaSO4 coated integrating spheres fitted with a baffled quartz halogen lamp to provide excellent illumination uniformity, and are 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 200mm diameter SRS8, fitted with a baffled 50W quartz halogen lamp provides an ouput, fitted with a diffuser window, of 50mm diameter. The SRS8 requires a precision constant current DC power supply at 4.000A.

A small diameter aperture can be fitted to the window of the SRS8 (option RI), supplied with a spectral radiant intensity calibration. Other options include quartz diffuser window in lieu of glass and a filter holder to accomodate a range of neutral density and colour temperature shifting filters.

Bentham offers a 250W rated constant current p.s.u. for use with calibration lamps, model 610.



Luminance 18000 cd.m-2
Colour temperature 3200K
Chromaticity x = 0.465, y = 0.415


SRS8 ans SRS12 spectra


RI Calibration with radiant intensity adapter
FH Filter holder up to 50x50mm
Q Quartz diffuser window
EX_ND Neutral density filter with additional calibration
EX1 Extension of calibration from 800-1100nm
EX2 Extension of calibration from 800-2500nm
EX3 Extension of calibration from 300-380nm, used with option Q
EX-F Customer-selected filter with additional calibration