A detector based measurement system was designed and established in UME optics laboratory for the calibration of solar UV radiometers. Filter radiometer, made up of a silicon trap detector, band-pass filters and. precision aperture in a temperature-con trolled enclosure was constructed for this purpose. Spectral responsivity of trap detector was evaluated to be traceable to the cryogenic radiometer and electrically calibrated pyroelectric detector. Uncertainties in the filter radiometer's responsivities at 291 nm, 296 nm, 313 nm, 357 nm, and 378 nm wavelengths were calculated as 1.6%, 1.3%. 0.8%. 0.6% and 0.2% respectively. Relative uncertainities in irradiance measurements were found to be between 3.4% and 0.9% in the region of 291-378 nm. © 2005 Elsevier Ltd. All rights reserved.