A NEW METHOD FOR MEASUREMENT OF ERYTHEMAL IRRADIANCE

A composite system of four dosimeter materials, nalidixic acid (NDA), polysulphone, 8-methoxypsoralen (8-MOP) and phenothiazine, is presente d for the passive measurement of the UV spectrum. The properties of th e materials were investigated and found to be suitable to allow the ma terials to be applied in a system to evaluate the UV spectrum. The eva luation of the spectrum reduces by 70% the errors arising when only po lysulphone dosimeters are employed to measure the exposure due to a so urce spectrum that differs from the spectrum they have been calibrated against. Knowledge of the spectrum provides an advantage over the Rob ertson-Berger meter and polysulphone dosimeters, as the biologically e ffective exposure for any biological process may be calculated with be tter than 20% accuracy. The composite system was miniaturised to a siz e of 3 cmX3 cm to eliminate errors due to spatial variation of the spe ctrum and to allow the application at any site on objects with complic ated topography in a similar way as polysulphone dosimeters. Unlike th e polysulphone dosimeters, the composite system does not require calib ration against a specific source of UV in order to maintain a high deg ree of accuracy in the collected data.