On the use of broadband ultraviolet detector calibration

Abstract

Measurement of ultraviolet radiation is a common issue in many fields of applications. The easy way to approach to ultraviolet measurement is by using broad band probes. Their use should be straightforward, but their calibration is not always simple to be applied in small industrial, test and research laboratories. The paper presents the two main approaches to the calibration of ultraviolet probes, with their related limitation on their use and difficulties in the extension of the calibration to the cases considering radiating source different from the one used in the calibration. Starting from the approach applied at metrological laboratories, an attempt to overcome this problem is presented which takes advantage of the information commonly provided by manufacturer on data sheets of probes and sources, i.e. data easily achievable by all laboratories

Commercial TiO<inf>2</inf> P25 activation: Evaluation of efficacy in photodegration processes of different radiating sources

“…The scheme of the photoreactor with an array of 4x4 UV-LEDs is shown in figure 3. Each LED is fed with DC current equal to 25mA, the total radiating power measured [1] at a distance of 5 mm was 15 W/m 2 , the peak wavelength λ peak is at 360 nm. The power distributions along the UV and visible range are shown in figure 5 and 6 for the Hg-UV lamps, and UV-LEDs, respectively.…”

“…The photoreactors have been designed and assembled in the Photometric Laboratory of the University of Padova. One photoreactor uses two UV lamps PL-S 9W/11/2PICT (see figure 2), the radiation wavelengths are within the range from 280 nm to 480 nm (peak at 310 nm); the lamps are fed at 230 V with a conventional ballast; the radiating power was measured at 20 cm [1]: UV A 3.5 W/m 2 ; UV B 7 W/m 2 ; UV C 130 mW/m 2 . The scheme of the photoreactor with an array of 4x4 UV-LEDs is shown in figure 3.…”

“…An easy measurement of the power would require a flat response of the probes within their wavelength working range and a zero out of band response, but, unfortunately it does not happens and calibration problems arouse [1]. On the other hand an accurate evaluation of the power applied to the handled sample is of fundamental importance in the definition of the process efficacy.…”