SG01XL-E5 (ERYCA_science) high precision UV-Index photodiodeGeneral FeaturesProperties of the ERYCA_science photodiode DIN5050/ CIE087 UV-Index measurement with very small error < 3% TO5 housing, 1 UVI (2,5 µW/cm2) ≈ 8 nA, cosine correction Information about the UV-Index (UVI) The UV index is an international standard measurement of how strong the ultraviolet (UV) radiation from the sun is at a particular place on a particular day. It is a scale primarily used in daily forecasts aimed at the general public. The UV-Index is calculated by integrating the sun’s UV spectrum multiplied with the Erythema action curve (fig. 1, black curve and fig. 2, formula 1). That integral is divided by 25 mW/m2 to generate a convenient index value, which becomes essentially a scale of 0 to 10. The Erythema action curve is a wavelength resolved measure of the sunburn danger. It is maximised at 297nm (UVB) and then strongly decreases towards UVA radiation. Literature: A. F. McKinlay and B. L. Diffey, “A reference action spectrum for ultraviolet induced erythema in human skin” CIE Journal, 6-1, 17-22 (1987) About the sglux ERYCA sensors The ERYCA is designed for accurate measurement of the UV-Index. ERYCA’s error is <3% only which is sufficiently small for scientific and high performance commercial applications. The ERYCA is available as: ERYCA_custom (SG01M-E18) photodiode, 0,5nA/UVI (0,20mm2 SiC detector chip) ERYCA_advanced (SG01L-E5) cosine corrected photodiode, 2nA/UVI (1,0mm2 SiC chip) ERYCA_science (SG01XL-E5) cosine corrected photodiode, 8nA/UVI (4,0mm2 SiC chip) TOCON_ERYCA pre-amplified cosine corrected hermetically sealed low noise sensor with 5-15V power supply and approx. 100mV/UVI voltage output (SiC detector chip) How ERYCA’s <3% error is calculated? A good erythema sensor’s response needs to fol ow the Erythema Action curve (fig 1) as close as possible. Additionally the visible blindness needs to be extremely high as the visible part of sun’s radiation exceeds the erythema causing radiation by five orders of magnitude. ERYCA works with a 4H SiC detector chip providing a visible blindness of more than ten orders of magnitude. That means that absolutely no visible light interferes the sensors output value. Sensors with a visible blindness of less than six orders of magnitude are unsuited for UVI measurement even if they match with the CIE curve. ERYCA’s curve (fig. 1, red curve) has a near perfect match from 295nm to 320nm. From 320nm a leakage of approx. 0,1% is seen. To find out how that leakage negatively influences the UVI measurement a closer look at different sun spectra (varying tilt angle and ozone layer thickness) is needed. Fig. 4 shows different sun UV spectra issued by the Swiss governmental institute of meteorology. In total nine different sun spectra calculating an UVI from 1,12 to 10,92 were used. For error calculation the different sun spectra were integrated with the Erythema action curve and subsequently the integral of the same spectra with ERYCA’s response curve (fig. 2, formula 1 and 2) were calculated. Finally the error was calculated by using formula 3 (fig. 2). As shown by the blue curve (fig. 3) the error of all UVI is less than 3%. Rev. 5.2 specifications subject to change without notice Page 1 [4] Manufacturer: sg lux GmbH, Max-Planck-Str. 3, D-12489 Berlin, Tel. +49 30 5301 5211, Fax +49 30 5301 5209 mail: welcome@sglux.de - web: www.sglux.de - WEEE No. DE 76297302