UVB Detector With Liquid Light Guide Adaptor
The detector’s spectral response follows closely the erythema action spectrum (Fig.1.)[1]. Due to built-in Teflon diffuser the detector has negligible azimuthal error making the measurement insensitive to the rotation of the detector. Extended measurement range of 600 MED/Hr enables measurement of intense radiation. In conjunction with the Solar Simulator and XPS200 Xenon Lamp Power Supply the PMA2100 with the PMA2103 detector can operate as a smart dose controller/monitor substantially enhancing the functionality of the Solar Simulator. The measurement result can be shown in MED/Hr, µW/cm2 as well as a time to accumulate 1 MED. The detector's high dynamic range allows measurements down to 0.1 µW/cm2 with the ability to measure radiation as strong as 3.5 mW/cm2. The biologic effectiveness of ultraviolet radiation is strongest for wavelengths between 280 to 315 nm, classified as UV-B by the CIE. Several biologic action spectra, functions relating wavelength and the biologic effectiveness, are shown in Figure 3. The most commonly used, erythema action spectrum [1], also referred to as CIE 1987 action spectrum, represents the sensitivity of human skin to sunburn. Other biologic action spectra also exhibit rapid decline in UV effect with an increase of wavelength over the UV-B range. In general the reading of an erythemally weighted detector cannot be directly interpreted as biological effectiveness other than erythemal. However, there are ways to make the necessary correction numerically [2]. The biologic effectiveness of the UV radiation can be measured in terms of effective irradiance in radiometric units, for example [µW/cm2]. It is often related to the sensitivity of the human skin to sunburn and expressed in Minimal Erythemal Doses per Hour [MED/Hr]. One MED/Hr is the effective irradiance capable of causing minimum redness (erythema) in an average number 2 skin. Based on a study [3], the relationship between MED/Hr and radiometric units was determined to be: 1 [MED/Hr] = 5.83 [µW/cm2] This formula is programmed into the PMA2103 detector allowing for easy conversion of units. Consequently, the integrated effective dose can be expressed in [mJoules/cm2] or MED. Many sources produce UV radiation with a spectral irradiance changing rapidly over narrow wavelengths range. Spectral irradiance of the solar UV (Fig. 4) is an extreme example of such steep slope due to the UV-B and UV-C absorbing ozone layer. |
FEATURES
APPLICATIONS
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The PMA2103 detector gives an accurate
measurement of biologically weighted ultraviolet radiation from Solar Simulators
manufactured by Solar Light Co. Special mounting hardware allows direct coupling with
8mm or 10mm Liquid Light Guides (LLG’s).
