The PMA2103 sensor 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).

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U.S.Pat.5,946,641

U.S.Pat.5,790,432

FEATURES

• Dynamic range 2*105
• Excellent long term stability
• NIST traceable calibration
• Radiometric and biological units
• Dose controller functionality

APPLICATIONS

• Skin and SPF testing
• Clinical studies
• In-vitro testing
• Phototherapy
• Photobiology
• Material testing
• Chemistry laboratories
  

> Sensors need to be used with a Radiometer

> Analog version of this sensor can be used with any 0 to 5 VDC or 4 to 20mA recording device

The sensor’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 ontroller/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 sensor'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 320 nm, classified as UVB 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 sensor 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.

Figure 3: Selected Biologic Action Spectra

Specifications

• Spectral response Follows erythema action spectrum Figure 1
• Range600 [MED/Hr], 3.5 [mW/cm²]
• Display resolution 0.01 [MED/Hr], 0.1[µW/cm²]
• Operating environment 32 to 120 °F (0 to +50 °C) no precipitation
• Temperature coefficient 1% /°C
• Cable  5ft (1.5m)
• Diameter 1.6" (40.6 mm)
• Height 1.8" (45.8 mm)
• Weight 7.1 oz. (200 grams)
  

Analog versions of this detector are available See PMA1103

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Download Application Notes & Technical Papers:

Interfacing PMA detectors to a Campbell data logger - app111.pdf

PMA Series capabilities and applications - app112.pdf

PMA detector integration - app120.pdf