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PMA 2105 UVB Detector with Beam Splitter Adapter

 

The PMA2105 detector gives an accurate measurement of biologically weighted ultraviolet radiation from Solar Simulators manufactured by Solar Light Co.

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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

> Detectors need to be used with a Radiometer

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

Special mounting hardware allows direct coupling with beam splitter available for 16S Solar Simulators.

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.

The TLV for UV radiation specified by ACGIH apply to sources which subtend an angle less than 80°. Sources which subtend a greater angle need to be measured only over an angle of 80°.

The instantaneous value indicates how long an exposure at the intensity being measured is required to produce a dose of 3 mJ/cm2. The PMA can also be set to continuously monitor UV and sound an alarm when the preset dose or irradiance level is reached.

In conjunction with the Solar Simulator and XPS200 Xenon Lamp Power Supply the PMA2100 with the PMA2105 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. High dynamic range of the detector 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 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 is the effective UV dose 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 assumed:

1 [MED/Hr] = 5.83 [µW/cm2]


This formula is programmed into the PMA2105 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 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
  • Range 600 [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 PMA1105

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