B&W Tek SpectraRad® Xpress Miniature Spectral Irradiance Meter

B&W Tek SpectraRad® Xpress Miniature Spectral Irradiance Meter

  • Spectral Range: 380-750nm, 350-1050nm
  • Input Optics: Transmissive Cosine Corrector (default)
  • CIE 127 Compliant Adaptor (ADP-CIE127 option)
  • NIST Traceable Calibration
  • Wavelength Accuracy: better than 0.3nm



The SpectraRad Xpress is a miniature spectral irradiance meter designed for field, industrial, and lab applications with a plug-and-play USB 2.0 interface. A transmissive cosine corrector is coupled to a spectrometer which then is irradiance calibrated against a NIST traceable Tungsten light source. Optimized software is provided for characterization and measurement of many application lighting devices and systems. Standard software features include timeline recording, data smoothing, illuminance (lux), chromaticity, color temperature, external triggered pulsed light capturing, and other data handling functions. The SpectraRad Xpress is ideal for lamp and LED characterization (requires input optic option), color analysis, solar studies, photostability testing, photobiology and photochemistry.


  • Lamp and LED Characterization (requires input optic option)
  • Illumination and Color Rendering from Lighting
  • Solar Irradiance Monitoring (outdoors)
  • Solar Simulator Validation (indoors)
  • Photobiology and Photochemistry
  • Photostability Testing
  • UV Curing System QC
  • Color Analysis


Power Input USB at < 350mA
Detector Type Response enhanced 2048 element linear Silicon CCD Array
Detector Pixel Format 14μm x 200μm
Spectrograph f# 3.0
Spectrograph Optical Layout Crossed Czerny-Turner
Dynamic Range 1300:1 typical
Digitizer Resolution 16-bit or 65,535:1
Readout Speed >2.0 MHz
Data Transfer Speed Up to 480 spectra per second via USB 2.0
Effective Integration Time 1 to >=20,000 ms
External Trigger Aux Port
Operating Temperature 15°C – 35°C
Relative Humidity 0 – 85% RH Non Condensing
Weight ~0.23 kg (0.5 lbs)
Dimensions See Drawings
Computer Interface USB 2.0/1.1
Operating Systems Windows XP, 7, 8, 10 (32-bit & 64-bit)

Advantages of Spectral vs. Filter Based Instruments

Although filter based instruments are desired for certain properties such as cost, speed and portability, they are not always the best choice for analytical measurements. Filter based instruments only acquire three data points across the entire spectrum of light to yield colorimetric values. This is accomplished by the use of filters corresponding to the normal human eye response. These filters can only be manufactured to a certain degree of accuracy. Due to these facts, filter based meters are susceptible to errors because of the deviation of the filter response from the ideal human eye response and the lack of resolution needed to accurately describe narrow bandwidth light sources.

The SpectraRad Xpress avoids these problems at a comparable cost, higher speed, and small footprint because it acquires hundreds of data points across the visible spectrum. In addition, the 2048 pixel linear CCD array provides the precision required to accurately measure narrow bandwidth light sources or LEDs. Having multiple sensors also enables the unit to report spectral data and display spectral graphs, making it the ideal instrument for evaluating LEDs, which are today’s dominant light source.

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