ILT Spectroradiometers

The ILT 970 and ILT 570 spectroradiometers form a family of precision light metrology instruments that can be configured – and reconfigured – for measurements of spectral radiant flux, spectral radiance, spectral radiant intensity and spectral irradiance, and the derived colorimetric and photometric parameters. The ILT 970 series comprises four models that are optimised for different bands in the UV-VIS-NIR range from 200 to 1650nm. The ILT 570 is a miniature spectroradiometer for the visible wavelength range from 400 to 800nm. All models provide the reassurance of ISO/IEC 17025:2017 accredited, NIST-traceable calibrations.

The ILT Spectroradiometer Family

The ILT 970 family comprises four spectroradiometers that are optimised for measurements in the UV, broadband UV-VIS-NIR, VIS-NIR and NIR spectral bands respectively.

Each ILT spectroradiometer system includes the ILT 970 or ILT 570 spectrometer, an optical fiber, a measurement head that attaches to the optical fibre for the measurement of spectral irradiance, spectral radiance, or spectral flux, plus ILT’s SpectrILight III control software & DLLs, and a convenient case for transportation and storage. In addition, each spectroradiometer system is supplied with an ISO/IEC 17025:2017 accredited, NIST-traceable calibration.

Measurement Heads

Input optics attach to the spectrometer’s optical fibre and define the type of measurement and measurement units. For detailed information on the available measurement heads, click on the “Input Optics” tab above. There are four basic measurement types that can be performed:

• For total flux measurements, there is a choice of 5cm or 15cm integrating spheres, the models INT50 and INT150
• For irradiance and illuminance measurements, a cosine diffuser is attached to the optical fibre. A choice of models is available: the W5E is a miniature, in-line diffuser; the RAA4 is a right-angle diffuser that is held normal to the direction of illumination; the W/A2 is also an in-line cosine diffuser with a larger collecting area.
• For intensity measurements, the irradiance or illuminance is recorded using a cosine diffuser as above, and the intensity calculated using the inverse squared rule.
• For luminance and radiance measurements, a lens is used to define a known measurement spot on the light emitting surface. The R3 small spot optic captures light from an 8mm spot at a working distance of 50cm. The R2 optic has a 2 deg. field of view for the measurement of uniformly lit, extended sources. Remember that when measuring the luminance of an object, the instrument’s measurement spot must be positioned well within the lit area of the object, otherwise you will record an erroneous reading, being the average of the light and dark areas.

Combining Spectroradiometers & Measurement Heads

It is possible to use multiple measurement heads with one spectroradiometer, provided that the particular input optic is calibrated with the spectrometer. Moreover, it is also possible to use one measurement head with two spectrometers to extend the spectral range of your spectroradiometer system. For example, to measure irradiance from 200-1650nm, you can use a W/A2 cosine receiver with a custom bifurcated optical fibre that connects to an ILT 970BB (200-1000nm) and an ILT 970NIR (900-1650nm). In this case, two calibrations would be required, one for each spectrometer.

SpectrILight Software

The ILT 970 & 570 spectroradiometers connect to a host PC via an [USB] interface and are controlled from ILT’s SpectrILight™ III application software. SpectrILight™ III is a LabView™ based software package for Windows that allows you to acquire spectral and colour data. Analysis of the data is now calculated instantly within the same programme – no exporting is required! SpectrILight™ III includes calculations for spectroradiometric, radiometer, photometric and colorimetric parameters. The overlay feature allows the user to compare a reference reading to current readings. Wavelength range, integration time, scan average and other controls can be easily set through pop-up windows, menus and tool bars.