The IL1 is a general-purpose light source for use in the UV, visible and infra-red spectral regions from 350nm to 2.5mm.
A quartz halogen lamp controlled by a current stabilised power supply is employed.
A single quartz condenser lens is used to fill the height and width of the slit and to match to the F/4 optics of the monochromator. The quartz halogen lamp is unsurpassed for stability by any other source and should always be used where it provides sufficient output in the wavelength region of interest.