Source xenon arc

ISO 4892-2, 1994. Plastics. Methods of exposure to artificial light sources. Xenon Arc lamps. 

Fig. 2.17. Schematic layout of a microscope spectrophotometer system used to measure polarized absorption spectra of very small mineral crystals. The computer-operated, single-beam instrument shown here comprises a polarizing microscope equipped with a stabilized light source (xenon arc lamp or tungsten lamp cover the range 250-2000 nm), a modulator that chops the light beam with a frequency of 50 Hz (the amplifier for the photodetector signals is modulated with the same phase and frequency), and a Zeiss prism double monochromator. Single crystals as small as 10 ji.m diameter may be measured with this system. A diamond-windowed high-pressure cell can be readily mounted on the microscope scanning table for spectral measurements at very high pressures (after Burns, 1985, reproduced with the publisher s permission).

As the fluorescence is directly proportional to the number of photons absorbed by the sample (in the absence of inner-filter/self-shadowing effects of excessive absorption), it is advantageous to employ very high intensity light sources xenon arcs are highly suitable. Additional excitation intensity may be achieved by greater spectral bandwidths employed on the excitation side, although this may... 

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