ABSTRACT

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1.6 Measurements in the vacuum-ultraviolet region The wavelength region between about 0.2 and 200 nm is called the vacuum-ultraviolet (abbreviated to VUV) region; most of the VUV spectrometers need to be evacuated in this region because of the opacity of oxygen in air to this radiation. Following Samson’s definition,1 the region between 100 and 200 nm is called the Schumann UV region; here, the H2 discharge lamp can provide useful radiation as an excitation light source. The wavelength region between 100 and 0.2 nm is known as the extreme UV (EUV) region, and it includes the region of 0.2 to 30 nm, called the soft X-ray region.