| 摘要 |
PURPOSE:To remove hyperfine structure, to eliminate the need for large-scale incidental facilities and to reduce cost by using a metallic element for emitting far ultraviolet rays composed of a single isotope or an isotope having nuclear magnetic moment of zero as metallic vapor excited. CONSTITUTION:A lighting unit 1 has a metallic vapor lamp 2 as an exposure light source emitting light by exciting metallic vapor, a reflecting condenser 3 condensing while covering one part of the lamp 2 and a power supply 4 as the excitation source of the metallic vapor lamp 2. Metallic vapor consists of a single isotope in one metallic element in mercury, cadmium, zinc and lead or the isotope having nuclear spin of zero of these elements. Consequently, metallic vapor is constituted of the single isotope, thus preventing the spread of the width of a spectrum generated by an isotope shift due to the mixed presence of different isotopes, then narrowing the spectral band width of far ultraviolet rays. Metallic vapor is organized of the isotope having the nuclear spin of zero, thus obviating the splitting of a spectral line due to the nuclear magnetic moment of an atomic nucleus, then narrowing the spectral band width of the far ultraviolet rays. |
