| 摘要 |
PROBLEM TO BE SOLVED: To obtain a silica glass without a deterioration in transmittance of light in the vacuum ultraviolet region and having a lifetime prolonged by improving the durability against ultraviolet ray or radiation. SOLUTION: The silica glass consists mainly of silicon oxide SiO<SB>2</SB>and is doped with fluorine of≤10 ppm. Dissolved hydrogen is controlled to be preferably 1×10<SP>17</SP>-1×10<SP>19</SP>molecule/cm<SP>3</SP>and the each content of transition metals, alkaline earth metals and alkali metals is≤50 ppb in the silica glass. As a result, the vacuum ultraviolet characteristic and radiation resistant characteristic are improved. COPYRIGHT: (C)2004,JPO
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