| 摘要 |
PURPOSE:To provide a method for selecting such a material as causing no absorption, when excimer laser light is transmitted for a long time by irradiating a synthetic silica glass with X-rays, easily in a short time. CONSTITUTION:Silicon tetrachloride is subjected to hydrosis in hydrogen flame and deposited directly to produce a synthetic silica glass sample which is then irradiated with excimer laser of KrF, ArF, F2, etc., or X-rays. In this regard, a linear relationship exists between absorption coefficients alpha derived through irradiation. Extent of absorption when the sample is subjected to 10<6> shots (about 2.8 hours) of 100HZ KrF excimer laser, for example, can be predicted by irradiating the sample with Rh target X-rays of 50mA, 5OkV for 10-15 min in the vacuum of about 10<-2>Torr. When X-rays are used, generation of 220nm absorption band can be decided in a short time and the extent of absorption can be predicted when the sample is irradiated with excimer laser having photon energy of 5eV or above. Consequently, a material causing no absorption even after transmission of excimer laser for a long time can be selected. |
