抄録
The aim of this research is to understand and control the preionization processes in high pressure discharges used for excimer lasers. For this purpose, a chamber having a spark light source at one end was designed and fabricated so that it could achieve ultra-high and oil-free vacuum. Photocharge signals were collected by a set of pairs of plate electrodes placed inside the test chamber. Special care was paid to mix small amounts of addition gases uniformly in the Ne gas at 1 atm. These efforts have enabled us to observe the basic photoionization characteristics of the addition gases. The result showed that, for the case of Xe gas as an addition gas, the photocharge signal increased linearly with the Xe pressure below 0.1 Torr, while rapidly decreased at higher pressures (_??_0.1 Tort). Xe gas was then added to mixed gases used for excimer lasers (the Ne, F2 and Ar mixture) in order to examine the possibility of actively controlling the preionization process. The signal when 0.1 Torr Xe gas was added was more than 10 times higher than that without Xe, suggesting that an active control may be possible.
