Photoelectric effects in x-ray preionization for excimer laser gases

Abstract

We present detailed measurements on the x-ray preionization electron density in a discharge chamber filled with different gases relevant to discharge pumped high-pressure excimer lasers. By comparing experimental results with the theoretical electron densities, we conclude that the observed preionization is inconsistent with the standard picture of direct ionization through x-ray absorption in the gas. We conclude that depending on the gas pressure, type of gas, and the gap length between the discharge electrodes used, x-ray preionization in excimer gases is, to a significant extent or even dominantly, based on a different mechanism. We identify that this mechanism is based on fast photoelectrons emitted by the cathode into the discharge chamber.

Investigating the Effectiveness of Predict-Observe- Explain Strategy on Teaching Photo Electricity Topic

“…In the current education system, at 12 th grade level, the issue of photo-electricity in the content of light theories is one of the issues that the students could not be able to imagine in their minds easily. The necessity of placing more emphasizes on practical works which enable to convert those kinds of abstract concepts included issues into the concrete issues and to exhibit real situations are stand out (Foong et al, 2009;Gemici et al, 2000;Guo et al, 2009;Azarov et al, 2008). It has seen that the inadequacy of studies on abstract concepts which could be hard to learn, imagine in mind, enable students to develop scientific process skills, and solve the problems that they have faced and the necessity of those kinds of studies.…”

Numerical investigation of discharge evolution and breakdown characteristics of ArF excimer lasers

“…On the one hand, the generation of pre-ionization has gained attention: D Levko explored the roles of runaway electrons, X-ray, and photoionization in pre-ionization [24,25] and evaluated their relative importance. Azarov et al investigated the photoelectric effect in X-ray pre-ionization [26]. Depending on the different pressure, gas ratio, and electrode gap, the pre-ionization can be based on different mechanisms, with fast electrons emitted from the cathode sometimes playing the dominant role.…”