Improved gain for the Ar 2 * excimer laser at 126 nm

Kinetics of Ar*2in high-pressure pure argon

“…The important absorption, spontaneous emission and radiation processes used in the code calculation are listed in table 3. All of the rate constants and cross sections are obatined from literature [11][12][13][14][15][16][19][20][21][22][23][24][25][26][27]. Generally speaking, argon atoms, such as those in discharge Xe * 2 dimer 2 + e → Ar * * + Ar III Electron ion formation and destruction 20 Ar + + e → Ar + (4s) + e 21 Ar + + e → Ar + (4p) + e 22 Ar + + e → Ar + (4d) + e 23 Ar + (4s) + e → Ar + (4p) + e 24 Ar + 3 + e → Ar + + Ar + Ar + e 25 Ar + e → Ar + (4p) + e + e 26 Ar + e → Ar + (4s) + e + e 27 Ar + e → Ar + (4d) + e + e kinetics [28], are ionized by multi-step processes to provide the electron source.…”

“…Therefore, at high pumping rates where n e is large, the destruction of the dimers is accounted for by the reduced formation rate. This is the case for an argon plasma excited by an e-beam with a pulse duration of τ exc = 20 ns [6,14], where we have τ V −T τ exc . However, for electric discharges, as in [11], the principal pumping time scale is only a few nanoseconds, comparable to the V-T time constant τ V −T .…”

“…To test the validity of our model, calculations were performed and compared with the more abundant e-beam experimental data [6,13,14]. In the experiments reported in [13,14], a coaxial e-beam diode driven by a 1 MV voltage pulse of 20 ns duration was used to excite the argon gas. The gas chamber can be filled with argon gas up to 30 atm and the gas temperature can be reduced to 140 K by circulation cooling.…”

“…In the experiment of Wrobel et al [6], up to 50 J energy was deposited in 5 cm 3 of argon at a pressure of 60 atm in 20 ns. Using the same conditions of the e-beam-excited plasma reported in [14], the calculated temporal evolution of the number density of Ar + 3 at a pressure of P = 4 atm with a gas initial temperature of 300 K and an input energy density of 5.2 meV/atom is shown in figure 5, where the full triangles indicate the measured data by Neeser et al [14]. For comparison, we also show the calculated results (dashed curve) obtained with a fixed temperature in [14].…”

“…Figure 6 shows the calculated fluorescence energy against the e-beam excitation energy density at the argon pressure of 2 atm (solid curve) and 4 atm (dashed curve), where the open circles (P = 4 atm) and full circles (P = 2 atm) are the experimental data from [14]. The calculated net small signal gains (dotted and full curves) and absorption coefficients (dot-dashed and dashed curves) together with the measured data (open circles [13,14], full circles [13] and full squares [6]), for the temperatures of T = 170 K (dashed curve), and 300 K (full curve), respectively, are plotted in figure 7. It is seen from figure 7 that the model predictions for the net small signal gain (g − α) are in good agreement with most of the data obtained from different authors under a very wide range of gas pressures and at two different temperatures.…”