Spectroscopic measurements in a plasma gas discharge

• The linear behavior of L TE parameters as a function of the emitted photon energy (e V), as shown in figures from (6-8) to (6-24), reveals the ability of applying LTE model for the considered helium glow discharge in the applied range of gas pressure and discharge current density.Accordingly the behavior of the estimated plasma temperature Teas a function of the gas pressure and discharge current density reveals an agreement with the expected behavior for both the pressure and the current density (27), (29), as shown in figures from (6-25) to (6-34). This shows the possibility of applying this method, in situ, for glow discharge processing. The advantage of this method with respect to the other electric probe methods is that it neither disturbs nor pollutes the plasma (30), (31), (32).Also, the measured electron temperature behavior has been compared with these calculated using another method such as relative intensities of two lines with (22) and without (26) taking plasma depth into consideration. The calculated behaviors show lower values than the measured one but with the same exponentially decreased behavior as a function of gas pressure. This difference could be attributed due to their dependence on some geometrical parameters such as plasma depth.Finally, one concludes that, LTE model can be used for describing helium glow discharge in the applied range of gas pressure and discharge current density.