Characterization of imprisoned Xe resonant photons in He-Xe and Ne-Xe mixtures

Abstract

The Holstein's theory of the imprisonment of resonance radiation for pressure-broadened Lorentzian profiles is extended to the Xe-based binary gas mixtures which are widely employed in practical discharge devices. In the binary mixtures, collisions between radiating and buffer atoms modify the emission and absorption spectrum profiles, affecting the imprisonment characteristics. It is found that the imprisonment time Tp is independent of total or partial pressures, provided that the Xe mixture ratio m and discharge tube diameter D are kept constant. Tp is proportional to D1/2. It is also proportional to m1/2 when m is sufficiently small, and becomes independent of m when m approaches unity. The 'broadening coefficients' xi Xe, xi He and xi Ne are defined as degrees of broadening of the Xe emission/absorption profiles due to collisions with Xe, He and Ne, respectively, in terms of half-widths at half-maxima per unit ground state atom density. By measuring Tp using cylindrical discharge tubes of diameters D=2, 5, 10 and 25 mm filled with various mixtures of He-Xe and Ne-Xe, the unknown coefficients are determined to be xi He=1.2*10-16 m3 s-1 and xi Ne=8.0*10-17 m3 s-1. These are 0.059 and 0.039 times that of xi X3, respectively. Knowledge of the coefficients allows us to calculate imprisonment times for any gas mixture and discharge space configuration. A reduction in Tp favours an increase of luminance and luminous efficiency in two ways. One is that luminance saturation with respect to the discharge current becomes less likely to occur, and the other is that, even under the fully saturated condition, luminance is higher with smaller Tp. Smaller Xe mixture ratios and tube diameters favour shortening of Tp. A reduction of m from 1 to 0.01 results, for any value of D, in a decrease in Tp by a factor of 2.6, assuring quicker escape of VUV from the volume. Since neither the total pressure nor Xe, He or Ne partial pressures affect Tp as long as the Xe mixture ratio is kept constant, these pressures can be chosen by considering only the conditions that provide the best discharge.

High‐frequency drive of high‐Xe‐content PDPs for high efficiency and low‐voltage performance

“…The intensity of the 147-nm resonance line saturates with respect to the discharge current due to electronic de-excitation of the excited Xe atoms. 9 This so-called plasma saturation causes luminous-efficiency deterioration. An increase of the drive frequency enhances the saturation since the excited Xe atoms are more likely to be destroyed by the discharge current in the following sustain pulse.…”

Inhomogeneous model of an Ar–Hg direct current column discharge

“…The same approach has been applied to the other resonance line, 185 nm, which is also reabsorbed. 53,64,74,75 In the general case, the effective transition probability can be estimated using the formulas of Igarashi et al 76 for a mixture of gases or the analytical formulas derived by Curry and Lawler. 77,78 The pressure broadening due to Ar atoms is accounted for through the parameter ␥ ϭvn Ar /2, where is the interaction cross section, v is the relative velocity, and n Ar is the argon density.…”

Plasma study of a moly-oxide-argon discharge bulb

“…The escape factors provide effective lifetimes for the radiative transitions and depend on the lower state density, the gas temperature, and the bulb dimensions. The general formulas for the escape factors are taken from [45].…”