Collisional radiative model for the sputtered copper atoms and ions in a direct current argon glow discharge

Assessment of the relative role of Penning ionization in low-pressure glow discharges

Pulsed resonant optogalvanic effect is investigated in a neon hollow cathode discharges utilizing a nitrogen pumped dye laser We have studied by the pulsed technique transient effects in the discharge plasma such as fast relaxation of level population density and population inversion The experimental results are correlated with a four states phenomenological model of the pulsed optogalvanic effect taking into account lumped relevant levels of the 3s and 3p manifolds of neon The time integration of the pulsed optogalvanic siganls (OGS) yields the previously measured cw signals and explains their sign changes

Pulsed resonant optogalvanic effect in neon discharges

Optogalvanic spectra of atomic neon and argon have been obtained by irradiating miniature glow discharge lamps with a pulsed, tunable dye laser. The method is shown to be useful for wavelength calibration of tunable lasers, and the resonant lines are cataloged. Two-photon absorption lines in neon are observed when the laser is focused into a small region of the discharge.

Optogalvanic spectra of neon and argon in glow discharge lamps

Two-step optogalvanic effect using intersecting laser beams: A pinpoint discharge diagnostic

Inverted population observation using pulsed optogalvanic effect

The optogalvanic effect is proposed and demonstrated as a new technique for quasiresonant Penning ionization spectroscopy in a discharge plasma of mixtures of rare gases and metal vapors. A calcium and neon mixture is used as a prototype. Neon’s lowest metastable level, 3P2 at 134 034 cm−1, is within kT from the excited state of 2D3/2,5/2 of Ca+. Thus Penning ionization occurs to an excited state of the ion. This process strongly alters the optogalvanic signal and has its own signature. In fact, other energy transfer processes should also change the time dependence of the optogalvanic signal.

Penning ionization spectroscopy using the optogalvanic effect

A study of the pulsed optogalvanic effect in a Sr/Ne hollow cathode tube for Penning ionization spectroscopy in this system is described. In the case of strontium this ionization is a multichannel process due to the quasi-resonance between the four excited 3s states of neon with the high density of Rydberg states close to a Sr+ ionization continuum. A detailed investigation of the signal as a function of tube current and its spatial dependence as well as a comparison with Ca/Ne Penning rate is also reported.

Observation of Penning ionization in Sr/Ne discharge by the optogalvanic effect.

Quasi‐resonant Penning ionization in a Ne–Ca discharge is detected and studied by using the pulsed optogalvanic effect on the neon 1si→2pj transitions. The ensuing signals exhibit extra features which appear at longer times following the signals obtained in pure neon discharge. A phenomenological model is used to describe the signal and to extract an estimate of the Penning cross section, which is on the order of 10−14 cm2. At high discharge currents the Penning contribution becomes unimportant and the related features in the optogalvanic signal disappear. A correlation between the dependence of the emission intensity of certain transitions of Ca and Ca+ related to the Penning effect and the dependence of the optogalvanic signal due to the Penning ionization on the discharge current is demonstrated. A similar correlation between the I–V characteristics and the dependence of the optogalvanic signal on the discharge current is also shown.

A. Ben-Amar

Papers

Pulsed resonant optogalvanic effect in neon discharges

Inverted population observation using pulsed optogalvanic effect

Penning ionization spectroscopy using the optogalvanic effect

Observation of Penning ionization in Sr/Ne discharge by the optogalvanic effect.

Optogalvanic spectroscopy of quasi‐resonant Penning ionization