Buildup of a Discharge in Argon

Abstract

Measurements were made of the rate of buildup of an electrical discharge in argon in the pressure range from 5 to 60 cm Hg. The results are interpreted on the basis of a secondary mechanism due to delayed photons. The photon delay times which fit the observed data are in the neighborhood of five microseconds over the range of pressures investigated. These photon delay times are compared with (a) calculated imprisonment times for resonance radiation, and (b) delay times for molecular radiation as observed by Colli. Considering the uncertainty in the calculations and the lack of knowledge about the energy distribution between the two main resonance lines, the imprisonment times are of the right magnitude to explain the observed buildup rates. The Colli-process delay times are in fair agreement with the data at the higher pressures; at the low pressures they are definitely too slow to explain the observed buildup rates.

Cold-cathode discharges and breakdown in argon: surface and gas phase production of secondary electrons

“…Firstly, we show in figure 4 measured breakdown [88,[106][107][108][109][110][111][112] and low-current discharge-maintenance voltages [90,113,114] as a function of the product of pressure and electrode spacing pd, in what is known as the Paschen curve [32,33,35,88,89]. Later, we reformulate these data so as to emphasize the production of secondary electrons.…”

The Development of Theories of the Electrical Breakdown of Gases

“…The resulting expression gives the current at large times in terms of the factor exp(At), in which the growth constant A is related to all the various delay processes. An expression of similar form had been obtained by Menes (1959) on the basis of a delayed nonresonance (a/a) process, the photons being emitted from an excited state with a lifetime sufficient to cause the delay. To apply these results to the nonsteady state temporal growth of ionization, it is necessary to obtain detailed expressions for I(x,t) incorporating the various secondary processes, and then to compare the theoretical {I(x,t) vs. t} curves with those found experimentally; agreement would then indicate the particular secondary processes acting.…”

“…This gas was also investigated using the voltage collapse technique (Davies and Llewellyn-Jones, 1960). Argon, with copper electrodes, was studied by Menes (1959) using a similar method and finding A from: d A = dt{R,n I(t)} for large t's. It was concluded that the slow growth rates found were possibly due to the two different photon-delaying processes.…”

Prebreakdown current growth in crossed electric and magnetic fields at low gas pressures: III. Temporal growth of current

“…Although a number of models have been proposed to account for formative time lags measured in electric fields only, and at gas pressures where h<d (Bartholomeyczyk 1940, Davidson 1953, 1955, 1959, 1962, none of these are really applicable to the present E x B, h B d conditions. In particular, as Davidson (1953) has remarked, 'Bartholomeyczyk's theory is not an accurate solution of the problem, since it does not reduce, at time t = 0, to the charge distribution actually present then, and, moreover, the boundary conditions omit an additive constant, l o , due to external illumination'.…”