Talk:Townsend discharge

Suggested merge
would seem to be usefully merged and redirected here; there's not much to say about these things that this article doesn't already say, and discussing the whole proces in one place would minimize the jumping around one would have to do to understand the subject. --Wtshymanski (talk) 16:24, 9 December 2010 (UTC)
 * Townsend coefficient
 * Townsend avalanche

Agree with this. there would be a proliferation of unecessary articles, which would be confusing. Dougsim (talk) 09:58, 21 December 2010 (UTC)
 * Done. Have a look, see if there's more redundancy that can be taken out or polishing that can be done. --Wtshymanski (talk) 14:57, 21 December 2010 (UTC)
 * This article now contains text from the former Townsend coefficient and Townsend avalanche, see those pages for their contribution history. --Wtshymanski (talk) 17:45, 22 January 2012 (UTC)

Avalanche figures
The avalanche figures are misleading. The current figure suggests the initial ionization event released two electrons instead of one. Subsequent events give the impression of an electron getting captured by an atom and then that atom releasing two electrons. A new pair is generated by a collision, but the generated pair is an electron - ion. The figures ignore the ion. The original colliding electron is not destroyed. Better image is at way down on page, but it has cascade fiction, too (and more photon interaction). Electron paths are given as straight lines. Freed electron would not have a lot of kinetic energy; the electric field gives it that energy. Paths would bend toward anode. Better version may be at. Mean free path issues. Glrx (talk) 01:55, 24 October 2012 (UTC)


 * Yes you're quite right, so there's only one electron from the original ionisation event now, and the ionising and the liberated electron are indicated. Yes they will tend towards a a perpendicular angle to the anode, but I think the main point is to show the generation process. The previous graphic was singularly unhelpful. Dougsim (talk) 21:15, 27 October 2012 (UTC)


 * Thanks for the improvements. I know it takes a lot of work, and WP is grateful. I'll put the movie in an external link. Glrx (talk) 23:30, 27 October 2012 (UTC)

Thanks, there's still some other odd stuff in the original article, such as the total number of electrons being 2n where n is the number of collisons, which is incorrect. Also some confused tenses and ambiguity in the account of early experiments. Still needs quite a bit of work to make it a coherent article. I'm also sorting out better graphics for the GM tube avalanche and the prop counter mechanism. Dougsim (talk) 11:43, 28 October 2012 (UTC)

Another merge
I am suggesting that a merge is made of the article "electron avalanche" into the Townsend avalanche article - with the title Townsend avalanche. Any comments? The electron avalanche appears to duplicate part of the TA article, and says less. Dougsim (talk) 16:50, 8 February 2013 (UTC)


 * Oppose. Townsend avalanche context is a gas; electron avalanche is more general topic that can include vacuum (photomultiplier) and solid-state. Glrx (talk) 18:21, 8 February 2013 (UTC)

First Townsend coefficient
Right now it says: "*$$\alpha_n$$ is the first Townsend ionization coefficient, expressing the number of ion pairs generated per unit length (e.g. meter) by a negative ion (anion) moving from cathode to anode."

I have found similar statements online, but don't think it is a good definition. It suggests that kation/anion-pairs are created, while usually (at least in noble gases) kation/electron-pairs are created. An electron is not an anion. Also, if a collision creates, say, Atom++ plus 2 electrons, then 3 charge carriers are created, not a pair. Can someone find a better definition in the literature? — Preceding unsigned comment added by Herbmuell (talk • contribs) 05:18, 19 July 2014 (UTC)

Gap size contradiction
"An exponential increase as the plate gaps became small" seems to contradict the equation for I, which implies that in increase in d should increase current. Two things are being mixed up here: the gap distance and the field gradient. Comfr (talk) 04:43, 9 June 2017 (UTC)