Talk:Cavity magnetron

== On the discovery of the magnetron and radar. This article omits a number of historical facts, including work on magnetron by Okabe in Japan and Pointe/Gutton in France, the latter devices being sent to Britain in June 1940 and then to USA as part of the Tisza mission.

Here is a good source : https://www.researchgate.net/publication/251950186_Maurice_PONTE_and_Henri_GUTTON_pioneers_of_early_French_studies_on_resonant_magnetron_1932-1940  — Preceding unsigned comment added by 2A02:2F05:F20A:4D00:ED6E:5B45:117:A71E (talk) 19:34, 3 September 2023 (UTC) 

Health hazard: electromagnetic waves or x-rays ??

At the end of the paragraph on radar (application), it says that magnetrons could pose a health risk because of their "electromagnetic radiation". Shouldn't it say "x-rays" (which magnetrons inadvertently also produce)? Otherwise (as mentioned in the last sentence) newer radars which replace the magnetron with solid state electronics wouldn't be any safer...? Greetings, 85.3.83.62 (talk) 20:52, 3 November 2010 (UTC)

• Negligible amount. 75.82.59.19 (talk) 18:43, 4 September 2015 (UTC)

We need a more-typical illustration (or a few)

I'm a retired electronic tech, with Navy radar experience, and a lifelong interest in electronics.

There are a few pertinent Wikimedia images, apparently all for non-English-language Wikipedia sites, such as [1]

Primarily, however, I called up Google images for magnetrons, and found a "lot" of them, many for microwave ovens, or similar, and also magnetron sputtering equipment (another Wikipedia article to be written?). How I do wish that copyright owners would/could release these images!

• There's an excellent image, Fig 13, in the notably-good article (written by a Russian?) at

[2]

• Please see also (several photos here):

[3] That's my idea of a traditional magnetron. The bright square in the middle is the flange for the rectangular waveguide that carries the microwaves to (typically) a radar antenna. That site, [4], has a search arrangement; you have to select "Magnetron" in the right search field to get a list of magnetron images, linked by their type numbers. I looked at some, and a good number are without their magnets. The CV series, of which there are many, are British.

• Another: [5]

The magnetron on the left is an early version of a traditional (X-band) radar magnetron. The horn-shaped structures are the field magnet, most likely alnico. The glass structure at the top has the connections for the cathode heater; they also provide the high-voltage negative pulsed operating power. The magnetron is inside a display case, which explains the bright white dots from the camera's flash.

• Another good one; this is a modern one with integral horseshoe magnets.

[6]

• Historic, with magnets:

[7]

• Cavity magnetron anode:

[8]

• Navy training series, with a few illustrations:

[9]

• Present-day magnetrons — Small, but good images:

[10]

• Vane-type anode (still essentially like a cavity magnetron), "strapped" to improve performance (less frequency shift during a pulse? I need to do some homework):

[11]

• General illustration, and different types of anode cavities:

[12]

• Original cavity magnetron anode, apparently:

[13]

Regards, (Nikevich; I somehow [mis]managed to log out...) 173.48.76.50 (talk) 11:54, 5 November 2010 (UTC)

I have changed this paragraph from "In a conventional vacuum tube, electrons are emitted from a heated cathode and are attracted to the anode due to the different electrical charge placed on the two plates. The components are normally arranged in line, at opposite ends of the tube, giving them their traditional cylindrical shape. In a diode the current can flow only from the cathode to the anode, providing rectification. A triode adds a control grid which allows the flow of current to be further controlled in magnitude as well as direction, and thereby provides an amplification function." to ...

"In a conventional vacuum tube, electrons are emitted from a heated cathode and are attracted to the anode as it is positive with respect to the cathode. The components are normally arranged concentrically, with the cathode at the centre, giving them their traditional cylindrical shape. In vacuum tubes (valves), the current can flow only from the cathode to the anode, providing rectification although this function is usually performed by the diode. A triode adds a control grid which allows the flow of current to be further controlled in magnitude, and thereby provides an amplification function." to remove some inaccuracies and make it more concise.SUPERHETRODYNE (talk) 18:43, 15 November 2014 (UTC)

"The CV series, of which there are many, are British." - the 'CV' stands for 'common valve' and was the standard British designation for thermionic valves (vacuum tubes) at the time. The designation was used as a cover for the magnetron so as to fit in with normal valve designations as might be recovered by the Germans from aircraft wreckage.

" In a conventional vacuum tube....": It is electrons which flow from cathode to anode. Electric CURRENT flows from anode to cathode! — Preceding unsigned comment added by 86.165.158.111 (talk) 15:17, 7 May 2015 (UTC)

synchrotron radiation

So in this article under Microwave source, it says the effect is known as synchrotron radiation. However I have not found any source that coincides with this. Because I am not familiar with radiation I cannot add a citation needed, but from what I gather I believe the radiation to be cyclotron radiation and not synchrotron radiation, but again, I am not overly familiar with the subject so I could be wrong. I would like this to be reviewed by someone who can provide a source. Thanks :) — Preceding unsigned comment added by Accusedbold (talk • contribs) 08:21, 17 March 2015 (UTC)

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Edit reversion - Magee

@Wtshymanski: Yesterday when I was cleaning up Magee (a disambiguation page) there is an entry that infers that a magnetron is nicknamed a "magee". This needs to be mentioned in the article (per MOS:DABMENTION) so I looked at Cavity magnetron. I saw that in the reference named "brookner" (Eli Brookner, "From $10,000 Magee to $7 Magee and $10 Transmitter and Receiver (T/R) on Single Chip", IEEE) - currently footnote 6 in the article - the word magee is used to refer to a magnetron in the title of the work and in the introduction. I then added 'sometimes nicknamed a "magee"' to the same sentence in which the reference is used. You reverted my edit [14]. Either I have misunderstood the reference, or your reversion is inappropriate. Can you explain please. Shhhnotsoloud (talk) 05:22, 15 May 2017 (UTC)

Seems to me to be an obscure nickname, even if apparently used in a paper published by IEEE at some unknown date. A quick hit of Google Books shows people named Magee writing about magnetrons and no-one calling a magnetron "magee". Could this be one author's pet name for magnetrons and not representative of industry practice? "Magee" isn't listed in the IEEE dictionary, for example - and they give a lot of nick-names there. We want to be careful not to create Wikipedia's equivalent of dord. --Wtshymanski (talk) 15:38, 15 May 2017 (UTC)

@Wtshymanski: Thanks for the dord ref! I agree, it's obscure. But there it is, from a prize-winning author, in an IEEE publication. I've improved the referencing of the citation (by putting the author's name into IEEE Xplore) and reinstated my edit with different phrasing. Shhhnotsoloud (talk) 08:08, 16 May 2017 (UTC)

@Shhhnotsoloud: I have worked in radar systems nearly all my working life right from when radar system were entirely vacuum tube based. I have never heard the term 'magee' used when refering to the cavity magnetron (or indeed any form of magnetron) until your edit. If the claim is to be retained, I think that some evidence should be provided that the term is in sufficient world wide usage to meet the requirements of WP:COMMONNAME on not just in a one off document. Indeed the document cited uses the term 'magee' but also the term 'magnetron' throughout the text. Nowhere does it state that a magnetron and a 'magee' is the same device. Nor does it claim that 'magee' an alternate term in general use. 86.145.209.23 (talk) 14:34, 16 May 2017 (UTC)

Then you'll know who Eli Brookner is.

I've never heard them called a "magee" either. But I'm in the UK, and I'm happy to accept that this is a US term. If someone of Brookner's calibre is using it in a title for an IEEE historical paper, then that's good enough for me. Andy Dingley (talk) 16:48, 16 May 2017 (UTC)

If it's a US term, then it's hardly world wide. I am aware of a few localised nicknames for various radar parts and systems, but I would not dream of putting them in a article such as this. Articles should be accessible to a world wide readership. But as I have stated: if it can be shown that the term is in much more widespread usage than one country, then we are good to go. 86.145.209.23 (talk) 16:54, 16 May 2017 (UTC)

There is no reason at all why it needs to be world wide. There are many alternate terms that are either UK or US specific, yet WP gives both. A RS has given this as a recognised nickname in a large area: that's enough for inclusion here. No-one is claiming it as a replacement for magnetron, or as some sort of worldwide term. Andy Dingley (talk) 21:19, 16 May 2017 (UTC)

I remember the term "Magee" in conjunction with the (now) old H2S systems (still in service in the 1980's). However, my recollection is that it was spelt "Maggie", but this just might be a US/UK spelling difference. It was a reference to an important part of the scanner assembly, but it was not the magnetron. The term was an abbreviation of "magslip' which was itself an unofficial term for the synchro transmitter. This was used to generate the X and Y scan signals for the display so that the line on the CRT was traced in the direction the scanner was pointing. 85.255.233.4 (talk) 10:47, 17 May 2017 (UTC)

Third time lucky: '(which one author nicknames a "magee")'. Shhhnotsoloud (talk) 10:12, 22 May 2017 (UTC)

Against. There's no indication that it was invented and used by just one author. It would be most unusual for such an author to use a self-invented term in the title of an IEEE paper. Andy Dingley (talk) 10:35, 22 May 2017 (UTC)

@GraemeLeggett: and others. Well, this is tiresome. A notable author uses the expression "magee" in the title of a paper which is referenced at the end of the sentence in the lead section. So far all these have been reverted: "nicknamed"; "occasionally referred to as"; and "one author nicknames". Since the nickname used by one author is undeniable, what else do you suggest? Shhhnotsoloud (talk) 10:59, 22 May 2017 (UTC)

I don't know about Magee, but some words do appear first in physics journals. Boojum was introduced by Mermin in a Physical Review Letters paper, and when published started the use of the name. Gah4 (talk) 16:26, 18 January 2022 (UTC)

Why does megatron dab page point here?

...since this page says that the thing is not to be confused with a megatron. Equinox ◑ 23:24, 12 July 2017 (UTC)

Two different devices

The WWII RADAR high-precision multi-cavity device which produced very short high intensity bursts of microwave energy is a quite different cat from the simple mass-produced device in your microwave oven, which I suspect is a magnetically-focused reflex klystron. Doug butler (talk) 23:45, 3 July 2018 (UTC)

I won't argue the point about a reflex klystron, but I did want to add (edited today) that there are other kinds of magnetron besides cavity magnetrons. I suspect it's one of those terms (magnetron, that is) that grew organically and at various times meant something different to different people. I am not remotely an expert on HiPIMS (high-power impulse magnetron sputtering) but I gather that the "magnetron" is not a cavity magnetron (similar, but not the same) - although, confusingly enough, there may also be conventional cavity magnetrons involved for the production of the microwave power used in HiPIMS. An expert on HiPIMS and/or DC planar magnetron sputtering is welcome to chime in. Petwil (talk) 19:30, 14 December 2020 (UTC)

Reading High-power_impulse_magnetron_sputtering, it doesn't mention magnetron at all, except in the title. (Unless I missed it.) As well as I understand it, the name came from an attempt to get around the DeForest triode patent, by using a varying magnetic field instead of electric field (from a grid) that DeForest used. It was found that the resulting device would often oscillate undesirably. That led to devices designed around the oscillating modes, which led to the (resonant) cavity magnetron. As well as I know, either when the patent ran out, or earlier, work on the early device stopped. Electrons go in circles in a magnetic field, more complicated patterns when electric and magnetic fields are both present. Gah4 (talk) 20:37, 14 December 2020 (UTC)

Reading Sputter_deposition it isn't obvious that the word magnetron is used to describe the device, but only its operational mode. That is, electrons and/or ions go around in circles while sputtering, a magnetron-like effect, but the device isn't named for it. We should have a WP:RS either way. Gah4 (talk) 20:48, 14 December 2020 (UTC)

Sounds like you know the background there better than I do. I've only tangentially heard of HiPIMS on the job. Feel free to re-word (or I will) the paragraph I put in, then. Mainly, I was putting that section there as clarification to myself, since the term "magnetron" in DC sputtering and in HiPIMS is otherwise confusing. Thanks for the input. Petwil (talk) 23:18, 15 December 2020 (UTC)

It looks to me, and this would be WP:OR if I actually did any R, that magnetron is used as an adjective. The operation has some similarities to the operation of an actual magnetron, but it isn't one. Magnetron-like might have been more appropriate, but it is rare to make sure that names are actually appropriate. If it sounds good, it sells better. Among other important differences is that magnetrons normally operate as vacuum tubes, not filled with gas or plasma. But I hadn't heard of HiPIMS before this, either. Gah4 (talk) 00:14, 16 December 2020 (UTC)

Magnetron cut with Colt revolver jigs, not Colt pistol jigs

Pistol refers to a semi automatic with no cylinder. — Preceding unsigned comment added by TomHynes75 (talk • contribs) 14:36, 24 September 2018 (UTC)

No, it really doesn't. Pistol could be any type of pistol. A revolver is just one type. There are single shots, semi-auto, auto, flint lock, etc etc etc. Revolver is simply one specific type of pistol While I do agree that the word 'revolver' is correct here for obvious reasons, I disagree with your statement above since it is not true that the word "pistol" refers to a semi-automatic weapon. That is false. 73.6.96.168 (talk) 08:55, 10 April 2021 (UTC)

centimeters long

What shape antenna was used with early magnetrons? Long is one dimension, but antennas often (but not always) need three dimensions. Gah4 (talk) 16:18, 18 January 2022 (UTC)

accelerators and phase

The article mentions linear accelerators as a current use. All that I know of use klystrons, because they need to get the phase right. Gah4 (talk) 12:28, 30 March 2023 (UTC)