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WikiProject Physics (Rated B-class, Low-importance)
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Klystrons are "tuned" to a specific frequency, i.e. the size of the microwave cavity at the output stage (at least on the klystron that I work with) is adjustable so that it's resonant at different frequencies. This makes it a great amplifier, but with a narrow bandwidth. At 800MHz, the klystron only operates (efficiently) within a MHz or two. Next time I get the chance I'll get a photograph.

Some modern klystrons do have substantial bandwidth - 10% is pretty much the upper limit though. Dont think twice 04:41, 6 August 2007 (UTC)

I'd presume that 6MHz bandwidth at 470-804 MHz would be the minimum requirement to pass a broadcast communication signal in the UHF TV bands; PAL would in most countries widen that to 8MHz. Is the intent that this tube pass the entire broadcast signal or just the carrier? -- (talk) 19:54, 3 January 2009 (UTC)

Has anyone actually seen a klystron used as an oscillator? As I understand it they need an imput frequency to operate and are strictly amplifiers. I suppose it could be argued that they are part of the frequency standard for particle accelerators, but even then they are ultimatly coordinated to an atomic standard. Does anyone have a different perspective to offer?

There are two types of klystrons: reflex klystrons, which have a single cavity, and operate as oscillators, and multi-cavity klystrons, which are amplifiers. Nowdays, nobody uses reflex klystrons, so it is safe to say that all modern klystrons are amplifiers.Dont think twice 04:24, 6 August 2007 (UTC)

Anyone in Sunnyvale, California should pop into Fry's Electronics there, where they have on display a giant Varian klystron tube, taken from a 1950s naval radar set (the tube is about ten feet tall and maybe three inches in diameter). It would be great if wikipedia had a photo of it, but Fry's don't let you take photos inside the building. I suppose someone could ask them if that would be okay, but they're probably to stupid to understand. Smellycat

Klystrons can be used as either single-frequency (resonant) amplifiers or oscillators, the small reflex types were often used as oscillators only. Big klystrons are used to drive the particles in accelerators, they are commonly fed from a common frequency source. It need not be a very accurate source, but if you are using a giant linac for serious science, a stable and reliable source is a good idea.


The "Two Cavity Klystron" section shows the anode right next to the electron gun. Should't it be down by the collector at the end of the drift tube, or at least to the right of the seccond cavity?

Actually, the anode is right by the electron gun. The electrons are created on the cathode, and then accelerated by the anode. They are "tricked" into passing through a hole in the anode, however, and continue to travel through the RF interaction circuit with a constant velocity. Dont think twice 04:24, 6 August 2007 (UTC)

I also wander what on earth they need a klystron for at a deep space listening station. The one pictured at the bottom on the article would easily be the biggest klystron I have ever seen, and useless at a station that is intended only for listening. Is it possible that it is in fact some other piece of equipment?

It would be nice if there were some indication of the size in the excellent picture of the high-power klystron used at the Canberra Deep Space Communications Complex. Dawright12 (talk) —Preceding undated comment added 17:45, 7 December 2012 (UTC)

Request for expansion[edit]

Klystron tube#Multibeam klystron needs more (or at least more comprehensible) details to differentiate it from the other types of klystron already well-writen on that page. --Kgf0 21:14, 13 October 2005 (UTC)

It's not clear from a quick glance at this page which klystron one would deploy to build a powerful UHF TV transmitter or how these are used, although some individual station articles do appear to link here because the failure of a tube this powerful can take a megawatt broadcast station off the air rather effectively. -- (talk) 19:54, 3 January 2009 (UTC)

Developed by?[edit]

I was under the impression that almost all German WWII radars were Klystron based. If this is true, then the history section of this article appears to be wrong. Maury 15:10, 17 December 2005 (UTC)

Diagram text[edit]

Collector is spelled wrongly--Light current 21:29, 10 April 2006 (UTC)

And 'spelled' is spelt wrongly in the above comment. (talk) 13:15, 14 January 2010 (UTC)


Does anybody know if the Varian Associates mentioned in the article is the same company as Varian Medical Systems? -- RoySmith (talk) 00:04, 4 June 2006 (UTC)

Varian was started by the Varian brothers to develop klystrons, as the article states. Eventually, they got into medical systems, since klystrons are used to drive x-ray systems. The medical part of the business overtook the klystron part, and Varian Medical Systems was spun off. The original part of Varian that made klystrons is now called CPI (Communications Power Industries), and is still located on essentially the same campus with Varian Medical. Dont think twice 04:24, 6 August 2007 (UTC)
I think it probably is (or at least stems from the same origins) but I have no proof. 8-(--Light current 00:06, 4 June 2006 (UTC)
See [1]. 121a0012 01:16, 4 June 2006 (UTC)

Tuning a klystron[edit]

Somebody else wrote that passage; all I did was edit. As for beryllium, I can verify that it's toxic, but I doubt that these days people use beryllium alloys for working in high mag fields. I know that service tools for MRI machines with superconducting magnets have mostly gone to titanium alloys. Before that, aluminum and copper alloys were popular. I can't imagine beryllium. Must be one of those zillion dollar military thingies.

As for giving advice, that whole section is advice-giving. The difference between advice and encylopedia writing is merely style. "This is how you do X" is advice. "This is how many people do X" is encyclopedic. Many people do wash hands after handling beryllium. :). Steve 23:56, 30 June 2006 (UTC)

RE: Tuning[edit]

Actually the US Air Force uses beryllium tools to tune thier klystrons for thier aging TRITAC microwave[2] and SATCOM [3] equipment systems. Even with the Air Force being safety concious, beryllium tools are still in use to-date.

As far as that TRC-170 shown in the link, I have to say they are rugged and dated machines, but they are still in use. The beryllium tools were included in the equipment's "Kit n' Kaboodle", might as well use what came with it. These systems, by the way, are listed in FEDLOG[4] for approximately 1 million USD.

Thanks though for your advice on in article advice :P, I will apply this methodology to future article additions. M jurrens 19:06, 25 July 2006 (UTC)

Interesting. Perhaps use of beryllium is an aircraft weight thing from the bad old cost-plus days of SAC. By the way, the name is not capitalized. Names of elements are lowercase when written out (carbon, oxygen, iron, beryllium), and only capitalized when in chem symbol (C, O, Fe, Be).SBHarris 19:30, 25 July 2006 (UTC)
Funny you should mention SAC(Strategic Air Command), I happen to be assigned under ACC(Air Combat Command) which is the same thing in present day terms ;0. M jurrens 21:00, 25 July 2006 (UTC)

Performed minor copy editing and added a few internal links for clarity (the explanation of ferrous tools was a bit clunky). HuntingTarg (talk) 02:42, 6 May 2009 (UTC)

What are the oscillation frequencies attainable[edit]

for a given power level for various designs? Little discussion of that in current article except about one type in 3GHz range. Thanks,Rich 15:30, 2 December 2006 (UTC)

Proper explanation[edit]

I replaced the previous 'explanation' with a new one because it was, quite frankly, crap, and didn't explain anything. It is however a reasonable introduction, so I put it there. If somebody needs to nitpick about the details of my explanation please do it here. I showed previous and current explanation to a girl who studies psychology and doesn't know anything about physics. She understands mine. Tip for PHD's and professors: An explanation should be EXPLANATORY (ie. after one you know how it works). Crusty007 (talk) 20:08, 5 February 2008 (UTC)

+1 to that. One of the cardinal rules of teaching is "you don't understand it until you can (successfully) explain it to someone else." —Preceding unsigned comment added by HuntingTarg (talkcontribs) 02:44, 6 May 2009 (UTC)