[sdiy] Re: OT Klystron

[The Peasant]

Quoting Magnus Danielson <cfmd at swipnet.se>:

> From: The Peasant <epeasant at telusplanet.net>
> Subject: Re: OT Klystron [was Re: [sdiy] Tube ring mod]
> Date: Wed, 18 Jun 2003 11:44:28 -0700
> 
> > Well, every day I work work with 10 megawatt klystrons
> and 
> > 5 megawatt magnetrons in linear accelerators. Would you
> 
> > like me to save you one?  ;-)=
> 
> Please... ;O)

OK, but you pay shipping on the 200 pound wooden crate!
 
> > We pulse them up to 110KV @ 100A, fun stuff! Then we
> use 
> > the RF output to excite the actual accelerating
> waveguide, 
> > which is basically a large tube with tuned RF cavities,
> 
> > 2.998 gigahertz. Anyone for a 22 MeV electron beam?
> (That's 
> > 22 million volts, folks, please stand back) How about
> 18 
> > MeV of photon (gamma) radiation?
> 
> So this tube is what? A klystron and magnetron enhanced
> mode diode?


Sure, it's basically a huge x-ray tube, but with RF 
exitation for accelerating the electrons through the tube 
instead of a DC power supply. It's a whole lot easier to do 
it this way than trying to build a high current megavoltage 
DC supply. ;-)

The beam is focussed with servo coils, steered with other 
coils, and then is either scattered for a uniform diverging 
electron beam, or blasted into a water-cooled target to 
generate X-rays instead.

Smaller machines use magnetrons for the RF input, larger 
ones use klystrons. BTW, the klystron was invented by the 
Varian brothers, who combined two "rumbatron" tubes (named 
for the similarity between the "Rumba" type dance and the 
tubes internal field fluctuations) into a *dual rumbatron*. 
They then decided that Klystron sounded better. Ahhhh, the 
golden age of tube research!
 
> No fancy gates to modulate it with?

The beam is multi-servoed in many ways (freq., pulse rate, 
instantaneous output, average output, flatness, symmetry, 
etc.), but the sound that they generate is mainly the pulse 
repetition rate (180 or 360Hz), mostly because I'm unable 
to hear the 2.998GHz with my particular ears. (Good place 
for freq. shifting?) The accelerators 15 years ago were all 
analogue control, listening to the drone as the servos 
regulated output with frequency modulation was pretty cool. 
Now they regulate by digital means, dropping pulses, so 
they sound much more boring.
 
> Could be used as a diode receiver maybe?

You could connect it directly to the transmitters output!
 
> Rectifier for a smaller power-supply I guess.
> 
Right, just a *little* 22 Megavolt power supply, give your 
friends fun shocks!

Take care,
Doug
______________________
The Electronic Peasant

www.electronicpeasant.com