How does a Klystron work?

Answer 1

A klystron is a specialized vacuum tube (evacuated electron tube) called a linear-beam tube.

Two-cavity klystron amplifier
In the two-chamber klystron, an electron beam from the cathode of an electron gun is injected into a resonant cavity. The electron beam is constrained by an axial magnetic field and is accelerated through a connecting passage (called a drift tube) to a second resonant chamber containing a positively charged anode. While passing through the connecting chamber the electron beam is velocity modulated (periodically bunched) by the weaker RF signal. The negative electrons are attracted to the positive anode contained in the second resonant chamber. As the bunched electrons enter the second chamber they induce standing waves at the same frequency as the input signal. The signal induced in the second chamber is much stronger than that in the first.

Two-cavity klystron oscillator
The two-cavity amplifier klystron is readily turned into an oscillator klystron by providing a feedback loop between the input and output cavities. Two-cavity oscillator klystrons have the advantage of being among the lowest-noise microwave sources available, and for that reason have often been used in the illuminator systems of missile targeting radars. The two-cavity oscillator klystron normally generates more power than the reflex klystron—typically watts of output rather than milliwatts. Since there is no reflector, only one high-voltage supply is required; however, to cause the tube to oscilate, the voltage must be adjusted to a particular value. This is because the electron beam must produce the bunched electrons in the second cavity in order to generate output power. Voltage must be adjusted by varying the velocity of the electron beam to a suitable level due to the fixed physical separation between the two cavities. Often several "modes" of oscillation can be observed in a given klystron.

For more see: http://en.wikipedia.org/wiki/Klystron

Answer 2

A klystron looks and works something like an organ pipe.
In an organ pipe:
Blowing into the organ pipe produces a flow of air.
Flowing air excites vibrations in the cavity of the whistle.
The vibrations flow into the surrounding air as sound waves

In a klystron:

The electron gun produces a flow of electrons.
The bunching cavities regulate the speed of the electrons so that they arrive in bunches at the output cavity.
The bunches of electrons excite microwaves in the output cavity of the klystron.
The microwaves flow into the waveguide , which transports them to the accelerator.
The electrons are absorbed in the beam stop.

Answer 3

Klystrons are used as an oscillator or amplifier at microwave and radio frequencies to produce both low power reference signals for superheterodyne radar receivers and to produce high-power carrier waves for communications and the driving force for linear accelerators. It has the advantage (over the magnetron) of coherently amplifying a reference signal and so its output may be precisely controlled in amplitude, frequency and phase. Many klystrons have a waveguide for coupling microwave energy into and out of the device, although it is also quite common for lower power and lower frequency klystrons to use coaxial couplings instead. In some cases a coupling probe is used to couple the microwave energy from a klystron into a separate external waveguide.

Answer 4

williegod's answer is a good one, however neither he nor the article give an idea of how big these things can be.

I used to work at one of the missile radars mentioned in the article and those Klystrons were about 6 feet long. Our radar put out pulses with about 4 to 5 Megawatts of power (we had our own coal powered plant for generating electricity). When one of those blew, you could hear it everywhere on the site.

Answer 5

There are different types of Klystron depending on your applicaiton. I'm only familiar with the type in Linacs however you can check out the wikipedia site for a good description or there are numerous books on Radiaiton Therapy that have a thorough description of one type.

Answer 6

check on the science journal

Answer 7

It works just fine.

Answer 8

god dont you even no that