Klystron output voltage, cavity field strength
时间：04-04
整理：3721RD
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Hi I am reading about klystrons for some time, Now I understand the bunching and velocity modulation due to the E field between the cavity plates where the electrons pass through the hole in the middle,
here is the thing that I think i'm still missing,
so the electrons come out of a electron gun and are accelerated by a large DC potential , say 450kV for example, the beam itself has a current of say 450A. Now as this current passes the first cavity some parts of the beam feel an opposing E field while some feel an accelerating one, now the electrons as they travel along the drift tube bunch up as these bunches travel through the output cavity they induce E fields between the cavity plates , which I assume are strong , probably on the order of kV/cm, then further I assume that this E field charges up the cavity plates and as they charge and discharge through the cavity torus it creates a current in the torus which sets up a toroidal shaped B field within the torus,
1)so the coax or waveguide output is taken from a single loop located within the torus structure , does this mean that the output from a klystron is coupled via the B field inside the torus?
2)Also are there any estimates as to how strong this toroidal B field is for a given klystron?
3)And another question, I read on some papers that the E field at the output cavity windows (where waveguide is attached) can reach strengths up to say 60MV/cm, I cannot understand how can one have such a strong E field given the klystron beam accelerating voltage is 610kV?
https://www.osti.gov/servlets/purl/1110653
see page 17
here is the thing that I think i'm still missing,
so the electrons come out of a electron gun and are accelerated by a large DC potential , say 450kV for example, the beam itself has a current of say 450A. Now as this current passes the first cavity some parts of the beam feel an opposing E field while some feel an accelerating one, now the electrons as they travel along the drift tube bunch up as these bunches travel through the output cavity they induce E fields between the cavity plates , which I assume are strong , probably on the order of kV/cm, then further I assume that this E field charges up the cavity plates and as they charge and discharge through the cavity torus it creates a current in the torus which sets up a toroidal shaped B field within the torus,
1)so the coax or waveguide output is taken from a single loop located within the torus structure , does this mean that the output from a klystron is coupled via the B field inside the torus?
2)Also are there any estimates as to how strong this toroidal B field is for a given klystron?
3)And another question, I read on some papers that the E field at the output cavity windows (where waveguide is attached) can reach strengths up to say 60MV/cm, I cannot understand how can one have such a strong E field given the klystron beam accelerating voltage is 610kV?
https://www.osti.gov/servlets/purl/1110653
see page 17
Can anybody say anything with regards to my post ?
thanks.
This is such a specialized field that I doubt may people would have experience to share. You are probably more likely to get answers by contacting a Klystron manufacturer. 75 Megawatts is a LOT of power, I've used Klystrons but only low power ones ~5W as CW generators and that was about 40 years ago so my recollections are fuzzy to say the least.
I think the answer to question 1 is yes, that is exactly how the coupling probe works but I'm afraid I can't help with your other questions.
Brian.