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Can an amatur biult Cyclotron power a free electron laser?

  1. Apr 10, 2006 #1
    has anyone attempted this as a project?
     

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  3. Apr 11, 2006 #2

    ZapperZ

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    Forget about the cyclotron itself. Can you just tell me how you are going to produce 1 nC of charge in roughly 10 ps pulse time scale with an emittance of 1 mm-mrad or better? That is the standard to produce a FEL using a typical undulator insertion device.

    Zz.
     
  4. Apr 11, 2006 #3
    I planned to use a very high resolution modern computer based signal generator in conjuction with a very specialized amplifier. To drive a pair of large specialy tuned tesla coils to produce the 1 nC of charge at roughly 10 ps pulse time,The Beam spot radius is the hard part..... I was hoping i might be able to focus it with electro magnets(focusing coils) before entering the undulator. does that sound viable??


    ps:please excuse spelling
     
    Last edited: Apr 11, 2006
  5. Apr 11, 2006 #4

    ZapperZ

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    Er.. how? Tesla coils? What does that have anything to do with your ability to create 10 ps electron bunches? What do you think most FEL facilities use to do that? A Photoinjector! And the magnetic field has zero ability to affect the TRANSVERSE emittance of the electron beam, which is what will muck up ANY FEL.

    Again, this is all way before the bunches get into your "cyclotron". So we haven't even talked about the problems that pop up in there.

    Zz.
     
  6. Apr 11, 2006 #5
    so how does the undulator work?

    the t-coils are to power the Photoinjector.
     
    Last edited: Apr 11, 2006
  7. Apr 11, 2006 #6

    ZapperZ

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    Yikes. Don't you think you need to know this before you start wanting to produce an FEL?

    Er... power? Do you know what a "photoinjector" is?

    Zz.
     
  8. Apr 11, 2006 #7
    RF photoinjector is a kind of high-brightness electron beam source.

    to work it requires high potencials at rf frequency wich you generate from specalised tesla coils(tuned resonant coils).
     
    Last edited: Apr 11, 2006
  9. Apr 11, 2006 #8

    ZapperZ

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    What's with this obsession with tesla coils?

    A photoinjector is an electron source, sure, but you missed a very important element of it - the PHOTO part. It generates electron pulses via intense laser pulses. These laser pulses are 10 ps long, something NOT very easy to do. We have something the size of a refrigerator called a ReGen (regenerative amplifier) that does the pulse timing and pulse shaping. You then have to mode-lock the trigger with the RF that goes into the photoinjector cavity, which, btw, has to be extremely carefully TUNED to the fundamental TEM mode frequency coming from the Klystron. Then you need to be able to get the laser pulse to hit the photocathode at just the RIGHT timing on the RF phase to cause not only an acceleration but also a bunch compression. Not only that, the photocathode you choose must have a work function that is JUST below the photon energy from the laser because you want the electrons to be generated COLD to minimize a large energy spread of the photoelectrons... etc.... etc.

    Again, this is JUST at the photoinjector side of it. We haven't even gotten into the ring yet.

    I work at a facility that not only does research on producing high brightness beams for particle colliders, but also for FEL, and in particular SASE FEL with a potential to produce THz radiation. I think before you embark on something like this, you should at least understand the physics involved (not just the engineering aspect), especially beam physics, and also go visit an FEL facility. Reading about it, and seeing pictures, are very superficial.

    Zz.
     
  10. Apr 11, 2006 #9
    its those big sparks :rolleyes:

    what type of laser is it?


    :eek:

    well.. give me half a chance, thats why im here :wink:
     
    Last edited: Apr 11, 2006
  11. Apr 12, 2006 #10
    ok so the photoinjector is pumped with a laser pulse...... your obviously the person to ask,so perhaps you could anser a few more questions.

    What can you tell me about the laser itself?,is it solid state, tube,die, diode?

    What wavelength (NM) output is it?

    How many whatts of output does it produce?

    How do you time the laser pulse's?,is it with the lasers input or is it done by a unit somewhere after the beam leaves the laserhead?
     
    Last edited: Apr 12, 2006
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