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Is it possible to make a gamma-ray laser?

  1. Jun 11, 2008 #1
    Hi:

    Is it possible to make a free-electron laser that emit coherent gamma
    rays? If so, could this laser be used to ignite Hydrogen-Boron fusion?

    Thanks,

    Radium
     
  2. jcsd
  3. Jun 11, 2008 #2
    Green Xenon [Radium] wrote:
    > Hi:
    >
    > Is it possible to make a free-electron laser that emit coherent gamma
    > rays? If so, could this laser be used to ignite Hydrogen-Boron fusion?


    Since by definition gamma rays are emitted by nuclei I'd say its
    impossible. X-rays of the same wavelength however...

    --
    Dirk

    http://www.transcendence.me.uk/ - Transcendence UK
    Remote Viewing classes in London
     
  4. Jun 12, 2008 #3
    On 10 Jun, 17:52, "Green Xenon [Radium]" <gluceg...@excite.com> wrote:
    > Hi:
    >
    > Is it possible to make a free-electron laser that emit coherent gamma
    > rays? If so, could this laser be used to ignite Hydrogen-Boron fusion?
    >

    Yes it is. A nuclear bomb though is required to pump it. Any
    wavelength can theoretically lase. There has in fact been a proposal
    to use an X/Gamma ray laser in an ABM system. The theory is all known.
    The idea is to point rods towards incoming missiles and then detonate
    a nuclear bomb. The material will stay in place just long enough for
    the laser pulse.

    A free electron laser is I feel impossible as you would need the sort
    of magnetic fields you get round black holes.

    Whether the laser should be built or not is a political and moral
    question. There are you know limits for moral scientific enquiry.


    - Ian Parker
     
  5. Jun 12, 2008 #4
    ive got to admit though it would be cool to see
     
  6. Jun 12, 2008 #5

    mgb_phys

    User Avatar
    Science Advisor
    Homework Helper

    Technically 'seeing' it would be a bit tricky!
    I suppose it would be cool to see it melt your head.
     
  7. Jun 13, 2008 #6
    Dirk Bruere at NeoPax wrote:

    > Green Xenon [Radium] wrote:


    >> Hi:
    >>
    >> Is it possible to make a free-electron laser that emit coherent gamma
    >> rays? If so, could this laser be used to ignite Hydrogen-Boron fusion?


    >
    > Since by definition gamma rays are emitted by nuclei I'd say its
    > impossible. X-rays of the same wavelength however...
    >


    Then could an X-ray laser be used to initiate HB fusion?
     
  8. Jun 13, 2008 #7
    On Jun 10, 9:52=A0am, "Green Xenon [Radium]" <gluceg...@excite.com>
    wrote:
    > Hi:
    >
    > Is it possible to make a free-electron laser that emit coherent gamma
    > rays? If so, could this laser be used to ignite Hydrogen-Boron fusion?
    >
    > Thanks,
    >
    > Radium


    A high energy FEL appears theoretically possible and allows a modest
    energy. A several MeV energy level is allowed. What happens is a
    bunch as the wiggled electron set can not be aligned as a whole
    packet, disallowing ultra high energy levels.

    A 5 MeV limit effectively exists. Distortion of the bunch causes the
    magnetic field to also distort. A focusing is not present in FEL's
    because of the difficulty in field gradient versus field x-axis
    acceleration. x-axis as the wiggled axis must be a suitably high
    displacement and the magnetic field density as a length causes the
    field to wiggle as a whole set of accelerator magnets. Meaning the
    whole length emitts as a laser, it is not magnet element by element
    Bremsstralung.

    So the axis free energy as a local effect becomes the stimulated atom
    set, in effect, in analogy to a gas laser. FELs are true lasers, but
    atomic excitation does not occur.

    Axis acceleration versus length magnetic field gradient allows a state
    as a wire coil excitation. Excited field coils form the laser in FELs,
    not excited gas atoms. A property of the coil allows focusing to
    overcome this limitation. An RF waveguided cavity inside the FEL can
    allow ultrahigh energy levels. A small linac field will cause a
    slight bunching preventing distortion of the wire coil's magnetic
    field.

    A literal vacuum cavity using suseptable metal becomes the interior of
    a good simple wiggler magnet.
     
  9. Jun 13, 2008 #8
    Ian Parker wrote:
    > On 10 Jun, 17:52, "Green Xenon [Radium]" <gluceg...@excite.com> wrote:
    >> Hi:
    >>
    >> Is it possible to make a free-electron laser that emit coherent gamma
    >> rays? If so, could this laser be used to ignite Hydrogen-Boron fusion?
    >>

    > Yes it is. A nuclear bomb though is required to pump it. Any
    > wavelength can theoretically lase. There has in fact been a proposal
    > to use an X/Gamma ray laser in an ABM system. The theory is all known.
    > The idea is to point rods towards incoming missiles and then detonate
    > a nuclear bomb. The material will stay in place just long enough for
    > the laser pulse.
    >
    > A free electron laser is I feel impossible as you would need the sort
    > of magnetic fields you get round black holes.
    >
    > Whether the laser should be built or not is a political and moral
    > question. There are you know limits for moral scientific enquiry.


    AIUI the US tried to build such a laser and failed.
    Too little energy was converted to gamma rays.

    Ditto induced gamma emmision from pumped isomers, although any major
    success would probably be classified immediately because of its military
    implications.
    http://en.wikipedia.org/wiki/Induced_gamma_emission

    --
    Dirk

    http://www.transcendence.me.uk/ - Transcendence UK
    Remote Viewing classes in London
     
  10. Jun 13, 2008 #9
    I dont think i would really 'see' it melting my head, do you ?
     
  11. Jun 13, 2008 #10

    Astronuc

    User Avatar

    Staff: Mentor

    It appears mgb_phys is reacting to the comment about 'seeing' a gamma-ray laser, but I don't believe that is what one meant. I believe one meant that it would be interesting to see/observe the effects of an operating gamma laser, or rather, a concentration of gamma radiation.

    Clearly X-ray and gamma rays are 'invisible', i.e. like UV they are outside of the visible spectrum. X-rays and gamma rays are highly penetrating, with the penetration increasing as a function of energy. They are also ionizing since they interact with atomic electrons (photoelectric effect and Compton scattering) and nuclei (electron-positron pair production).


    Basically X-rays/gamma rays of wavelengths comparable to atomic lattices can be focused. With shorter wavelengths, they can't be focused but would more likely scatter, and the scattering increases with energy.


    Free electron laser are somewhat limited in wavelength/frequency.

    http://en.wikipedia.org/wiki/Free_electron_laser

    But - http://www.anl.gov/Media_Center/Frontiers/2002/b2excell.html

     
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