Is it possible to make a gamma-ray laser?

  • Thread starter Green Xenon [Radium]
  • Start date
  • #1
Green Xenon [Radium]

Main Question or Discussion Point

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
 

Answers and Replies

  • #2
Dirk Bruere at NeoPax
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/ [Broken] - Transcendence UK
Remote Viewing classes in London
 
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  • #3
Ian Parker
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
 
  • #4
ive got to admit though it would be cool to see
 
  • #5
mgb_phys
Science Advisor
Homework Helper
7,774
12
ive got to admit though it would be cool to see
Technically 'seeing' it would be a bit tricky!
I suppose it would be cool to see it melt your head.
 
  • #6
Green Xenon [Radium]
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?
 
  • #7
Douglas Eagleson
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.
 
  • #8
Dirk Bruere at NeoPax
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/ [Broken] - Transcendence UK
Remote Viewing classes in London
 
Last edited by a moderator:
  • #9
Technically 'seeing' it would be a bit tricky!
I suppose it would be cool to see it melt your head.
I dont think i would really 'see' it melting my head, do you ?
 
  • #10
Astronuc
Staff Emeritus
Science Advisor
18,704
1,718
I dont think i would really 'see' it melting my head, do you ?
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.

The free-electron laser has the widest frequency range of any laser type, and can be widely tunable, currently ranging in wavelength from microwaves, through terahertz radiation and infrared, to the visible spectrum, to ultraviolet, to soft X-rays.
http://en.wikipedia.org/wiki/Free_electron_laser

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

Scientists and engineers at Argonne National Laboratory’s Advanced Photon Source (APS) achieved "saturation" of self-amplified spontaneous emission in a mirrorless free-electron laser at a wavelength more than 1,000 times shorter than the previous record. This accomplishment demonstrated that free-electron lasers based on this process may one day provide laser-quality X-ray beams and open exciting new horizons for research in dozens of scientific fields.

The beam of light produced in the experiment had a wavelength of 385 nanometers, placing it in the ultraviolet region of the spectrum. The success of the particular process employed at Argonne is gauged by whether the free-electron laser effect has "saturated," meaning the point at which the maximum power has been yielded by the electron beam and converted to coherent synchrotron radiation. The Argonne device clearly exhibited saturation of the process.
 
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