Is there a gamma ray gun?

[0rbytal]

A couple of questions in this one, and I don't know if these have been addressed before - if so, disregard thread:

I have been told that frequent exposure to x-ray's causes cancer (but what doesn't!), so what are the physiological effects of gamma ray exposure? Where do gamma rays come from naturally? If we have a device that takes x-rays ( or "shoots" x-rays ), do we have a device that shoots gamma rays? (i.e. a gamma ray gun?)

[Q.E.D.]

Gamma rays are produced naturally by radioactive decay and in supernovae, and artificially in particle accelerator experiments. We don't have any way of producing large amounts of them, AFAIK.

[Mangetout]

I suppose a gamma ray gun could be a gamma-emitting isotope in a box made from something that blocks gamma rays, with a window in the box.

Isn't gamma radiation what they (want to) use for preserving foodstuffs?

[scr4]

IIRC they use both hard X-rays and gamma rays for food irradiation. They use radioactive isotopes for that. Also, almost all laboratory experiments with gamma rays are done using radioactive isotopes. Same with non-destructive testing.

X-rays are fairly easy to generate - you heat a filament in vacuum to get a supply of free electrons, apply 60,000 volts or so to accelerate the electrons, and smash those electrons onto a target (typically tungsten). Voila, 60 keV X-rays, just what you need to see through human bodies and luggage. But to make 1-MeV gamma rays you need a 1-million volt power supply. Those are not easy to come by, as I understand. Radioactive isotopes are so much easier to use.

[CalMeacham]

The distinction between x-rays and gamma rays is fuzzy. The wavelength ranges definitely overlap. Gamma rays are higher in energy (shorter in wavelength) and are the kind you get from atomic decay. X-rays typically come from bremstrahlung (accelerating or decelerating charges).

It has been the goal of laser physicsts to produce a gamma-ray laser, which could also be a short x-ray laser (long wavelength x-ray lasers already exist). Some people call this a GRASER, for Gamma Ray Amplification by Stimulated Emission of Radiation, but one researcher suggested calling it a GRAIL, especially since it was so hard to achieve.

There are no gamma-ray lasers AFAIK. A lot of the problems associated with building a Laser become even harder at the short gamma ray wavelengths, especially the problems of finding a good mirror material. There are no solids transparent at really short wavelengths (LiF is the solid that is transparent farthest into the UV, and I believe that it cuts out before getting as low as 180 nm).


Edward Teller's "Excaliber" "third generation nuclear weapon" , which set off Resagan's SDI love, wasn't so much a laser as a case of ASE (Amplified Stimulated Emission) directed along the axes of the wires vaporized by the nuclear blast that pumped it. I've heard that there was controversy about whether they really achieved Lasing/ASE with their underground tests of the device, just as there was controversy (and later disbelief) over the claims of laser-driven X-Ray laser at the University of Utah back in the 1970s.

[Squink]

Here's a device that produces a gamma ray beam at 2.4 GeV. Apparently they generate the beam by bouncing a UV laser off of an accelerator generated 8GeV electron beam.
If you're willing to settle for a bit less power and directionality, you could use a Pelletron to irradiate fluorine gas. The beauty here is that the device is small enough to fit in a typical basement.

[FriendRob]

Biological effects: IANA biological physicist, but I expect gamma rays would do more damage than X-rays because they carry more energy. Radiation therapy for cancer can involve putting a radioactive substance near the tumor where it releases gamma rays that kill the cancer cells.

Sources: Many astrophysical sources create gamma rays. There is an orbiting Gamma Ray Observatory (GRO) that looks for such things. Gamma rays from space usually don't make it to earth: they hit atoms in the atmosphere and cause showers of "cosmic rays". This is fortunate for us (see above).

[scm1001]

It depends hw you measure the radiation FriendRob. Gamma rays are more penetrating so less are absorbed by the body. So in Curie terms (disintegrations per second) they are less dangerous than say X-rays or beta rays. In terms of Rads, all radiation is equivalent, as a Rad measure the energy absorbed by the body

[Napier]

CalMeacham is right - the distinction is fuzzy between X-Rays and Gamma rays. By some authorities, the definitional difference between them is whether they are man-made (X-rays) or emitted by radioactive elements (Gamma rays). By this definition you could never make a Gamma ray gun, unless you used the Gamma radioemitter in a box.

[ccsccs]

There are PATENTS on gamma ray lasers!
Just go to the US patent website: http://www.uspto.gov/

Check out patent #3557370 (1971)
Gamma Ray Laser Having A Low Temp. Closed Resonating Cavity
Notable quote from that patent:
" For instance, calculations indicate that when a one curie source of Sn119m is stimulated, it will release its entire energy in a period of less than 100 nanoseconds, thereby providing an energy source of approximately 30,000 megawatts..."

or #3233107 (1966) Coherent Gamma Radiation.

#3234099, 3281600 have further details on how it is done, using Mossbauer isotopes.

There are also patents on how to modulate a gamma ray laser beam so it can be used to send voice, data, even video over it. NOTHING will stop it or interfere with it! Even at the bottom of the ocean....

[Mijin]

Gamma rays are used relatively routinely in radiosurgery. There is the concept of the "gamma knife" which is a bunch of converging rays intended to ablate a target area and spare the surrounding tissue (cite).

I don't know if it is effective against zombies though.

[Malacandra]

Ah, they're 1920s-style "Death Rays".

[Napier]

Originally Posted by ccsccs

There are PATENTS on gamma ray lasers!
Just go to the US patent website: http://www.uspto.gov/

Check out patent #3557370 (1971)
Gamma Ray Laser Having A Low Temp. Closed Resonating Cavity
Notable quote from that patent:
" For instance, calculations indicate that when a one curie source of Sn119m is stimulated, it will release its entire energy in a period of less than 100 nanoseconds, thereby providing an energy source of approximately 30,000 megawatts..."

or #3233107 (1966) Coherent Gamma Radiation.

#3234099, 3281600 have further details on how it is done, using Mossbauer isotopes.

There are also patents on how to modulate a gamma ray laser beam so it can be used to send voice, data, even video over it. NOTHING will stop it or interfere with it! Even at the bottom of the ocean....

The patents don't mean these things work. They can be "paper patents" that protect hypothetical devices. The "calculations indicate" quote smells like this to me. A paper patent is only worth the paper it is printed on if it does not turn out to work.

At least, that's my understanding based on courses I took years ago. Please correct me if I have muddled something!

[Zsofia]

I thought they just gave you really bad taste in purple pants?

[The Tao's Revenge]

Originally Posted by Zsofia

I thought they just gave you really bad taste in purple pants?

Hey those pants don't rip. Thank goodness for those pants.

[Rampant Coypu]

There are X-ray lasers which could be build and are pretty close to a gamma ray gun. Main problem is that they need to be pumped by a nuclear explosion, so you are not gonna get an an X-ray pistol. This is a space based weapon fit for a mine or missile.

But there's one big problem here. The effects of the nuclear explosion happen so fast that the x-ray lasers will not bumped off target. But the chemical trigger for the nuke will make shock waves that will spoil the aim of the bomb pumped x-ray lasers. Of course you could initiate the nuke with lasers or particle beams, but if you could sacrifice such things to an x-ray laser, why not use them as your primary weapons?

This is what I understand from the Atomic Rockets website.

[Rhythmdvl]

So how do we find out how gamma rays affect man-in-the-moon marigolds?

[The Niply Elder]

Originally Posted by Napier

The patents don't mean these things work. They can be "paper patents" that protect hypothetical devices. The "calculations indicate" quote smells like this to me. A paper patent is only worth the paper it is printed on if it does not turn out to work.

At least, that's my understanding based on courses I took years ago. Please correct me if I have muddled something!

Even more when the equations have energy with units of megawatts...

[Rampant Coypu]

There are a few laws f futuristic weapons.

The first is that anything traveling over 3kn/sec packs its own weight in kaboom.

The second is that anything that could power a pulse laser that was effective as an assault rifle shot would be more useful as a new type of bomb.

I would add a third: any device that could initiate an x-ray laser without jarring it off target would be an more effective weapon than an x-ray laser.

[Mijin]

Originally Posted by Mijin

Gamma rays are used relatively routinely in radiosurgery. There is the concept of the "gamma knife" which is a bunch of converging rays intended to ablate a target area and spare the surrounding tissue (cite).

To add to this; I see that the gamma knife works by simply housing radioactive cobalt within a heavily-shielded box, with a space to allow a (very narrow) beam out.

So it's nothing like how a laser gun works, and it would get weaker over time, but you could make a box that was pistol-shaped, and the trigger could simply open and close the barrel. Job done.