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Gamma-Ray Bending Opens New Door For Optics 65

sciencehabit writes "Lenses are a part of everyday life—they help us focus on words on a page, the light from stars, and the tiniest details of microorganisms. But making a lens for highly energetic light known as gamma rays had been thought impossible. Now, physicists have created such a lens, and they believe it will open up a new field of gamma-ray optics for medical imaging, detecting illicit nuclear material, and getting rid of nuclear waste."
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Gamma-Ray Bending Opens New Door For Optics

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  • Other uses (Score:4, Funny)

    by azalin ( 67640 ) on Wednesday May 09, 2012 @02:49AM (#39938687)
    ... and irradiated spiders that bite school children who become photographers
  • I bet this is what the mysterious "fogbank" material that the Feds forgot how to make actually does inside Thermonuclear devices.

    • Re:Fogbank? (Score:4, Insightful)

      by Anonymous Coward on Wednesday May 09, 2012 @03:21AM (#39938833)

      when you think to yourself "I know, I'll mention something obscure that people will need to look up on Wikipedia to know wtf I'm talking about!", you might want to double-check that Wikipedia doesn't contradict your claim.

      • Fact checking is outdated.
      • by ka9dgx ( 72702 )

        I'm just trying to figure out how the puzzle pieces go together.

        It wouldn't surprise me to learn that when "fogbank" is turned into a million degree plasma, that it has a refractive index high enough to focus gamma rays, or high energy x-rays. Or it could turn out that there it acts as a negative index metamaterial.

        Gadgets are fascinating things, one can never truly be sure of how they work, unless one has a clearance, and a well defined need to know. (I have neither).

        For example,I was surprised when read

        • It would surprise me and most Atomic physicists. The exact made up of weapon components is secret but the interactions of X-rays with matter, even hot dense matter is not and such experiments are well within the domain of even an average university lab.
  • Not impressive yet (Score:5, Insightful)

    by sFurbo ( 1361249 ) on Wednesday May 09, 2012 @02:55AM (#39938729)
    While this is an interesting deveopment, it is important to note the caveats: The refractive index in silicon, the only material tested so far, is only 1.000000001. IF this theory of how this is accomplished is correct, this MIGHT be higher for heavier elements. That's a big IF.
    • Even if it's guaranteed to be higher, say a factor 10 (i mean 1.00000001) , then the big IF is if this is usable.

  • by Anonymous Coward

    I call: "This will never work the way you want it too."

    • Re:n = 1.000000001 (Score:5, Insightful)

      by goodmanj ( 234846 ) on Wednesday May 09, 2012 @04:04AM (#39938977)

      Agree. Even if you do it with depleted uranium, and you suppose the "virtual electron effect" increases in proportional to the square of the number of protons in the nucleus, you might get an index of refraction in the ballpark of n = 1.000000033. Applying the lensmaker's formula [], a convex lens with radii of curvature of 1 cm will have a focal length of ....

      150 kilometers.

      So the gamma ray imaging camera you want to build for airport security will have to be roughly the same size as your flight. No, not the length of the plane, the mileage.

      • by azalin ( 67640 )
        Where are the "artists conception"s when you need one. Maybe if you built it on top, you could have a dome over the entire continental US. That should be big enough to provide a reason to raise the TSA budget again. Because security!
      • I'd use a Bose-Einstein condensate, with (light) refractive indexes between 1X10^6 and infinity
      • Re:n = 1.000000001 (Score:4, Informative)

        by kebes ( 861706 ) on Wednesday May 09, 2012 @09:12AM (#39940985) Journal
        I'm somewhat more hopeful than you, based on advances in x-ray optics.

        For typical x-ray photons (e.g. 10 keV), the refractive index is 0.99999 (delta [] = 1E-5). Even though this is very close to 1, we've figured out how to make practical lenses. For instance Compound Refractive Lenses [] use a sequence of refracting interfaces to accumulate the small refractive effect. Capillary optics can be used to confine x-ray beams. A Fresnel lens [] design can be used to decrease the thickness of the lens, giving you more refractive power per unit length of the total optic. In fact, you can use a Fresnel zone plate [] design, which focuses the beam due to diffraction (another variant is a Laue lens which focuses due to Bragg diffraction [], e.g. multilayer Laue lenses are now being used for ultrahigh focusing of x-rays). Clever people have even designed lenses that simultaneously exploit refractive and diffractive focusing (kinoform lenses []).

        All this to say that with some ingenuity, the rather small refractive index differences available for x-rays have been turned into decent amounts of focusing in x-ray optics. We have x-rays optics now with focal lengths on the order of meters. It's not trivial to do, but it can be done. It sounds like this present work is suggesting that for gamma-rays the refractive index differences will be on the order of 1E-7, which is only two orders-of-magnitude worse than for x-rays. So, with some additional effort and ingenuity, I could see the development of workable gamma-ray optics. I'm not saying it will be easy (we're still talking about tens or hundreds of meters for the overall camera)... but for certain demanding applications it might be worth doing.
        • You're right, that something can be done with this. But the original poster's point was that "This will never work the way you want it to." Not that it can never work, but it's a hell of a lot more complicated than anyone would hope. My post was intended to show just how badly "the way you want it to work" fails.

          • I would assume that "work the way you want it to" means the effect as in "lets us do the things we want to do", not the mechanism for achieving it as long as that mechanism is reasonable -- this is why the naive single-lens method doesn't work, because it's completely unreasonable to build such a giant lens, right? But who cares if there's a nice relatively compact way to make it work?

            If "the way you want it to" work is with a single lens, most visual optic devices outside of spectacles don't "work", eithe

      • 150 km, so what? They're largely non interacting with the atmosphere, you could set up your lenses in one place and your detector in another. No more difficult than any number of neutrino experiments. Or use a constellation of satellites, you could put the detector thousands of miles away if need be. Might be a 'big science' kind of project, but that doesn't mean it's not a usable phenomenon.

      • by modecx ( 130548 )

        150 kilometers.

        Low orbit particle cannon, you say?

      • Re:n = 1.000000001 (Score:4, Insightful)

        by rgbatduke ( 1231380 ) <rgb@ph y .> on Wednesday May 09, 2012 @11:16AM (#39942621) Homepage
        Well, yeah, except that all of the bending occurs at the interface surface. So in principle, one could stack 150 lensing surfaces constructed Fresnel-style and bring that right down to a kilometer. Depending on what the "interface surface" is for gamma rays. Or, stack 1500 of them and bring it down to 100 meters. Or stack 15,000 of them, in a 3D structure created with e.g. molecular beam epitaxy, and bring it down to 10 meters (with a lens with a total length of perhaps a meter). At that point it is conceivable that it might be useful, although probably not as an optical grade lens (wouldn't it be uber cool to build a gamma ray telescope with an aperture lens a meter across? Sure it would!)

        I think that a lot of these same principles are involved in building x-ray lenses -- the lens is less like a glass lens, more like building an interferometric scattering array that causes a single central primary peak. But not my specialty, just thinking out loud...

      • Agree. Even if you do it with depleted uranium, and you suppose the "virtual electron effect" increases in proportional to the square of the number of protons in the nucleus, you might get an index of refraction in the ballpark of n = 1.000000033. Applying the lensmaker's formula [], a convex lens with radii of curvature of 1 cm will have a focal length of ....

        150 kilometers.

        Well first they can get much smaller radii of curvature using the good old fashioned fresnel lens [] technology; with photolithographic [] fabrication the could not only get the lens radii of curvature down into the micrometer range they could stack hundreds or thousands into a lens system only a cm thick and only expend trivial effort.

  • to see this applied to Gamma Ray Bursts bearing in mind they burn more energy in an hour than our Sun will in it's 4 billion year life! Of course there's also applications for Gamma Ray Specs!!! Kewl
    • Gamma ray bursts are not objects themselves, but the result of the death of a supermassive star (or more rarely the merging of two neutron stars) and last no more than a few minutes, though most last under one minute. The energy output is considerable, but it's larger than you listed, putting out more energy than the sun ever will over the course of 10 billion years (from initial formation through red giant). We really don't want a nearby one pointed at us.

      On the totally unrelated topic of your signature,

  • by Anonymous Coward

    Admittedly, Gammasphere is quite primitive. It uses time and energy differentially ordered spectra to deduce rotation and energy levels of very short lived multi- level Yrast Gamma levels. Through computer analysis; the data is otherwise really quite disordered. And there is no focussing, Gammasphere is what is known as a 4pi detector. Omnidirectional.

    Focussed X-Ray spectroscopy is routinely performed now, at Light Sources, through advances in Material science; how to best deduce spectr

  • It's too small to be useful in tradition lens applications. Even at lower X-ray/Gamma energies when the refractive index is much bigger ( see: []) you can't really use make reasonable lens.

    It would be far far easier to increase the "commonly" available divergent sources' intensity than attempt to recover losses due to divergence with such a weakly focusing system. Hell, you could likely achieve a much bigger intensity increase by moving the source closer.

  • by Anonymous Coward

    It seems the idea of focusing gamma rays isn't as new. ESA made a study on it years ago. They proposed multilayer coatings and Laue crystals.
    ESA study on gamma lens []

  • So, is Gamma-ray-bending a special form of Energybending []?

  • shhhh... (Score:5, Insightful)

    by harvey the nerd ( 582806 ) on Wednesday May 09, 2012 @05:41AM (#39939355)
    don't tell TSA or they'll gamma nuke everybody until they glow.
    • by Anonymous Coward
      Too bad I don't have mod points. The security scanner industry execs must be lining up around the corner to shove these things in every bus depot, airport, and mall in the world. who cares about a little bit of cancer.
  • How about chip fabbing? I'm sure the likes of Intel and TSMC are looking at this closely.

  • by Stirling Newberry ( 848268 ) on Wednesday May 09, 2012 @10:29AM (#39941901) Homepage Journal
    While []considered very desirable. [] was known not to be impossible. []

    As with x-ray lensing, the question was of feasibility for certain applications.

  • Currently, integrated circuits like CPUs are fabricated using UV light, wavelength 10^-8m. Gamma rays are 10^-12m long. All other things being equal (but they never are...), this may lead to chips with 10^4*10^4=10^8 more features. This might be worth constructing a 100m long gamma ray lens or two.
  • When I was reading the article, I noticed that they said that these gamma ray optics might help in getting rid of Nuclear waste. That really piqued my interest. I assume that this newly discovered material for gamma ray optics will help scientists focus gamma rays, and make the gamma ray source focused/focused enough to help accelerate the “evaporating” of protons or neutrons from nuclear waste?

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