Bending the Rules (Gamma ray lenses)

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Discussion Overview

The discussion centers on the possibility of bending gamma rays using lenses, a concept that challenges existing theories regarding the refraction of high-energy x-rays and gamma rays. Participants explore the implications of recent experimental findings and the theoretical limitations surrounding the focusing of these rays.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants note that researchers at Institut Laue–Langevin have demonstrated a method to bend gamma rays, suggesting that lenses made from heavy elements like gold could enhance this effect.
  • Others question the theoretical basis for the impossibility of refraction for x-rays and gamma rays, seeking clarification on which theories support this view.
  • One participant emphasizes that high-energy x-rays and gamma rays are typically focused using reflection methods rather than lenses, citing the limitations of current technologies like grazing incident mirrors and coded apertures.
  • Another participant argues against the notion of a theoretical impossibility, suggesting that while deflection angles may be small, the proposed mechanism involving pair creation could significantly enhance deflection.

Areas of Agreement / Disagreement

Participants express differing views on the theoretical limitations of bending gamma rays, with some asserting that it is impossible while others argue that recent findings challenge this notion. The discussion remains unresolved regarding the feasibility and implications of using gamma ray lenses.

Contextual Notes

The discussion highlights the dependence on theoretical frameworks regarding the refraction of high-energy rays, as well as the practical challenges associated with current focusing technologies. There are unresolved questions about the extent to which new materials could influence gamma ray deflection.

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http://news.sciencemag.org/sites/default/files/styles/thumb_article_l/public/article_images/sn-gammarays.jpg?itok=vYTMw8My Researchers at Institut Laue–Langevin have found a way to bend gamma rays.

Gamma ray lenses, which theory had suggested were impossible, could be made from heavy elements such as gold.

The bending in the group's experiment isn't much—about a millionth of a degree, which corresponds to a refractive index of about 1.000000001. However, it could be boosted using lenses made of materials with larger nuclei such as gold, which should contain more virtual electron-positron pairs. With some refinement, gamma-ray lenses could be made to focus beams of a specific energy.
 
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What theory suggests that is impossible to have refraction of x-rays?
 
nasu said:
What theory suggests that is impossible to have refraction of x-rays?

High-energy x-rays and gamma rays are effectively impossible to focus using a lens. Currently they rely on reflection of these rays off of long, concentric metal or ceramic grazing incident mirrors, or on coded apertures, which are flat grills that way less than mirrors, but require lots of post-processing to get an image.

http://en.wikipedia.org/wiki/X-ray_telescope
http://en.wikipedia.org/wiki/Wolter_telescope
 
Drakkith said:
High-energy x-rays and gamma rays are effectively impossible to focus using a lens. Currently they rely on reflection of these rays off of long, concentric metal or ceramic grazing incident mirrors, or on coded apertures, which are flat grills that way less than mirrors, but require lots of post-processing to get an image.

http://en.wikipedia.org/wiki/X-ray_telescope
http://en.wikipedia.org/wiki/Wolter_telescope
I know this. My problem is with a theoretical impossibility. Or breaking the rules, as the OP suggest.
 
There is no theoretical impossibility. If you extend the usual influence to gamma rays, the deflection angles are too small to be practical. The proposed pair creation mechanism seems to enhance the deflection a lot.
 

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