A few weeks ago, we had a discussion about using strontium-90 for illumination by Cerenkov radiation in a swimming pool (the concept has since been expanded to ponds and water features). I've blogged about it too.

The real show stopper to the operation was the emission of 2 MeV gamma photons from yttrium-90, the decay product of strontium-90. I'm talking with a friend now about it and we started thinking about more innovative solution to gamma ray shielding.

We have a single wavelength of gamma to worry about, 5.7e-13m. What is the possibility of blocking this by making use of destructive interference?

Unfortunately, 10^-13 m is about two orders of magnitude smaller than the spacing of atoms in a crystal. So, you have the problem of finding a periodic structure which has a periodicity of the order of the wavelength.

At first glance you would need to pack charged particles much closer than the average distance between an electron and the nucleus in an atom (well, there is a reason why gamma radiation is linked to nuclear reactions).

Also, the interference pattern from a periodic structure depends on the direction (just think about the double slit experiment).

Assuming you can find a solution to the spacing problem, I do not see how you can make a shield with interference alone.
Probably you could think of some setup where interference is used to enhance the probability for gamma photons to be absorbed (for example, increasing the path length within an absorbing material).

[...]

On second thought, I seem to have a faint memory of something that works like a mirror but uses interference. Unfortunately you would still have the wavelength problem.

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papageno


"Why waste time learning, when ignorance is instantaneous?" - Hobbes (Calvin and Hobbes)

"It's all about context!" - Vince Noir (The Mighty Boosh)

"I've never heard of such a brutal and shocking injustice that I cared so little about!" - Zapp Brannigan (Futurama)

"...because the logic of the lines traced from reality is as poor of aesthetic value as it is strict in consistency. " - Paolo Bozzi (Naive Physics - free translation)

It occurred to me that you could use muons instead of electrons.
Muons are about 200 times heavier than electrons, and therefore the corresponding Bohr radius would be about 2.5 x 10^-13 m, which is just right for your 2 MeV gamma photons.

Unfortunately, muons have a finite lifetime, and I do not know whether putting them into a crystal would make them stable.

__________________
papageno


"Why waste time learning, when ignorance is instantaneous?" - Hobbes (Calvin and Hobbes)

"It's all about context!" - Vince Noir (The Mighty Boosh)

"I've never heard of such a brutal and shocking injustice that I cared so little about!" - Zapp Brannigan (Futurama)

"...because the logic of the lines traced from reality is as poor of aesthetic value as it is strict in consistency. " - Paolo Bozzi (Naive Physics - free translation)