# What if $\gamma$-rays in Electron microscope?

I was referring Electron microscopes and read that the electrons have wavelength way less than that of visible light. But, the question I can't find an answer was that, If gamma radiation has the smallest of wavelengths of all, why can't it be used to reach to even finer details in microscopy?

As X-Rays & $\gamma$-rays have very low wavelength, one could think of building an X-Ray or gamma-ray microscope. But, the problem only arrives at focusing both. They can't be focused as visible light is focused using refractive convex lenses (in microscope) thus providing a magnification of about 2000. Another problem with gamma rays is that they've very high ionizing power and interact with matter to the maximum extent thereby destroying it (causing atomic decay).

But on the other hand, we've Electron microscopes which work on the principle of wave nature of moving electrons. Electrons accelerated through a potential difference of 50 kV have a wavelength of about 0.0055 nm. (which is according to de-Broglie relation of wave-particle duality - $\lambda=\frac{h}{\sqrt{2meV}}=\frac{1.227}{\sqrt{V}}$nm) This is $10^5$ times less than the wavelength of visible light there by multiplying the magnification by $10^5$.

If you've read enough about electron microscopes, you should've known the fact that Electrons could be easily focused using electric & magnetic fields than going into a more complex one... :)

Even if these great physicists try something of focusing the gamma rays, it's production and maintenance would be far too difficult and expensive either. Because, we know that $\gamma$-rays could be produced only by means of radioactive decays which is biologically hazardous...

• ok..that focussing point of ur's makes sense..!! Commented Oct 12, 2012 at 15:52
• A couple of comments on this (old) answer: (i) while transmission optics don't really work there's a good deal you can do to focus x-rays using reflective optics, and (ii) electron microscopes can also be very damaging to biological tissue, and having a 50 keV electron whizz past and deposit even a small fraction of its energy can be as bad or worse as gamma radiation. In-vivo electron microscopy is possible but very challenging ─ that's why super-resolution optical microscopy was such a huge breakthrough. Commented Jul 11, 2017 at 10:04

I think the main principal problem would be with high transmission of gamma radiation. It is almost unaffected by matter so you cannot imprint information about your sample on it very efficiently. Then, there are also many other practical difficulties -- it would probably be rather complicated to create directed gamma beams and you would need to use plenty of radioactive material and screen it well from radiating anywhere.

• i think instruments must be there to measure that precision and blocking radiation is much of a trivial job these days...given the device and observer need no contact and can be handled via robots...do u have some confirmed info on your first argument ? Commented Oct 12, 2012 at 12:27

There are phase plates and other techniques that are being developed to be able to focus X-rays and thus create usable microscopes which promise resolution better than what is possible by refractive optics with visible light. However, these are not yet commercially available. Further, with the high penetrating power of gamma radiation no equivalents are being explored with gamma radiation. The reason could be the availability of electron microscopes with what is now simpler technology, that can provide resolution down to tens of picometres.