What happens when ion pairs recombine?

[Chunky1106]

As far as I know:

When an source of ionizing radiation, such as alpha particles, Americium-241 for example, is present in a gas it results in the ionization (stripping of electrons from atomic nuclei) of the gas to form ion pairs. When these ion pairs recombine (radiative recombination) into atoms, excess energy is released from the atom in the form of a photon of electromagnetic radiation. The energy of the photon is equivalent to the energy of the free electron - the energy of the bound electron energy level.

If I am correct so far then how come when an alpha source is exposed to air, the recombination of the ion pairs produced from the air (nitrogen and oxygen etc) does not cause the emission of visible light, or any other wavelength/frequency of electromagnetic radiation far that matter. Or does it?

Thanks, Kieran

 

[Vanadium 50]

It does. You can see x-rays through a process called x-ray fluorescence. This is usually done with solids rather than gasses.