What Causes the Spikes in X-ray Spectra?

[Badrakhandama]

Hello,

I have studied X-ray emission when an electron beam is fired at a tungsten target - But when I was presented with the graph of Intensity versus wavelength, I was confused...

I saw a curve, and on it there were spikes. What are these spikes, and why are they caused?

Something to do with supersposition?


Thanks In Advance!

 

[Delphi51]

Most interesting! I never heard of this before. But a Google search for
x-ray emission spectrum
turns up some spectra and explanations. I found this one
http://docs.google.com/viewer?a=v&q=cache:iImAsSNxwOYJ:www.iupac.org/publications/analytical_compendium/Cha10sec212.pdf+x-ray+emission+spectrum&hl=en&gl=ca&sig=AHIEtbQ-9jo-NS86kPmazM8ullZOjbtklA
particularly interesting.

 

[Badrakhandama]

This is an example http://images.google.co.uk/imgres?i...ox-a&rls=org.mozilla:en-GB:official&sa=G&um=1 the spike puzzles me - how does it arise. Also, what is that Bremstrahlung thing?

 

[Dadface]

The smooth curve is due to bremmstrahlung,the electrons radiating energy as a result of being decelerated on striking the tungsten target.The spikes are caused by some electrons penetrating deep into the target atoms and raising electrons from shells to higher energy levels with the electrons then jumping back and releasing their excess energy as photons.This mechanism is similar to that responsible for optical spectra etc but the energies involved are greater.The spikes are characteristic of the target atoms.