|
 |
|
|
|
Nuclear Resonance Analysis (NRA)
|
|
By careful selection of the energy of the incident ion beam, element-specific reactions which have much greater resolving power than standard RBS can be utilized. Thus the targeted element, and only the targeted element, can be made to resonate with the ion beam, increasing it’s detection sensitivity by a factor of 10 or more over the other elements in the sample.
Typical Applications
Carbon resonance for ultra-thin carbon overcoats. The reaction utilized, 12C(p,p)12C, an elastic resonance, involves 1.7 MeV protons:
12C + p -> 13N* -> 12C + p
Resonant protons are emitted with the same energy as scattered protons, but with a much higher cross-section so that the yield for resonant protons is higher.
Typical example of NRA analysis: The above spectrum shows how very thin layers of C, < 100Å, which are too thin to be resolved with RBS, can be measured with excellent signal-to-noise with this technique.
|
|
|
|
|
|
