1

Assuming there is an incident beam(i.e. $p$ or $\alpha$) and a target. How can I be sure if a rutherford backscattering will take place?

I know that for high $Z$ it more likely to happen as well as for higher beam energies. Is there a boundary/formula/criterion to tell me that at that beam, for that energy, for this $Z$ target I will have rutherford backscattering.

To rephrase it, for a certain beam(i.e. $p$) and a certain target(i.e. $SbF_3$) at what energies I am going to have Rutherford Backscattering?

Thanos
  • 703
  • http://en.wikipedia.org/wiki/Rutherford_backscattering_spectrometry seems to cover everything, including a calculation of the energy of the backscattered particles. – John Rennie Nov 28 '13 at 10:30
  • @JohnRennie: Thank you very much for your comment! I have already read this article, but there is no clear answer on whether there is a criterion for Rutherford Backscattering. – Thanos Nov 28 '13 at 11:22
  • 2
    I'm not sure what you mean by "criterion". Rutherford backscattering always happens. The only questions are the intensity and energy of the backscattering and the latter is explained in the Wikipedia article. Also if you're going to be depth profiling the energy loss with depth is probably something you'll need to determine experimentally. A quick Google found http://www2.mtec.or.th/th/seminar/msativ/pdf/C18.pdf and this has lots of useful info. – John Rennie Nov 28 '13 at 11:40

1 Answers1

1

Rutherford back scattering is part of the large angle scattering that has been used ever since the famous experiment to detect a hard core instead of what one would expect from a uniform density medium.

So any scattering experiment against matter that has a hard core will display large angle scattering. The criterion is "scatter against material that has hard cores".

Another necessary criterion will be that the energy of the projectile should be such as to be able to distinguish a scatter from a single core element. If the energy is low the scattering cannot see the individual cores.

Before Quantum Chromodynamics was established as the theory of the strong interactions the model of the proton was proposed by Feynman himself , called "the parton model". The models at the time predicted only small angle scatterings. It was the large angle scattering that gave a clue that there existed a hard core within the hadrons, and not a uniform distribution of partons.

anna v
  • 233,453
  • Thank you very much for your answer! I am aware of the fact that the lower the energy, the least likely, backscattering will occur. I am looking for a "formula" that given the beam energy or/and beam's and target's $Z$'s or/and anything relevant, will give the possibility to have such a scattering. I am not sure if such thing exists, however... – Thanos Nov 29 '13 at 08:19
  • The formula is the scattering formula that exists in the wiki link. The probability is given by the second formula. – anna v Nov 29 '13 at 10:06
  • Although I can see the famous $1/\sin^4{\theta/2}$ formula, there isn't any probability formula on http://en.wikipedia.org/wiki/Rutherford_Scattering_Formula – Thanos Dec 25 '13 at 12:50
  • The scattering crossection connected directly with the probability of scatter by construction. look up paragraph 5 here : http://web.mit.edu/atsommer/www/qmscat.xhtml – anna v Dec 25 '13 at 19:47