text: NRA can also be used non-resonantly (of course,  RBS is non-resonant). For example, deuterium can easily be profiled with a He beam without changing the incident energy by using the
  :He + D = α + p + 18.353 MeV
  reaction,  usually written H(He,p)α.  The energy of the fast proton detected depends on the depth of the deuterium atom in the sample.