High energy 4He backscattering

Advantages and limitations associated with use of 4He analysis beams with energies in excess of 2.5 MeV for analysis of thin films by backscattering spectrometry are discussed. Use of the higher energy analysis beams reduces overlap of backscattering peaks, frequently allowing simplified and/or more accurate analysis of thicker films. The fact that cross sections for backscattering of 4He by the elements lighter than Ar are non-Rutherford (for 4He energies 2-5 MeV) requires accurate measurement of these cross sections. The authors survey the availability of measured values of these non- Rutherford cross sections for the elements Be-Si for 4He energies 2-10 MeV