Hydrogen desorption induced by heavy-ions during surface layer analysis with ERDA

The modification of the surface layer composition during Elastic Recoil Detection Analysis (ERDA) of different carbon materials which had been loaded with hydrogen has been determined experimentally. For an amorphous C:H layer there is an initial overall loss of about 7 X 10(6) hydrogen atoms and about 2.3 X 10(6) carbon atoms per incident 200 MeV iodine ion from the analysing beam. Besides erosion of the amorphous C:H layer there is a depletion of the hydrogen in the carbon layer. For ERDA analysis with 130 MeV Ni ions the hydrogen release is about a factor of 3 lower compared to the ERDA analysis with 200 MeV I-ions. However the Rutherford cross section is more than a factor of 7 larger for 200 MeV I-ions compared to 130 MeV Ni ions, resulting in a higher sensitivity for the ERDA analysis with the heavier ions.