Backward Secondary Electron Emission Yield of Thick Targets Induced by MeV Ions

The backward secondary electron emission yields of MeV ions (H⁺, He⁺, He⁺⁺, Cl, Si, and Cu ) impinging on thick carbon and gold targets are studied. The measured results for H⁺ (1 MeV≤ E≤ 5MeV) on carbon are proportional to the electronic stopping power. Our experimental data and fitting formula of yields for H⁺ (1 MeV≤ E≤ 4.5 MeV) impacting Au are compared with the theoretical expectation. The influence of the collective field and the charge state of ions on the secondary electron emission yield is discussed.