ENERGY-LOSS OF 10 MEV AMU ATOMIC HELIUM IN CARBON/

Mean energy losses of 31.8 MeV neutral He-3 atoms penetrating through thin carbon foils of 1.6-7.2 mu g/cm(2) were measured using a high-res olution magnetic spectrograph. The measured particles are those entere d into the carbon foil as He-3(0) and emerged from it as He-3(0). From the attenuation measurement of He-3(0) in the foils, we can regard th e measured energy losses as those of He-3(0) in a frozen charge stare. The measured stopping power of carbon for 31.8 MeV He-3(0) is 58.2 +/ - 4.9 eV/mu g/cm(2). Including our previous data for other partially c lothed ions of the same velocity, the projectile atomic number depende nce of the screening effect due to the bound electrons is roughly repr oduced by the theoretical predictions based on the Born approximation. (C) 1997 Elsevier Science B.V.