He3-Alpha Scattering

Differential cross sections for scattering of He 4 by He 3 have been measured at E α =27.7, 28.5, 29.4, 30.0, 32.0, 33.4, 34.7, 36.5, 38.4, 41.0 MeV using a scintillation counter spectrometer, at the center of mass angles from ∼30° to ∼150°. Three distinct minima were found at about 45°, 100°, and 140°. The absolute cross-section and the pattern of the angular distribution showed no appreciable change in the energy range investigated: thus, there was found no sharp resonance in the He 3 +He 4 system corresponding to an excited state of Be 7 between 13.4 and 19.2 MeV. Differential cross-sections of the protons from He 3 (α, p )Li 6 Li 6* were observed. Differential cross-sections of alpha-alpha scattering were also measured at E α =33.5 and 35.5 MeV.