Elastic and Inelastic Collisions of 55 MeV Proton with 4He

Elastic and inelastic collisions induced by 55 MeV protons with 4 He nuclei were investigated by use of the Δ E - E counter detecting protons and deuterons, and the solid counter detecting recoil 4 He and 3 He nuclei. The differential cross sections at 15°–160° were measured for the elastic scattering and for the inelastic process 4 He( p ; d ) 3 He, as shown in Fig. 6. The total cross section for the latter is 40 mb. The total cross section for all inelastic events were estimated from the continuum portion in the energy spectra of protons as 50–80 mb. The existence of an excited state in 4 He at the excitation of about 22 MeV was indicated by searching an anomalous peak in the energy spectra of protons.