Electroproduction of alpha particles from various nuclei

Alpha particles from the electrodistintegration of six nuclei with Z between 29 and 73 have been observed. Energy spectra at 50° in the lab for all six nuclei and angular distributions for copper and thulium have been measured. The cross sections exhibit a broad peak whose magnitude decreases with increasing Z; the energy of the peak increases as Z increases. The copper angular distributions are isotropic, but the thulium distributions show strong forward peaking above 16 MeV. This peaking is taken as possible evidence of the existence of α-clusters in this nucleus.