Study on atomic nuclei by electron scattering

Study of the giant resonance caused by electron scattering was performed with an electron linear accelerator of 300 MeV. The highly excited state of Zr-90 was investigated by the experiment. The Zr targets were enriched metal foils with thickness of 7 mg/cm2, 18.9 mg/cm2, 49.9 mg/cm2 and 68.8 mg/cm2. The observed spectra of scattered electrons were analyzed by multipole expansion. The models used for the analysis were the Goldhaber-Teller model and the Tassie model. The obtained results for E1 resonance were consistent with those from photo-nuclear reaction experiment. The giant resonances of E2 with T=0 and T=1 were seen at the excited energy reported previously. The structure of E3 was observed, and E4 structure distributed all over the spectra. It is considered that the background considered so far consists of the components with high multipole and transverse component. From the precise analysis of E2 resonance, the existence of monopole giant resonance was seen at 17 MeV in case of the electron scattering with Zr-90. The obtained results were compared with the theory by Krewald and Speth, and showed good agreement with the theory. (Kato, T.)