Novel internal target for electron scattering off unstable nuclei

A novel internal target has been developed, which will make electron scattering off short-lived radioactive nuclei possible in an electron storage ring. An ion trapping phenomenon in the electron storage ring was successfully utilized for the first time to form the target for electron scattering. Approximately 7x10(6) stable (133)Cs ions were trapped along the electron beam axis for 85 ms at an electron beam current of 80 mA. The collision luminosity between the stored electrons and trapped Cs ions was determined to be 2.4(8)x10(25) cm(-2) s(-1) by measuring elastically scattered electrons.