Electroexcitation of nickel nuclei with detection of the scattered electron and secondary charged particles in coincidence

An ultrathin internal target in an electron storage ring was used to measure differential cross sections for the reaction Ni(e,e'c), where c represents protons and α particles, at momentum transfer q∼0.5 F-1 over a broad range of excitation energy of the nucleus (from 0 to 70 MeV). The target was a jet of nickel micropowder with particles of 2μm diameter. In the region of the isoscalar giant quadrupole resonance (14.3--18.3 MeV) the ratio of the yields of α particles and protons is 0.25 +- 0.05