  The ion beam of 58Ni19+ with the energy of 6.39MeV/u was accumulated in the
main ring of HIRFL-CSR with the help of electron cooling. The related angle
between ion and electron beams in the horizontal and vertical planes was
intentionally created by the steering coils in the cooling section after
maximized the accumulated ion beam in the ring. The radial electron intensity
distribution was changed by the ratio of potentials of grid electrode and anode
of the electron gun, the different electron beam profiles were formed from
solid to hollow in the experiments. In these conditions, the maximum
accumulated ion beam intensity in the 10 seconds was measured, the lifetime of
ion beam was measured, simultaneously the momentum spread of the ion beam
varying with particle number was measured during the ion beam decay,
furthermore, and the power coefficient was derived from these data. In
additional, the momentum spread in the case of constant particle number was
plotted with the angle and electron beam profile. The oscillation and shift of
the central frequency of the ion beam were observed during the experiments. The
upgrade and improvement in the CSRm cooler and the progress in the CSRe cooler
were presented. These results were useful to attempt the crystal beam forming
investigation in the CSR.
