The motion of electron beam in toroid

The electron beam is deflected into and out interaction region by toroid in the electron cooling device for HIRFL-CSR. The magnetic field distribution in toroid and interface among toroid and solenoids is very complicated. The properties of the magnetic field in toroid give rise to a change in the transverse energy of the electron. A program was developed to study the spatial transverse energy distribution of electron in the beam as it moves through the toroid. The space charge effect was taken into account in the calculation. The simulation results show that the increase of the transverse energy can be minimized when the ratio of the central length of toroid and the cyclotron wavelength of electron is integer.