On formation of uniform magnetic field in the injection section of the LIU-30 accelerator using ferromagnetic rings

The results of experiments on formation of an uniform magnetic field in the LIU-30 injection section are given. To improve the uniformity of longitudinal magnetic field, it is suggested to use coaxial ferromagnetic shims. During minimization of a functional the necessary parameters of shims and focusing solenoids are selected. It is shown that the contribution of the shim field to the general field at the axis of the accelerator channel reached 50%. The field uniformity at the axis inside sections within limits of ± 1-2% and in gaps between sections within the limits of ± 8% can be obtained by means of ferromagnetic shims. 5 refs.; 6 figs.; 1 tab