Calculation method for electric focusing in central area of cyclotron

Abstract

The invention discloses a calculation method for electric focusing in a central area of a cyclotron. The method comprises the following steps of: preparing physical quantities which possibly cause electric focusing change in the central area of the cyclotron; calculating electric field data and magnetic field data of all physical quantities, possibly causing enhancement or weakening of electric focusing, of the accelerator at present, and inputting the electric field data and the magnetic field data to particle tracking software; using a particle tracking method, obtaining the motion condition of particles in a phase space according to the current physical quantity, and calculating the radial oscillation frequency Nur and the axial oscillation frequency Nuz of the particles according to x, px, z and pz; independently calculating focuses, i.e. NurM and NuzM, contributed by the magnetic field; and according to the Nur, Nuz, NurM and NuzM, calculating the electric focusing: NurE and NuzE, and according to the calculated electric focusing values NurE and NuzE, verifying the conjecture of all physical quantities possibly causing the electric focusing change of the central area. The problem that focusing force in the height direction of the central area is insufficient is solved, meanwhile, the magnetic field is optimized according to the calculation result of NuzE, and enough focusing capacity is kept when Nuz is close to the minimum value.

Description

technical field [0001] The invention belongs to the technical field of cyclotrons, in particular to a calculation method for electric focusing in the central area of ​​a cyclotron. Background technique [0002] In the general cyclotron design, a symmetrical accelerating gap structure is used, such as figure 2 As shown, h1 and h2 are equal. When the beam passes through the acceleration gap, the electric field will provide a focusing force for the beam in the height direction, such as figure 1 shown. According to the formula of focus force, the strength of focus can be adjusted by adjusting the height of the acceleration gap, the lower the height, the stronger the focus. However, there are limitations in this method, because the first half of the beam in the acceleration gap is focused downward, and the second half is defocused upward, and the downward part is closer to the center plane of the accelerator, while The stronger the electric field in the upward direction, the...

AI Technical Summary

Problems solved by technology

[0007] In order to solve the problems existing in the prior art, the present invention proposes a calculation method for electric focusing in the central area of ​​the cyclotron. The force cannot be improved, and the particle will be lost along the radius of the accelerator where the electric field and magnetic field are zero.

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