Operation method for eliminating hysteresis effect influence of synchronous accelerator

Abstract

The invention relates to an operation method for eliminating a hysteresis effect influence of a synchronous accelerator. The operation method is used for solving the problem that the position and intensity of heavy ion beams in the synchronous accelerator under different energy conditions are inconsistent because a magnet has a hysteresis effect. The operation method of an accelerator in a magnetic field major cycle mode mainly comprises the following steps of: 1, determining the maximal energy value of a beam of the synchronous accelerator required for a tumor cell therapy; 2, calculating a power operation curve of a dipolar magnet, a quadrupole magnet and a sectupole magnet for controlling a beam track by using magnetism measuring parameters; 3, uploading an operation curve data packet of the magnets to a remote database connected with a power supply controller; 4, analyzing the data packet by the remote database and issuing data to corresponding control front-ends; and 5, trigging data by using a trigger to output the data to the power source of the related power supply and control the track of the heavy ion beam.

Description

technical field [0001] The invention relates to an accelerator operating method for eliminating the influence of the hysteresis effect of the synchronous accelerator. Background technique [0002] Ion beams (protons and heavy ions) are characterized by their inverted depth dose distribution, small side scattering, high relative biological effect (RBE) and low oxygen enhancement ratio (OER), making ion beam cancer treatment a Internationally advanced and effective radiation therapy. When the heavy ions used for radiotherapy of tumor cells pass through the human body, they lose less energy in their channels, forming a relatively low-dose plateau, and lose most of their incident kinetic energy near the end of their range, forming a high-dose The energy loss peak is called the Bragg peak. The position of the Bragg peak in the body is controlled by changing the energy of the heavy ion beam, thereby achieving the treatment of tumor cells at different depths. The current device ...

AI Technical Summary

Problems solved by technology

In order to treat tumors of different positions and sizes in different patients, the accelerator needs to change the energy of the extracted beam many times, which is accompanied by the change of the magnetic field curve of the magnet in the entire accelerator. Hysteresis effect), so the reference values ​​of the magnetic field curves under different energies are different, and finally the position and intensity of the heavy ion beam are different due to the existence of this effect, for example 12 C 6+ The operating curves of the two-pole magnet power supply when accelerating to energy 200MeV and 300MeV are as follows figure 1 As shown, the highest magnetic field value rises under the two energy conditions are different, so the residual magnetism of the magnet is inconsistent

The difference in the extraction position and intensity of the beam under different energies causes a series of effects such as increased difficulty in the treatment of tumor patients, inaccurate positioning, and poor effect. The present invention aims to solve the above problems

[0004] At present, there are few methods to eliminate the hysteresis effect in synchrotrons. It is possible to change the strength of the correction magnet under different energies to achieve the accumulation of the beam current and the consistency of the extracted orbit. However, this method requires a lot of hardware improvements and control system upgrades, and Different beam energies need to be adjusted one by one, which takes a long time

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