Cavity exercising method of high-current compact type editcyclotron

Abstract

The invention relates to a radio-frequency cavity exercising method of a high-current compact type editcyclotron. The method is mainly characterized in that a cavity is primarily exercised through long-cycle narrow pulses, and the range of a multi-electron multiplication effect generated voltage is judged; according to color changes of the surface of a radio-frequency cavity, a magnetic pole face or a panel of the editcyclotron in the process, a graphite material is brushed at corresponding positions so as to reduce the secondary electron emission coefficient of the region; afterwards, by means of closing a magnetic field of the editcyclotron, all multi-electron effect regions are exercised from low to high in sequence by using a continuous power increase method, when all the multi-electron effect regions are passed, power feed is tuned and maintained for a period of time to accelerate gas outlet on a surface, then, push power is reduced at fixed time interval, and all the multi-electron effect regions are exercised from high to low; and after the processes are repeated ten times, the power supply of the magnetic field is switched on, and the exercise of the radio-frequency cavity can be completed rapidly by using the same method.

Description

technical field [0001] The invention relates to a technique for effectively overcoming the multiple electron multiplication effect in a compact cyclotron, in particular to a method for exercising a cavity of a compact cyclotron with high current. Background technique [0002] Under vacuum environment, especially the vacuum degree is better than 5×10 -5 At mbar, a small amount of radio frequency power is enough to generate electron cloud reciprocating oscillations related to frequency, power and distance on the metal geometric surface with secondary electron emission coefficient higher than 1. The normal operation of the device has a fatal impact. The reason is that, firstly, the electron cloud is a nonlinear load, which will affect the matching of the RF system; secondly, if the energy of the electron bombardment is not limited, it will cause the change and failure of the surface material, and even damage such as the accelerator RF ceramic coupling window. key components. ...

AI Technical Summary

Problems solved by technology

The reason is that, firstly, the electron cloud is a nonlinear load, which will affect the matching of the radio frequency system; secondly, if the energy of the electron bombardment is not limited, it will cause the change and failure of the surface material, and even damage such as the accelerator radio frequency ceramic coupling window. key components of

In particular, in a compact cyclotron, due to the small space and complex types of materials, especially in the influence of the fringe field where the electrodes of the radio frequency cavity are located at the junction of the magnet peaks and valleys, these factors objectively aggravate the multi-electron multiplication of this type of accelerator. complexity of effects

At present, the more popular method in the world is the pulse exercise method, that is, the pulse exercise with a short repetition period and a duty cycle of about 10% is used for exercise. Relatively speaking, the safety factor is relatively high, but the disadvantage is that it is very time-consuming, so that in the compact roundabout Accelerators are hard to get practical

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