RFQ accelerator and acceleration method thereof

Abstract

The invention relates to an RF quadrupole (RFQ) accelerator and an acceleration method thereof. The accelerator comprises a radial matching section, a forming section, a low energy receiving section and an acceleration section according to a change rule of basic parameters. The low energy receiving section is used for bunching a beam from the forming section. In the bunching process, a low energy acceptance is achieved by configuring a low modulation factor and slowly increasing the modulation factor, and 2% to 3% of the beam is lost by the low energy acceptance. The accelerator deliberately loses a small portion of the beam (the transmission efficiency is still higher than 95%), so that the lost beam cannot obtain the energy gain and is lost at the low energy, thereby significantly reducing the damage of the lost beam to an RFQ accelerator electrode. The acceleration section of the accelerator further includes an energization section and a conventional acceleration section, and the forming section obtains a lower longitudinal emittance, thereby obtaining a clean high-quality beam at an RFQ accelerator exit.

Description

technical field [0001] The invention relates to the technical field of dynamic design of a radio frequency quadrupole field accelerator, in particular to a radio frequency quadrupole field accelerator and an acceleration method thereof. Background technique [0002] The radio frequency quadrupole (RFQ) accelerator is a low-energy ion linear accelerator proposed in the late 1960s, which is usually used to directly accelerate the DC beam drawn from the ion source. This kind of accelerator can not only accelerate the particles, but also has the function of horizontal focusing and longitudinal focusing of the ion beam at the same time, and can efficiently accelerate the high-current ion beam of the milliampere level or even the hundred milliampere level to a frequency per Hz A few MeVs. This kind of accelerator has been widely used in front-end injectors of accelerator systems, ion implantation, intense neutron sources, and accelerator-driven clean energy. High beam intensity ...

AI Technical Summary

Problems solved by technology

[0007] In recent years, it has been found that although the transmission efficiency of existing RFQ accelerators can reach very high (greater than 98%), after several years of operation of RFQ accelerators, RFQ transmission efficiency has declined to varying degrees, and even began to appear unstable. One of the possible reasons for this is that there are particles in the RFQ that have the same energy as the RFQ exit. The loss of high-energy particles will cause greater damage to the electrode and severely shorten the service life of the RFQ accelerator.

In addition, the exit beam of the existing RFQ accelerator contains 99.9% of the particles, and the emittance is too high, which is not conducive to the accelerated transmission in the subsequent acceleration structure, and the probability of particles being lost in the subsequent acceleration structure is high

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