What is the working principle of a pre injector and an electron linear accelerator

The working principle of the pre injector:
The pre injector is mainly responsible for generating and initially accelerating the electron beam, and its core component is the electron gun. The electron gun emits electrons by heating the cathode material and forms an electron beam under the action of a high-voltage electric field. This electron beam is then further focused and shaped by the beam focusing system inside the pre injector to ensure its quality meets the requirements of the subsequent acceleration process. The design of a pre injector typically considers the efficiency of electron beam generation, acceleration, and transmission, as well as its compatibility with an electron linear accelerator.

The working principle of an electronic linear accelerator:
The electron linear accelerator utilizes high microwave power to establish a longitudinal electric field in the traveling wave and standing wave acceleration structures, accelerating the electron beam. The electron beam is continuously accelerated by the microwave electromagnetic field inside the accelerator tube and exits at a speed close to the speed of light. This acceleration method is based on the principle of traveling wave acceleration, which provides an electric field that accelerates electrons in a straight line along the Z-axis near the axis, and electrons continuously gain energy on the peak of the electric field. Electron linear accelerators can generate high-energy rays, such as X-rays, for use in medical, industrial radiation processing, and other fields.

The relationship between the pre injector and the electron linear accelerator:
The pre injector is the starting part of an electron linear accelerator, providing a stable and high-quality electron beam source for the accelerator. After initial acceleration, the electron beam generated by the pre injector enters the electron linear accelerator for further acceleration. Good matching and transmission between the pre injector and the electron linear accelerator are required to ensure that the electron beam can smoothly enter the accelerator tube and be effectively accelerated. Meanwhile, the pre injector and the electron linear accelerator share a common control system to ensure synchronization and coordination between the two.

The working principles of the pre injector and the electron linear accelerator involve the generation, initial acceleration, and further acceleration of the electron beam, as well as their matching and transmission. These principles together constitute the core part of the electron linear accelerator system.