The acceleration structure of an electron linear accelerator is its core component, which determines how the electron beam is effectively accelerated to the desired high-energy state. The following is a detailed description of the acceleration structure of an electron linear accelerator:
Electron Gun:
An electron gun is a device that generates and emits an electron beam. It contains a cathode (usually made of heated tungsten wire or lanthanum hexaborate), which emits electrons when heated to an appropriate temperature.
The electron gun also includes one or more anodes for attracting and accelerating electron beams. When the electron beam leaves the electron gun, it already has a certain initial kinetic energy.
Accelerating Tube:
The accelerator tube is the most important part of an electron linear accelerator, which contains one or more resonant cavities used to establish and maintain high-frequency electromagnetic fields.
When electron beams enter the accelerator tube, they interact with high-frequency electromagnetic fields, continuously gaining energy and gradually increasing speed.
The acceleration tube usually includes two parts: the beam focusing section and the acceleration section. The focusing section is used to focus the electron beam into a stable beam, while the acceleration section is used for high-energy acceleration of the electron beam.
RF Power Source:
A high-frequency power source is used to generate and maintain high-frequency electromagnetic fields in an accelerator tube. Common high-frequency power sources include magnetrons (Klystron) and klystrons (K-VNA).
The microwave power generated by the high-frequency power source is transmitted through the waveguide system to the accelerator tube, providing the energy required for electron beam acceleration.
Focusing System:
The focusing system is used to control the trajectory of the electron beam during acceleration, preventing its diffusion in space. Common focusing systems include quadrupole focusing coils and hexapole focusing coils.
The magnetic field generated by the focusing coil interacts with the charge of the electron beam, maintaining a stable trajectory of the electron beam during acceleration.
Microwave Transmission System:
The microwave transmission system is used to transfer the microwave power generated by the high-frequency power source to the accelerator tube. It usually includes components such as waveguides, couplers, isolators, filters, etc.
The microwave transmission system needs to ensure the stable transmission of microwave power, while preventing microwave leakage from causing harm to the environment and personnel.
Beam Diagnostic System:
The beam diagnostic system is used to monitor and control the beam parameters of the electron beam, such as beam intensity, beam spot size, beam position, etc.
A beam diagnostic system typically includes equipment such as a beam position detector, a beam intensity measuring instrument, and a beam spot size measuring instrument.
Vacuum System:
Electronic linear accelerators need to operate in a high vacuum environment to avoid collisions between gas molecules and electron beams, which can affect the acceleration effect.
The vacuum system includes components such as a vacuum pump, vacuum chamber, and seals, which are used to maintain a high vacuum environment inside the accelerator tube.
The acceleration structure of an electron linear accelerator is a complex system, including an electron gun, an accelerator tube, a high-frequency power source, a focusing system, a microwave transmission system, a beam diagnosis system, and a vacuum system. These parts work together to achieve efficient acceleration and stable transmission of the electron beam.