Linear Accelerator Energy Variation via Beam Current

The patent applies parameter changes by systematically varying the beam current (number of particles per macropulse) to control both the particle flux and the resulting acceleration voltage. By changing the beam loading parameter, the system achieves different operating points where higher beam currents produce more particles but reduce the acceleration voltage through beam loading effects, while the high-frequency power remains constant.

The patent resolves this contradiction by changing the beam current parameter to control particle energy while maintaining constant high-frequency power. When higher particle energy is required, the system reduces the beam current, which increases the acceleration voltage (since beam loading is reduced). Conversely, for lower energy requirements, higher beam currents are used. This parameter change approach allows the system to trade off between particle energy and particle flux while keeping the high-frequency power supply constant.

The patent applies parameter changes by utilizing the beam current-dependent impedance of the accelerator structure. As the beam current changes, the effective impedance of the cavity resonators changes due to beam loading effects. This impedance variation naturally adjusts the power coupling from the high-frequency source to the accelerator, allowing the system to operate at different power coupling points corresponding to different beam currents and particle energies, all while maintaining constant high-frequency power.