Radiofrequency source having a phase stabilization element

A radiofrequency source for a linear accelerator system, comprising:

• a microwave generator configured to generate microwaves;
• a circulator, the circulator having ferrites to isolate the microwave generator from backscattered microwaves by influencing a phase of the microwaves according to a magnetic field, the circulator including an electrical phase stabilization element;
• a control unit configured to receive a measured variable describing a magnetic permeability of the circulator, the control unit being further configured to adjust at least one of a current of the electrical phase stabilization element or a voltage of the electrical phase stabilization element to influence the magnetic field based on the received measured variable such that an amplitude difference between the generated microwaves and the backscattered microwaves is a maximum;
• and
• a measuring apparatus configured to measure an electromagnetic variable of the backscattered microwaves, the measured electromagnetic variable being the measured variable describing the magnetic permeability of the circulator and the measured electromagnetic variable describing at least one of an amplitude of the backscattered microwaves or a phase of the backscattered microwaves.