An x-ray source assembly includes an anode having a spot upon which electrons impinge based on power level supplied to the assembly, and an optic coupled to receive divergent x-rays generated at the spot and transmit output x-rays from the assembly. A control system is provided for maintaining intensity of the output x-rays dynamically during operation of the x-ray source assembly, notwithstanding a change in at least one operating condition of the x-ray source assembly, by changing the power level supplied to the assembly. The control system may include at least one actuator for effecting the change in the power level supplied to the assembly, by, e.g., controlling a power supply associated with the assembly. The control system may also change the temperature and/or the position of the anode to maintain the output intensity.