At least one power supply produces a voltage between a cathode and an anode. The cathode and anode are operable such that electrons emitted from the cathode interact with the anode with energies corresponding to the voltage. The electrons interact with the anode at a focal spot to generate X-rays. The power supply provides the cathode with a cathode current. An electron detector is positioned relative to the anode, and a backscatter electron signal is measured from the anode. The measured backscatter electron signal is provided to a processing unit, which determines a cathode current correction and/or a correction to the voltage between the cathode and the anode using the measured backscatter electron signal and a correlation between anode surface roughness and backscatter electron emission.