A radiation generator is provided that includes a target, a cathode to emit electrons in a downstream direction toward the target, a first conductive member downstream of the cathode, and a second conductive member downstream of the cathode. The first and second conductive members have a potential difference with the cathode such that a resultant electric field accelerates the electrons toward the target. A diagnostic current in the second conductive member and a target current in the target may be measured, and an electrical property of the first conductive member may be adjusted based upon the diagnostic current and the target current.