Voltage monitors for high-power 10–20 MV pulsed electron accelerators

Four monitoring techniques that can determine peak voltage (Vp) to a precision of ∼5% for high-intensity, pulsed electron accelerators operating in the 10 to 20 MV range are discussed and applied to the 14-TW HERMES III accelerator. The techniques utilize parapotential flow theory, the range of H− ions, the bremsstrahlung from electron interactions with an electron target, and the photoneutron fluence from neutrons generated in a bremsstrahlung target. Application of these techniques to HERMES III shows that when the accelerator is operating under nominal conditions, Vp=(18.7±0.7) MV.