An electro-optic voltage sensor for electron beam position and current monitoring

The current and position of high-energy electron beams are traditionally monitored using B-dot loops and resistive wall monitors. Such techniques are well demonstrated for relatively short pulses in the 100 ns time regime. The second axis of the dual axis radiographic hydro test (DARHT) facility currently under construction at Los Alamos National Laboratory requires a substantially longer pulse exceeding 2 μs in duration. This application poses various difficulties for conventional sensors and has driven the development of an electro-optic sensor for electron beam monitoring. Such sensors offer complete galvanic isolation and do not require time integration or droop correction. The design of a prototype electro-optic sensor is discussed and calibration data is presented along with preliminary beam line measurements