Michael Allen Brubaker

Temperature sensor and extensometer

A thermometer and extensometer for cables and conductors is described. The travel time of one or more acoustic signals along a conductor is used to determine the temperature along the conductor and the length of the conductor. The acoustic frequency is selected to minimize temporal dispersion of the propagating acoustic energy. The technique can be used to measure the temperature and sag of an overhead power line, the temperature of the windings in a transformer, or the temperature of the central conductor in a coaxial power cable.

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 /spl mu/s 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.

Pockels cell voltage probe for noninvasive electron-beam measurements

Accurate measurements of beam position and current are critical for the operation of the high-energy electron accelerators used for radiographic applications. Traditional short-pulse (e.g., 70 ns) machines utilize B-dot loops to monitor these parameters with great success. For long-pulse (e.g., 2 micros) accelerators, beam position and current measurements become more challenging and may require new technology. A novel electro-optic voltage probe has been developed for this application and provides the advantages of complete galvanic isolation, excellent low-frequency performance, and no time integration requirement. The design of a prototype sensor is presented along with preliminary accelerator test data.