Enabling Correlated Electrical and Optical Diagnostics for Fast Transient Events
Abstract
Electrical breakdown by surface flashover is the single most prevalent failure mechanism incomponents and systems at high voltages and affects industries from high-density powerelectronics to directed energy weapons. It profoundly affects system reliability and the mitigationtechnique of increased distance results in increased size, weight and power (SWaP). UNM isdeveloping a ceramic-based high gradient insulator technology to increase the initiation of surfaceflashover in vacuum.UNM is requesting a spectrometer and timing calibration suite to expand the capabilities for a Ross1000 Streak Camera. Light emission can be correlated with the associated fast transient electricalmeasurements with time resolved spectroscopy. The proposed equipment will be used to (1)uncover the failure mechanism in high gradient insulators and (2) investigate an unexplored nuanceof the predominant theory of surface flashover ??? the saturated secondary emission electronavalanche (SSEEA) model. Examining the electron trajectories, the SSEEA models implies thatthe saturation condition drives the insulator???s secondary electron emission coefficient backtowards an effective value of 1, regardless of the material???s properties and that flashover proceedsin the electron-desorbed outgassing of the insulator. By exploiting the unique nature of thepolycrystalline aluminum nitride as well as polymer materials and measuring the temporalevolution of outgassing, the validity of the saturation condition in the SSEEA model can beevaluated. The outcome of these experiments may change the criterion by which critical insulatingmaterials are chosen. That is, the outgassing properties may be more important than the secondaryelectron emission curve for an insulator. The outgassing rate for materials under electronbombardment can be measured with time resolved laser shadowography. The nature of the specieswill be identified by time resolved spectroscopy.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 10, 2018
- Source ID
- N000141812379
Entities
People
- Jane M Lehr
Organizations
- Office of Naval Research
- United States Navy
- University of New Mexico