Rep-rate explosive whisker emission cathode investigations
- Army Research Lab., Adelphi, MD (United States)
- Berkeley Research Associates, Springfield, VA (United States)
An experiment is underway to study the performance of several materials as field emission cathodes for low voltage ({<=} 100 kV), repetitive (< 1 kHz) electron accelerators. A thyratron-switched Blumlein line modulator with a 70 0 characteristic impedance, and 1 {mu}s pulse width, is operated between 20 and 100 kV, from single-shot to 300 Hz rep-rate. This provides a high average power (50 kW) test bed for the study. A comparison is made of cathodes fabricated from velvet, carbon, diamond coatings, niobium wire nanocomposite, and polycrystalline tungsten. Surface emission is monitored by an array of Faraday Cups. The ``turn-on`` time, uniformity of emission, and gap closure time are measured as a function of the spatially averaged, macroscopic electric field at the cathode. The carbon fiber cathode produces the largest current density and has the lowest threshold voltage for emission.
- OSTI ID:
- 51846
- Report Number(s):
- CONF-940142--; ISBN 0-8194-1449-2
- Country of Publication:
- United States
- Language:
- English
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