Investigation of UHF multipactor onset and suppression in a 50 ohm microstripline test cell
Abstract
Multipactor is a cascade avalanche of secondary electrons in resonance with an oscillating RF electric field in vacuum conditions. It can disrupt transmission of high power electromagnetic fields and even cause surface damage in waveguides or RF components. We have developed a broadband microstripline test cell to investigate two-surface multipactor susceptibility and suppression. The input and output vacuum-sealed, high power, coaxial couplers are well-matched to the 50 ohm, low-loss test-cell impedance, with excellent transmission from 0.1 - 1.5 GHz. The top surface of the section where multipactor occurs is replaceable, enabling studies with surfaces having different secondary emission coefficients. Photoelectric electron seeding by a UV source ensures statistically reliable multipactor initiation. We will describe the results from initial experiments, including the effects of varying UV illumination intensity, surface conditions, and multi-tone RF field excitation.
supported by AFOSR MURI Grant FA9550-18-1-0062.- Publication:
-
APS Division of Plasma Physics Meeting Abstracts
- Pub Date:
- 2019
- Bibcode:
- 2019APS..DPPTO7001B