AUTHOR=Lewellen John W. , Buechler Cynthia E. , Carlsten Bruce E. , Dale Gregory E. , Holloway Michael A. , Patrick Douglas E. , Storms Steven A. , Nguyen Dinh C. TITLE=Space-Borne Electron Accelerator Design JOURNAL=Frontiers in Astronomy and Space Sciences VOLUME=6 YEAR=2019 URL=https://www.frontiersin.org/journals/astronomy-and-space-sciences/articles/10.3389/fspas.2019.00035 DOI=10.3389/fspas.2019.00035 ISSN=2296-987X ABSTRACT=

Renewed interest in active experiments with relativistic particle beams in space has led to the development of solid-state radio-frequency (RF) linear accelerators (linac) that can deliver MeV electron beams but operate with low-voltage DC power supplies. The solid-state RF amplifiers used to drive the accelerator are known as high-electron mobility transistors (HEMTs), and at C-band (5–6 GHz) are capable of generating up to 500 watts of RF power at 10% duty factor in a small package, i.e., the size of a postage stamp. In operation, the HEMTs are powered with 50 V DC as their bias voltage; they thus can tap into the spacecraft batteries or electrical bus as the primary power source. In this paper we describe the initial testing of a compact space-borne RF accelerator consisting of individual C-band cavities, each independently powered by a gallium nitride (GaN) HEMT. We show preliminary test results that demonstrate the beam acceleration in a single C-band cavity powered by a single HEMT operating at 10% duty factor. An example of active beam experiments in space that could benefit from the HEMT-powered accelerators is the proposed Magnetosphere-Ionosphere Connection (CONNEX) experiment (Dors et al., 2017).