Design, fabrication, and tuning of a THz-driven electron gun

TL;DR

This paper details the design, fabrication, and testing of a novel THz-driven electron gun that uses a copper tip and resonant cavity to generate high-energy electrons with low power input.

Contribution

It introduces a new two-cell standing-wave electron gun design powered by a 110 GHz gyrotron, including fabrication methods and tuning techniques for the cavity resonances.

Findings

Successfully fabricated the gun structures with high precision.

Achieved electromagnetic and particle simulation validation.

Demonstrated cavity resonance tuning via azimuthal compression.

Abstract

We present the design, fabrication, and low power testing of a THz-driven field emission electron gun. The two cell standing-wave gun is designed to be powered by a 110 GHz gyrotron and produce 360 keV electrons with 500 kW of input power. Several gun structures were fabricated using a high precision diamond turned mandrel and copper electroforming. The field emission source is a copper tip with a 50 $\mu$m radius inserted halfway into first cell. The frequencies of the cavity resonances were mechanically tuned using azimuthal compression. This work presents electromagnetic and particle simulations of the design and cold test measurements of the fabricated structures.