Design of a High-bunch-charge 112-MHz Superconducting RF Photoemission Electron Source

TL;DR

This paper presents the design and development of a 112 MHz superconducting RF photoinjector aimed at producing high-bunch-charge electron beams in continuous wave mode for advanced accelerator applications.

Contribution

It introduces a novel 112 MHz SRF electron gun with a quarter-wave resonator and high-QE photocathodes, tailored for high-brightness, high-charge electron bunches.

Findings

Successfully developed a 112 MHz SRF electron gun at BNL.

Achieved high-bunch-charge electron bunches suitable for CeC experiments.

Demonstrated advantages of SRF technology for continuous wave high-current electron sources.

Abstract

High-bunch-charge photoemission electron-sources operating in a continuous wave (CW) mode are required for many advanced applications of particle accelerators, such as electron coolers for hadron beams, electron-ion colliders, and free-electron lasers (FELs). Superconducting RF (SRF) has several advantages over other electron-gun technologies in CW mode as it offers higher acceleration rate and potentially can generate higher bunch charges and average beam currents. A 112 MHz SRF electron photoinjector (gun) was developed at Brookhaven National Laboratory (BNL) to produce high-brightness and high-bunch-charge bunches for the Coherent electron Cooling Proof-of-Principle (CeC PoP) experiment. The gun utilizes a quarter-wave resonator (QWR) geometry for assuring beam dynamics, and uses high quantum efficiency (QE) multi-alkali photocathodes for generating electrons.