Experiment Research on Feasibility of In-Situ Plasma Cleaning in Normal-conducting Copper Cavities

TL;DR

This study demonstrates that in-situ plasma cleaning using an Ar/O + Ar/H method effectively reduces field emission and improves the performance of copper cavities in accelerator systems.

Contribution

It develops a plasma cleaning platform and optimizes procedures specifically for copper cavities, confirming its feasibility and effectiveness.

Findings

In-situ plasma cleaning reduces field emission in copper cavities.

The Ar/O + Ar/H method enhances copper surface work function.

Field emission mitigation improves cavity stability and acceleration gradient.

Abstract

To assess the feasibility of in-situ plasma cleaning for copper cavities, a 13.56 MHz inductively coupled plasma platform with a built-in coil was developed at Tsinghua University. Experiments were conducted using this platform to optimize plasma discharge parameters and procedures specific to copper cavities. The results indicate that the "Ar/O + Ar/H method" significantly enhances the work function of the copper surface while reducing field enhancement effects induced by surface burrs. Consequently, this study confirms that in-situ plasma cleaning effectively mitigates field emission within copper cavities, thereby enhancing the stability and acceleration gradient of the accelerator system.