Field Emission Analysis in SRF Cavities for PIP-II Using GEANT4

TL;DR

This paper uses Geant4 simulations to analyze field emission-induced radiation in SRF cavities, aiming to improve diagnostic methods and cavity preparation for the PIP-II project.

Contribution

It introduces a detailed Geant4 simulation approach to study FE-induced radiation in SRF cavities, enhancing diagnostic accuracy and aiding cavity optimization.

Findings

Initial simulation results of FE radiation in LB650 cavity

Potential for improved radiation diagnostics

Guidance for cavity preparation and testing procedures

Abstract

Field emission (FE) remains a significant hurdle for achieving optimal performance and reliability in super-conducting radiofrequency (SRF) cavities used in accelerator cryomodules. A thorough understanding of the generation and propagation of FE-induced radiation is therefore essential to mitigate this problem. The absence of standardized measurement protocols further complicates the comparison of radiation data across different testing phases and facilities. This highlights the need for a precise quantitative method to diagnose and analyze FE-induced radiation. Such efforts could prove beneficial for improving cavity preparation and cleanroom assembly techniques during the prototype and production stages of Fermilab's Proton Improvement Plan-II (PIP-II) project. This study presents the initial steps of detailed Geant4 simulations aimed at analyzing FE-induced radiation in the low-beta 650 MHz 5-cell elliptical (LB650) cavity. Our goal is to combine these results with radiation diagnostics to enhance diagnostic accuracy and optimize detector positioning. This integrated approach ultimately aims to improve the preparation, assembly, and testing procedures for PIP-II SRF cavities, ensuring the delivery of FE-free cryomodules.