Fermilab Cryomodule Test Stand RF Interlock System

TL;DR

This paper describes the design and implementation of an interlock system for Fermilab's Cryo-module Test Stand, ensuring safe operation of RF cavities and amplifiers during testing for the LCLS-II project.

Contribution

It introduces a novel interlock system with 8 independent subsystems for fault detection and safety control in cryomodule testing environments.

Findings

Effective fault detection in RF systems

Rapid shutdown capability for safety

Remote monitoring and data recording

Abstract

An interlock system has been designed for the Fermilab Cryo-module Test Stand (CMTS), a test bed for the cryomodules to be used in the upcoming Linac Coherent Light Source 2 (LCLS-II) project at SLAC. The interlock system features 8 independent subsystems, one per superconducting RF cavity and solid state amplifier (SSA) pair. Each system monitors several devices to detect fault conditions such as arcing in the waveguides or quenching of the SRF system. Additionally each system can detect fault conditions by monitoring the RF power seen at the cavity coupler through a directional coupler. In the event of a fault condition, each system is capable of removing RF signal to the amplifier (via a fast RF switch) as well as turning off the SSA. Additionally, each input signal is available for remote viewing and recording via a Fermilab designed digitizer board and MVME 5500 processor.