200 MV Record Voltage Of vCM And LCLS-II-HE Cryomodules Production Start At Fermilab

TL;DR

This paper reports on the production and testing of high-voltage cryomodules for the LCLS-II-HE project at Fermilab, highlighting improvements, validation results, and lessons learned from previous LCLS-II cryomodules.

Contribution

It details the successful assembly and testing of the first and second cryomodules for LCLS-II-HE, including validation of design changes based on prior experience.

Findings

Achieved 200 MV record voltage in vCM

Validated design improvements with successful tests

Provided insights on cryomodule production challenges

Abstract

The Linac Coherent Light Source (LCLS) is an X-ray science facility at SLAC National Accelerator Laboratory. The LCLS-II project (an upgrade to LCLS) is in the commissioning phase; the LCLS-II-HE (High Energy) project is another upgrade to the facility, enabling higher energy operation. An electron beam is accelerated using superconducting radio frequency (SRF) cavities built into cryomodules. It is planned to build 24 1.3 GHz standard cryomodules and one 1.3 GHz single-cavity Buncher Capture Cavity (BCC) cryomodule for the LCLS-II-HE project. Fourteen of these standard cryomodules and the BCC are planned to be assembled and tested at Fermilab. Procurements for standard cryomodule components are nearing completion. The first LCLS-II-HE cryomodule, referred to as the verification cryomodule (vCM) was assembled and tested at Fermilab. Fermilab has completed the assembly of the second cryomodule. This paper presents LCLS-II-HE cryomodule production status at Fermilab, emphasizing the changes done based on the successes, challenges, mitigations, and lessons learned from LCLS-II; validation of the changes with the excellent vCM results.