The Continuous Electron Beam Accelerator Facility at 12 GeV

TL;DR

This paper reviews the upgrade of the CEBAF accelerator to 12 GeV, detailing new superconducting modules, system improvements, and performance achievements, ensuring reliable operation for future scientific experiments.

Contribution

It provides a comprehensive overview of the 12 GeV CEBAF upgrade, including technical innovations and performance data, which were not previously documented in detail.

Findings

Achieved 12 GeV beam energy with 88 superconducting cavities

Enhanced accelerator components for improved performance and reliability

Documented operational experience and future upgrade plans

Abstract

This review paper describes the energy-upgraded CEBAF accelerator. This superconducting linac has achieved 12 GeV beam energy by adding 11 new high-performance cryomodules containing eighty-eight superconducting cavities that have operated CW at an average accelerating gradient of 20 MV/m. After reviewing the attributes and performance of the previous 6 GeV CEBAF accelerator, we discuss the upgraded CEBAF accelerator system in detail with particular attention paid to the new beam acceleration systems. In addition to doubling the acceleration in each linac, the upgrade included improving the beam recirculation magnets, adding more helium cooling capacity to allow the newly installed modules to run cold, adding a new experimental hall, and improving numerous other accelerator components. We review several of the techniques deployed to operate and analyze the accelerator performance, and document system operating experience and performance. In the final portion of the document, we present much of the current planning regarding projects to improve accelerator performance and enhance operating margins, and our plans for ensuring CEBAF operates reliably into the future. For the benefit of potential users of CEBAF, the performance and quality measures for beam delivered to each of the experimental halls is summarized in the appendix.