LINAC2026 - 33rd Linear Accelerator Conference

Low-Power RF Measurement and Tuning of the Linac4 RFQ2 at CERN

Not scheduled

2h

Daejeon Convention Center

Poster Presentation MC3.A05: RFQs Poster Session

Speaker

Pablo Martinez-Reviriego (European Organization for Nuclear Research)

Description

The first RF accelerating structure in CERN’s Linac4 is a 352.2 MHz radio-frequency quadrupole (RFQ), which focuses, bunches, and accelerates the 45 keV H⁻ beam from the ion source. As the RFQ constitutes a single point of failure (SPOF) in Linac4, a nearly identical spare cavity (RFQ2) has been manufactured at CERN.
After fabrication and assembly, a combined field and frequency tuning procedure was employed to meet the target specifications for field flatness, transverse field symmetry, and resonant frequency. After the initial low-power measurement and tuning campaign, the cavity was transported to the high-power test area, where a final in situ adjustment was performed.
In this contribution, the procedures used to tune the frequency, electromagnetic field profile, and power coupler of RFQ2 are described, and the final results are presented.