Tuning methods for multigap drift tube linacs

O Shelbaya; R Baartman; P Braun; P M Jung; O Kester; T Planche; H Podlech; S D Rädel

doi:10.1063/5.0191603

Tuning methods for multigap drift tube linacs

Rev Sci Instrum. 2024 Mar 1;95(3):033302. doi: 10.1063/5.0191603.

Authors

O Shelbaya^{1

2}, R Baartman^{1

2}, P Braun³, P M Jung^{1

2}, O Kester^{1

2}, T Planche^{1

2}, H Podlech^{3

4}, S D Rädel¹

Affiliations

¹ TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada.
² Department of Physics and Astronomy, University of Victoria, P.O. Box 1700 STN CSC, Victoria, British Columbia V8W 2Y2, Canada.
³ Institute for Applied Physics, Goethe Universität, Max-von-Laue-Straße 1, D-60438 Frankfurt a. M., Germany.
⁴ Helmholtz Research Academy Hesse for FAIR (HFHF), 60438 Frankfurt a. M, Germany.

PMID: 38456758
DOI: 10.1063/5.0191603

Abstract

Multigap cavities are used extensively in linear accelerators to achieve velocities up to a few percent of the speed of light, driving nuclear physics research around the world. Unlike for single-gap structures, there is no closed-form expression to calculate the output beam parameters from the cavity voltage and phase. To overcome this, we propose to use a method based on the integration of the first and second moments of the beam distribution through the axially symmetric time-dependent fields of the cavity. A beam-based calibration between the model's electric field scaling and the machine's rf amplitudes is presented, yielding a fast online energy change method, returning cavity amplitude and phase necessary for a desired output beam energy and energy spread. The method is validated with 23Na6+ beam energy measurements.