Measurement and optimization of the beam coupling impedance of a novel 3D-printed titanium alloy cage inside the thin-wall vacuum chamber

Shaohui Du; Jie Liu; Guangyu Zhu; Jiancheng Yang; Jiqiang Jiao; Xiang Zhang; Guodong Shen; Junxia Wu; Cheng Luo; Jun Meng

doi:10.1063/5.0161008

Measurement and optimization of the beam coupling impedance of a novel 3D-printed titanium alloy cage inside the thin-wall vacuum chamber

Rev Sci Instrum. 2023 Oct 1;94(10):103308. doi: 10.1063/5.0161008.

Authors

Shaohui Du^{1

2}, Jie Liu¹, Guangyu Zhu^{1

2}, Jiancheng Yang^{1

2}, Jiqiang Jiao¹, Xiang Zhang¹, Guodong Shen^{1

2}, Junxia Wu^{1

2}, Cheng Luo^{1

2}, Jun Meng^{1

2}

Affiliations

¹ Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China.
² University of Chinese Academy of Sciences, Beijing 100049, China.

PMID: 37843419
DOI: 10.1063/5.0161008

Abstract

Dipole magnet vacuum chambers are among the most critical and costly components of rapid-cycling accelerator facilities. Alternative approaches to traditional ceramic chambers have been explored for the implementation of fast-ramping dipole-magnet vacuum chambers, including thin-wall metallic beam pipe chambers strengthened with transverse ribs and ceramic rings inside thin-walled chambers. Here, we report a novel 3D-printed titanium alloy cage inside the thin-wall vacuum chamber, which is designed for high-intensity heavy ion accelerator facility (HIAF) to reduce manufacturing difficulty and cost, shorten the production cycle, and improve the quality. Comprehensive studies were undertaken to characterize the impedance of the 3D-printed titanium alloy cage inside the thin-wall vacuum chamber. The beam-coupling impedance and eddy currents of the new thin-wall vacuum chamber were studied mostly numerically. Strategies for further reducing the beam-coupling impedance were explored. In addition, impedance bench measurements using the "half wavelength" resonant method were conducted to identify the longitudinal and transverse impedances of the 3D-printed titanium alloy cage inside the thin-wall vacuum chamber prototype experimentally. The simulated and measured results for the impedance were consistent. Furthermore, a campaign for resonance-check measurements on the 3D-printed titanium alloy ring loaded inside a thin-wall vacuum chamber prototype was launched. This novel thin-wall vacuum chamber structure is now entering the fabrication stage and will soon be ready for installation in the Booster Ring (BRing).