Development of a novel approach for construction of high gradient braze-free S-band cavities

Mahdi Aghayan; S Farhad Masoudi; Farshad Ghasemi; Walter Wuensch; Hamed Shaker

doi:10.1038/s41598-021-98238-8

Development of a novel approach for construction of high gradient braze-free S-band cavities

Sci Rep. 2021 Sep 22;11(1):18840. doi: 10.1038/s41598-021-98238-8.

Authors

Mahdi Aghayan¹, S Farhad Masoudi², Farshad Ghasemi³, Walter Wuensch⁴, Hamed Shaker⁵

Affiliations

¹ Department of Physics, K.N. Toosi University of Technology, P.O. Box 15875-4416, Tehran, Iran.
² Department of Physics, K.N. Toosi University of Technology, P.O. Box 15875-4416, Tehran, Iran. masoudi@kntu.ac.ir.
³ Physics and Particle Accelerators Research School, Nuclear Science and Technology Research Institute, Tehran, Iran.
⁴ CERN, European Organization for Nuclear Research, Geneva, Switzerland.
⁵ Canadian Light Source, Saskatoon, Canada.

Abstract

Vacuum breakdown is one of the main limitations to the operating accelerating gradient in radio frequency linear accelerators. Recent studies of copper cavities have been shown that harder copper conditions more quickly and can reach higher accelerating gradients than soft copper cavities. Exploiting this advantage requires the development of assembly methods that do not involve the copper-softening high-temperature heating cycles that are used in for example bonding and brazing. A shrink-fit method, which was already implemented successfully in the operation the IPM linac, is proposed for the construction high-gradient test S-band standing wave structure operating at 2998.5 MHz. The three cells cavity is designed to have a maximum gradient in the middle cell that is twice that of the adjacent cells. Mechanical considerations relating to the shrink-fit construction method have been performed using Ansys. To validate the simulations and ensure the feasibility of construction by shrink-fit method, a sample cavity was constructed and cold tests was performed.