Measurements of Electrodynamics Parameters of a Cylindrical RF-Cavity with Stainless Steel Samples

Stainless steel with galvanic copper coating is often used as a material for ion linear accelerators RF cavities. However, for the cavities with complex inner surfaces obtaining a uniform copper coating becomes technologically challenging. The solution might be found in manufacturing the cavity without copper coating at all, though in that case the amount of power losses in the cavity should be carefully estimated. To make such estimations the experiment was carried out, where the electrodynamic properties of a test cavity with two coupling loops were measured with the stainless steel samples placed inside it. The results of this experiment showed sufficient difference between the simulated and measured Q-factor values for the same 12Х18Н10Т sample steel grade. Thus, an assumption was made the magnetic properties of austenitic steel samples could have changed during the manufacturing process, so the magnetic permeability values for the steel samples were estimated.