Development of a low-loss magnetic-coupling pickup for 166.6-MHz quarter-wave beta $$=$$ 1 superconducting cavities

Design and performance tests of a modular 166.6-MHz 50-kW compact solid-state power amplifier for the HEPS-TF project

“…A 2021 JINST 16 P04011 simplified schematic of the HEPS RF system is shown in figure 1. Before the construction of HEPS, an R&D project namely HEPS -Test Facility (HEPS-TF) was funded between 2016 and 2018 to prototype key hardware technologies [17][18][19][20][21][22][23]. A 166.6-MHz 50-kW SSA was thus developed as the first prototype to maximize learning on high-power SSA technologies in collaboration with a domestic company.…”

Multipacting suppression of the HOM-damped 166.6-MHz β=1 quarter-wave superconducting cavities at HEPS

“…In order to use as much as possible the mature technologies for the rf system, the third harmonic frequency has finally been chosen as 499.8 MHz, thus the fundamental was 166.6 MHz. A new development on the 166.6 MHz 𝛽 = 1 srf system has subsequently been conducted including extensive R&D on cavities [7][8][9][10] and ancillaries [11][12][13]. The 166.6-MHz srf cavity will be operated at 4.2 K and provides 1.2 MV of accelerating voltage and 180 kW of beam power.…”

“…This is to enable HOMs to propagate to the downstream ferrite damper installed on the beam pipe to be absorbed, thus reducing the HOM impedance to be below the stringent threshold of the coupled-bunch instabilities. Besides, the pickup antenna was relocated to one of the high-pressure rinsing (HPR) ports adopting a magnetic-loop structure, and the original pickup port on the opposite side of the power coupler was consequently removed [12]. The geometries of both cavities are shown in figure 1.…”