5 papers
Two-port CW measurements on RF cavities: Notes on self-consistency assessment and indirect methods
Walter H. Hartung, Wei Chang, Sang-Hoon Kim +2
In the case of a radio-frequency (RF) cavity with a mismatched input coupler, a direct calculation of the power dissipation in the cavity and the intrinsic quality factor from cont…
Report on first plasma processing trial for a FRIB quarter-wave resonator cryomodule
Walter Hartung, Wei Chang, Yoo-Lim Cheon +6
Plasma processing has been shown to help mitigate degradation of the performance of superconducting radio-frequency cavities, providing an alternative to removal of cryomodules fro…
Plasma Processing of FRIB Low-Beta Cryomodules using Higher-Order-Modes
P. Tutt, W. Chang, K. Elliott +4
Improvement in SRF accelerator performance after in-tunnel plasma processing has been seen at SNS and CEBAF. Plasma processing development for FRIB quarter-wave and half-wave reson…
Improved high-gradient performance for medium-velocity superconducting half-wave resonators: Surface preparation and trapped flux mitigation
Yuting Wu, Kenji Saito, Alex Taylor +13
A development effort to improve the performance of superconducting radio-frequency half-wave resonators (SRF HWRs) is underway at the Facility for Rare Isotope Beams (FRIB), where…
Time-Delayed Koopman Network-Based Model Predictive Control for the FRIB RFQ
Jinyu Wan, Shen Zhao, Wei Chang +1
The radio-frequency quadrupole (RFQ) at the Facility for Rare Isotope Beams (FRIB) is a critical device to accelerate heavy ion beams from 12 keV/u to 0.5 MeV/u for state-of-the-ar…