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Title: Electro-mechanical properties of spoke-loaded superconducting cavities.

Conference ·
OSTI ID:971165

This paper presents experimental data characterizing the electro-mechanical properties of superconducting spoke-loaded cavities developed for high-intensity ion-linac applications, such as the cw ANL Advanced Exotic Beams Laboratory (AEBL) driver linac and the pulsed FNAL High Intensity Neutrino Source (HINS, now project X) proton driver linac. High-gradient cw operation at 4.2 K can produce violent boiling in the liquid helium coolant causing microphonic frequency noise. A spoke cavity designed to minimize the effects of helium pressure on RF eigenfrequency, the total microphonic induced RF frequency variations, were found to be on the level of the phase noise in the reference oscillator. To determine the pulsed cavity RF performance, the Lorentz transfer function was measured and used to predict the dynamic detuning in pulsed operation. There is good agreement between the predicted fit and the measured data, demonstrating the utility of the Lorentz transfer function, which can completely characterize the dynamics of the coupling between the mechanical cavity structure and the cavity RF field due to the Lorentz force.

Research Organization:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Organization:
USDOE Office of Science (SC)
DOE Contract Number:
DE-AC02-06CH11357
OSTI ID:
971165
Report Number(s):
ANL/PHY/CP-60367; TRN: US1001049
Resource Relation:
Conference: 13th International Workshop on RF Superconductivity (SRF07); Oct. 14, 2007 - Oct. 19, 2007; Beijing, China
Country of Publication:
United States
Language:
ENGLISH