High-power magnetron transmitter as an RF source for superconducting linear accelerators
Grigory Kazakevich, Rolland Johnson, Gene Flanagan, Frank Marhauser, Vyacheslav Yakovlev, Brian Chase, Valeri Lebedev, Sergei Nagaitsev, Ralph Pasquinelli, Niko… 展开作者
Grigory Kazakevich, Rolland Johnson, Gene Flanagan, Frank Marhauser, Vyacheslav Yakovlev, Brian Chase, Valeri Lebedev, Sergei Nagaitsev, Ralph Pasquinelli, Nikolay Solyak, Kenneth Quinn, Daniel Wolff, Viatcheslav Pavlov
A concept of a high-power magnetron transmitter for operation within a wideband control feedback loop in phase and amplitude is presented. This transmitter is proposed to drive Superconducting RF (SRF) cavities for intensity-frontier GeV-scale proton/ion linacs. The transmitter performance at the dynamic control was verified in experiments with CW, S-Band, 1 kW magnetrons. The wideband control of magnetrons, required for the superconducting linacs, was realized using the magnetrons, injection-locked by the phase-modulated signals. The capabilities of the magnetrons injection-locked by the phase-modulated signals and adequateness for feeding of SRF cavities were verified by measurements of the transfer function magnitude characteristics of single and 2-cascade magnetrons, by measurements the magnetrons phase performance and by measurements of spectra of the carrier frequency. At the ratio of power of locking signal to output power less than -13 dB (in 2-cascade scheme per magnetron, respectively) we demonstrated a phase modulation bandwidth of over 1.0 MHz. The carrier frequency spectrum width about of 1 Hz at the level less than -60 dBc did not demonstrate broadening at wide range of magnitude and frequency of the phase modulation of the injection-locking signal. The wideband dynamic control of output power of the transmitter model was first experimentally demonstrated using two magnetrons, combined in power and injection-locked by the phase-modulated signals. The experiments with the injection-locked magnetrons adequately emulated the wideband dynamic control with a feedback control system, which will allow suppressing all known parasitic modulation of the accelerating field in the SRF cavities. The magnetron transmitter concept, tests of the setups and injection-locking of magnetrons by phase-modulated signals are discussed in this work.
