The Cornell Main Linac Cryomodule: A Full Scale, High Q Accelerator Module for cw Application

Eichhorn, Ralf; Bullock, B. W.; Elmore, Brendan; Clasby, Brian; Furuta, Fumio; He, Yun; Hoffstaetter, Georg; Liepe, Matthias; O’Connell, Tim; Conway, Joseph; Quigley, Peter; Sabol, Daniel; Sears, J.; Smith, E.; Veshcherevich, V.

doi:10.1016/j.phpro.2015.06.133

Cited by 5 publications

(1 citation statement)

References 3 publications

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“…The injector cryomodule [24,25] consists of five 2-cell SRF cavities [26] and is configured to provide 6 MeV of energy gain to the electron beam for injection into the CBETA loop and is operated with a low external quality factor due to high beam loading. The main linac [11,27] on the other hand incorporates six 7cell SRF cavities [28] with a design energy gain of 36 MeV and will be used to execute energy recovery. Operated at Q L ≈ 6 × 10 7 with solid state amplifiers, the peak detuning which can be tolerated by the main linac cavities is limited to 54 Hz with a 5 kW RF source, consequently microphonics detuning presents a significant operational bottleneck and needs to be mitigated.…”

Section: Resultsmentioning

confidence: 99%

Active suppression of microphonics detuning in high QL cavities

Banerjee

Hoffstaetter

Liepe

et al. 2019

Phys. Rev. Accel. Beams

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Operation of Superconducting Radio Frequency (SRF) cavities with high loaded quality factors is becoming increasingly preferred for applications which involve low beam loading including Energy Recovery Linacs (ERL). Vibration induced microphonics detuning poses a major operational bottleneck in these low bandwidth systems, adversely affecting field stability. Besides passive measures of mitigating the vibration sources, modern SRF cavities are also attached to fast tuners incorporating piezo-electric actuators. We demonstrate the narrow band active noise control algorithm for realizing active resonance control and propose a modification based on the Least Mean Square approach to adaptively tune the control parameters and study it's stability and performance. We discuss our experience of using passive mitigation techniques while commissioning the Main Linac Cryomodule of the Cornell-BNL ERL Test Accelerator (CBETA) and report a net reduction in peak detuning by more than a factor of 2 in its unstiffened cavities. Finally, we demonstrate stable performance of our resonance control system with consistent reduction of peak microphonics detuning by almost a factor of 2 on multiple cavities.

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Section: Resultsmentioning

confidence: 99%