IPAC2019 - List of Authors (Fong, K.)

Paper	Title	Page
MOPGW004	Microphonics Suppression in ARIEL ACM1 Cryomodule	65
	Y. Ma, K. Fong, J.J. Keir, D. Kishi, S.R. Koscielniak, D. Lang, R.E. Laxdal, R.S. Sekhon TRIUMF, Vancouver, Canada
	Now the stage of the 30MeV portion of ARIEL (The Advanced Rare Isotope Laboratory) e-Linac is under commissioning which includes an injector cryomodule (ICM) and the 1st accelerator cryomodule (ACM1) with two cavities configuration. The two ACM1 cavities are driven by a single klystron with vector-sum control and running in CW mode. During the commissioning, the ACM1 cavities gradient and stability was limited by ponderomotive effect. Acoustic noise from the environment vibration generated by cooling water system, cryogenic system and vacuum system have been identified to certain external source and some damping has been installed. In this paper, the progress of the microphonics suppression of ACM1 is presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW004
About •	paper received ※ 01 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
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WEPRB003	Parametric Pumped Oscillation by Lorentz Force in Superconducting Rf Cavity	2798
	K. Fong, R. Leewe TRIUMF, Vancouver, Canada
	Mechanical instabilities have been observed in superconducting RF cavities, when multiple cavities are driven by a single klystron and these cavities are regulated by vector-summing the outputs from these cavities. A nonlinear theory has been developed to study the source of this mechanical instability, which is due to the coupling between Lorentz force detuning and mechanical oscillation by parametric pumping. Analytical and numerical analysis of this model show regions of stability, limit cycles and instabilities. These results are in agreement with the observed oscillations by TRIUMF eLinac Acceleration Module.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB003
About •	paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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WEPRB004	Sawtooth Generation and Regulation with a Single FPGA for TRIUMF’s ARIEL Prebuncher	2801
	X.L. Fu, T. Au, K. Fong, Q. Zheng TRIUMF, Vancouver, Canada
	TRIUMF’s ARIEL prebuncher is powered by a sawtooth waveform which is the combination of an 11.79MHz, a 23.57MHz and a 35.36MHz components. The generation, control and regulation of these three components are all incorporated digitally inside a single FPGA. This FPGA can be standalone or inserted inside a VXI module. Commands and controls of these components can be directly through Ethernet, or indirectly through register-base or message-base VXI addresses.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB004
About •	paper received ※ 10 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019
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THPRB011	Norm-optimal Iterative Learning Control to Cancel Beam Loading Effect on the Accelerating Field	3824
SUSPFO005	use link to see paper's listing under its alternate paper code
	Z. Shahriari, K. Fong TRIUMF, Vancouver, Canada G.A. Dumont UBC, Vancouver, Canada
	Iterative learning control (ILC) is an open loop control strategy that improves the performance of a repetitive system through learning from previous iterations. ILC can be used to compensate for a repetitive disturbance like the beam loading effect in resonators. In this work, we aim to use norm-optimal ILC to cancel beam loading effect. Norm-optimal ILC updates the control signal with the goal of minimizing a performance index, which results in monotonic convergence. Simulation results show that this controller improves beam loading compensation compared to a PI controller.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB011
About •	paper received ※ 14 May 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Microphonics Suppression in ARIEL ACM1 Cryomodule

65

Y. Ma, K. Fong, J.J. Keir, D. Kishi, S.R. Koscielniak, D. Lang, R.E. Laxdal, R.S. Sekhon
TRIUMF, Vancouver, Canada

Now the stage of the 30MeV portion of ARIEL (The Advanced Rare Isotope Laboratory) e-Linac is under commissioning which includes an injector cryomodule (ICM) and the 1st accelerator cryomodule (ACM1) with two cavities configuration. The two ACM1 cavities are driven by a single klystron with vector-sum control and running in CW mode. During the commissioning, the ACM1 cavities gradient and stability was limited by ponderomotive effect. Acoustic noise from the environment vibration generated by cooling water system, cryogenic system and vacuum system have been identified to certain external source and some damping has been installed. In this paper, the progress of the microphonics suppression of ACM1 is presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-MOPGW004

About •

paper received ※ 01 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRB003

Parametric Pumped Oscillation by Lorentz Force in Superconducting Rf Cavity

2798

K. Fong, R. Leewe
TRIUMF, Vancouver, Canada

Mechanical instabilities have been observed in superconducting RF cavities, when multiple cavities are driven by a single klystron and these cavities are regulated by vector-summing the outputs from these cavities. A nonlinear theory has been developed to study the source of this mechanical instability, which is due to the coupling between Lorentz force detuning and mechanical oscillation by parametric pumping. Analytical and numerical analysis of this model show regions of stability, limit cycles and instabilities. These results are in agreement with the observed oscillations by TRIUMF eLinac Acceleration Module.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB003

About •

paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

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reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPRB004

Sawtooth Generation and Regulation with a Single FPGA for TRIUMF’s ARIEL Prebuncher

2801

X.L. Fu, T. Au, K. Fong, Q. Zheng
TRIUMF, Vancouver, Canada

TRIUMF’s ARIEL prebuncher is powered by a sawtooth waveform which is the combination of an 11.79MHz, a 23.57MHz and a 35.36MHz components. The generation, control and regulation of these three components are all incorporated digitally inside a single FPGA. This FPGA can be standalone or inserted inside a VXI module. Commands and controls of these components can be directly through Ethernet, or indirectly through register-base or message-base VXI addresses.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPRB004

About •

paper received ※ 10 May 2019 paper accepted ※ 22 May 2019 issue date ※ 21 June 2019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRB011

Norm-optimal Iterative Learning Control to Cancel Beam Loading Effect on the Accelerating Field

3824

SUSPFO005

use link to see paper's listing under its alternate paper code

Z. Shahriari, K. Fong
TRIUMF, Vancouver, Canada
G.A. Dumont
UBC, Vancouver, Canada

Iterative learning control (ILC) is an open loop control strategy that improves the performance of a repetitive system through learning from previous iterations. ILC can be used to compensate for a repetitive disturbance like the beam loading effect in resonators. In this work, we aim to use norm-optimal ILC to cancel beam loading effect. Norm-optimal ILC updates the control signal with the goal of minimizing a performance index, which results in monotonic convergence. Simulation results show that this controller improves beam loading compensation compared to a PI controller.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB011

About •

paper received ※ 14 May 2019 paper accepted ※ 19 May 2019 issue date ※ 21 June 2019

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)