IPAC2018 - List of Authors (Fong, K.)

Paper	Title	Page
THPAK105	Construction Progress of Two Superconducting Cyclotrons for Proton Therapy and Proton Irradiation at CIAE	3477
	T.J. Zhang, S. An, H.R. Cai, L.C. Cao, X.L. Cao, T. Cui, X.L. Fu, T. Ge, P.F. Gong, F.P. Guan, L.L. Guan, S.G. Hou, B. Ji, X.L. Jia, M. Li, X.L. Li, Y.Q. Li, J. Lin, J.Y. Liu, X.T. Lu, Y.L. Lv, C. Wang, F. Wang, F. Wang, L. Wang, J.Y. Wei, S.M. Wei, J.S. Xing, G. Yang, J.J. Yang, M. Yin, Z.G. Yin, D.S. Zhang, S.P. Zhang, X. Zhen CIAE, Beijing, People's Republic of China K. Fong TRIUMF, Vancouver, Canada
	Funding: Supported partly by the National Natural Science Foundation of China (Grant No. 11375273 and 11475269) and by the Ministry of Science and Technology under Grant 2016YFC0105300. There are very strong demand for mid-energy of proton machine recent years due to the surging cancer patients and fast progress of the space science in China. For the applications of proton therapy and proton irradiation, the energy range of proton beam usually is from 200 MeV to 250 MeV, or even higher for astronavigation. Based on the R&D starting from 2009, two construction projects of 230 MeV and 250 MeV superconducting cyclotron, which have been implemented recently at China Institute of Atomic Energy(CIAE). That was started in Jan 2015 for the 230 MeV machine, for the program of proton therapy and space science launched by China National Nuclear Corporation (CNNC), and in Jan 2016 for the 250 MeV machine, for the program of proton therapy launched by the Ministry of Science and Technology of China (MOST). In this paper, the designs for the two SC cyclotrons and their key components, including the main magnet, SC coils, RF system, internal ion source and central region, extraction system, etc, and the construction progress of the machines will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK105
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THPAK106	400 MHz Frequency/phase Detector and Counter	3481
	X.L. Fu, B. Ji, Z.G. Yin, T.J. Zhang CIAE, Beijing, People's Republic of China G. Dennison UBC & TRIUMF, Vancouver, British Columbia, Canada K. Fong, M.P. Laverty, Q. Zheng TRIUMF, Vancouver, Canada
	To enhance the performance and precision of TRIUMF Low Level RF system, a frequency/phase detector and counter based on FPGA is developed. The frequency/phase detector and counter is designed as a daughter board of the low level RF control system, and is connected to the mother board with mixed signal connectors. It sends the frequency error data to the PC though VXI databus, and provides two analog phase errors outputs. In current design, one single unit supports four channel discriminations of RF frequencies/phases. Preliminary tests show that the reported phase detector has a bandwidth of 400MHz. A unique implementation of frequency discrimination was carefully carried out to ensure the resolution can reach as high as 1Hz. The phase-frequency detector has been successfully applied to the Accelerator Cryo Module (ACM) system and the requirement of the low level RF control system is satisfied. After a long-term running test, the stability and reliability of the phase-frequency detector are verified.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK106
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THPMK090	First RF Test Results of Two-Cavities Accelerating Cryomodule for ARIEL eLinac at TRIUMF	4512
	Y. Ma, Z.T. Ang, K. Fong, J.J. Keir, D. Kishi, D. Lang, R.E. Laxdal, R.R. Nagimov, B.S. Waraich, Z.Y. Yao, V. Zvyagintsev TRIUMF, Vancouver, Canada
	The Advanced Rare Isotope Laboratory (ARIEL) pro-ject requires a 50 MeV, 10 mA continuous-wave (CW) electron linear accelerator (e-Linac) as a driver accelera-tor. Now the stage of the 30MeV portion of the e-Linac is under commissioning which includes an injector cry-omodule(ICM) and the 1st accelerator cryomodules (ACM1) with two cavities configuration. A single 290kW klystron is used to feed the two ACM1 cavities in vector sum closed-loop control. In this paper the initial commis-sioning results of the ACM1 RF system will be present.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK090
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THPMK095	Design of an RF Modulated Thermionic Electron Source at TRIUMF	4524
	K. Fong, D.W. Storey TRIUMF, Vancouver, Canada
	The electron source in the TRIUMF ARIEL project is a gridded dispenser cathode. The cathode is biased at -300kV, and the grid requires a RF control signal of up to 150V at 650 MHz. The required RF power is approximately 20 W and is provided by an RF amplifier located outside the gun vessel. This RF power is coupled into the gun circuit through a ceramic transmission line. The design of this ceramic transmission line, as well as the impedance transformation circuit which provides both the impedance matching and the dc powers to the gun assembly are described.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK095
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THPMK096	Tuners Alignment on Two 9-Cell Cavities with Single Amplifier under Self-Excited Loop	4527
	K. Fong, Z.T. Ang, M.P. Laverty, Q. Zheng TRIUMF, Vancouver, Canada
	The TRIUMF eLinac ACM consists of two 9-cell cavities which are driven by a single klystron. The output power from the klystron are split by a variable power divider and send down 2 independently phase adjustable transmission lines to their respective cryomodules. The vector sum of the fields from both cryomodules is used for phase-locked self-excited loop regulation. A semi-automatic procedure to tune the 2 cyromodules to provide the correct amplitudes and phases for self-excitation as well as beam acceleration is described.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK096
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THPML025	Operation of an RF Modulated Thermionic Electron Source at TRIUMF	4705
	F. Ames, K. Fong, B. Humphries, S.R. Koscielniak, A. Laxdal, Y. Ma, T. Planche, S. Saminathan, E. Thoeng TRIUMF, Vancouver, Canada
	ARIEL (Advanced Rare IsotopE Laboratory) at TRIUMF will use a high-power electron beam to produce radioactive ion beams via photo-fission. The system has been designed to provide up to 10 mA of electrons at 30 MeV. The electron source delivers electron bunches with charge up to 16 pC at a repetition frequency of 650 MHz at 300 keV. The main components of the source are a gridded dispenser cathode (CPI - Y845) in an SF6 filled vessel and an in-air HV power supply. The beam is bunched by applying DC and RF fields to the grid. A macro pulse structure can be applied by additional low frequency modulation of the RF signal. This allows adjusting the average beam current by changing the duty factor of the macro pulsing. Unique features of the gun are its cathode/anode geometry to reduce field emission, and transmission of RF modulation via a dielectric (ceramic) waveguide through the SF6. The source has been installed and fully commissioned to a beam power up to 1 KW and tests with accelerated beams have been performed. Measurements of the beam properties and results from the commissioning and operational experiences of the source will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML025
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THPML082	Reflected Power Based Extremum Seeking Control Algorithm to Tune the Resonance Frequency of Room Temperature Cavities	4844
	R. Leewe, K. Fong, Z. Shahriari TRIUMF, Vancouver, Canada M. Moallem SFU, Surrey, Canada
	A sliding mode extremum seeking algorithm to tune the resonance frequency was implemented in two of TRIUMF's DTL tanks. The tuning algorithm searches for the minimum reflected power point and was developed to eliminate the highly temperature dependent phase measurement, which was previously used to tune the resonance frequency. Short and long term measurement results show that the tuning algorithm compensates for the RF heating effect as well as for diurnal temperature variations. Reflected power measurements of TRIUMF's DTL tank 3 were taken for both cases of operating the phase based tuning system and the reflected power based tuning system, with an outcome of a higher tuning accuracy of the newly developed system. Another advantage is a quick cavity start up time, as the reflected power based system does not rely on a reference set point which has do be adjusted manually. The sliding mode extremum seeking control loop is currently commissioned in further room temperature cavities of the TRIUMF's ISAC I facility.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML082
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THPML083	Iterative Learning Control to Cancel Beam Loading Effect on Amplitude and Phase of the Accelerating Field	4847
	Z. Shahriari, K. Fong TRIUMF, Vancouver, Canada G. A. Dumont UBC, Vancouver, Canada
	Funding: This research is supported by TRIUMF through federal funding via a contribution agreement with the National Research Council of 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. Assuming that the beam loading disturbance is identical for all iterations, the learning law can be non-causal; it can anticipate the disturbance and preemptively counteract its effect. In this work, we aim to use ILC to cancel beam loading effect on amplitude and phase. Feedback controllers are not fast enough for this purpose. A normal feed forward controller may not be sufficient as well if there is a difference between the feed forward signal and the beam loading current. Therefore, the goal is to use ILC to adaptively cancel the beam loading effect.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML083
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Paper

Title

Page

Construction Progress of Two Superconducting Cyclotrons for Proton Therapy and Proton Irradiation at CIAE

3477

T.J. Zhang, S. An, H.R. Cai, L.C. Cao, X.L. Cao, T. Cui, X.L. Fu, T. Ge, P.F. Gong, F.P. Guan, L.L. Guan, S.G. Hou, B. Ji, X.L. Jia, M. Li, X.L. Li, Y.Q. Li, J. Lin, J.Y. Liu, X.T. Lu, Y.L. Lv, C. Wang, F. Wang, F. Wang, L. Wang, J.Y. Wei, S.M. Wei, J.S. Xing, G. Yang, J.J. Yang, M. Yin, Z.G. Yin, D.S. Zhang, S.P. Zhang, X. Zhen
CIAE, Beijing, People's Republic of China
K. Fong
TRIUMF, Vancouver, Canada

Funding: Supported partly by the National Natural Science Foundation of China (Grant No. 11375273 and 11475269) and by the Ministry of Science and Technology under Grant 2016YFC0105300.
There are very strong demand for mid-energy of proton machine recent years due to the surging cancer patients and fast progress of the space science in China. For the applications of proton therapy and proton irradiation, the energy range of proton beam usually is from 200 MeV to 250 MeV, or even higher for astronavigation. Based on the R&D starting from 2009, two construction projects of 230 MeV and 250 MeV superconducting cyclotron, which have been implemented recently at China Institute of Atomic Energy(CIAE). That was started in Jan 2015 for the 230 MeV machine, for the program of proton therapy and space science launched by China National Nuclear Corporation (CNNC), and in Jan 2016 for the 250 MeV machine, for the program of proton therapy launched by the Ministry of Science and Technology of China (MOST). In this paper, the designs for the two SC cyclotrons and their key components, including the main magnet, SC coils, RF system, internal ion source and central region, extraction system, etc, and the construction progress of the machines will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK105

Export •

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THPAK106

400 MHz Frequency/phase Detector and Counter

3481

X.L. Fu, B. Ji, Z.G. Yin, T.J. Zhang
CIAE, Beijing, People's Republic of China
G. Dennison
UBC & TRIUMF, Vancouver, British Columbia, Canada
K. Fong, M.P. Laverty, Q. Zheng
TRIUMF, Vancouver, Canada

To enhance the performance and precision of TRIUMF Low Level RF system, a frequency/phase detector and counter based on FPGA is developed. The frequency/phase detector and counter is designed as a daughter board of the low level RF control system, and is connected to the mother board with mixed signal connectors. It sends the frequency error data to the PC though VXI databus, and provides two analog phase errors outputs. In current design, one single unit supports four channel discriminations of RF frequencies/phases. Preliminary tests show that the reported phase detector has a bandwidth of 400MHz. A unique implementation of frequency discrimination was carefully carried out to ensure the resolution can reach as high as 1Hz. The phase-frequency detector has been successfully applied to the Accelerator Cryo Module (ACM) system and the requirement of the low level RF control system is satisfied. After a long-term running test, the stability and reliability of the phase-frequency detector are verified.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK106

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THPMK090

First RF Test Results of Two-Cavities Accelerating Cryomodule for ARIEL eLinac at TRIUMF

4512

Y. Ma, Z.T. Ang, K. Fong, J.J. Keir, D. Kishi, D. Lang, R.E. Laxdal, R.R. Nagimov, B.S. Waraich, Z.Y. Yao, V. Zvyagintsev
TRIUMF, Vancouver, Canada

The Advanced Rare Isotope Laboratory (ARIEL) pro-ject requires a 50 MeV, 10 mA continuous-wave (CW) electron linear accelerator (e-Linac) as a driver accelera-tor. Now the stage of the 30MeV portion of the e-Linac is under commissioning which includes an injector cry-omodule(ICM) and the 1st accelerator cryomodules (ACM1) with two cavities configuration. A single 290kW klystron is used to feed the two ACM1 cavities in vector sum closed-loop control. In this paper the initial commis-sioning results of the ACM1 RF system will be present.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK090

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THPMK095

Design of an RF Modulated Thermionic Electron Source at TRIUMF

4524

K. Fong, D.W. Storey
TRIUMF, Vancouver, Canada

The electron source in the TRIUMF ARIEL project is a gridded dispenser cathode. The cathode is biased at -300kV, and the grid requires a RF control signal of up to 150V at 650 MHz. The required RF power is approximately 20 W and is provided by an RF amplifier located outside the gun vessel. This RF power is coupled into the gun circuit through a ceramic transmission line. The design of this ceramic transmission line, as well as the impedance transformation circuit which provides both the impedance matching and the dc powers to the gun assembly are described.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK095

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THPMK096

Tuners Alignment on Two 9-Cell Cavities with Single Amplifier under Self-Excited Loop

4527

K. Fong, Z.T. Ang, M.P. Laverty, Q. Zheng
TRIUMF, Vancouver, Canada

The TRIUMF eLinac ACM consists of two 9-cell cavities which are driven by a single klystron. The output power from the klystron are split by a variable power divider and send down 2 independently phase adjustable transmission lines to their respective cryomodules. The vector sum of the fields from both cryomodules is used for phase-locked self-excited loop regulation. A semi-automatic procedure to tune the 2 cyromodules to provide the correct amplitudes and phases for self-excitation as well as beam acceleration is described.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK096

Export •

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

THPML025

Operation of an RF Modulated Thermionic Electron Source at TRIUMF

4705

F. Ames, K. Fong, B. Humphries, S.R. Koscielniak, A. Laxdal, Y. Ma, T. Planche, S. Saminathan, E. Thoeng
TRIUMF, Vancouver, Canada

ARIEL (Advanced Rare IsotopE Laboratory) at TRIUMF will use a high-power electron beam to produce radioactive ion beams via photo-fission. The system has been designed to provide up to 10 mA of electrons at 30 MeV. The electron source delivers electron bunches with charge up to 16 pC at a repetition frequency of 650 MHz at 300 keV. The main components of the source are a gridded dispenser cathode (CPI - Y845) in an SF6 filled vessel and an in-air HV power supply. The beam is bunched by applying DC and RF fields to the grid. A macro pulse structure can be applied by additional low frequency modulation of the RF signal. This allows adjusting the average beam current by changing the duty factor of the macro pulsing. Unique features of the gun are its cathode/anode geometry to reduce field emission, and transmission of RF modulation via a dielectric (ceramic) waveguide through the SF6. The source has been installed and fully commissioned to a beam power up to 1 KW and tests with accelerated beams have been performed. Measurements of the beam properties and results from the commissioning and operational experiences of the source will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML025

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THPML082

Reflected Power Based Extremum Seeking Control Algorithm to Tune the Resonance Frequency of Room Temperature Cavities

4844

R. Leewe, K. Fong, Z. Shahriari
TRIUMF, Vancouver, Canada
M. Moallem
SFU, Surrey, Canada

A sliding mode extremum seeking algorithm to tune the resonance frequency was implemented in two of TRIUMF's DTL tanks. The tuning algorithm searches for the minimum reflected power point and was developed to eliminate the highly temperature dependent phase measurement, which was previously used to tune the resonance frequency. Short and long term measurement results show that the tuning algorithm compensates for the RF heating effect as well as for diurnal temperature variations. Reflected power measurements of TRIUMF's DTL tank 3 were taken for both cases of operating the phase based tuning system and the reflected power based tuning system, with an outcome of a higher tuning accuracy of the newly developed system. Another advantage is a quick cavity start up time, as the reflected power based system does not rely on a reference set point which has do be adjusted manually. The sliding mode extremum seeking control loop is currently commissioned in further room temperature cavities of the TRIUMF's ISAC I facility.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML082

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THPML083

Iterative Learning Control to Cancel Beam Loading Effect on Amplitude and Phase of the Accelerating Field

4847

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

Funding: This research is supported by TRIUMF through federal funding via a contribution agreement with the National Research Council of 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. Assuming that the beam loading disturbance is identical for all iterations, the learning law can be non-causal; it can anticipate the disturbance and preemptively counteract its effect. In this work, we aim to use ILC to cancel beam loading effect on amplitude and phase. Feedback controllers are not fast enough for this purpose. A normal feed forward controller may not be sufficient as well if there is a difference between the feed forward signal and the beam loading current. Therefore, the goal is to use ILC to adaptively cancel the beam loading effect.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPML083

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