NAPAC2019 - List of Keywords (LLRF)

Paper	Title	Other Keywords	Page
TUPLM29	Current Status and Prospects of FRIB Machine Protection System	operation, machine-protect, FPGA, controls	437
	Z. Li, D. Chabot, S. Cogan, S.M. Lidia FRIB, East Lansing, Michigan, USA
	Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661 The Facility for Rare Isotope Beams (FRIB) is designed to accelerate beam up to 400 kW power with kinetic energy ≥ 200 MeV/u. Fast response of the machine protection system is critical for FRIB beam commissioning and operation to prevent damage to equipment. The beam commissioning of the first linac segment, including fifteen cryomodules, has been completed. Four ion species were accelerated to a beam energy of 20.3 MeV/u with duty factors from 0.05 percent to continuous wave. The peak beam current exceeded 10 percent of the final requirements. This paper summarizes the status of the machine protection system deployed in the production, Machine interlock response time of ~8 μs was achieved. Incentives for future development include being able to achieve smooth and reliable beam operation, faster machine protection response time and real time data analysis of failure mode.
	Poster TUPLM29 [2.067 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM29
About •	paper received ※ 28 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPLH17	Design Study of Low-Level RF Control System for CW Superconducting Electron Linear Accelerator in KAERI	controls, SRF, linac, cavity	512
	S.H. Lee, J.Y. Lee Korea Atomic Energy Research Institute (KAERI), Daejeon, Republic of Korea P. Buaphad, I.G. Jeong, Y.J. Joo, H.R. Lee University of Science and Technology of Korea (UST), Daejeon, Republic of Korea M.-H. Chun, I.H. Yu PAL, Pohang, Republic of Korea Y. Kim KAERI, Jeongeup-si, Republic of Korea
	Korea Atomic Energy Research Institute (KAERI) has been operating a 20 MeV superconducting RF linear accelerator (SRF LINAC) to conduct research on atom/nuclear reaction using neutron Time-Of-Flight (nTOF). It can accelerate electron beams up to 20 MeV with 1 kW continuous wave (CW) operation mode. Unfortunately, this machine has been aged over 15 years that brings about considerably difficulty in normal operation due to the performance degradation of sub-systems. To improve the operation condition of 20 MeV SRF LINAC, we has been carrying out an upgrade project with replacement and repair of old sub-systems from 2018. This paper describes a design study of Low-Level RF (LLRF) feedback system to raise the stability and acceleration efficiency of the electric field generated in the superconducting RF cavity structure in 20 MeV SRF LINAC.
	Poster TUPLH17 [0.644 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLH17
About •	paper received ※ 30 August 2019 paper accepted ※ 04 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPLE01	Python Scripts for RF Commissioning at FRIB	cavity, EPICS, controls, linac	563
	H. Maniar, E. Daykin, D.G. Morris, A.S. Plastun, H.T. Ren, S. Zhao FRIB, East Lansing, Michigan, USA
	Abstract RF commissioning at FRIB involves QWR cavities (β=0.085 and β=0.041), HWR cavities (β=0.29 and β=0.53) and few room temperature devices. Each RF system has many process variables for LLRF and amplifier control located on different pages of CS-Studio. Efficient handling of all these PVs can be challenging for RF experts. Several scripts using Python have been developed to facilitate this process. User interface application has been developed using Qt Designer and PyQt package of Python, for ease of access of all scripts. These scripts are useful for mass ac-tions (for multiple systems) including turning on/ off LLRF controllers and amplifiers, resetting interlocks/ errors, chang-ing a PV value, etc. Python scripts are also used to quickly prototype the auto-start procedure for QWR cavities, which eventually is implemented on IOC driver. The application sends commands to IOC driver with device name, PV name and value to be changed. Future developments can be con-verting to state-notation language on IOC to add channel access security. This application intends to reduce time and efforts for RF commissioning at FRIB.
	Poster TUPLE01 [0.429 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLE01
About •	paper received ※ 27 August 2019 paper accepted ※ 16 November 2020 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPLM01	Studies in Applying Machine Learning to Resonance Control in Superconducting RF Cavities	controls, cavity, simulation, resonance	659
	J.A. Diaz Cruz, S. Biedron, M. Martinez-Ramon, R. Pirayesh, S.I. Sosa Guitron University of New Mexico, Albuquerque, USA J.A. Diaz Cruz SLAC, Menlo Park, California, USA
	Traditional PID, active resonance and feed-forward controllers are dominant strategies for cavity resonance control, but performance may be limited for systems with tight detuning requirements, as low as 10 Hz peak detuning (few nanometers change in cavity length), that are affected by microphonics and Lorentz Force Detuning. Microphonic sources depend on cavity and cryomodule mechanical couplings with their environment and come from several systems: cryoplant, RF sources, tuners, etc. A promising avenue to overcome the limitations of traditional resonance control techniques is machine learning due to recent theoretical and practical advances in these fields, and in particular Neural Networks (NN), which are known for their high performance in complex and nonlinear systems with large number of parameters and have been applied successfully in other areas of science and technology. In this paper we introduce NN to resonance control and compare initial performance results with traditional control techniques. An LCLS-II superconducting cavity type system is simulated in an FPGA, using the Cryomodule-on-Chip model developed by LBNL, and is used to evaluate machine learning algorithms.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM01
About •	paper received ※ 05 September 2019 paper accepted ※ 15 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPLM03	The LLRF Control Design and Validation at FRIB	controls, cavity, MMI, cryomodule	667
	S. Zhao, W. Chang, S.H. Kim, H. Maniar, D.G. Morris, P.N. Ostroumov, J.T. Popielarski, H.T. Ren, N.R. Usher FRIB, East Lansing, Michigan, USA N.R. Usher Ionetix, Lansing, Michigan, USA
	Funding: This work is supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661. One of the challenges in designing the low level radio frequency (LLRF) controllers for the Facility for Rare Isotope Beams (FRIB) is the various types of cavities, which include 5 different frequencies ranging from 40.25 MHz up to 322 MHz, and 4 different types of tuners. In this paper, the design strategy taken to achieve flexibility and low cost and the choices made to accommodate the varieties will be discussed. The approach also allowed easy adaptation to major design changes such as replac-ing two cryo-modules with two newly designed room temperature bunchers and the addition of high-voltage bias to suppress multi-pacting in half wave resonators (HWRs). With the successful completion of the third accelerator readiness review (ARR03) commissioning in early 2019, most of the design has been validated in the real accelerator system, leaving only HWRs which are constantly undergoing tests in cryo-module bunker. The integrated spark detector design for HWRs will also be tested in the near future.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM03
About •	paper received ※ 31 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPLM07	Low Level RF Test System for the Compact X-Ray Light Source at Arizona State University	controls, klystron, electron, cavity	680
	H.S. Marks, W.S. Graves, M.R. Holl, L.E. Malin Arizona State University, Tempe, USA
	A compact femtosecond X-Ray Light Source (CXLS) for time-resolved scientific and medical studies is being constructed at Arizona State University. The CXLS X-rays will be generated by the inverse Compton scattering (ICS) collision of 200 mJ, 1 ps, IR laser pulses with 300 fs electron bunches with energy up to 35 MeV. The electron beam is accelerated via a photoinjector and three standing-wave 20-cell linac sections driven by two klystrons delivering up to 6 MW 1 µs pulses at 9.3 GHz with a pulse repetition rate of 1 kHz. For initial testing of the CXLS klystrons a hybrid digital-analog low-level RF (LLRF) driver has been developed which allows for inter-pulse phase and amplitude corrections based on feedback from waveguide-couplers. The micro-controller based system can also be programmed to adjust continuously in advance of predictable drifts.
	Poster WEPLM07 [2.226 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM07
About •	paper received ※ 27 August 2019 paper accepted ※ 03 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPLM49	New RF System for First Drift Tube Linac Cavity at LANSCE	controls, DTL, cavity, power-supply	703
	J.T.M. Lyles, R.E. Bratton, G. Roybal, M. Sanchez Barrueta, G.M. Sandoval, Jr., D.J. Vigil, J.E. Zane LANL, Los Alamos, New Mexico, USA
	Funding: Work supported by the United States Department of Energy, NNSA, under contract 89233218CNA000001 From 2014-2016, the three highest power 201 MHz power amplifier (PA) systems were replaced at the Los Alamos Neutron Science Center 100 MeV DTL. The initial DTL cavity provides 4.25 MeV of energy gain and has been powered by a Photonis (RCA) 4616 tetrode driving a 7835 triode PA for over 30 years. It consumes 110 kW of electrical power for tube filaments, power supplies and anode modulator. The modulator is not required with modern tetrode amplifiers. In 2020 we plan to replace this obsolete 6 tube transmitter with a design using a single tetrode PA stage without anode modulator, and a 20 kW solid-state driver stage. This transmitter needs to produce no more than 400 kW, and will use a coaxial circulator. Cooling water demand will reduce from 260 to 70 gal/min of pure water. High voltage DC power comes from the same power supply/capacitor bank that supplied the old system. The old low-level RF controls will be replaced with digital LLRF with learning capability for feedforward control, I/Q signal processing, and PI feedback. All high power components have been assembled in a complete mockup system for extended testing. Installation of the new RF system begins in January of 2020.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM49
About •	paper received ※ 28 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

TUPLM29

Current Status and Prospects of FRIB Machine Protection System

operation, machine-protect, FPGA, controls

437

Z. Li, D. Chabot, S. Cogan, S.M. Lidia
FRIB, East Lansing, Michigan, USA

Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
The Facility for Rare Isotope Beams (FRIB) is designed to accelerate beam up to 400 kW power with kinetic energy ≥ 200 MeV/u. Fast response of the machine protection system is critical for FRIB beam commissioning and operation to prevent damage to equipment. The beam commissioning of the first linac segment, including fifteen cryomodules, has been completed. Four ion species were accelerated to a beam energy of 20.3 MeV/u with duty factors from 0.05 percent to continuous wave. The peak beam current exceeded 10 percent of the final requirements. This paper summarizes the status of the machine protection system deployed in the production, Machine interlock response time of ~8 μs was achieved. Incentives for future development include being able to achieve smooth and reliable beam operation, faster machine protection response time and real time data analysis of failure mode.

Poster TUPLM29 [2.067 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM29

About •

paper received ※ 28 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019

Export •

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

TUPLH17

Design Study of Low-Level RF Control System for CW Superconducting Electron Linear Accelerator in KAERI

controls, SRF, linac, cavity

512

S.H. Lee, J.Y. Lee
Korea Atomic Energy Research Institute (KAERI), Daejeon, Republic of Korea
P. Buaphad, I.G. Jeong, Y.J. Joo, H.R. Lee
University of Science and Technology of Korea (UST), Daejeon, Republic of Korea
M.-H. Chun, I.H. Yu
PAL, Pohang, Republic of Korea
Y. Kim
KAERI, Jeongeup-si, Republic of Korea

Korea Atomic Energy Research Institute (KAERI) has been operating a 20 MeV superconducting RF linear accelerator (SRF LINAC) to conduct research on atom/nuclear reaction using neutron Time-Of-Flight (nTOF). It can accelerate electron beams up to 20 MeV with 1 kW continuous wave (CW) operation mode. Unfortunately, this machine has been aged over 15 years that brings about considerably difficulty in normal operation due to the performance degradation of sub-systems. To improve the operation condition of 20 MeV SRF LINAC, we has been carrying out an upgrade project with replacement and repair of old sub-systems from 2018. This paper describes a design study of Low-Level RF (LLRF) feedback system to raise the stability and acceleration efficiency of the electric field generated in the superconducting RF cavity structure in 20 MeV SRF LINAC.

Poster TUPLH17 [0.644 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLH17

About •

paper received ※ 30 August 2019 paper accepted ※ 04 September 2019 issue date ※ 08 October 2019

Export •

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

TUPLE01

Python Scripts for RF Commissioning at FRIB

cavity, EPICS, controls, linac

563

H. Maniar, E. Daykin, D.G. Morris, A.S. Plastun, H.T. Ren, S. Zhao
FRIB, East Lansing, Michigan, USA

Abstract RF commissioning at FRIB involves QWR cavities (β=0.085 and β=0.041), HWR cavities (β=0.29 and β=0.53) and few room temperature devices. Each RF system has many process variables for LLRF and amplifier control located on different pages of CS-Studio. Efficient handling of all these PVs can be challenging for RF experts. Several scripts using Python have been developed to facilitate this process. User interface application has been developed using Qt Designer and PyQt package of Python, for ease of access of all scripts. These scripts are useful for mass ac-tions (for multiple systems) including turning on/ off LLRF controllers and amplifiers, resetting interlocks/ errors, chang-ing a PV value, etc. Python scripts are also used to quickly prototype the auto-start procedure for QWR cavities, which eventually is implemented on IOC driver. The application sends commands to IOC driver with device name, PV name and value to be changed. Future developments can be con-verting to state-notation language on IOC to add channel access security. This application intends to reduce time and efforts for RF commissioning at FRIB.

Poster TUPLE01 [0.429 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLE01

About •

paper received ※ 27 August 2019 paper accepted ※ 16 November 2020 issue date ※ 08 October 2019

Export •

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

WEPLM01

Studies in Applying Machine Learning to Resonance Control in Superconducting RF Cavities

controls, cavity, simulation, resonance

659

J.A. Diaz Cruz, S. Biedron, M. Martinez-Ramon, R. Pirayesh, S.I. Sosa Guitron
University of New Mexico, Albuquerque, USA
J.A. Diaz Cruz
SLAC, Menlo Park, California, USA

Traditional PID, active resonance and feed-forward controllers are dominant strategies for cavity resonance control, but performance may be limited for systems with tight detuning requirements, as low as 10 Hz peak detuning (few nanometers change in cavity length), that are affected by microphonics and Lorentz Force Detuning. Microphonic sources depend on cavity and cryomodule mechanical couplings with their environment and come from several systems: cryoplant, RF sources, tuners, etc. A promising avenue to overcome the limitations of traditional resonance control techniques is machine learning due to recent theoretical and practical advances in these fields, and in particular Neural Networks (NN), which are known for their high performance in complex and nonlinear systems with large number of parameters and have been applied successfully in other areas of science and technology. In this paper we introduce NN to resonance control and compare initial performance results with traditional control techniques. An LCLS-II superconducting cavity type system is simulated in an FPGA, using the Cryomodule-on-Chip model developed by LBNL, and is used to evaluate machine learning algorithms.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM01

About •

paper received ※ 05 September 2019 paper accepted ※ 15 September 2019 issue date ※ 08 October 2019

Export •

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

WEPLM03

The LLRF Control Design and Validation at FRIB

controls, cavity, MMI, cryomodule

667

S. Zhao, W. Chang, S.H. Kim, H. Maniar, D.G. Morris, P.N. Ostroumov, J.T. Popielarski, H.T. Ren, N.R. Usher
FRIB, East Lansing, Michigan, USA
N.R. Usher
Ionetix, Lansing, Michigan, USA

Funding: This work is supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661.
One of the challenges in designing the low level radio frequency (LLRF) controllers for the Facility for Rare Isotope Beams (FRIB) is the various types of cavities, which include 5 different frequencies ranging from 40.25 MHz up to 322 MHz, and 4 different types of tuners. In this paper, the design strategy taken to achieve flexibility and low cost and the choices made to accommodate the varieties will be discussed. The approach also allowed easy adaptation to major design changes such as replac-ing two cryo-modules with two newly designed room temperature bunchers and the addition of high-voltage bias to suppress multi-pacting in half wave resonators (HWRs). With the successful completion of the third accelerator readiness review (ARR03) commissioning in early 2019, most of the design has been validated in the real accelerator system, leaving only HWRs which are constantly undergoing tests in cryo-module bunker. The integrated spark detector design for HWRs will also be tested in the near future.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM03

About •

paper received ※ 31 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019

Export •

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

WEPLM07

Low Level RF Test System for the Compact X-Ray Light Source at Arizona State University

controls, klystron, electron, cavity

680

H.S. Marks, W.S. Graves, M.R. Holl, L.E. Malin
Arizona State University, Tempe, USA

A compact femtosecond X-Ray Light Source (CXLS) for time-resolved scientific and medical studies is being constructed at Arizona State University. The CXLS X-rays will be generated by the inverse Compton scattering (ICS) collision of 200 mJ, 1 ps, IR laser pulses with 300 fs electron bunches with energy up to 35 MeV. The electron beam is accelerated via a photoinjector and three standing-wave 20-cell linac sections driven by two klystrons delivering up to 6 MW 1 µs pulses at 9.3 GHz with a pulse repetition rate of 1 kHz. For initial testing of the CXLS klystrons a hybrid digital-analog low-level RF (LLRF) driver has been developed which allows for inter-pulse phase and amplitude corrections based on feedback from waveguide-couplers. The micro-controller based system can also be programmed to adjust continuously in advance of predictable drifts.

Poster WEPLM07 [2.226 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM07

About •

paper received ※ 27 August 2019 paper accepted ※ 03 September 2019 issue date ※ 08 October 2019

Export •

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

WEPLM49

New RF System for First Drift Tube Linac Cavity at LANSCE

controls, DTL, cavity, power-supply

703

J.T.M. Lyles, R.E. Bratton, G. Roybal, M. Sanchez Barrueta, G.M. Sandoval, Jr., D.J. Vigil, J.E. Zane
LANL, Los Alamos, New Mexico, USA

Funding: Work supported by the United States Department of Energy, NNSA, under contract 89233218CNA000001
From 2014-2016, the three highest power 201 MHz power amplifier (PA) systems were replaced at the Los Alamos Neutron Science Center 100 MeV DTL. The initial DTL cavity provides 4.25 MeV of energy gain and has been powered by a Photonis (RCA) 4616 tetrode driving a 7835 triode PA for over 30 years. It consumes 110 kW of electrical power for tube filaments, power supplies and anode modulator. The modulator is not required with modern tetrode amplifiers. In 2020 we plan to replace this obsolete 6 tube transmitter with a design using a single tetrode PA stage without anode modulator, and a 20 kW solid-state driver stage. This transmitter needs to produce no more than 400 kW, and will use a coaxial circulator. Cooling water demand will reduce from 260 to 70 gal/min of pure water. High voltage DC power comes from the same power supply/capacitor bank that supplied the old system. The old low-level RF controls will be replaced with digital LLRF with learning capability for feedforward control, I/Q signal processing, and PI feedback. All high power components have been assembled in a complete mockup system for extended testing. Installation of the new RF system begins in January of 2020.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM49

About •

paper received ※ 28 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019

Export •

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