LINAC2014 - List of Keywords (LLRF)

Paper	Title	Other Keywords	Page
MOPP055	RF Tests of Dressed 325 MHz Single-Spoke Resonators at 2 K	cavity, network, operation, resonance	180
	A. Hocker, E. Cullerton, B.M. Hanna, W. Schappert, A.I. Sukhanov Fermilab, Batavia, Illinois, USA
	Funding: United States Department of Energy, Contract No.DE- AC02-07CH11359 Fermilab has recently completed an upgrade to its spoke resonator test cryostat to enable testing of cavities in superfluid helium. Two single-spoke resonators with differing helium vessel designs have been tested in this new configuration. Gradient and Q0 performance was studied along with microphonics control and sensitivity of the resonant frequency to pressure variations. A description of the testing and the results obtained are presented.
	Poster MOPP055 [0.437 MB]

MOPP074	Digital Filters Used for Digital Feedback System at cERL	controls, cavity, feedback, operation	227
	F. Qiu, D.A. Arakawa, H. Katagiri, H. Matsumoto, S. Michizono, T. Miura KEK, Ibaraki, Japan
	As a test facility for the future KEK 3-GeV energy recovery linac (ERL) project, the compact ERL (cERL) features three two-cell cavities for the injector and two nine-cell cavities for the main linac. Digital low-level radio frequency (LLRF) systems have been developed to realize highly accurate RF control. In order to reduce the influence of clock jitter and to suppress the parasitic modes in the multi-cell cavities, we have developed several types of digital filters, including a first-order IIR filter, a fourth-order conjugate poles IIR filter and a notch filter. Furthermore, to design a more effective and robust controller (such as an H-infinite controller, or repetitive controller), we need to acquire more detailed system knowledge. This knowledge can be gained by using modern system identification methods. In this paper, we present the latest applications in the LLRF systems of the cERL. identification methods. In this paper, we have compared the performance of these different type filters in cERL. The preliminary result of the system identification will be also described.

TUPP043	Design of the Phase Reference Distribution System at ESS	controls, radiation, cavity, linac	529
	R. Zeng, H. Hassanzadegan, M. Jensen, J.M. Jurns, O.A. Persson, A. Sunesson ESS, Lund, Sweden K. Strniša Cosylab, Ljubljana, Slovenia
	PRDS (Phase reference distribution system) at ESS will provide phase reference signals for all LLRF systems and BPM systems with low phase noise and low phase drift. Phase stability requirement is currently 0.1° for short term (during pulse), 1° for long term (days to months). There are 155 LLRF systems and 165 BPM systems in total at current ESS accelerator design.

TUPP058	RF System Development for the New 10⁸ MHz Heavy Ion High-Energy Linac at GSI	linac, controls, ion, operation	556
	B. Schlitt, M. Hoerr, A. Schnase, G. Schreiber, W. Vinzenz GSI, Darmstadt, Germany
	The GSI UNILAC is in operation successfully since about 40 years. A replacement of the post stripper section is proposed to provide heavy ion beams for the future FAIR facility. Design studies for a new 10⁸ MHz high-energy (HE) linac optimized to accelerate high brilliance and high current ion beams up to U²⁸⁺ for synchrotron injection are in progress. Thus, the UNILAC will be converted into a short-pulse accelerator, the RF duty cycle being reduced from around 30 % to <2 %. To feed the future HE linac and to prepare for the FAIR commissioning, a major modernisation of the existing post stripper RF systems is planned from 2015 to 2017. Besides, the development of a new 1.8 MW cavity amplifier prototype was started recently, based on the widely-used THALES tetrode TH558SC promising an availability for at least 25 years. New 120 - 150 kW solid state driver amplifiers will replace the existing tube drivers. A digital LLRF system designed by industry was integrated into an existing amplifier driving a single gap resonator and was tested including ion beam tests. An overview of the RF system design and of the planned upgrades will be reported including some results of the LLRF tests.

TUPP111	SwissFEL C-band LLRF Prototype System	controls, feedback, electron, klystron	683
	A. Hauff, M. Broennimann, I. Brunnenkant, A. Dietrich, Z. Geng, F. Gärtner, M. Jurcevic, R. Kalt, S. Mair, A. Řežaeizadeh, L. Schebacher, T. Schilcher, W. Sturzenegger PSI, Villigen PSI, Switzerland
	SwissFEL is driven by more than 30 RF stations at different frequencies (S-, C-, X-band). To control the RF a new, in-house developed digital Low Level RF (LLRF) system measures up to 24 RF signals per station and performs a pulse-to-pulse feedback at a repetition rate of 100 Hz. The RF signals are down-converted to a common intermediate frequency. The state-of-the-art digital processing units are integrated into the PSI’s EPICS controls environment. Emphasis has been put on modularity of the system to provide a well-defined path for upgrades. Thus the RF front ends are separated from the digital processing units with their FMC standard interfaces for ADCs and DACs. A first prototype of the LLRF system consisting of the digital back end together with a C-band RF front end was installed in the SwissFEL C-band test facility. In this report the performance of the prototype system has been compared with the LLRF system requirements for SwissFEL. The critical parameters are high intra-pulse phase and amplitude resolutions, good channel-to-channel isolations, very low phase to amplitude modulation and a negligible temperature drift.

WEIOA06	Low Level RF for SRF Accelerators	cavity, controls, SRF, operation	760
	J. Branlard DESY, Hamburg, Germany
	Low level radio frequency (LLRF) systems are a fundamental component of superconducting RF accelerators. Since the release of the MicroTCA standard (MTCA.4), major developments in MTCA.4-based LLRF systems have taken place. State-of-the-art LLRF designs deliver better than 10^-4 relative amplitude and 10 mdeg phase stability for the vector sum control of SRF cavities. These developments in LLRF systems architecture and technology, driven by research institutes and supported by the industry are of highest importance for the European XFEL, but also for other SRF-based projects such as LCLS-II and the ESS, as well as for the next generation accelerators with 10-5 and mdeg regulation requirements.
	Slides WEIOA06 [5.812 MB]

THPP027	Commissioning of the Linac4 Low Level RF and Future Plans	cavity, linac, klystron, DTL	892
	P. Baudrenghien, J. Galindo, G. Hagmann, J. Noirjean, D. Stellfeld, D. Valuch CERN, Geneva, Switzerland
	Linac4 is a new 86-m long normal-conducting linear accelerator that will provide 160 MeV H⁻ to the CERN PS Booster (PSB), and replace the present 50 MeV proton Linac2. The Low Level RF (LLRF) system has to control the RFQ, two choppers, three bunching cavities, twenty two accelerating cavities and one debuncher in the transfer line to the PSB. To optimize the transfer into the 1 MHz PSB bucket, the machine includes fast choppers (synchronized with the PSB RF) and a voltage modulation of the last two cavities that will provide Longitudinal Painting for optimum filling. The commissioning in the tunnel with beam has started in October 2013. So far the part consisting of the RFQ, the three bunching cavities, and the first DTL is operational. The rest of the machine will be progressively commissioned till end 2015. The paper presents the LLRF system. First results from the commissioning (with a prototype regulation system) are shown and the more sophisticated algorithms under development are presented.

THPP113	Architecture Design for the SwissFEL LLRF System	controls, software, hardware, feedback	1114
	Z. Geng, M. Broennimann, I. Brunnenkant, A. Dietrich, F. Gärtner, A. Hauff, M. Jurcevic, R. Kalt, S. Mair, A. Řežaeizadeh, L. Schebacher, T. Schilcher, W. Sturzenegger PSI, Villigen PSI, Switzerland
	The SwissFEL under construction at the Paul Scherrer Institut (PSI) requires high quality electron beams to generate x-ray Free Electron Laser (FEL) for various experiments. The LLRF system is used to control the klystron to provide highly stable RF field in accelerator structures for beam acceleration. There are more than 30 RF stations in the SwissFEL accelerator with different frequencies (S-band, C-band and X-band) and different types of cavities (standing wave cavities and traveling wave structures). Each RF station will be controlled by a LLRF control node and all RF stations will be connected to the real-time network in the scope of the global beam based feedback system. High level applications and automation procedures will be defined to fit the LLRF control nodes into the global control applications for the accelerator operation. In order to handle the complexity of the LLRF system, the system architecture is carefully designed considering the external interfaces, functions and performance requirements to the LLRF system. The architecture design of the LLRF system will be described in this paper with the focus on the fast networks, digital hardware, firmware and software.

THPP130	Development of FPGA-based Predistortion-type Linearization Algorithms for Klystrons within Digital LLRF Control Systems for ILC-like Electron Accelerators	klystron, controls, target, FPGA	1162
	M. Omet Sokendai, Ibaraki, Japan B. Chase, P. Varghese Fermilab, Batavia, Illinois, USA T. Matsumoto, S. Michizono, T. Miura, F. Qiu KEK, Ibaraki, Japan
	Two different kinds of predistortion-type linearization algorithms have been implemented and compared on an FPGA within the digital LLRF control system the Advanced Superconducting Test Facility (ASTA) at the Fermi National Accelerator Laboratory (FNAL). The algorithms are based on 2nd order polynomial functions and lookup tables with interpolation by which complex correction factors are obtained. The algorithms were tested in an actual setup including a 5 MW klystron and a superconducting 9-cell TESLA-type cavity at ASTA. By this a proof of concept was demonstrated.
	Poster THPP130 [2.411 MB]

THPP133	LLRF System for the CEBAF Separator Upgrade	cavity, controls, extraction, electron	1171
	T. E. Plawski, R. Bachimanchi, C. Hovater, D.J. Seidman, M.J. Wissmann JLab, Newport News, Virginia, USA
	The Continuous Electron Beam Accelerator Facility (CEBAF) energy upgrade from 6 GeV to 12 GeV includes the installation of four new 750 MHz deflecting, normal conducting cavities in the 5th pass extraction region. This system will work together with existing 499 MHz RF Separator in order to allow simultaneous delivery of the beam to four CEBAF experimental halls. The RF system employs two digital LLRF systems controlling four cavities in a vector sum. Cavity tune information of the individual cavities is also obtained using a multiplexing scheme of the forward and reflected RF signals. In this paper we will present detailed LLRF design and current status of the CEBAF 750 MHz beam extraction system.

Paper

Title

Other Keywords

Page

MOPP055

RF Tests of Dressed 325 MHz Single-Spoke Resonators at 2 K

cavity, network, operation, resonance

180

A. Hocker, E. Cullerton, B.M. Hanna, W. Schappert, A.I. Sukhanov
Fermilab, Batavia, Illinois, USA

Funding: United States Department of Energy, Contract No.DE- AC02-07CH11359
Fermilab has recently completed an upgrade to its spoke resonator test cryostat to enable testing of cavities in superfluid helium. Two single-spoke resonators with differing helium vessel designs have been tested in this new configuration. Gradient and Q0 performance was studied along with microphonics control and sensitivity of the resonant frequency to pressure variations. A description of the testing and the results obtained are presented.

Poster MOPP055 [0.437 MB]

MOPP074

Digital Filters Used for Digital Feedback System at cERL

controls, cavity, feedback, operation

227

F. Qiu, D.A. Arakawa, H. Katagiri, H. Matsumoto, S. Michizono, T. Miura
KEK, Ibaraki, Japan

As a test facility for the future KEK 3-GeV energy recovery linac (ERL) project, the compact ERL (cERL) features three two-cell cavities for the injector and two nine-cell cavities for the main linac. Digital low-level radio frequency (LLRF) systems have been developed to realize highly accurate RF control. In order to reduce the influence of clock jitter and to suppress the parasitic modes in the multi-cell cavities, we have developed several types of digital filters, including a first-order IIR filter, a fourth-order conjugate poles IIR filter and a notch filter. Furthermore, to design a more effective and robust controller (such as an H-infinite controller, or repetitive controller), we need to acquire more detailed system knowledge. This knowledge can be gained by using modern system identification methods. In this paper, we present the latest applications in the LLRF systems of the cERL. identification methods. In this paper, we have compared the performance of these different type filters in cERL. The preliminary result of the system identification will be also described.

TUPP043

Design of the Phase Reference Distribution System at ESS

controls, radiation, cavity, linac

529

R. Zeng, H. Hassanzadegan, M. Jensen, J.M. Jurns, O.A. Persson, A. Sunesson
ESS, Lund, Sweden
K. Strniša
Cosylab, Ljubljana, Slovenia

PRDS (Phase reference distribution system) at ESS will provide phase reference signals for all LLRF systems and BPM systems with low phase noise and low phase drift. Phase stability requirement is currently 0.1° for short term (during pulse), 1° for long term (days to months). There are 155 LLRF systems and 165 BPM systems in total at current ESS accelerator design.

TUPP058

RF System Development for the New 10⁸ MHz Heavy Ion High-Energy Linac at GSI

linac, controls, ion, operation

556

B. Schlitt, M. Hoerr, A. Schnase, G. Schreiber, W. Vinzenz
GSI, Darmstadt, Germany

The GSI UNILAC is in operation successfully since about 40 years. A replacement of the post stripper section is proposed to provide heavy ion beams for the future FAIR facility. Design studies for a new 10⁸ MHz high-energy (HE) linac optimized to accelerate high brilliance and high current ion beams up to U²⁸⁺ for synchrotron injection are in progress. Thus, the UNILAC will be converted into a short-pulse accelerator, the RF duty cycle being reduced from around 30 % to <2 %. To feed the future HE linac and to prepare for the FAIR commissioning, a major modernisation of the existing post stripper RF systems is planned from 2015 to 2017. Besides, the development of a new 1.8 MW cavity amplifier prototype was started recently, based on the widely-used THALES tetrode TH558SC promising an availability for at least 25 years. New 120 - 150 kW solid state driver amplifiers will replace the existing tube drivers. A digital LLRF system designed by industry was integrated into an existing amplifier driving a single gap resonator and was tested including ion beam tests. An overview of the RF system design and of the planned upgrades will be reported including some results of the LLRF tests.

TUPP111

SwissFEL C-band LLRF Prototype System

controls, feedback, electron, klystron

683

A. Hauff, M. Broennimann, I. Brunnenkant, A. Dietrich, Z. Geng, F. Gärtner, M. Jurcevic, R. Kalt, S. Mair, A. Řežaeizadeh, L. Schebacher, T. Schilcher, W. Sturzenegger
PSI, Villigen PSI, Switzerland

SwissFEL is driven by more than 30 RF stations at different frequencies (S-, C-, X-band). To control the RF a new, in-house developed digital Low Level RF (LLRF) system measures up to 24 RF signals per station and performs a pulse-to-pulse feedback at a repetition rate of 100 Hz. The RF signals are down-converted to a common intermediate frequency. The state-of-the-art digital processing units are integrated into the PSI’s EPICS controls environment. Emphasis has been put on modularity of the system to provide a well-defined path for upgrades. Thus the RF front ends are separated from the digital processing units with their FMC standard interfaces for ADCs and DACs. A first prototype of the LLRF system consisting of the digital back end together with a C-band RF front end was installed in the SwissFEL C-band test facility. In this report the performance of the prototype system has been compared with the LLRF system requirements for SwissFEL. The critical parameters are high intra-pulse phase and amplitude resolutions, good channel-to-channel isolations, very low phase to amplitude modulation and a negligible temperature drift.

WEIOA06

Low Level RF for SRF Accelerators

cavity, controls, SRF, operation

760

J. Branlard
DESY, Hamburg, Germany

Low level radio frequency (LLRF) systems are a fundamental component of superconducting RF accelerators. Since the release of the MicroTCA standard (MTCA.4), major developments in MTCA.4-based LLRF systems have taken place. State-of-the-art LLRF designs deliver better than 10^-4 relative amplitude and 10 mdeg phase stability for the vector sum control of SRF cavities. These developments in LLRF systems architecture and technology, driven by research institutes and supported by the industry are of highest importance for the European XFEL, but also for other SRF-based projects such as LCLS-II and the ESS, as well as for the next generation accelerators with 10-5 and mdeg regulation requirements.

Slides WEIOA06 [5.812 MB]

THPP027

Commissioning of the Linac4 Low Level RF and Future Plans

cavity, linac, klystron, DTL

892

P. Baudrenghien, J. Galindo, G. Hagmann, J. Noirjean, D. Stellfeld, D. Valuch
CERN, Geneva, Switzerland

Linac4 is a new 86-m long normal-conducting linear accelerator that will provide 160 MeV H⁻ to the CERN PS Booster (PSB), and replace the present 50 MeV proton Linac2. The Low Level RF (LLRF) system has to control the RFQ, two choppers, three bunching cavities, twenty two accelerating cavities and one debuncher in the transfer line to the PSB. To optimize the transfer into the 1 MHz PSB bucket, the machine includes fast choppers (synchronized with the PSB RF) and a voltage modulation of the last two cavities that will provide Longitudinal Painting for optimum filling. The commissioning in the tunnel with beam has started in October 2013. So far the part consisting of the RFQ, the three bunching cavities, and the first DTL is operational. The rest of the machine will be progressively commissioned till end 2015. The paper presents the LLRF system. First results from the commissioning (with a prototype regulation system) are shown and the more sophisticated algorithms under development are presented.

THPP113

Architecture Design for the SwissFEL LLRF System

controls, software, hardware, feedback

1114

Z. Geng, M. Broennimann, I. Brunnenkant, A. Dietrich, F. Gärtner, A. Hauff, M. Jurcevic, R. Kalt, S. Mair, A. Řežaeizadeh, L. Schebacher, T. Schilcher, W. Sturzenegger
PSI, Villigen PSI, Switzerland

The SwissFEL under construction at the Paul Scherrer Institut (PSI) requires high quality electron beams to generate x-ray Free Electron Laser (FEL) for various experiments. The LLRF system is used to control the klystron to provide highly stable RF field in accelerator structures for beam acceleration. There are more than 30 RF stations in the SwissFEL accelerator with different frequencies (S-band, C-band and X-band) and different types of cavities (standing wave cavities and traveling wave structures). Each RF station will be controlled by a LLRF control node and all RF stations will be connected to the real-time network in the scope of the global beam based feedback system. High level applications and automation procedures will be defined to fit the LLRF control nodes into the global control applications for the accelerator operation. In order to handle the complexity of the LLRF system, the system architecture is carefully designed considering the external interfaces, functions and performance requirements to the LLRF system. The architecture design of the LLRF system will be described in this paper with the focus on the fast networks, digital hardware, firmware and software.

THPP130

Development of FPGA-based Predistortion-type Linearization Algorithms for Klystrons within Digital LLRF Control Systems for ILC-like Electron Accelerators

klystron, controls, target, FPGA

1162

M. Omet
Sokendai, Ibaraki, Japan
B. Chase, P. Varghese
Fermilab, Batavia, Illinois, USA
T. Matsumoto, S. Michizono, T. Miura, F. Qiu
KEK, Ibaraki, Japan

Two different kinds of predistortion-type linearization algorithms have been implemented and compared on an FPGA within the digital LLRF control system the Advanced Superconducting Test Facility (ASTA) at the Fermi National Accelerator Laboratory (FNAL). The algorithms are based on 2nd order polynomial functions and lookup tables with interpolation by which complex correction factors are obtained. The algorithms were tested in an actual setup including a 5 MW klystron and a superconducting 9-cell TESLA-type cavity at ASTA. By this a proof of concept was demonstrated.

Poster THPP130 [2.411 MB]

THPP133

LLRF System for the CEBAF Separator Upgrade

cavity, controls, extraction, electron

1171

T. E. Plawski, R. Bachimanchi, C. Hovater, D.J. Seidman, M.J. Wissmann
JLab, Newport News, Virginia, USA

The Continuous Electron Beam Accelerator Facility (CEBAF) energy upgrade from 6 GeV to 12 GeV includes the installation of four new 750 MHz deflecting, normal conducting cavities in the 5th pass extraction region. This system will work together with existing 499 MHz RF Separator in order to allow simultaneous delivery of the beam to four CEBAF experimental halls. The RF system employs two digital LLRF systems controlling four cavities in a vector sum. Cavity tune information of the individual cavities is also obtained using a multiplexing scheme of the forward and reflected RF signals. In this paper we will present detailed LLRF design and current status of the CEBAF 750 MHz beam extraction system.