LINAC2018 - List of Keywords (LLRF)

Paper	Title	Other Keywords	Page
MO2A03	Technology Developments for ELI-NP Gamma Beam System	laser, gun, electron, linac	13
	L. Piersanti, D. Alesini, A. Battisti, M. Bellaveglia, S. Bini, F. Cardelli, R.D. Di Raddo, A. Falone, A. Gallo, V.L. Lollo, L. Pellegrino, S. Pioli, S. Tomassini, A. Variola INFN/LNF, Frascati (Roma), Italy N. Beaugerard SEIV, Mérignac, France K. Cassou, D. Douillet, K. Dupraz, T. Le Barillec, A. Martens, C.F. Ndiaye, Y. Peinaud, Z.F. Zomer LAL, Orsay, France L. Ficcadenti, A. Mostacci, L. Palumbo, V. Pettinacci INFN-Roma, Roma, Italy M. Migliorati INFN-Roma1, Rome, Italy D.T. Palmer, L. Serafini Istituto Nazionale di Fisica Nucleare, Milano, Italy H. Rocipon ALSYOM, Argebteuil, France
	ELI-NP gamma beam system (GBS) is a linac based gamma-source in construction in Magurele (RO) by the European consortium EuroGammaS led by INFN. Photons with tunable energy, from 0.2 to 19.5 MeV, and with intensity and brilliance beyond the state of the art, will be produced by Compton back-scattering between a high quality electron beam (up to 740 MeV) and an intense laser pulse at 100 Hz repetition rate. Production of very intense photon flux with narrow bandwidth requires multi-bunch operation and laser recirculation at the interaction point. In this paper, the main technological developments carried out by the EuroGammaS consortium for the generation of the ELI-NP gamma beam will be described with a special emphasis on the electron linac technology, such as: RF-gun and C-band accelerating structures design fabrication and tests; low level RF (LLRF) and synchronization systems specifications and development. Finally, the laser recirculation apparatus design is briefly described and first results reported.
	Slides MO2A03 [9.121 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MO2A03
About •	paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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MOPO038	RF Operation Experience at the European XFEL	cavity, FEL, MMI, operation	109
	J. Branlard, V. Ayvazyan, L. Butkowski, M.K. Grecki, M. Hierholzer, M.G. Hoffmann, M. Hoffmann, M. Killenberg, D. Kostin, T. Lamb, L. Lilje, U. Mavrič, M. Omet, S. Pfeiffer, R. Rybaniec, H. Schlarb, Ch. Schmidt, N. Shehzad, V. Vogel, N. Walker DESY, Hamburg, Germany
	After its successful commissioning which took place during the first half of 2017, the European X-ray free electron laser is in now in regular operation delivering photons to users since September 2017. This paper presents an overview on the experience gathered during the first couple of years of operation. In particular, the focus is set on RF operation, maintenance activities, availability and typical failures. A first look on machine performance in terms of RF and beam stability, energy reach, radiation related investigations and microphonics studies will also be presented.
	Slides MOPO038 [2.421 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO038
About •	paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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MOPO081	Light Proton Therapy Linac LLRF System Development	controls, cavity, proton, interface	171
	B.B. Baricevic, A. Bardorfer, R. Cerne I-Tech, Solkan, Slovenia G. De Michele, Ye. Ivanisenko AVO-ADAM, Meyrin, Switzerland
	Proton cancer therapy is a state-of-the-art medical treatment technique based on an accelerator beam production facility. The LIGHT linear accelerator design by AVO-ADAM offers a modular compact solution for precise control of the treatment dose delivery, both position and energy wise. Proton energy can be modulated at up to 200 Hz in a range from 70 to 230 MeV by varying the gradient of the accelerating structures. The normal conducting LINAC RF system is based on a 750 MHz RFQ and 12 S band stations individually controlled. A customized LLRF system is being developed on the Libera LLRF platform for the LIGHT project. The paper is describing the required cavity field control functionality and the other subsystems such as master oscillator reference, cavity tuning, real-time control, data acquisition, control system and synchronization interfaces.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO081
About •	paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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MOPO094	RF Stability Test of RFQ Cavity with Prototype Low-level Radio Frequency in RAON	rfq, cavity, controls, experiment	204
	D.Y. Lee, B.H. Choi, C.O. Choi, H. Jang, H.C. Jung, K.T. Son IBS, Daejeon, Republic of Korea
	RAON is a heavy ion accelerator of the Institute for Basic Sciences (IBS) in Korea. The prototype Low-Level Radio Frequency (LLRF) operated at 81.25 MHz has been designed and fabricated for a prototype Radio Fre-quency Quadrupole (RFQ) cavity in RAON. Stabilities of ±1 % in amplitude and ±1 degree in phase are required for specifications of the RFQ system. The prototype LLRF controls the RF amplitude and phase in the cavity by PID feedback loop. The prototype LLRF has been tested with one RFQ cavity and stabilities have been measured. In this paper, we present the design and results of stability test.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO094
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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MOPO102	Progress of MicroTCA.4 based LLRF System of TARLA	controls, cavity, hardware, operation	220
	C. Gumus, M. Hierholzer, H. Schlarb, Ch. Schmidt DESY, Hamburg, Germany A.A. Aksoy, A. Aydin, C. Kaya Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey O.F. Elcim Ankara University Institute of Accelerator Technologies, Golbasi, Turkey
	The Turkish Accelerator and Radiation Laboratory in Ankara (TARLA) is constructing a 40 MeV Free Electron Laser with continuous wave RF operation. DESY is responsible for delivering a turnkey LLRF system based on MicroTCA.4 standard that will be used to control four superconducting (SC) TESLA type cavities as well as the two normal conducting buncher cavities. This highly modular system is further used to control the mechanical tuning of the SC cavities by control of piezo actuators and mechanical motor tuners. With the usage of ChimeraTK framework, integration to EPICS control system is also implemented. This poster describes the system setup and integration to the existing accelerator environment with hardware and software components along with the latest updates from the facility.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO102
About •	paper received ※ 10 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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MOPO104	LLRF R&D Towards CW Operation of the European XFEL	FEL, cavity, controls, resonance	223
	A. Bellandi, V. Ayvazyan, J. Branlard, C. Gumus, S. Pfeiffer, K.P. Przygoda, R. Rybaniec, H. Schlarb, Ch. Schmidt, J.K. Sekutowicz DESY, Hamburg, Germany W. Cichalewski TUL-DMCS, Łódź, Poland
	The ever growing request for machines with a higher average beam pulse rate and also with a relaxed (< 1 MHz) pulse separation calls for superconducting linacs that operate in Long Pulse (LP) or Continuous Wave (CW) mode. For this purpose the European X-ray Free Electron Laser (European XFEL) could be upgraded to add the ability to run in CW/LP mode. Cryo Module Test Bench (CMTB) is a facility used to perform tests on superconducting cavity cryomodules. Because of the interest in upgrading European XFEL to a CW machine, CMTB is now used to perform studies on XM-3, a 1.3 GHz European XFEL-like cryomodule with modified coupling that is able to run with very high quality factor (QL = 10E7…10E8) values. The RF power source allows running the cavities at gradients larger than 16 MV/m. Because of the QL and gradient values involved in these tests, detuning effects like mechanical resonances and microphonics became more challenging to regulate. The goal is then to determine the appropriate set of parameters for the LLRF control system to keep the error to be less than 0.01° in phase and 0.01% in amplitude.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO104
About •	paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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MOPO106	New Digital LLRF System for HIT	controls, cavity, linac, feedback	227
	E. Feldmeier, Th. Haberer, A. Peters HIT, Heidelberg, Germany
	The Heidelberg Ion Therapy Center HIT is in clinical operation since 2009. The accelerator complex consists of a linear accelerator and a synchrotron to provide carbon ions and protons for clinical use as well as helium and oxygen ions. The analog LLRF system for the linac should be replaced after more than 10 years of continuous operation. In its life-time the LLRF caused no interruption of the clinical operation with a downtime of more than 15 minutes. In order to keep the reliability in the next 10 years at least as high, a new digital LLRF system is planned. Further difficulties for the installation of a new system are due to the clinical full time usage of the accelerator and the short maintenance slots of only two days in series.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO106
About •	paper received ※ 12 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019
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MOPO111	Development of New LLRF System at the J-PARC Linac	linac, FPGA, low-level-rf, feedback	233
	K. Futatsukawa, Z. Fang, Y. Fukui KEK, Ibaraki, Japan Y. Sato Nippon Advanced Technology Co., Ltd., Tokai, Japan S. Shinozaki JAEA/J-PARC, Tokai-mura, Japan
	In the J-PARC linac, the LLRF system with the digital feedback (DFB) and the digital feedforward (DFF) was adopted for satisfying requirement of amplitude and phase stabilities. It has been operated without serious problems. However, it has been used since the beginning of the J-PARC and more than ten years have already passed since the development. The increase of the failure frequency for this system is expected. Additionally, it is difficult to maintain it for some discontinued boards of DFB and DFF and the older developing environment of software. Therefore, we are starting to study the new LLRF system of the next generation. In the present, we are exploring several possibilities of a new way and investigating each advantage and disadvantage. The project and the status of the development for the new system in the J-PARC linac LLRF are introduced.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO111
About •	paper received ※ 22 September 2018 paper accepted ※ 09 November 2018 issue date ※ 18 January 2019
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MOPO115	CEBAF Photo Gun RF System	FPGA, operation, laser, gun	236
	T. E. Plawski, R. Bachimanchi, M. Diaz, H. Higgins, C. Hovater, C.I. Mounts, D.J. Seidman JLab, Newport News, Virgina, USA
	Funding: Authored by JSA, LLC under U.S. DOE Contract DE-AC05- 06OR23177 and DE-SC0005264. During the CEBAF 12 GeV Upgrade at Jefferson Lab, a fourth experimental hall, ’D’, was added to the existing three halls. To produce four beams and deliver them to all halls concurrently requires new frequencies and a new timing pattern of the electron bunches. Since a photo-gun is used to produce electron bunches, the gun’s drive laser pulses need to be synchronized with the required bunch rate frequencies of 499 MHz or 249.5 MHz. To meet these new operational requirements, the new LLRF system has been proposed. Very specific requirements (dual frequency operation) on one side and the simple RF drive mode operation on the other imply the use of a commercial off-the-shelf digital platform rather than a system typical for RF cavity field control. We have chosen the Texas Instruments FPGA board along with a high-speed 8-Channel, 14-Bit board, and a 4-Channel, 16-Bit board. The DAC board includes the clock generator for clocking ADCs, DACs and the FPGA. The complete Gun Laser LLRF system has been designed, built, and recently commissioned in the CEBAF Injector. This paper will detail the design and report on commissioning activities.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO115
About •	paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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TUPO017	The New Light Ion Injector for NICA	cavity, linac, diagnostics, rfq	362
	B. Koubek, M. Basten, H. Höltermann, H. Podlech, U. Ratzinger, A. Schempp, R. Tiede BEVATECH, Frankfurt, Germany A.V. Butenko, D.E. Donets, B.V. Golovenskiy, A. Govorov, K.A. Levterov, D.A. Lyuosev, A.A. Martynov, V.A. Monchinsky, D.O. Ponkin, K.V. Shevchenko, I.V. Shirikov, E. Syresin JINR, Dubna, Moscow Region, Russia C. K. Kampmeyer, H. Schlarb DESY, Hamburg, Germany
	Within the upgrade scheme of the injection complex of the NICA project and after a successful beam commissioning of a heavy ion linac, Bevatech GmbH will build a first part of a new light ion linac as an injector for the Nuclotron ring. The linac will provide a beam of polarised protons and light ions with a mass to charge ratio up to 3 and an energy of 7 MeV/u. The mandate of the Linac does not only include the hardware for the accelerating structures, focusing magnets and beam diagnostic devices, but also the LLRF control soft- and hardware based on the MicroTCA.4 standard in collaboration with the MicroTCA Technology Lab at DESY. An overview of the Linac is presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO017
About •	paper received ※ 10 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019
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TUPO027	Series Production of the Specific Waveguide Distribution for the European XFEL at DESY	GUI, cavity, cryomodule, FEL	380
	B. Yildirim, S. Choroba, V.V. Katalev, P. Morozov, Y. Nachtigal DESY, Hamburg, Germany E.M. Apostolov Technical University of Sofia, Sofia, Bulgaria
	Series Production of the Specific Waveguide Distribution for the European XFEL at DESY B.Yildirim, S.Choroba, V.Katalev, P.Morozov, Y.Nachtigal, E.Apostolov The European XFEL uses 100 accelerating cryomodules. One RF station with 10 MW klystron supplies four cryomodules, each with eight cavities, through a waveguide distribution system. The RF station operates at 1.3 GHz, 1.37 ms pulse width and 10 Hz repetition rate. The results of the cryomodule test have shown however different maximum gradients for each cavity. The maximum gradient has been measured between 11 MV/m and 31 MV/m, which requires the cavity power from 29 kW to 230 kW. To operate with the maximum energy for every cryomodule, it is necessary to supply individual power to the cavity. In this case the weakest cavity problem can be avoided. For this goal a specific waveguide distribution has been developed. 100 waveguide distributions have been successfully tailored, produced and tested at the Waveguide Assembly Test Facility (WATF) at DESY and finally assembled to the cryomodules. We present the series production of the specific waveguide distributions at the WATF.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO027
About •	paper received ※ 06 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019
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TUPO040	Tests of Multi-frequency Coaxial Resonators	cavity, TRIUMF, controls, niobium	420
	Z.Y. Yao, J.J. Keir, P. Kolb, A. Kong, R.E. Laxdal, B. Matheson, E. Thoeng, B.S. Waraich, Q. Zheng, V. Zvyagintsev TRIUMF, Vancouver, Canada
	A significant issue in low beta resonators is medium field Q-slope (MFQS) at 4K. To study the MFQS and the field dependence of surface resistance in low beta resonators, a quarter-wave resonator (QWR) and a half-wave resonator (HWR) were designed to be tested at integer harmonic frequencies of 200MHz, and up to 1.2GHz. A series of chemistry and heat treatments are proposed to these cavities. A systemic study on the surface resistance of the coaxial resonators associating with post-processing, RF field, and frequency is in progress. The cavities were designed and fabricated. The cold test results will be discussed in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO040
About •	paper received ※ 17 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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TUPO132	Implementation of the Beam Loading Compensation Algorithm in the LLRF System of the European XFEL	controls, cavity, FEL, FPGA	594
	Ł. Butkowski, J. Branlard, M. Omet, R. Rybaniec, H. Schlarb, Ch. Schmidt DESY, Hamburg, Germany
	In the European XFEL, a maximum number of 2700 electron bunches per RF pulse with beam currents up to 4.5mA can be accelerated. Such large beam currents can cause a significant drop of the accelerating gradients, which results in large energy changes across the macro-pulse. But, the electron bunch energies should not deviate from the nominal energy to guarantee stable and reproducible generation of photon pulses for the European XFEL users. To overcome this issue, the Low Level RF system (LLRF) compensates in real-time the beam perturbation using a Beam Loading Compensation algorithm (BLC) minimizing the transient gradient variations. The algorithm takes the charge information obtained from beam diagnostic systems e.g. Beam Position Monitors (BPM) and information from the timing system. The BLC is a part of the LLRF controller implemented in the FPGA. The article presents the implementation of the algorithm in the FPGA and shows the results achieved with the BLC in the European XFEL.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO132
About •	paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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THPO007	MESA - Status of the Implementation of the MicroTCA.4-based LLRF Control System	cavity, controls, experiment, simulation	691
	J.N. Bai, K. Aulenbacher, J. Diefenbach, F. Fichtner IKP, Mainz, Germany P. Echevarria HZB, Berlin, Germany R.G. Heine KPH, Mainz, Germany
	MESA at the Institut für Kernphysik (KPH) at Johannes Gutenberg-Universität Mainz is a multi-turn energy recovery linac (ERL), aiming to serve as user facility for particle physics experiments. The RF-accelerating systems of MESA consist of four 9-cell TESLA superconducting cavities, four normal conducting (NC) pre-accelerator cavities, two NC buncher cavities and two NC chopper cavities. They operate in continuous wave (CW) mode. In order to control the radio frequency (RF) amplitude and phase within the 12 cavities with the required accuracy and stability in the range of better than 0.01% and 0.01°, the MicroTCA.4 based digital low-level RF (LLRF) control system based on the development at DESY, Hamburg will be well adapted for the MESA cavities. In this paper, we describe the theoretical modelling of superconducting cavity and PID controller in SIMULINK which is useful to find the suitable control parameter for the PID controller and to predict the system performance. The progress to date of the implementation and tests of the LLRF system at MESA will also be presented.
	Poster THPO007 [1.274 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO007
About •	paper received ※ 11 September 2018 paper accepted ※ 09 October 2018 issue date ※ 18 January 2019
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THPO103	Application of Solid State Amplifiers in ADS Project at IHEP	cavity, power-supply, controls, MMI	914
	O. Xiao Institute of High Energy Physics (IHEP), People’s Republic of China Y.L. Chi, N. Gan, X. Ma, Z.S. Zhou IHEP, Beijing, People’s Republic of China
	The solid state amplifier is an important part of the RF power source system of ADS project at IHEP. Three kinds of solid state amplifier with different power and frequency have been applied. In this paper, the specifications of solid state amplifier are presented. In addition, the principle of breakdown of power modules during the high power test of coupler are analyzed.
	Poster THPO103 [0.195 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO103
About •	paper received ※ 17 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019
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Paper

Title

Other Keywords

Page

MO2A03

Technology Developments for ELI-NP Gamma Beam System

laser, gun, electron, linac

13

L. Piersanti, D. Alesini, A. Battisti, M. Bellaveglia, S. Bini, F. Cardelli, R.D. Di Raddo, A. Falone, A. Gallo, V.L. Lollo, L. Pellegrino, S. Pioli, S. Tomassini, A. Variola
INFN/LNF, Frascati (Roma), Italy
N. Beaugerard
SEIV, Mérignac, France
K. Cassou, D. Douillet, K. Dupraz, T. Le Barillec, A. Martens, C.F. Ndiaye, Y. Peinaud, Z.F. Zomer
LAL, Orsay, France
L. Ficcadenti, A. Mostacci, L. Palumbo, V. Pettinacci
INFN-Roma, Roma, Italy
M. Migliorati
INFN-Roma1, Rome, Italy
D.T. Palmer, L. Serafini
Istituto Nazionale di Fisica Nucleare, Milano, Italy
H. Rocipon
ALSYOM, Argebteuil, France

ELI-NP gamma beam system (GBS) is a linac based gamma-source in construction in Magurele (RO) by the European consortium EuroGammaS led by INFN. Photons with tunable energy, from 0.2 to 19.5 MeV, and with intensity and brilliance beyond the state of the art, will be produced by Compton back-scattering between a high quality electron beam (up to 740 MeV) and an intense laser pulse at 100 Hz repetition rate. Production of very intense photon flux with narrow bandwidth requires multi-bunch operation and laser recirculation at the interaction point. In this paper, the main technological developments carried out by the EuroGammaS consortium for the generation of the ELI-NP gamma beam will be described with a special emphasis on the electron linac technology, such as: RF-gun and C-band accelerating structures design fabrication and tests; low level RF (LLRF) and synchronization systems specifications and development. Finally, the laser recirculation apparatus design is briefly described and first results reported.

Slides MO2A03 [9.121 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MO2A03

About •

paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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MOPO038

RF Operation Experience at the European XFEL

cavity, FEL, MMI, operation

109

J. Branlard, V. Ayvazyan, L. Butkowski, M.K. Grecki, M. Hierholzer, M.G. Hoffmann, M. Hoffmann, M. Killenberg, D. Kostin, T. Lamb, L. Lilje, U. Mavrič, M. Omet, S. Pfeiffer, R. Rybaniec, H. Schlarb, Ch. Schmidt, N. Shehzad, V. Vogel, N. Walker
DESY, Hamburg, Germany

After its successful commissioning which took place during the first half of 2017, the European X-ray free electron laser is in now in regular operation delivering photons to users since September 2017. This paper presents an overview on the experience gathered during the first couple of years of operation. In particular, the focus is set on RF operation, maintenance activities, availability and typical failures. A first look on machine performance in terms of RF and beam stability, energy reach, radiation related investigations and microphonics studies will also be presented.

Slides MOPO038 [2.421 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO038

About •

paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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MOPO081

Light Proton Therapy Linac LLRF System Development

controls, cavity, proton, interface

171

B.B. Baricevic, A. Bardorfer, R. Cerne
I-Tech, Solkan, Slovenia
G. De Michele, Ye. Ivanisenko
AVO-ADAM, Meyrin, Switzerland

Proton cancer therapy is a state-of-the-art medical treatment technique based on an accelerator beam production facility. The LIGHT linear accelerator design by AVO-ADAM offers a modular compact solution for precise control of the treatment dose delivery, both position and energy wise. Proton energy can be modulated at up to 200 Hz in a range from 70 to 230 MeV by varying the gradient of the accelerating structures. The normal conducting LINAC RF system is based on a 750 MHz RFQ and 12 S band stations individually controlled. A customized LLRF system is being developed on the Libera LLRF platform for the LIGHT project. The paper is describing the required cavity field control functionality and the other subsystems such as master oscillator reference, cavity tuning, real-time control, data acquisition, control system and synchronization interfaces.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO081

About •

paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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MOPO094

RF Stability Test of RFQ Cavity with Prototype Low-level Radio Frequency in RAON

rfq, cavity, controls, experiment

204

D.Y. Lee, B.H. Choi, C.O. Choi, H. Jang, H.C. Jung, K.T. Son
IBS, Daejeon, Republic of Korea

RAON is a heavy ion accelerator of the Institute for Basic Sciences (IBS) in Korea. The prototype Low-Level Radio Frequency (LLRF) operated at 81.25 MHz has been designed and fabricated for a prototype Radio Fre-quency Quadrupole (RFQ) cavity in RAON. Stabilities of ±1 % in amplitude and ±1 degree in phase are required for specifications of the RFQ system. The prototype LLRF controls the RF amplitude and phase in the cavity by PID feedback loop. The prototype LLRF has been tested with one RFQ cavity and stabilities have been measured. In this paper, we present the design and results of stability test.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO094

About •

paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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

MOPO102

Progress of MicroTCA.4 based LLRF System of TARLA

controls, cavity, hardware, operation

220

C. Gumus, M. Hierholzer, H. Schlarb, Ch. Schmidt
DESY, Hamburg, Germany
A.A. Aksoy, A. Aydin, C. Kaya
Ankara University, Accelerator Technologies Institute, Golbasi / Ankara, Turkey
O.F. Elcim
Ankara University Institute of Accelerator Technologies, Golbasi, Turkey

The Turkish Accelerator and Radiation Laboratory in Ankara (TARLA) is constructing a 40 MeV Free Electron Laser with continuous wave RF operation. DESY is responsible for delivering a turnkey LLRF system based on MicroTCA.4 standard that will be used to control four superconducting (SC) TESLA type cavities as well as the two normal conducting buncher cavities. This highly modular system is further used to control the mechanical tuning of the SC cavities by control of piezo actuators and mechanical motor tuners. With the usage of ChimeraTK framework, integration to EPICS control system is also implemented. This poster describes the system setup and integration to the existing accelerator environment with hardware and software components along with the latest updates from the facility.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO102

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paper received ※ 10 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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MOPO104

LLRF R&D Towards CW Operation of the European XFEL

FEL, cavity, controls, resonance

223

A. Bellandi, V. Ayvazyan, J. Branlard, C. Gumus, S. Pfeiffer, K.P. Przygoda, R. Rybaniec, H. Schlarb, Ch. Schmidt, J.K. Sekutowicz
DESY, Hamburg, Germany
W. Cichalewski
TUL-DMCS, Łódź, Poland

The ever growing request for machines with a higher average beam pulse rate and also with a relaxed (< 1 MHz) pulse separation calls for superconducting linacs that operate in Long Pulse (LP) or Continuous Wave (CW) mode. For this purpose the European X-ray Free Electron Laser (European XFEL) could be upgraded to add the ability to run in CW/LP mode. Cryo Module Test Bench (CMTB) is a facility used to perform tests on superconducting cavity cryomodules. Because of the interest in upgrading European XFEL to a CW machine, CMTB is now used to perform studies on XM-3, a 1.3 GHz European XFEL-like cryomodule with modified coupling that is able to run with very high quality factor (QL = 10E7…10E8) values. The RF power source allows running the cavities at gradients larger than 16 MV/m. Because of the QL and gradient values involved in these tests, detuning effects like mechanical resonances and microphonics became more challenging to regulate. The goal is then to determine the appropriate set of parameters for the LLRF control system to keep the error to be less than 0.01° in phase and 0.01% in amplitude.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO104

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paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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MOPO106

New Digital LLRF System for HIT

controls, cavity, linac, feedback

227

E. Feldmeier, Th. Haberer, A. Peters
HIT, Heidelberg, Germany

The Heidelberg Ion Therapy Center HIT is in clinical operation since 2009. The accelerator complex consists of a linear accelerator and a synchrotron to provide carbon ions and protons for clinical use as well as helium and oxygen ions. The analog LLRF system for the linac should be replaced after more than 10 years of continuous operation. In its life-time the LLRF caused no interruption of the clinical operation with a downtime of more than 15 minutes. In order to keep the reliability in the next 10 years at least as high, a new digital LLRF system is planned. Further difficulties for the installation of a new system are due to the clinical full time usage of the accelerator and the short maintenance slots of only two days in series.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO106

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paper received ※ 12 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019

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MOPO111

Development of New LLRF System at the J-PARC Linac

linac, FPGA, low-level-rf, feedback

233

K. Futatsukawa, Z. Fang, Y. Fukui
KEK, Ibaraki, Japan
Y. Sato
Nippon Advanced Technology Co., Ltd., Tokai, Japan
S. Shinozaki
JAEA/J-PARC, Tokai-mura, Japan

In the J-PARC linac, the LLRF system with the digital feedback (DFB) and the digital feedforward (DFF) was adopted for satisfying requirement of amplitude and phase stabilities. It has been operated without serious problems. However, it has been used since the beginning of the J-PARC and more than ten years have already passed since the development. The increase of the failure frequency for this system is expected. Additionally, it is difficult to maintain it for some discontinued boards of DFB and DFF and the older developing environment of software. Therefore, we are starting to study the new LLRF system of the next generation. In the present, we are exploring several possibilities of a new way and investigating each advantage and disadvantage. The project and the status of the development for the new system in the J-PARC linac LLRF are introduced.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO111

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paper received ※ 22 September 2018 paper accepted ※ 09 November 2018 issue date ※ 18 January 2019

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MOPO115

CEBAF Photo Gun RF System

FPGA, operation, laser, gun

236

T. E. Plawski, R. Bachimanchi, M. Diaz, H. Higgins, C. Hovater, C.I. Mounts, D.J. Seidman
JLab, Newport News, Virgina, USA

Funding: Authored by JSA, LLC under U.S. DOE Contract DE-AC05- 06OR23177 and DE-SC0005264.
During the CEBAF 12 GeV Upgrade at Jefferson Lab, a fourth experimental hall, ’D’, was added to the existing three halls. To produce four beams and deliver them to all halls concurrently requires new frequencies and a new timing pattern of the electron bunches. Since a photo-gun is used to produce electron bunches, the gun’s drive laser pulses need to be synchronized with the required bunch rate frequencies of 499 MHz or 249.5 MHz. To meet these new operational requirements, the new LLRF system has been proposed. Very specific requirements (dual frequency operation) on one side and the simple RF drive mode operation on the other imply the use of a commercial off-the-shelf digital platform rather than a system typical for RF cavity field control. We have chosen the Texas Instruments FPGA board along with a high-speed 8-Channel, 14-Bit board, and a 4-Channel, 16-Bit board. The DAC board includes the clock generator for clocking ADCs, DACs and the FPGA. The complete Gun Laser LLRF system has been designed, built, and recently commissioned in the CEBAF Injector. This paper will detail the design and report on commissioning activities.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-MOPO115

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paper received ※ 12 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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TUPO017

The New Light Ion Injector for NICA

cavity, linac, diagnostics, rfq

362

B. Koubek, M. Basten, H. Höltermann, H. Podlech, U. Ratzinger, A. Schempp, R. Tiede
BEVATECH, Frankfurt, Germany
A.V. Butenko, D.E. Donets, B.V. Golovenskiy, A. Govorov, K.A. Levterov, D.A. Lyuosev, A.A. Martynov, V.A. Monchinsky, D.O. Ponkin, K.V. Shevchenko, I.V. Shirikov, E. Syresin
JINR, Dubna, Moscow Region, Russia
C. K. Kampmeyer, H. Schlarb
DESY, Hamburg, Germany

Within the upgrade scheme of the injection complex of the NICA project and after a successful beam commissioning of a heavy ion linac, Bevatech GmbH will build a first part of a new light ion linac as an injector for the Nuclotron ring. The linac will provide a beam of polarised protons and light ions with a mass to charge ratio up to 3 and an energy of 7 MeV/u. The mandate of the Linac does not only include the hardware for the accelerating structures, focusing magnets and beam diagnostic devices, but also the LLRF control soft- and hardware based on the MicroTCA.4 standard in collaboration with the MicroTCA Technology Lab at DESY. An overview of the Linac is presented in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO017

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paper received ※ 10 September 2018 paper accepted ※ 19 September 2018 issue date ※ 18 January 2019

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TUPO027

Series Production of the Specific Waveguide Distribution for the European XFEL at DESY

GUI, cavity, cryomodule, FEL

380

B. Yildirim, S. Choroba, V.V. Katalev, P. Morozov, Y. Nachtigal
DESY, Hamburg, Germany
E.M. Apostolov
Technical University of Sofia, Sofia, Bulgaria

Series Production of the Specific Waveguide Distribution for the European XFEL at DESY B.Yildirim, S.Choroba, V.Katalev, P.Morozov, Y.Nachtigal, E.Apostolov The European XFEL uses 100 accelerating cryomodules. One RF station with 10 MW klystron supplies four cryomodules, each with eight cavities, through a waveguide distribution system. The RF station operates at 1.3 GHz, 1.37 ms pulse width and 10 Hz repetition rate. The results of the cryomodule test have shown however different maximum gradients for each cavity. The maximum gradient has been measured between 11 MV/m and 31 MV/m, which requires the cavity power from 29 kW to 230 kW. To operate with the maximum energy for every cryomodule, it is necessary to supply individual power to the cavity. In this case the weakest cavity problem can be avoided. For this goal a specific waveguide distribution has been developed. 100 waveguide distributions have been successfully tailored, produced and tested at the Waveguide Assembly Test Facility (WATF) at DESY and finally assembled to the cryomodules. We present the series production of the specific waveguide distributions at the WATF.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO027

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paper received ※ 06 September 2018 paper accepted ※ 21 September 2018 issue date ※ 18 January 2019

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TUPO040

Tests of Multi-frequency Coaxial Resonators

cavity, TRIUMF, controls, niobium

420

Z.Y. Yao, J.J. Keir, P. Kolb, A. Kong, R.E. Laxdal, B. Matheson, E. Thoeng, B.S. Waraich, Q. Zheng, V. Zvyagintsev
TRIUMF, Vancouver, Canada

A significant issue in low beta resonators is medium field Q-slope (MFQS) at 4K. To study the MFQS and the field dependence of surface resistance in low beta resonators, a quarter-wave resonator (QWR) and a half-wave resonator (HWR) were designed to be tested at integer harmonic frequencies of 200MHz, and up to 1.2GHz. A series of chemistry and heat treatments are proposed to these cavities. A systemic study on the surface resistance of the coaxial resonators associating with post-processing, RF field, and frequency is in progress. The cavities were designed and fabricated. The cold test results will be discussed in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO040

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paper received ※ 17 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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TUPO132

Implementation of the Beam Loading Compensation Algorithm in the LLRF System of the European XFEL

controls, cavity, FEL, FPGA

594

Ł. Butkowski, J. Branlard, M. Omet, R. Rybaniec, H. Schlarb, Ch. Schmidt
DESY, Hamburg, Germany

In the European XFEL, a maximum number of 2700 electron bunches per RF pulse with beam currents up to 4.5mA can be accelerated. Such large beam currents can cause a significant drop of the accelerating gradients, which results in large energy changes across the macro-pulse. But, the electron bunch energies should not deviate from the nominal energy to guarantee stable and reproducible generation of photon pulses for the European XFEL users. To overcome this issue, the Low Level RF system (LLRF) compensates in real-time the beam perturbation using a Beam Loading Compensation algorithm (BLC) minimizing the transient gradient variations. The algorithm takes the charge information obtained from beam diagnostic systems e.g. Beam Position Monitors (BPM) and information from the timing system. The BLC is a part of the LLRF controller implemented in the FPGA. The article presents the implementation of the algorithm in the FPGA and shows the results achieved with the BLC in the European XFEL.

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-TUPO132

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paper received ※ 11 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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THPO007

MESA - Status of the Implementation of the MicroTCA.4-based LLRF Control System

cavity, controls, experiment, simulation

691

J.N. Bai, K. Aulenbacher, J. Diefenbach, F. Fichtner
IKP, Mainz, Germany
P. Echevarria
HZB, Berlin, Germany
R.G. Heine
KPH, Mainz, Germany

MESA at the Institut für Kernphysik (KPH) at Johannes Gutenberg-Universität Mainz is a multi-turn energy recovery linac (ERL), aiming to serve as user facility for particle physics experiments. The RF-accelerating systems of MESA consist of four 9-cell TESLA superconducting cavities, four normal conducting (NC) pre-accelerator cavities, two NC buncher cavities and two NC chopper cavities. They operate in continuous wave (CW) mode. In order to control the radio frequency (RF) amplitude and phase within the 12 cavities with the required accuracy and stability in the range of better than 0.01% and 0.01°, the MicroTCA.4 based digital low-level RF (LLRF) control system based on the development at DESY, Hamburg will be well adapted for the MESA cavities. In this paper, we describe the theoretical modelling of superconducting cavity and PID controller in SIMULINK which is useful to find the suitable control parameter for the PID controller and to predict the system performance. The progress to date of the implementation and tests of the LLRF system at MESA will also be presented.

Poster THPO007 [1.274 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO007

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paper received ※ 11 September 2018 paper accepted ※ 09 October 2018 issue date ※ 18 January 2019

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THPO103

Application of Solid State Amplifiers in ADS Project at IHEP

cavity, power-supply, controls, MMI

914

O. Xiao
Institute of High Energy Physics (IHEP), People’s Republic of China
Y.L. Chi, N. Gan, X. Ma, Z.S. Zhou
IHEP, Beijing, People’s Republic of China

The solid state amplifier is an important part of the RF power source system of ADS project at IHEP. Three kinds of solid state amplifier with different power and frequency have been applied. In this paper, the specifications of solid state amplifier are presented. In addition, the principle of breakdown of power modules during the high power test of coupler are analyzed.

Poster THPO103 [0.195 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-LINAC2018-THPO103

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paper received ※ 17 September 2018 paper accepted ※ 20 September 2018 issue date ※ 18 January 2019

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