IPAC2013 - List of Keywords (LLRF)

Paper	Title	Other Keywords	Page
MOPEA048	Operation Status of RF System for the PLS-II Storage Ring	cryomodule, SRF, klystron, status	187
	M.-H. Chun, J.Y. Huang, Y.D. Joo, H.-G. Kim, S.H. Nam, C.D. Park, H.J. Park, I.S. Park, Y.U. Sohn, I.H. Yu PAL, Pohang, Kyungbuk, Republic of Korea
	Funding: Supported by the Korea Ministry of Science and Technology The RF system of the Pohang Light Source-II (PLS-II) storage ring is operating at the 3.0GeV/200mA with two superconducting RF (SRF) cavities. Each RF station is composed with a 300kW klystron with power supply unit, transmission components, a digital LLRF and a SRF cavity. And a cryogenic system of 700W capacities is supplied the LHe and LN2 to three cryomodules of SRF cavities. The second SRF cavity is installed during at the beginning in 2013 and the third one will be installed during summer shutdown in 2014 for stable 400mA operation with all 20 insertion devices. Also the third high power RF station with a 300kW klystron, power supply unit and WR1800 waveguide components will be prepared in 2013. The third LLRF system is already installed, but improved stabilities of amplitude, phase and tuner control. This paper describes the present operation status and improve plan of the RF system for the PLS-II storage ring.

WEPWO041	Beam Commissioning Superconducting RF Cavities for PLS-II Upgrade	SRF, cavity, vacuum, storage-ring	2390
	Y.U. Sohn, M.-H. Chun, J.Y. Huang, Y.D. Joo, S.H. Nam, C.D. Park, H.J. Park, I.S. Park, I.H. Yu PAL, Pohang, Kyungbuk, Republic of Korea
	Two superconducting RF cavities were commissioned with electron beam at PLS-II, which is upgraded machine from PLS with 3 GeV, 20 insertion devices, and now on user service. These srf cavities have been prepared during last 3 years. Each cavity was tested with higher than 2 MV rf voltage and 125 kW standing wave power at CW mode after installation at storage ring. PLS-II is on user operation with 200 mA beam current now, and on the way of beam current improvement upto 400mA, by synchrotron conditioning for beam chamber and in-vacuum udulators. Upto 200 mA beam current no beam instability from the higher order modes is observed. With top-up mode operation, the errors of amplitude of rf field and phase are recorded as 0.3% and 0.3 degree peak to peak, respectively during one day. Successful PLS-II upgrade with hardware and its designed performance will be declared at the end of 1st half user run in 2013.

WEPWO043	IFMIF-EVEDA SRF Linac Couplers Test Bench	vacuum, linac, SRF, controls	2396
	D. Regidor, I. Kirpitchev, J. Molla, P. Méndez, A. Salom, M. Weber CIEMAT, Madrid, Spain M. Desmons, N. Grouas, P. Hardy, V.M. Hennion, H. Jenhani, F. Orsini CEA/IRFU, Gif-sur-Yvette, France
	The IFMIF-EVEDA SRF Linac is a cryomodule equipped with eight superconducting HWR cavities, operating at the frequency of 175 MHz and powered by 200kW CW RF couplers. Before assembling the couplers to the cryomodule, it is necessary to process them using high levels of RF power. In order to perform this conditioning, the power couplers must be connected to a RF network which is fed by an RF source and ended with a load or a short-circuit, depending on the conditioning mode to be applied. A test bench has been designed for the conditioning of the SRF LINAC couplers. The main component is the “test box”, a resonant cavity where two couplers will be assembled to transmit the 200 kW from the RF source to the appropriate termination. The test box includes a large pumping port allowing an efficient pumping of the entire vacuum volume limited by the coupler ceramic windows. Several diagnostics as light detectors, vacuum gauges and thermal transducers will provide information on the relevant parameters for the control of the RF conditioning process. In addition, a support frame has been designed to maintain the whole assembly and reduce the mechanical stress on the couplers.

WEPEA065	Beam Tests and Plans for the CERN PS Booster Wideband RF System Prototype	cavity, feedback, controls, booster	2660
	M.M. Paoluzzi, M. E. Angoletta, A. Findlay, M. Haase, M. Jaussi CERN, Geneva, Switzerland
	In the framework of the LHC Injectors Upgrade project (LIU) and in view of a complete replacement of the existing CERN PS Booster (PSB) RF systems, a prototype cavity has been installed beginning of 2012 in the machine. This modular, wideband (0.5 / 4 MHz), Finemet® loaded system uses solid-state power stages and includes fast RF feedback for beam loading compensation. In depth studies have been performed during 2012 to evaluate the system interaction with the new low-level digital electronics, its ability to accelerate the beam and cope with high beam intensity. The encouraging results suggest that this innovative approach can indeed be used to replace all the existing PSB RF systems but additional testing with a full scale prototype is required. This paper reports about the project status, the achieved results, the encountered difficulties and the foreseen prototype completion in preparation during 2013.

WEPFI007	Amplitude, Phase and Temperature Stabilization of the ELSA RF System	cavity, controls, HOM, feedback	2717
	D. Sauerland, W. Hillert, A. Roth, M. Schedler ELSA, Bonn, Germany D. Teytelman Dimtel, San Jose, USA
	In the stretcher ring of the accelerator facility ELSA electrons are accelerated to a maximum energy of 3.2 GeV applying a fast energy ramp of up to 6 GeV/s. In order to be able to offer higher external beam currents one has to increase the current of the internal beam in ELSA accordingly. The beam current is limited due to excitation of multi bunch instabilities which are mainly caused by higher order modes of the two PETRA cavities used for particle acceleration in the stretcher ring. To control the resonance frequency of these modes, a variable bypass of the cavities' cooling system has been installed which allows a stabilization of their temperature. With this modification, it is possible to vary the temperature of the cavities between 26 °C and 65 °C and thus to shift the higher order modes by hundreds of kHz in frequency. Additionally, first operational studies with a prototype of a FPGA based LLRF system (Dimtel) have been performed which in future will be used to stabilize the amplitude and phase of the accelerating RF fields of the cavities.

WEPFI012	Conceptual Design of ILSF RF System	cavity, HOM, storage-ring, impedance	2723
	Kh.S. Sarhadi, H. Ajam, H. Azizi, M. Fereidani, M. Jafarzadeh, S. Pirani, J. Rahighi, R. Safian, A. Shahverdi ILSF, Tehran, Iran
	The Iranian Light Source Facility (ILSF) RF system, consisting of RF cavities, power sources and low-level RF systems, is conceptually designed in accordance with the requirements of ILSF 3GeV storage ring. To achieve the desired 400mA beam current, utilization of the existing HOM-damped cavities is explored and RF system parameters are compared based on the usage of each cavity. Moreover, the choice of solid state amplifier as the RF power source is presented with its available power and structure. This paper, furthermore, explains the conceptual design and functionality of the selected digital LLRF system.

WEPFI016	Upgrade of Power Supply System for RF-Chopper At J-PARC Linac	pick-up, linac, cavity, simulation	2735
	K. Futatsukawa, Z. Fang, Y. Fukui, M. Ikegami, T. Miyao KEK, Ibaraki, Japan E. Chishiro, K. Hirano, Y. Ito, N. Kikuzawa, A. Miura, F. Sato, S. Shinozaki JAEA/J-PARC, Tokai-mura, Japan T. Hori JAEA, Ibaraki-ken, Japan Y. Liu, T. Maruta KEK/JAEA, Ibaraki-Ken, Japan T. Suzuki Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan
	In the J-PARC Linac, the radio frequency deflector was adopted as a chopper to capture the particles into the RF-bucket in the next synchrotron. The chopper, consists of two deflectors, was installed on the medium-energy beam-transport line. In the operation of the RF-chopper, the fast rise/fall time of the pulse is a fundamental requirement to minimize the beam loss due to insufficient deflection to some beam bunches. In the previous system, the two series-connected chopper deflectors were driven by one solid- state amplifier. However, the fall time indicated a poor result to effect the ringing into each cavity. Therefore, the additional solid-state amplifier and low level RF system were installed in the summer 2012 and the connection changed to the parallel system from the series using two amplifiers. The rise/fall time of the chopped beam, is defined as the step height of 10% and 90%, was about 20 nsec in the beam current of 15 mA and the effect of the ringing was decreased. We would like to introduce the performance of the new chopper system.

WEPFI017	Performance of Cavity Phase Monitor at J-PARC Linac	cavity, linac, pick-up, DTL	2738
	K. Futatsukawa, S. Anami, Z. Fang, Y. Fukui, T. Kobayashi, S. Michizono KEK, Ibaraki, Japan F. Sato, S. Shinozaki JAEA/J-PARC, Tokai-mura, Japan
	The amplitude and the phase stabilities of the RF system play an important role for the cavity of a high intensity proton accelerator. For the J-PARC Linac, the accelerating field ambiguity must be maintained within ±1% in amplitude and ±1 degree in phase due to the momentum acceptance of the next synchrotron. To realize the requirement, a digital feedback (FB) control is used in the low level RF (LLRF) control system, and a feed-forward (FF) technique is combined with the FB control for the beam loading compensation. The stability of ±0.2% in amplitude and ±0.2 degree in phase of the cavity was achieved including the beam loading in a macro pulse. Additionally, the cavity phase monitors, which can measure the phase difference between any two cavities, were installed in summer, 2011. The monitor has the three different types, which are for the present 324-MHz RF system, the 972-MHz RF system and the combined system of 324-MHz RF and 972-MHz RF. The phase monitor for the 324-MHz RF has been in operated since Dec. 2011. We would like to introduce the phase monitor and indicate the phase stability at the J-PARC linac.

WEPFI027	The Measurement of the Ferrite Rings for the Mass Production RF Cavity of CSNS RCS	cavity, impedance, resonance, booster	2762
	H. Shi, W.L. Huang, B. Jiang, X. Li, W. Long, W.Y. Song, H. Sun, J.Y. Tang, C.L. Xie, C.L. Zhang, W. Zhang IHEP, Beijing, People's Republic of China
	The Rapid Cycling Synchrotron (RCS) of the China Spallation Neutron Source (CSNS) will install 8 ferrite-loaded coaxial resonant cavities. The construction and measurement of prototype cavity have been finished. Based on the existing experiences, the small inner diameter (ID) rings T500/250/25-4M2 (mm) have been adopted for the mass production RF cavity, and the test results have shown that such rings can bear more RF magnetic flux density and have lower power loss. The characteristics of 60 small ID rings have been measured with two-ring test system, and we figured out that the rings have good consistence and the shunt impedance of all rings is above 100 Ω.

WEPFI028	RF System of the CSNS Synchrotron	cavity, controls, feedback, synchrotron	2765
	H. Sun, W.L. Huang, X. Li, W. Long, H. Shi, C.L. Zhang, F.C. Zhao IHEP, Beijing, People's Republic of China
	The accelerator of China Spallation Neutron Source (CSNS) consists of a H− linac and a rapid cycling synchrotron (RCS). The protons injected into the RCS will be accelerated from 81MeV to 1.6GeV by the Ring RF system providing a maximum accelerating voltage of 165kV. The RF frequency sweeps from 1.02 MHz to 2.44 MHz. with a repetition rate of 25Hz. The ferrite-loaded RF cavities will be used in the ring RF system. Each cavity has own RF power tube amplifier, bias current supply and full digital LLRF control loops. The R&D of ring rf system have been completed, it compose of the prototypes of a full size ferrite loaded RF cavity, a high power tetrode amplifier, a switching type bias supply of 3000A and a full digital embedded controller of LLRF. CSNS ring RF system design and the results of the R&D will be described in this paper.

WEPFI041	Design of the RF System for the Accelerator Complex of Rare Isotope Science Project	cavity, rfq, controls, rf-amplifier	2794
	J. Han, O.R. Choi, J.-W. Kim IBS, Daejeon, Republic of Korea C.K. Hwang KAERI, Daejon, Republic of Korea
	The rare isotope beam facility planned in Korea utilizes superconducting linear accelerators and a cyclotron to accelerate heavy-ion and proton beams, in which an RFQ in the injection line and superconducting cavities are the main rf components. The RF systems to power the cavities and to control the system at the low level have been designed so as to acquire high-quality beam with precise controls of rf amplitude and phase. The superconducting cavity is sensitive to various perturbations like mechanical vibration and Lorentz force detuning due to narrow bandwidth. We plan to use the rf amplifier system based on solid state device for superconducting cavities, and a tetrode tube for the final stage of RF amplifier of the RFQ accelerator. An LLRF system to control the amplitude and phase, which was built and tested on a quarter-wave resonator, will be modified to control a superconducting cavity. We plan to test the LLRF system in the superconducting rf facility abroad.

WEPFI042	Installation and Operation of the RF System for the 100 MeV Proton Linac	linac, klystron, controls, proton	2797
	K.T. Seol, Y.-S. Cho, D.I. Kim, H.S. Kim, H.-J. Kwon, Y.-G. Song KAERI, Daejon, Republic of Korea
	Funding: This work was supported by the Ministry of Education, Science and Technology of the Korean Government. The RF system of the 100MeV proton linac for 1st phase of KOMAC has been installed at the Gyeong-ju site. Nine sets of LLRF control system and the HPRF system including 1MW klystrons, circulators and waveguide components have been installed at the klystron gallery, and four high voltage converter modulators has been installed at the modulator room. A RF reference system distributing 300MHz LO signal to each RF control system has also been installed with a temperature control system. The requirement of RF field control is within ± 1% in RF amplitude and ± 1 degree in RF phase, and the operation of RF system will start at the end of this year after installation. The installation and operation of the RF system for the 100MeV proton linac are presented in this paper.

WEPFI043	S-band High Stability Solid State Amplifier for 10 GeV PAL-XFEL	controls, FEL, klystron, monitoring	2800
	W.H. Hwang, J.Y. Huang, H.-S. Kang, H.-S. Lee, W.W. Lee PAL, Pohang, Kyungbuk, Republic of Korea
	In PAL, We are constructing a 10GeV PxFEL project. The output power of the klystron is 80 MW at the pulse width of 4 ㎲ and the repetition rate of 60 Hz. And the specifications of the rf phase and amplitude stability are 0.05 degrees(rms) and 0.05%(rms) respectively. The SSA(Solid State Amplifier) is used for driver of 80MW Klystron. The output power of SSA is 800W. Also, the measured rf stability of SSA output is 0.03 degrees rms and 0.025 % rms. This paper describes the microwave system and the SSA for the PxFEL.

WEPFI066	The RF System for the MICE Experiment	cavity, controls, diagnostics, linac	2848
	K. Ronald, A.J. Dick, C.G. Whyte USTRAT/SUPA, Glasgow, United Kingdom P.A. Corlett STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom A.J. DeMello, D. Li, S.P. Virostek LBNL, Berkeley, California, USA A.F. Grant, A.J. Moss, C.J. White STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom P.M. Hanlet IIT, Chicago, Illinois, USA C. Hunt, K.R. Long, J. Pasternak Imperial College of Science and Technology, Department of Physics, London, United Kingdom T.H. Luo, D.J. Summers UMiss, University, Mississippi, USA A. Moretti, R.J. Pasquinelli, D.W. Peterson, R.P. Schultz, J.T. Volk Fermilab, Batavia, USA P.J. Smith Sheffield University, Sheffield, United Kingdom T. Stanley STFC/RAL, Chilton, Didcot, Oxon, United Kingdom Y. Torun Illinois Institute of Technology, Chicago, IL, USA
	The International Muon Ionisation Cooling Experiment (MICE) is designed to demonstrate the effectiveness of ionisation cooling to reduce the phase space footprint of a muon beam, principally to allow the subsequent acceleration of muons for next generation colliders and/or neutrino factories. The experiment (and indeed any subsequent accelerator cooling channel based on the same principles) poses certain unusual requirements on its RF system, whilst the precision measurement of the ionisation cooling process demands special diagnostics. This paper shall outline the key features of the RF system, including the LLRF control, the power amplifier chain, distribution network, cavities, tuners and couplers, all of which must operate in a high magnetic field environment. The RF diagnostics which, in conjunction with the other MICE diagnostics, shall allow detailed knowledge of the amplitude and phase of the acceleration field during the transit of each individual Muon shall also be outlined.

WEPME008	Precision LLRF Controls for the S-Band Accelerator REGAE	laser, gun, electron, controls	2938
	M. Hoffmann, H. Kay, U. Mavrič, H. Schlarb, Ch. Schmidt DESY, Hamburg, Germany W. Jałmużna, T. Kozak, A. Piotrowski TUL-DMCS, Łódź, Poland
	The linear accelerator REGAE (Relativistic Electron Gun for Atomic Exploration) at DESY delivers electron bunches with a few femtosecond duration for time-resolved experiments of material structure in pump-probe configuration. To achieve the desired 10 fs resolution, the Low Level RF controls for the normal conducting S-band cavities must provide field stability of 0.01% in amplitude and of 0.01deg in phase. To achieve these demanding stability a recently developed LLRF controller based on the Micro-Telecommunications Computing Architecture (MTCA.4) have been installed and commission. In this paper, we report on measurement performance of the LLRF system, the achieved stability and current limitations.

WEPME009	Recent Developments of the European XFEL LLRF System	controls, cavity, laser, beam-loading	2941
	Ch. Schmidt, G. Ayvazyan, V. Ayvazyan, J. Branlard, L. Butkowski, M.K. Grecki, M. Hoffmann, T. Jeżyński, F. Ludwig, U. Mavrič, S. Pfeiffer, H. Schlarb, H.C. Weddig, B.Y. Yang DESY, Hamburg, Germany P. Barmuta, S. Bou Habib, K. Czuba, M. Grzegrzółka, E. Janas, J. Piekarski, I. Rutkowski, D. Sikora, L. Zembala, M. Żukociński Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland W. Cichalewski, K. Gnidzińska, W. Jałmużna, D.R. Makowski, A. Mielczarek, A. Napieralski, P. Perek, A. Piotrowski, T. Pożniak, K.P. Przygoda TUL-DMCS, Łódź, Poland S. Korolczuk, I.M. Kudla, J. Szewiński NCBJ, Świerk/Otwock, Poland K. Oliwa, W. Wierba IFJ-PAN, Kraków, Poland
	The European XFEL is comprised of more than 800 TESLA-type super-conducting accelerator cavities which are driven by 25 high-power multi-beam klystrons. For reliable, reproducible and maintainable operation of linac, the LLRF system will process more than 3000 RF channels. Beside the large number of RF channels to be processed, stable FEL operation demands field stability better than 0.010deg in phase and 0.01% in amplitude. To cope with these challenges the LLRF system is developed on MTCA.4 platform. In this paper, we will give an update of the latest electronics developments, advances in the feedback controller algorithm and measurement results at FLASH.

WEPME013	Development and Test of a Fully Automated PkQl Control Procedure at KEK STF	cavity, controls, feedback, klystron	2950
	M. Omet, A. Kuramoto Sokendai, Ibaraki, Japan H. Hayano, T. Matsumoto, S. Michizono KEK, Ibaraki, Japan
	In order to operate the cavities near their maximum gradients, cavity input (Pk) and cavity loaded Q (QL) should be controlled individually (PkQL control) at the International Linear Collider (ILC). A manual PkQL operation procedure was developed and performed at the linear electron accelerator at the Superconducting RF Test Facility (STF), in which the beam is accelerated up to 40 MeV by two superconducting 9-cell TESLA type L band cavities. The cavity gradients were set to 16 MV/m and 24 MV/m with QL values of 110⁶ and 3·10⁶. A 6.2 mA beam with a pulse length of 154 us was used. The field stabilities in amplitude were 0.160% and 0.097% for the cavities and 0.016% for the vector sum. The stabilities without beam are 0.057% and 0.054% for the cavities and 0.009% for the vector sum. For stability improvement during beam transient an adaptive beam feedforward for beam loading compensation is under development. So far an amplitude field stability of 0.013% for the vector sum was achieved at cavity gradients of 15 MV/m and 25 MV/m (no PkQL control) during a 6.8 mA beam with a pulse length of 123 us. Furthermore a fully automated PkQL control procedure is currently developed and tested.
	Poster WEPME013 [0.647 MB]

WEPME014	Progress in Development of New LLRF Control System for SuperKEKB	cavity, controls, klystron, pick-up	2953
	T. Kobayashi, K. Akai, K. Ebihara, A. Kabe, K. Nakanishi, M. Nishiwaki, J.-I. Odagiri KEK, Ibaraki, Japan H. Deguchi, K. Harumatsu, K. Hayashi, T. Iwaki, J. Mizuno, J. Nishio, M. Ryoshi Mitsubishi Electric TOKKI Systems, Amagasaki, Hyogo, Japan
	For the SuperKEKB project, a new LLRF control system was developed to realize high accuracy and flexibility. It is an FPGA-based digital RF feedback control system using 16-bit ADC's, which works on the μTCA platform. The FPGA boards control accelerating cavity fields and cavity tuning, and the EPICS-IOC is embedded in each of them. The CSS-BOY was adopted for a user interface of our system. High power test of the new LLRF control system was performed with the ARES Cavity of KEKB. The obtained feedback control stability with a klystron drive was sufficient as well as the low-level evaluation result. And auto tuner control also worded successfully. The start-up sequencer program for the cavity operation and auto-aging program also worked very well. The temperature characteristics of the system depend largely on band-pass filters (BPF). We tried to tune the BPF to reduce the temperature coefficient. Consequently the temperature dependence was improved to satisfy the required stability.

WEPME015	Evaluation of the Superconducting LLRF system at cERL in KEK	cavity, controls, coupling, linac	2956
	F. Qiu, D.A. Arakawa, H. Katagiri, T. Matsumoto, S. Michizono, T. Miura, T. Miyajima, K. Tsuchiya KEK, Ibaraki, Japan
	A low level RF (LLRF) design is being currently developed within the compact Energy Recover Linac (cERL) at KEK. One challenging task is to achieve the high amplitude and high phase stability required by the accelerating fields of up to 0.1% and 0.1°, respectively. To improve the performance of the LLRF system, a gain scanning experiment for determining the optimal controller gain was carried out on the cERL. Furthermore, as a substitute for the traditional PI controller, a more robust H∞-based multiple input multiple output (MIMO) controller was realized. This controller requires more detailed system information (transfer function or state equation), which can be acquired by using modern system identification methods. In this paper, we describe the current status of these experiments on the cERL.

WEPME022	Overview of the CSNS/RCS LLRF Control System	cavity, controls, feedback, beam-loading	2977
	X. Li, W. Long, H. Sun, C.L. Zhang, F.C. Zhao IHEP, Beijing, People's Republic of China
	The CSNS/RCS RF system consists of 8 ferrite-loaded RF cavities (h=2), each with individual digital LLRF control electronics. The injection and extraction energy of the beam are 80MeV and 1.6GeV respectively with a repetition rate of 25Hz. The RF system is designed to provide the maximum RF voltage of 165kV. The RF frequency range is from 1.02MHz at injection to 2.44MHz at extraction. The CSNS/RCS LLRF control system is based on FPGA, and composed of 7 control loops to achieve required acceleration voltage amplitude and phase regulation. A number of prototype and the first formal system have been completed and tested. In this paper we present an overview of the LLRF control system, and some operational results.

WEPME035	Overview of the RF Synchronization System for the European XFEL	laser, linac, booster, undulator	3001
	K. Czuba, D. Sikora, L. Zembala Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland J. Branlard, F. Ludwig, H. Schlarb, H.C. Weddig DESY, Hamburg, Germany
	One of the most important requirements for the European XFEL RF system is to assure a very precise RF field stability within the accelerating cavities. The required amplitude and phase stability equals respectively dA/A <3·10^-5, dphi<0.01 deg @ 1.3GHz in the injector and dA/A<10^-3, dphi <0.1 deg @1.3GHz in the main LINAC section. Fulfilling such requirements for the 3.4 km long facility is a very challenging task. Thousands of electronic and RF devices must be precisely phase synchronized by means of harmonic RF signals. We describe the proposed architecture of the RF Master Oscillator and the Phase Reference Distribution System designed to assure high precision and reliability. A system of RF cable based interferometers supported by femtosecond-stable optical links will be used to distribute RF reference signals with required short and long term phase stability. We also present test results of prototype devices performed to validate our concept.

WEPME036	The Development of LLRF System at PAL	controls, cavity, radio-frequency, monitoring	3004
	K.-H. Park, H.S. Han, Y.-G. Jung, D.E. Kim, H.-G. Lee, H.S. Suh PAL, Pohang, Kyungbuk, Republic of Korea J.-S. Chai, Y.S. Lee SKKU, Suwon, Republic of Korea B.-K. Kang POSTECH, Pohang, Kyungbuk, Republic of Korea
	The PAL has been developing the low level radio frequency (LLRF) system. The required field stabilities of the LLRF system are within ±0.75% in amplitude and 0.35° in phase in a cavity. All the hardware including RF front–end, FPGA with peripherals such as ADC, DAC, Oscillator and digital interface were assembled. The sub-modules for the RF signal processing were written by VHDL and integrated to test at the local facility. The macroblaze software processor was implemented to make the system simple in interfacing to peripherals and to secure flexibility later. This paper described the microblaze processor which was ported into the VERTEX6 FPGA. And also this paper showed the test results of the each module and integrated into the full system.

WEPME052	LLRF Characterisation of the Daresbury International Cryomodule	cavity, cryomodule, resonance, SRF	3046
	L. Ma STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom P.A. Corlett, A.J. Moss STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	The 2-cavity Superconducting RF (SRF) Linac cryomodule of the Accelerators and Lasers in Combined Experiments (ALICE) located at Daresbury Laboratory will be replaced by a new International ERL Cryomodule in early 2013. The improved 7-cell, 1.3 GHz SRF cavities will be characterised and compared with the original 9-cell cavities. Tests will be performed by driving the cavities by a VCO-PLL loop so that Q measurements, microphonics sensitivity and Lorentz force detuning can be analysed. A digital LLRF system using the LLRF4 board developed by Larry Doolittle has been developed at Daresbury Laboratory and will be installed on the upgraded cryomodule. This system is capable of controlled cavity filling to reduce waveguide reflection voltage, feedback/feed forward control and adaptive beam loading compensation. The new cryomodule will be evaluated with both the analog LLRF system and the digital LLRF system to allow for performance comparison. Cavity operation with high QL will also be tested to discover the feedback control limit as a function of inherent microphonics. This paper sets out to discuss the qualification process, testing and results of the upgraded cryomodule installation.

THPEA003	Use of FPGA-based Configurable Electronics to Calibrate Cavities	controls, synchrotron, ion, heavy-ion	3152
	S. Schäfer, A. Klaus, H. Klingbeil, B. Zipfel GSI, Darmstadt, Germany U. Hartel, H. Klingbeil TEMF, TU Darmstadt, Darmstadt, Germany
	At the GSI Helmholzzentrum für Schwerionen-forschung GmbH the accuracy requirements for synchrotron rf cavities have strongly increased in the last years, especially for multi-harmonic operation. For heavy-ion acceleration the amplitude and phase have to be well adjusted over a whole machine cycle. In order to compensate small deviations induced by low-level rf components (LLRF) and transmission lines in the control paths, a calibration electronic (CEL) with a characteristic map was developed. It is a real-time module which is based on modern FPGA (Field Programmable Gate Array) technology and adaptable to special cavities with various physical dependencies (e.g. attenuation, dispersion, temperature drift, aging etc.). The hardware and software architecture of this CEL module are presented here.

THPEA011	WPF Based EPICS Server and its Application in CSNS	EPICS, controls, linac, PLC	3170
	Y.L. Zhang, G. Lei IHEP, Beijing, People's Republic of China
	The control system of China Spallation Neutron Source(CSNS) is under construction based on EPICS. The Linac low level RF(LLRF) local control program running on a local control PC uses Windows Presentation Foundation( WPF) as its development tool and uses the C# codes to implement the functionality. The Linac LLRF control system is non-EPICS, so the Linac LLRF local variables can’t be accessed directly from EPICS. Therefore we need to port the Linac LLRF local control system to EPICS. This paper presents the WPF base EPICS server and its application in CSNS.

THPEA030	Improved Vector Modulator Card for MTCA-based LLRF Control System for Linear Accelerators	controls, power-supply, monitoring, radio-frequency	3207
	I. Rutkowski, K. Czuba, M. Grzegrzólka Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland D.R. Makowski, A. Mielczarek, P. Perek TUL-DMCS, Łódź, Poland H. Schlarb DESY, Hamburg, Germany
	Modern linear accelerators require high-precision RF field regulation of accelerating cavities. A critical component to achieve high-precision in the feedback loop a Low Level Radio Frequency (LLRF) controller is the vector modulator driving the high power RF chain. At FLASH, the Free Electron Laser in Hamburg and European XFEL the LLRF controls are based on MTCA.4 platform. This paper describes the concept, design and performance of an improved vector modulator module (DRTM-VM2). It is constructed as Rear Transition Module (RTM). The module consists of digital, analog, diagnostic and management subsystems. FPGA from Xilinx Spartan 6 family receives data from control module (AMC) using Multi-Gigabit Transceivers (MGTs). The FPGA controls the analog part which includes fast, high-precision DACs, I/Q modulator chips, programmable attenuators, power amplifier and fast RF gates for external interlock system. Pin assignment on the Zone3 connector is compliant with digital class D1.2 recommendations proposed by DESY. The design has been optimized for mass production and for easy extends to wider frequency range. Electronic switches offer software configuration of power and clock sources.

THPEA031	REGAE LLRF Control System Overview	controls, electron, laser, feedback	3210
	I. Rutkowski, L. Butkowski Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland M. Hoffmann, H. Schlarb, Ch. Schmidt DESY, Hamburg, Germany
	The linear accelerator REGAE (Relativistic Electron Gun for Atomic Exploration) at DESY delivers electron bunches with a few femtosecond duration for time-resolved investigation of material structures in pump-probe configuration. To achieve sub-10fs resolution, the Low Level RF controls for the normal conducting S-band cavities must provide field stability of .005% in amplitude and of .005deg in phase. To achieve these demands, the recently developed LLRF control modules based on the Micro-Telecommunications Computing Architecture (MTCA.4) platform are used. For precise field detection and control a rear transition module (DRTM-DWC8VM1) housing 8 down-converters and 1 vector-modulator has been developed. The down-converted signals are transmitted to low-noise ADCs on an advanced mezzanine card (SIS8300L) with two high speed DACs driving the vector-modulator. The on board FPGA device runs the advanced control algorithms with minimum latency. Shot-to-shot learning feed forward and ultra-fast analog and digital feedbacks are applied. In this paper, the first results of the new RTM-AMC module pairs are presented together with the achievements and limitations on the RF field stability.

THPEA060	LLRF System for LCLS-II at SLAC	controls, klystron, feedback, linac	3276
	Z. Geng, B. Hong, K.H. Kim, R.S. Larsen, D. Van Winkle, C. Xu SLAC, Menlo Park, California, USA
	Funding: Work supported by US Department of Energy Contract DE AC03 76SF00515 After LCLS-I successfully delivering the full operation for users, SLAC has been approved to build the second Linac Coherent Light Source, LCLS-II, which makes use of another third of the 2-mile long Linac from Sector 10 to Sector20. The LLRF System will use mTCA (Micro Telecommunication Computing Architecture) to replace the VME system for LCLS-II injector and some key stations along the LINAC. The faster data acquisition and more powerful FPGA and CPU in the mTCA system enable the LLRF system to extend its control ability to a 2.5 μsec beam pulse rate of 360Hz. The new LLRF system is more compact and has the capability of low latency intra-pulse feedback to reduce fast phase and amplitude jitter during a single pulse. The prototype of the mTCA based LLRF control system has been operating at RF station 28-2 in LCLS-I. Detailed design structure and the prototype experimental results will be presented that demonstrate the system meets the exacting phase and amplitude stability requirements for LCLS-II.

THPFI042	Design Considerations for Phase Reference Distribution System at ESS	linac, controls, cavity, radiation	3379
	R. Zeng ESS, Lund, Sweden A.J. Johansson Lund University, Lund, Sweden
	PRDS (Phase Reference Distribution System) will be serving as the phase alignment line for all cavities with high phase stability. With the current design of individually RF source powering for most cavities at ESS, phase reference distribution system should provide the reference signals for totally 34 LLRF systems at 100 meters long low-frequency section (for all 352.21MHz cavities, including RFQ, DTL, bunching cavities and spokes), and for totally 180 LLRF systems at 342 meters long high-frequency section (for all 704.42MHz cavities, including medium beta and high beta elliptical cavities). Coaxial cable based solution and optical fibre based solution are discussed in this note for PRDS (Phase reference distribution system) at ESS. Some possible schemes in each of these two distribution solutions are introduced and comparisons among these schemes are made. Some effort is made as well to find out a reasonable design for PRDS at ESS.

THPWA003	Novel Crate Standard MTCA.4 for Industry and Research	controls, monitoring, radio-frequency, free-electron-laser	3633
	T. Walter, F. Ludwig, K. Rehlich, H. Schlarb DESY, Hamburg, Germany
	Funding: This project is funded by the Helmholtz Association (Helmholtz Validation Fund HVF-0016). MTCA.4 is a novel electronic standard derived from the Telecommunication Computing Architecture (TCA) and championed by the xTCA for physics group, a network of physics research institutes and electronics manufacturers. MTCA.4 was released as an official standard by the PCI Industrial Manufacturers Group (PICMG) in 2011. Although the standard is originally physics-driven, it holds promise for applications in many other fields with equally challenging requirements. With substantial funding from the Helmholtz Association for a two-year validation project, DESY currently develops novel, fully MTCA.4-compliant components to lower the barriers to adoption in a wide range of industrial and research use scenarios. Core activities of the project are: refinement, test and qualification of existing components; market research, market education (web information services, workshops); coordinated development of missing MTCA.4 components; further advancement of the standard beyond the current PICMG specification; investigation of measures to counteract electro-magnetic interferences and incompatibilities; training, support and consultancy. This paper summarizes intermediate results and lessons learned at project half-time.

THPWO047	The LLRF Measurement and Analysis of the SSC-LINAC RFQ	rfq, cavity, linac, simulation	3875
	G. Liu, J.E. Chen, S.L. Gao, Y.R. Lu, Z. Wang, X.Q. Yan, K. Zhu PKU, Beijing, People's Republic of China X. Du, Y. He, G. Pan, Y.Q. Yang, X. Yin, Y.J. Yuan, Z.L. Zhang, H.W. Zhao IMP, Lanzhou, People's Republic of China
	Funding: Supported by NSFC(11079001) The manufacturing process of the SSC-LINAC RFQ went to end and the LLRF measurement has been done. The frequency of the RFQ is 53.557 MHz without tuning, which is not far from the design value 53.667 MHz. The unflatness of the field along the beam axis is less than ±4%, which meets the simulation results. The dipole field is in the acceptable margin as well. The frequency will be adjusted by tuning plungers in operation. In this paper, the field distribution along the cavity has been measured and compared with the modulated electrodes simulation. The difference and its influences on the beam transmission have been analyzed.

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MOPEA048

Operation Status of RF System for the PLS-II Storage Ring

cryomodule, SRF, klystron, status

187

M.-H. Chun, J.Y. Huang, Y.D. Joo, H.-G. Kim, S.H. Nam, C.D. Park, H.J. Park, I.S. Park, Y.U. Sohn, I.H. Yu
PAL, Pohang, Kyungbuk, Republic of Korea

Funding: Supported by the Korea Ministry of Science and Technology
The RF system of the Pohang Light Source-II (PLS-II) storage ring is operating at the 3.0GeV/200mA with two superconducting RF (SRF) cavities. Each RF station is composed with a 300kW klystron with power supply unit, transmission components, a digital LLRF and a SRF cavity. And a cryogenic system of 700W capacities is supplied the LHe and LN2 to three cryomodules of SRF cavities. The second SRF cavity is installed during at the beginning in 2013 and the third one will be installed during summer shutdown in 2014 for stable 400mA operation with all 20 insertion devices. Also the third high power RF station with a 300kW klystron, power supply unit and WR1800 waveguide components will be prepared in 2013. The third LLRF system is already installed, but improved stabilities of amplitude, phase and tuner control. This paper describes the present operation status and improve plan of the RF system for the PLS-II storage ring.

WEPWO041

Beam Commissioning Superconducting RF Cavities for PLS-II Upgrade

SRF, cavity, vacuum, storage-ring

2390

Y.U. Sohn, M.-H. Chun, J.Y. Huang, Y.D. Joo, S.H. Nam, C.D. Park, H.J. Park, I.S. Park, I.H. Yu
PAL, Pohang, Kyungbuk, Republic of Korea

Two superconducting RF cavities were commissioned with electron beam at PLS-II, which is upgraded machine from PLS with 3 GeV, 20 insertion devices, and now on user service. These srf cavities have been prepared during last 3 years. Each cavity was tested with higher than 2 MV rf voltage and 125 kW standing wave power at CW mode after installation at storage ring. PLS-II is on user operation with 200 mA beam current now, and on the way of beam current improvement upto 400mA, by synchrotron conditioning for beam chamber and in-vacuum udulators. Upto 200 mA beam current no beam instability from the higher order modes is observed. With top-up mode operation, the errors of amplitude of rf field and phase are recorded as 0.3% and 0.3 degree peak to peak, respectively during one day. Successful PLS-II upgrade with hardware and its designed performance will be declared at the end of 1st half user run in 2013.

WEPWO043

IFMIF-EVEDA SRF Linac Couplers Test Bench

vacuum, linac, SRF, controls

2396

D. Regidor, I. Kirpitchev, J. Molla, P. Méndez, A. Salom, M. Weber
CIEMAT, Madrid, Spain
M. Desmons, N. Grouas, P. Hardy, V.M. Hennion, H. Jenhani, F. Orsini
CEA/IRFU, Gif-sur-Yvette, France

The IFMIF-EVEDA SRF Linac is a cryomodule equipped with eight superconducting HWR cavities, operating at the frequency of 175 MHz and powered by 200kW CW RF couplers. Before assembling the couplers to the cryomodule, it is necessary to process them using high levels of RF power. In order to perform this conditioning, the power couplers must be connected to a RF network which is fed by an RF source and ended with a load or a short-circuit, depending on the conditioning mode to be applied. A test bench has been designed for the conditioning of the SRF LINAC couplers. The main component is the “test box”, a resonant cavity where two couplers will be assembled to transmit the 200 kW from the RF source to the appropriate termination. The test box includes a large pumping port allowing an efficient pumping of the entire vacuum volume limited by the coupler ceramic windows. Several diagnostics as light detectors, vacuum gauges and thermal transducers will provide information on the relevant parameters for the control of the RF conditioning process. In addition, a support frame has been designed to maintain the whole assembly and reduce the mechanical stress on the couplers.

WEPEA065

Beam Tests and Plans for the CERN PS Booster Wideband RF System Prototype

cavity, feedback, controls, booster

2660

M.M. Paoluzzi, M. E. Angoletta, A. Findlay, M. Haase, M. Jaussi
CERN, Geneva, Switzerland

In the framework of the LHC Injectors Upgrade project (LIU) and in view of a complete replacement of the existing CERN PS Booster (PSB) RF systems, a prototype cavity has been installed beginning of 2012 in the machine. This modular, wideband (0.5 / 4 MHz), Finemet® loaded system uses solid-state power stages and includes fast RF feedback for beam loading compensation. In depth studies have been performed during 2012 to evaluate the system interaction with the new low-level digital electronics, its ability to accelerate the beam and cope with high beam intensity. The encouraging results suggest that this innovative approach can indeed be used to replace all the existing PSB RF systems but additional testing with a full scale prototype is required. This paper reports about the project status, the achieved results, the encountered difficulties and the foreseen prototype completion in preparation during 2013.

WEPFI007

Amplitude, Phase and Temperature Stabilization of the ELSA RF System

cavity, controls, HOM, feedback

2717

D. Sauerland, W. Hillert, A. Roth, M. Schedler
ELSA, Bonn, Germany
D. Teytelman
Dimtel, San Jose, USA

In the stretcher ring of the accelerator facility ELSA electrons are accelerated to a maximum energy of 3.2 GeV applying a fast energy ramp of up to 6 GeV/s. In order to be able to offer higher external beam currents one has to increase the current of the internal beam in ELSA accordingly. The beam current is limited due to excitation of multi bunch instabilities which are mainly caused by higher order modes of the two PETRA cavities used for particle acceleration in the stretcher ring. To control the resonance frequency of these modes, a variable bypass of the cavities' cooling system has been installed which allows a stabilization of their temperature. With this modification, it is possible to vary the temperature of the cavities between 26 °C and 65 °C and thus to shift the higher order modes by hundreds of kHz in frequency. Additionally, first operational studies with a prototype of a FPGA based LLRF system (Dimtel) have been performed which in future will be used to stabilize the amplitude and phase of the accelerating RF fields of the cavities.

WEPFI012

Conceptual Design of ILSF RF System

cavity, HOM, storage-ring, impedance

2723

Kh.S. Sarhadi, H. Ajam, H. Azizi, M. Fereidani, M. Jafarzadeh, S. Pirani, J. Rahighi, R. Safian, A. Shahverdi
ILSF, Tehran, Iran

The Iranian Light Source Facility (ILSF) RF system, consisting of RF cavities, power sources and low-level RF systems, is conceptually designed in accordance with the requirements of ILSF 3GeV storage ring. To achieve the desired 400mA beam current, utilization of the existing HOM-damped cavities is explored and RF system parameters are compared based on the usage of each cavity. Moreover, the choice of solid state amplifier as the RF power source is presented with its available power and structure. This paper, furthermore, explains the conceptual design and functionality of the selected digital LLRF system.

WEPFI016

Upgrade of Power Supply System for RF-Chopper At J-PARC Linac

pick-up, linac, cavity, simulation

2735

K. Futatsukawa, Z. Fang, Y. Fukui, M. Ikegami, T. Miyao
KEK, Ibaraki, Japan
E. Chishiro, K. Hirano, Y. Ito, N. Kikuzawa, A. Miura, F. Sato, S. Shinozaki
JAEA/J-PARC, Tokai-mura, Japan
T. Hori
JAEA, Ibaraki-ken, Japan
Y. Liu, T. Maruta
KEK/JAEA, Ibaraki-Ken, Japan
T. Suzuki
Mitsubishi Electric System & Service Co., Ltd, Tsukuba, Japan

In the J-PARC Linac, the radio frequency deflector was adopted as a chopper to capture the particles into the RF-bucket in the next synchrotron. The chopper, consists of two deflectors, was installed on the medium-energy beam-transport line. In the operation of the RF-chopper, the fast rise/fall time of the pulse is a fundamental requirement to minimize the beam loss due to insufficient deflection to some beam bunches. In the previous system, the two series-connected chopper deflectors were driven by one solid- state amplifier. However, the fall time indicated a poor result to effect the ringing into each cavity. Therefore, the additional solid-state amplifier and low level RF system were installed in the summer 2012 and the connection changed to the parallel system from the series using two amplifiers. The rise/fall time of the chopped beam, is defined as the step height of 10% and 90%, was about 20 nsec in the beam current of 15 mA and the effect of the ringing was decreased. We would like to introduce the performance of the new chopper system.

WEPFI017

Performance of Cavity Phase Monitor at J-PARC Linac

cavity, linac, pick-up, DTL

2738

K. Futatsukawa, S. Anami, Z. Fang, Y. Fukui, T. Kobayashi, S. Michizono
KEK, Ibaraki, Japan
F. Sato, S. Shinozaki
JAEA/J-PARC, Tokai-mura, Japan

The amplitude and the phase stabilities of the RF system play an important role for the cavity of a high intensity proton accelerator. For the J-PARC Linac, the accelerating field ambiguity must be maintained within ±1% in amplitude and ±1 degree in phase due to the momentum acceptance of the next synchrotron. To realize the requirement, a digital feedback (FB) control is used in the low level RF (LLRF) control system, and a feed-forward (FF) technique is combined with the FB control for the beam loading compensation. The stability of ±0.2% in amplitude and ±0.2 degree in phase of the cavity was achieved including the beam loading in a macro pulse. Additionally, the cavity phase monitors, which can measure the phase difference between any two cavities, were installed in summer, 2011. The monitor has the three different types, which are for the present 324-MHz RF system, the 972-MHz RF system and the combined system of 324-MHz RF and 972-MHz RF. The phase monitor for the 324-MHz RF has been in operated since Dec. 2011. We would like to introduce the phase monitor and indicate the phase stability at the J-PARC linac.

WEPFI027

The Measurement of the Ferrite Rings for the Mass Production RF Cavity of CSNS RCS

cavity, impedance, resonance, booster

2762

H. Shi, W.L. Huang, B. Jiang, X. Li, W. Long, W.Y. Song, H. Sun, J.Y. Tang, C.L. Xie, C.L. Zhang, W. Zhang
IHEP, Beijing, People's Republic of China

The Rapid Cycling Synchrotron (RCS) of the China Spallation Neutron Source (CSNS) will install 8 ferrite-loaded coaxial resonant cavities. The construction and measurement of prototype cavity have been finished. Based on the existing experiences, the small inner diameter (ID) rings T500/250/25-4M2 (mm) have been adopted for the mass production RF cavity, and the test results have shown that such rings can bear more RF magnetic flux density and have lower power loss. The characteristics of 60 small ID rings have been measured with two-ring test system, and we figured out that the rings have good consistence and the shunt impedance of all rings is above 100 Ω.

WEPFI028

RF System of the CSNS Synchrotron

cavity, controls, feedback, synchrotron

2765

H. Sun, W.L. Huang, X. Li, W. Long, H. Shi, C.L. Zhang, F.C. Zhao
IHEP, Beijing, People's Republic of China

The accelerator of China Spallation Neutron Source (CSNS) consists of a H− linac and a rapid cycling synchrotron (RCS). The protons injected into the RCS will be accelerated from 81MeV to 1.6GeV by the Ring RF system providing a maximum accelerating voltage of 165kV. The RF frequency sweeps from 1.02 MHz to 2.44 MHz. with a repetition rate of 25Hz. The ferrite-loaded RF cavities will be used in the ring RF system. Each cavity has own RF power tube amplifier, bias current supply and full digital LLRF control loops. The R&D of ring rf system have been completed, it compose of the prototypes of a full size ferrite loaded RF cavity, a high power tetrode amplifier, a switching type bias supply of 3000A and a full digital embedded controller of LLRF. CSNS ring RF system design and the results of the R&D will be described in this paper.

WEPFI041

Design of the RF System for the Accelerator Complex of Rare Isotope Science Project

cavity, rfq, controls, rf-amplifier

2794

J. Han, O.R. Choi, J.-W. Kim
IBS, Daejeon, Republic of Korea
C.K. Hwang
KAERI, Daejon, Republic of Korea

The rare isotope beam facility planned in Korea utilizes superconducting linear accelerators and a cyclotron to accelerate heavy-ion and proton beams, in which an RFQ in the injection line and superconducting cavities are the main rf components. The RF systems to power the cavities and to control the system at the low level have been designed so as to acquire high-quality beam with precise controls of rf amplitude and phase. The superconducting cavity is sensitive to various perturbations like mechanical vibration and Lorentz force detuning due to narrow bandwidth. We plan to use the rf amplifier system based on solid state device for superconducting cavities, and a tetrode tube for the final stage of RF amplifier of the RFQ accelerator. An LLRF system to control the amplitude and phase, which was built and tested on a quarter-wave resonator, will be modified to control a superconducting cavity. We plan to test the LLRF system in the superconducting rf facility abroad.

WEPFI042

Installation and Operation of the RF System for the 100 MeV Proton Linac

linac, klystron, controls, proton

2797

K.T. Seol, Y.-S. Cho, D.I. Kim, H.S. Kim, H.-J. Kwon, Y.-G. Song
KAERI, Daejon, Republic of Korea

Funding: This work was supported by the Ministry of Education, Science and Technology of the Korean Government.
The RF system of the 100MeV proton linac for 1st phase of KOMAC has been installed at the Gyeong-ju site. Nine sets of LLRF control system and the HPRF system including 1MW klystrons, circulators and waveguide components have been installed at the klystron gallery, and four high voltage converter modulators has been installed at the modulator room. A RF reference system distributing 300MHz LO signal to each RF control system has also been installed with a temperature control system. The requirement of RF field control is within ± 1% in RF amplitude and ± 1 degree in RF phase, and the operation of RF system will start at the end of this year after installation. The installation and operation of the RF system for the 100MeV proton linac are presented in this paper.

WEPFI043

S-band High Stability Solid State Amplifier for 10 GeV PAL-XFEL

controls, FEL, klystron, monitoring

2800

W.H. Hwang, J.Y. Huang, H.-S. Kang, H.-S. Lee, W.W. Lee
PAL, Pohang, Kyungbuk, Republic of Korea

In PAL, We are constructing a 10GeV PxFEL project. The output power of the klystron is 80 MW at the pulse width of 4 ㎲ and the repetition rate of 60 Hz. And the specifications of the rf phase and amplitude stability are 0.05 degrees(rms) and 0.05%(rms) respectively. The SSA(Solid State Amplifier) is used for driver of 80MW Klystron. The output power of SSA is 800W. Also, the measured rf stability of SSA output is 0.03 degrees rms and 0.025 % rms. This paper describes the microwave system and the SSA for the PxFEL.

WEPFI066

The RF System for the MICE Experiment

cavity, controls, diagnostics, linac

2848

K. Ronald, A.J. Dick, C.G. Whyte
USTRAT/SUPA, Glasgow, United Kingdom
P.A. Corlett
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
A.J. DeMello, D. Li, S.P. Virostek
LBNL, Berkeley, California, USA
A.F. Grant, A.J. Moss, C.J. White
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
P.M. Hanlet
IIT, Chicago, Illinois, USA
C. Hunt, K.R. Long, J. Pasternak
Imperial College of Science and Technology, Department of Physics, London, United Kingdom
T.H. Luo, D.J. Summers
UMiss, University, Mississippi, USA
A. Moretti, R.J. Pasquinelli, D.W. Peterson, R.P. Schultz, J.T. Volk
Fermilab, Batavia, USA
P.J. Smith
Sheffield University, Sheffield, United Kingdom
T. Stanley
STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
Y. Torun
Illinois Institute of Technology, Chicago, IL, USA

The International Muon Ionisation Cooling Experiment (MICE) is designed to demonstrate the effectiveness of ionisation cooling to reduce the phase space footprint of a muon beam, principally to allow the subsequent acceleration of muons for next generation colliders and/or neutrino factories. The experiment (and indeed any subsequent accelerator cooling channel based on the same principles) poses certain unusual requirements on its RF system, whilst the precision measurement of the ionisation cooling process demands special diagnostics. This paper shall outline the key features of the RF system, including the LLRF control, the power amplifier chain, distribution network, cavities, tuners and couplers, all of which must operate in a high magnetic field environment. The RF diagnostics which, in conjunction with the other MICE diagnostics, shall allow detailed knowledge of the amplitude and phase of the acceleration field during the transit of each individual Muon shall also be outlined.

WEPME008

Precision LLRF Controls for the S-Band Accelerator REGAE

laser, gun, electron, controls

2938

M. Hoffmann, H. Kay, U. Mavrič, H. Schlarb, Ch. Schmidt
DESY, Hamburg, Germany
W. Jałmużna, T. Kozak, A. Piotrowski
TUL-DMCS, Łódź, Poland

The linear accelerator REGAE (Relativistic Electron Gun for Atomic Exploration) at DESY delivers electron bunches with a few femtosecond duration for time-resolved experiments of material structure in pump-probe configuration. To achieve the desired 10 fs resolution, the Low Level RF controls for the normal conducting S-band cavities must provide field stability of 0.01% in amplitude and of 0.01deg in phase. To achieve these demanding stability a recently developed LLRF controller based on the Micro-Telecommunications Computing Architecture (MTCA.4) have been installed and commission. In this paper, we report on measurement performance of the LLRF system, the achieved stability and current limitations.

WEPME009

Recent Developments of the European XFEL LLRF System

controls, cavity, laser, beam-loading

2941

Ch. Schmidt, G. Ayvazyan, V. Ayvazyan, J. Branlard, L. Butkowski, M.K. Grecki, M. Hoffmann, T. Jeżyński, F. Ludwig, U. Mavrič, S. Pfeiffer, H. Schlarb, H.C. Weddig, B.Y. Yang
DESY, Hamburg, Germany
P. Barmuta, S. Bou Habib, K. Czuba, M. Grzegrzółka, E. Janas, J. Piekarski, I. Rutkowski, D. Sikora, L. Zembala, M. Żukociński
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
W. Cichalewski, K. Gnidzińska, W. Jałmużna, D.R. Makowski, A. Mielczarek, A. Napieralski, P. Perek, A. Piotrowski, T. Pożniak, K.P. Przygoda
TUL-DMCS, Łódź, Poland
S. Korolczuk, I.M. Kudla, J. Szewiński
NCBJ, Świerk/Otwock, Poland
K. Oliwa, W. Wierba
IFJ-PAN, Kraków, Poland

The European XFEL is comprised of more than 800 TESLA-type super-conducting accelerator cavities which are driven by 25 high-power multi-beam klystrons. For reliable, reproducible and maintainable operation of linac, the LLRF system will process more than 3000 RF channels. Beside the large number of RF channels to be processed, stable FEL operation demands field stability better than 0.010deg in phase and 0.01% in amplitude. To cope with these challenges the LLRF system is developed on MTCA.4 platform. In this paper, we will give an update of the latest electronics developments, advances in the feedback controller algorithm and measurement results at FLASH.

WEPME013

Development and Test of a Fully Automated PkQl Control Procedure at KEK STF

cavity, controls, feedback, klystron

2950

M. Omet, A. Kuramoto
Sokendai, Ibaraki, Japan
H. Hayano, T. Matsumoto, S. Michizono
KEK, Ibaraki, Japan

In order to operate the cavities near their maximum gradients, cavity input (Pk) and cavity loaded Q (QL) should be controlled individually (PkQL control) at the International Linear Collider (ILC). A manual PkQL operation procedure was developed and performed at the linear electron accelerator at the Superconducting RF Test Facility (STF), in which the beam is accelerated up to 40 MeV by two superconducting 9-cell TESLA type L band cavities. The cavity gradients were set to 16 MV/m and 24 MV/m with QL values of 110⁶ and 3·10⁶. A 6.2 mA beam with a pulse length of 154 us was used. The field stabilities in amplitude were 0.160% and 0.097% for the cavities and 0.016% for the vector sum. The stabilities without beam are 0.057% and 0.054% for the cavities and 0.009% for the vector sum. For stability improvement during beam transient an adaptive beam feedforward for beam loading compensation is under development. So far an amplitude field stability of 0.013% for the vector sum was achieved at cavity gradients of 15 MV/m and 25 MV/m (no PkQL control) during a 6.8 mA beam with a pulse length of 123 us. Furthermore a fully automated PkQL control procedure is currently developed and tested.

Poster WEPME013 [0.647 MB]

WEPME014

Progress in Development of New LLRF Control System for SuperKEKB

cavity, controls, klystron, pick-up

2953

T. Kobayashi, K. Akai, K. Ebihara, A. Kabe, K. Nakanishi, M. Nishiwaki, J.-I. Odagiri
KEK, Ibaraki, Japan
H. Deguchi, K. Harumatsu, K. Hayashi, T. Iwaki, J. Mizuno, J. Nishio, M. Ryoshi
Mitsubishi Electric TOKKI Systems, Amagasaki, Hyogo, Japan

For the SuperKEKB project, a new LLRF control system was developed to realize high accuracy and flexibility. It is an FPGA-based digital RF feedback control system using 16-bit ADC's, which works on the μTCA platform. The FPGA boards control accelerating cavity fields and cavity tuning, and the EPICS-IOC is embedded in each of them. The CSS-BOY was adopted for a user interface of our system. High power test of the new LLRF control system was performed with the ARES Cavity of KEKB. The obtained feedback control stability with a klystron drive was sufficient as well as the low-level evaluation result. And auto tuner control also worded successfully. The start-up sequencer program for the cavity operation and auto-aging program also worked very well. The temperature characteristics of the system depend largely on band-pass filters (BPF). We tried to tune the BPF to reduce the temperature coefficient. Consequently the temperature dependence was improved to satisfy the required stability.

WEPME015

Evaluation of the Superconducting LLRF system at cERL in KEK

cavity, controls, coupling, linac

2956

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

A low level RF (LLRF) design is being currently developed within the compact Energy Recover Linac (cERL) at KEK. One challenging task is to achieve the high amplitude and high phase stability required by the accelerating fields of up to 0.1% and 0.1°, respectively. To improve the performance of the LLRF system, a gain scanning experiment for determining the optimal controller gain was carried out on the cERL. Furthermore, as a substitute for the traditional PI controller, a more robust H∞-based multiple input multiple output (MIMO) controller was realized. This controller requires more detailed system information (transfer function or state equation), which can be acquired by using modern system identification methods. In this paper, we describe the current status of these experiments on the cERL.

WEPME022

Overview of the CSNS/RCS LLRF Control System

cavity, controls, feedback, beam-loading

2977

X. Li, W. Long, H. Sun, C.L. Zhang, F.C. Zhao
IHEP, Beijing, People's Republic of China

The CSNS/RCS RF system consists of 8 ferrite-loaded RF cavities (h=2), each with individual digital LLRF control electronics. The injection and extraction energy of the beam are 80MeV and 1.6GeV respectively with a repetition rate of 25Hz. The RF system is designed to provide the maximum RF voltage of 165kV. The RF frequency range is from 1.02MHz at injection to 2.44MHz at extraction. The CSNS/RCS LLRF control system is based on FPGA, and composed of 7 control loops to achieve required acceleration voltage amplitude and phase regulation. A number of prototype and the first formal system have been completed and tested. In this paper we present an overview of the LLRF control system, and some operational results.

WEPME035

Overview of the RF Synchronization System for the European XFEL

laser, linac, booster, undulator

3001

K. Czuba, D. Sikora, L. Zembala
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
J. Branlard, F. Ludwig, H. Schlarb, H.C. Weddig
DESY, Hamburg, Germany

One of the most important requirements for the European XFEL RF system is to assure a very precise RF field stability within the accelerating cavities. The required amplitude and phase stability equals respectively dA/A <3·10^-5, dphi<0.01 deg @ 1.3GHz in the injector and dA/A<10^-3, dphi <0.1 deg @1.3GHz in the main LINAC section. Fulfilling such requirements for the 3.4 km long facility is a very challenging task. Thousands of electronic and RF devices must be precisely phase synchronized by means of harmonic RF signals. We describe the proposed architecture of the RF Master Oscillator and the Phase Reference Distribution System designed to assure high precision and reliability. A system of RF cable based interferometers supported by femtosecond-stable optical links will be used to distribute RF reference signals with required short and long term phase stability. We also present test results of prototype devices performed to validate our concept.

WEPME036

The Development of LLRF System at PAL

controls, cavity, radio-frequency, monitoring

3004

K.-H. Park, H.S. Han, Y.-G. Jung, D.E. Kim, H.-G. Lee, H.S. Suh
PAL, Pohang, Kyungbuk, Republic of Korea
J.-S. Chai, Y.S. Lee
SKKU, Suwon, Republic of Korea
B.-K. Kang
POSTECH, Pohang, Kyungbuk, Republic of Korea

The PAL has been developing the low level radio frequency (LLRF) system. The required field stabilities of the LLRF system are within ±0.75% in amplitude and 0.35° in phase in a cavity. All the hardware including RF front–end, FPGA with peripherals such as ADC, DAC, Oscillator and digital interface were assembled. The sub-modules for the RF signal processing were written by VHDL and integrated to test at the local facility. The macroblaze software processor was implemented to make the system simple in interfacing to peripherals and to secure flexibility later. This paper described the microblaze processor which was ported into the VERTEX6 FPGA. And also this paper showed the test results of the each module and integrated into the full system.

WEPME052

LLRF Characterisation of the Daresbury International Cryomodule

cavity, cryomodule, resonance, SRF

3046

L. Ma
STFC/DL, Daresbury, Warrington, Cheshire, United Kingdom
P.A. Corlett, A.J. Moss
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

The 2-cavity Superconducting RF (SRF) Linac cryomodule of the Accelerators and Lasers in Combined Experiments (ALICE) located at Daresbury Laboratory will be replaced by a new International ERL Cryomodule in early 2013. The improved 7-cell, 1.3 GHz SRF cavities will be characterised and compared with the original 9-cell cavities. Tests will be performed by driving the cavities by a VCO-PLL loop so that Q measurements, microphonics sensitivity and Lorentz force detuning can be analysed. A digital LLRF system using the LLRF4 board developed by Larry Doolittle has been developed at Daresbury Laboratory and will be installed on the upgraded cryomodule. This system is capable of controlled cavity filling to reduce waveguide reflection voltage, feedback/feed forward control and adaptive beam loading compensation. The new cryomodule will be evaluated with both the analog LLRF system and the digital LLRF system to allow for performance comparison. Cavity operation with high QL will also be tested to discover the feedback control limit as a function of inherent microphonics. This paper sets out to discuss the qualification process, testing and results of the upgraded cryomodule installation.

THPEA003

Use of FPGA-based Configurable Electronics to Calibrate Cavities

controls, synchrotron, ion, heavy-ion

3152

S. Schäfer, A. Klaus, H. Klingbeil, B. Zipfel
GSI, Darmstadt, Germany
U. Hartel, H. Klingbeil
TEMF, TU Darmstadt, Darmstadt, Germany

At the GSI Helmholzzentrum für Schwerionen-forschung GmbH the accuracy requirements for synchrotron rf cavities have strongly increased in the last years, especially for multi-harmonic operation. For heavy-ion acceleration the amplitude and phase have to be well adjusted over a whole machine cycle. In order to compensate small deviations induced by low-level rf components (LLRF) and transmission lines in the control paths, a calibration electronic (CEL) with a characteristic map was developed. It is a real-time module which is based on modern FPGA (Field Programmable Gate Array) technology and adaptable to special cavities with various physical dependencies (e.g. attenuation, dispersion, temperature drift, aging etc.). The hardware and software architecture of this CEL module are presented here.

THPEA011

WPF Based EPICS Server and its Application in CSNS

EPICS, controls, linac, PLC

3170

Y.L. Zhang, G. Lei
IHEP, Beijing, People's Republic of China

The control system of China Spallation Neutron Source(CSNS) is under construction based on EPICS. The Linac low level RF(LLRF) local control program running on a local control PC uses Windows Presentation Foundation( WPF) as its development tool and uses the C# codes to implement the functionality. The Linac LLRF control system is non-EPICS, so the Linac LLRF local variables can’t be accessed directly from EPICS. Therefore we need to port the Linac LLRF local control system to EPICS. This paper presents the WPF base EPICS server and its application in CSNS.

THPEA030

Improved Vector Modulator Card for MTCA-based LLRF Control System for Linear Accelerators

controls, power-supply, monitoring, radio-frequency

3207

I. Rutkowski, K. Czuba, M. Grzegrzólka
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
D.R. Makowski, A. Mielczarek, P. Perek
TUL-DMCS, Łódź, Poland
H. Schlarb
DESY, Hamburg, Germany

Modern linear accelerators require high-precision RF field regulation of accelerating cavities. A critical component to achieve high-precision in the feedback loop a Low Level Radio Frequency (LLRF) controller is the vector modulator driving the high power RF chain. At FLASH, the Free Electron Laser in Hamburg and European XFEL the LLRF controls are based on MTCA.4 platform. This paper describes the concept, design and performance of an improved vector modulator module (DRTM-VM2). It is constructed as Rear Transition Module (RTM). The module consists of digital, analog, diagnostic and management subsystems. FPGA from Xilinx Spartan 6 family receives data from control module (AMC) using Multi-Gigabit Transceivers (MGTs). The FPGA controls the analog part which includes fast, high-precision DACs, I/Q modulator chips, programmable attenuators, power amplifier and fast RF gates for external interlock system. Pin assignment on the Zone3 connector is compliant with digital class D1.2 recommendations proposed by DESY. The design has been optimized for mass production and for easy extends to wider frequency range. Electronic switches offer software configuration of power and clock sources.

THPEA031

REGAE LLRF Control System Overview

controls, electron, laser, feedback

3210

I. Rutkowski, L. Butkowski
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
M. Hoffmann, H. Schlarb, Ch. Schmidt
DESY, Hamburg, Germany

The linear accelerator REGAE (Relativistic Electron Gun for Atomic Exploration) at DESY delivers electron bunches with a few femtosecond duration for time-resolved investigation of material structures in pump-probe configuration. To achieve sub-10fs resolution, the Low Level RF controls for the normal conducting S-band cavities must provide field stability of .005% in amplitude and of .005deg in phase. To achieve these demands, the recently developed LLRF control modules based on the Micro-Telecommunications Computing Architecture (MTCA.4) platform are used. For precise field detection and control a rear transition module (DRTM-DWC8VM1) housing 8 down-converters and 1 vector-modulator has been developed. The down-converted signals are transmitted to low-noise ADCs on an advanced mezzanine card (SIS8300L) with two high speed DACs driving the vector-modulator. The on board FPGA device runs the advanced control algorithms with minimum latency. Shot-to-shot learning feed forward and ultra-fast analog and digital feedbacks are applied. In this paper, the first results of the new RTM-AMC module pairs are presented together with the achievements and limitations on the RF field stability.

THPEA060

LLRF System for LCLS-II at SLAC

controls, klystron, feedback, linac

3276

Z. Geng, B. Hong, K.H. Kim, R.S. Larsen, D. Van Winkle, C. Xu
SLAC, Menlo Park, California, USA

Funding: Work supported by US Department of Energy Contract DE AC03 76SF00515
After LCLS-I successfully delivering the full operation for users, SLAC has been approved to build the second Linac Coherent Light Source, LCLS-II, which makes use of another third of the 2-mile long Linac from Sector 10 to Sector20. The LLRF System will use mTCA (Micro Telecommunication Computing Architecture) to replace the VME system for LCLS-II injector and some key stations along the LINAC. The faster data acquisition and more powerful FPGA and CPU in the mTCA system enable the LLRF system to extend its control ability to a 2.5 μsec beam pulse rate of 360Hz. The new LLRF system is more compact and has the capability of low latency intra-pulse feedback to reduce fast phase and amplitude jitter during a single pulse. The prototype of the mTCA based LLRF control system has been operating at RF station 28-2 in LCLS-I. Detailed design structure and the prototype experimental results will be presented that demonstrate the system meets the exacting phase and amplitude stability requirements for LCLS-II.

THPFI042

Design Considerations for Phase Reference Distribution System at ESS

linac, controls, cavity, radiation

3379

R. Zeng
ESS, Lund, Sweden
A.J. Johansson
Lund University, Lund, Sweden

PRDS (Phase Reference Distribution System) will be serving as the phase alignment line for all cavities with high phase stability. With the current design of individually RF source powering for most cavities at ESS, phase reference distribution system should provide the reference signals for totally 34 LLRF systems at 100 meters long low-frequency section (for all 352.21MHz cavities, including RFQ, DTL, bunching cavities and spokes), and for totally 180 LLRF systems at 342 meters long high-frequency section (for all 704.42MHz cavities, including medium beta and high beta elliptical cavities). Coaxial cable based solution and optical fibre based solution are discussed in this note for PRDS (Phase reference distribution system) at ESS. Some possible schemes in each of these two distribution solutions are introduced and comparisons among these schemes are made. Some effort is made as well to find out a reasonable design for PRDS at ESS.

THPWA003

Novel Crate Standard MTCA.4 for Industry and Research

controls, monitoring, radio-frequency, free-electron-laser

3633

T. Walter, F. Ludwig, K. Rehlich, H. Schlarb
DESY, Hamburg, Germany

Funding: This project is funded by the Helmholtz Association (Helmholtz Validation Fund HVF-0016).
MTCA.4 is a novel electronic standard derived from the Telecommunication Computing Architecture (TCA) and championed by the xTCA for physics group, a network of physics research institutes and electronics manufacturers. MTCA.4 was released as an official standard by the PCI Industrial Manufacturers Group (PICMG) in 2011. Although the standard is originally physics-driven, it holds promise for applications in many other fields with equally challenging requirements. With substantial funding from the Helmholtz Association for a two-year validation project, DESY currently develops novel, fully MTCA.4-compliant components to lower the barriers to adoption in a wide range of industrial and research use scenarios. Core activities of the project are: refinement, test and qualification of existing components; market research, market education (web information services, workshops); coordinated development of missing MTCA.4 components; further advancement of the standard beyond the current PICMG specification; investigation of measures to counteract electro-magnetic interferences and incompatibilities; training, support and consultancy. This paper summarizes intermediate results and lessons learned at project half-time.

THPWO047

The LLRF Measurement and Analysis of the SSC-LINAC RFQ

rfq, cavity, linac, simulation

3875

G. Liu, J.E. Chen, S.L. Gao, Y.R. Lu, Z. Wang, X.Q. Yan, K. Zhu
PKU, Beijing, People's Republic of China
X. Du, Y. He, G. Pan, Y.Q. Yang, X. Yin, Y.J. Yuan, Z.L. Zhang, H.W. Zhao
IMP, Lanzhou, People's Republic of China

Funding: Supported by NSFC(11079001)
The manufacturing process of the SSC-LINAC RFQ went to end and the LLRF measurement has been done. The frequency of the RFQ is 53.557 MHz without tuning, which is not far from the design value 53.667 MHz. The unflatness of the field along the beam axis is less than ±4%, which meets the simulation results. The dipole field is in the acceptable margin as well. The frequency will be adjusted by tuning plungers in operation. In this paper, the field distribution along the cavity has been measured and compared with the modulated electrodes simulation. The difference and its influences on the beam transmission have been analyzed.