IPAC2021 - List of Keywords (LLRF)

Paper	Title	Other Keywords	Page
MOPAB192	LILac Energy Upgrade to 13 MeV	cavity, linac, proton, controls	651
	B. Koubek, S. Altürk, M. Busch, H. Höltermann, J.D. Kaiser, H. Podlech, U. Ratzinger, M. Schuett, M. Schwarz, W. Schweizer, D. Strehl, R. Tiede, C. Trageser BEVATECH, Frankfurt, Germany A. Brunzel, P. Nonn, H. Schlarb DESY, Hamburg, 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
	In the frame of the NICA (Nuclotron-based Ion Collider fAcility) ion collider upgrade a new light ion LINAC for protons and ions will be built in collaboration between JINR and BEVATECH GmbH. While ions with a mass-to-charge ratio up to 3 will be fed into the NUCLOTRON ring with an energy of 7 MeV/u, protons are supposed to be accelerated up to an energy of 13 MeV using a third IH structure. This energy upgrade comprises a third IH structure, a dual-use Debuncher cavity as well as an extension of the LLRF control system built on MicroTCA technology.
	Poster MOPAB192 [4.914 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB192
About •	paper received ※ 11 May 2021 paper accepted ※ 31 May 2021 issue date ※ 20 August 2021
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MOPAB290	Machine Learning-Based LLRF and Resonance Control of Superconducting Cavities	cavity, controls, simulation, SRF	920
	J.A. Diaz Cruz, S. Biedron, M. Martínez-Ramón UNM-ECE, Albuquerque, USA J.A. Diaz Cruz SLAC, Menlo Park, California, USA R. Pirayesh UNM-ME, Albuquerque, New Mexico, USA S. Sosa ODU, Norfolk, Virginia, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of High Energy Physics, under award number DE-SC0019468. Superconducting radio frequency (SRF) cavities with high loaded quality factors that operate in continuous wave (CW) and low beam loading are sensitive to microphonics-induced detuning. Cavity detuning can result in an increase of operational power and/or in a cavity quench. Such SRF cavities have bandwidths on the order of 10 Hz and detuning requirements can be as tight as 10 Hz. Passive methods to mitigate vibration sources and their impact in the cryomodule/cavity environment are widely used. Active resonance control techniques that use stepper motors and piezoelectric actuators to tune the cavity resonance frequency by compensating for microphonics detuning have been investigated. These control techniques could be further improved by applying Machine Learning (ML), which has shown promising results in other particle accelerator control systems. In this paper, we describe a Low-level RF (LLRF) and resonance control system based on ML methods that optimally and adaptively tunes the control parameters. We present simulations and test results obtained using a low power test bench with a cavity emulator.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB290
About •	paper received ※ 03 June 2021 paper accepted ※ 11 June 2021 issue date ※ 29 August 2021
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MOPAB334	Status and Recent Development of FAIR Ring RF Systems	cavity, power-supply, operation, status	1037
	U. Laier, R. Balß, C. Christoph, M. Frey, P. Hülsmann, H. Klingbeil, H.G. König, D.E.M. Lens, J.S. Schmidt, A. Stuhl, K.G. Thomin, T. Winnefeld GSI, Darmstadt, Germany H. Klingbeil TEMF, TU Darmstadt, Darmstadt, Germany
	Funding: GSI Helmholtzzentrum für Schwerionenforschung GmbH Five different Ring RF Systems are required for the operation of FAIR (Facility for Antiproton and Ion Research). These systems have to operate at frequencies between 310 kHz and 3.2 MHz, with gap voltages up to 40 kVp and duty cycles from 5·10^-4 up to cw. All systems will be realized using inductively loaded (ferrite or magnetic alloy) cavities driven by tetrode-based amplifiers fed by switch-mode power supplies. To stabilize the amplitude, resonance frequency and phase, versatile digital feedback and feedforward control will be used. This contribution will present the latest development on the power part and the LLRF of the four RF systems of the SIS100 (SIS100 Acceleration, SIS100 Bunch Compression, SIS100 Barrier Bucket and SIS100 Longitudinal Feedback) as well as the CR Debuncher system which is part of the Collector Ring. The progress of these systems varies by a large degree. This note will give an overview regarding the status of the design, procurement, realization, testing, optimization, commissioning and preparation for installation of these RF systems.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB334
About •	paper received ※ 18 May 2021 paper accepted ※ 07 June 2021 issue date ※ 12 August 2021
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MOPAB390	Development of a 166.6 MHz Low-Level RF System by Direct Sampling for High Energy Photon Source	cavity, controls, photon, pick-up	1189
	D.B. Li, H.Y. Lin, Q.Y. Wang, P. Zhang IHEP, Beijing, People’s Republic of China
	Funding: This work was supported by High Energy Photon Source, a major national science and technology infrastructure in China. A digital low-level radio frequency (LLRF) system by direct sampling has been proposed for 166.6 MHz superconducting cavities at High Energy Photon Source (HEPS). The RF field inside the cavities has to be controlled better than ±0.1% (peak to peak) in amplitude and ±0.1 deg (peak to peak) in phase. Considering that the RF frequency is 166.6 MHz, which is well within the analog bandwidth of modern high-speed ADCs and DACs, direct RF sampling and direct digital modulation can be achieved. A digital LLRF system utilizing direct sampling has therefore been developed with embedded experimental physics and industrial control system (EPICS) in the field programmable gate array (FPGA). The performance in the lab has been characterized in a self-closed loop with a residual peak-to-peak noise of ±0.05% in amplitude and ±0.03 deg in phase, which is well below the HEPS specifications. Further tests on a warm 166.6 MHz cavity in the lab are also presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB390
About •	paper received ※ 17 May 2021 paper accepted ※ 09 June 2021 issue date ※ 30 August 2021
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TUPAB295	Upgrade to the EPICS Control System at the Argonne Wakefield Accelerator Test Facility	controls, EPICS, interface, data-acquisition	2173
	W. Liu, J.M. Byrd, D.S. Doran, G. Ha, A.N. Johnson, P. Piot, J.G. Power, J.H. Shao, G. Shen, C. Whiteford, E.E. Wisniewski ANL, Lemont, Illinois, USA
	Funding: US Department of Energy, Office of Science The Argonne Wakefield Accelerator (AWA) Test Facility has used a completely homebrewed, MS Windows-based control system for the last 20 years. In an effort to modernize the control system and prepare for an active machine learning program, the AWA will work with the Advanced Photon Source (APS) controls group to upgrade its control system to EPICS. The EPICS control system is expected to facilitate collaborations and support the future growth of AWA. An overview of the previous AWA control and data acquisition system is presented, along with a vision and path for completing the EPICS upgrade.
	Poster TUPAB295 [1.108 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB295
About •	paper received ※ 19 May 2021 paper accepted ※ 01 July 2021 issue date ※ 30 August 2021
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TUPAB296	LLRF Upgrade at the Argonne Wakefield Accelerator Test Facility	laser, controls, klystron, pick-up	2176
	W. Liu, D.S. Doran, G. Ha, P. Piot, J.G. Power, J.H. Shao, C. Whiteford, E.E. Wisniewski ANL, Lemont, Illinois, USA L.R. Doolittle, D. Filippetto, D. Li, S. Paiagua, C. Serrano, V.K. Vytla LBNL, Berkeley, California, USA
	Funding: US Department of Energy, Office of Science The Argonne Wakefiled Accelerator (AWA) Test Facility designed and operated a homemade LLRF system for the last 20 years. It is based on NI-PXI products that has now become obsolete. The AWA’s LLRF cannot keep up with the increasing stability demands of AWA’s upgraded facility. An overhaul of the system is strongly desired. With the support from DOE-HEP, the AWA is collaborating with Lawrence Berkeley National Laboratory (LBNL)to upgrade its LLRF system with modern instrumentation to meet the growing stability demands. An overview of AWA’s current LLRF system performance is presented together with the upgrade plan and expectations.
	Poster TUPAB296 [1.943 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB296
About •	paper received ※ 19 May 2021 paper accepted ※ 05 July 2021 issue date ※ 26 August 2021
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TUPAB306	Status of Beam-Based Feedback Research and Development for Continuous Wave SRF Linac ELBE	controls, electron, feedback, cavity	2200
	A. Maalberg, M. Kuntzsch HZDR, Dresden, Germany E. Petlenkov TalTech, Tallinn, Estonia
	The superconducting electron linear accelerator ELBE at Helmholtz-Zentrum Dresden-Rossendorf is a versatile light source operated in continuous wave mode. As the demand on the beam stability increases, the improvement of the beam control schemes currently installed at ELBE becomes highly relevant. This improvement can be achieved by an upgrade of the existing digital MicroTCA.4-based LLRF control scheme by beam-based feedback. By presenting both the design and implementation details of the new control scheme this contribution reports the status of the work in progress.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB306
About •	paper received ※ 19 May 2021 paper accepted ※ 21 June 2021 issue date ※ 30 August 2021
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WEPAB038	Commissioning of a New X-Band, Low-Noise LLRF System	klystron, cavity, MMI, linac	2683
	A.V. Edwards, M. Boronat Arevalo, N. Catalán Lasheras, G. McMonagle CERN, Meyrin, Switzerland A.C. Dexter Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
	To increase beam energy in the CLEAR facility at CERN and study the CLIC accelerating structure prototype in operating conditions, the first X-band test facility at CERN was upgraded in 2020. Both, the acquisition and software systems at X-band test stand 1 (Xbox1) were upgraded to exhibit low phase noise which is relevant to klystron based CLIC and to the use of crab cavities in the beam delivery system. The new LLRF uses down-conversion which necessitates a local oscillator which can be produced by two different methods. The first is a PLL, a commonly used technique which has been previously employed at the other X-band facilities at CERN. The second is a novel application of a single sideband up-convertor. The up-convertor system has demonstrated reduced phase noise when compared with the PLL. The commissioning of the new system began in late 2020 with the conditioning of a 50 MW Klystron. Measurements of the quality of the new LLRF will be shown. These will compare the PLL and up-convertor with particular attention on the quality of the phase measurements. Also, a preliminary study of phase shifts in the waveguide network due to temperature changes will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB038
About •	paper received ※ 13 May 2021 paper accepted ※ 05 July 2021 issue date ※ 20 August 2021
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WEPAB073	An Overview of the Radio-Frequency System for an Inverse Compton X-Ray Source Based on CLIC Technology	klystron, controls, network, laser	2759
	T.G. Lucas, O.J. Luiten, P.H.A. Mutsaers, X.F.D. Stragier, H.A. Van Doorn, F.M. van Setten, H.J.M. van den Heuvel, M.L.M.C. van der Sluis TUE, Eindhoven, The Netherlands
	Funding: This project is financed by the "Interreg V programme Flanders-Netherlands" with financial support of the European Fund for Regional Development. Compact inverse Compton scattering X-ray sources are gaining in popularity as the future of lab-based x-ray sources. SmartLight is one such facility, under commissioning at Eindhoven University of Technology (TU/e), which is based on high gradient X-band technology originally designed for the Compact Linear Collider (CLIC) and its test stands located at CERN. Critical to the beam quality is the RF system which aims to deliver 10-24 MW RF pulses at repetition rates up to 1 kHz with a high amplitude and phase stability of <0.5\% and <0.65~^° allowing it to adhere to strict synchronicity conditions at the interaction point. This work overviews the design of the high power and low level RF systems for SmartLight.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB073
About •	paper received ※ 19 May 2021 paper accepted ※ 23 June 2021 issue date ※ 29 August 2021
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WEPAB294	LLRF Control and Synchronization System of the ARES Facility	gun, laser, experiment, distributed	3347
	S. Pfeiffer, J. Branlard, F. Burkart, M. Hoffmann, T. Lamb, F. Ludwig, H. Schlarb, S. Schulz, B. Szczepanski, M. Titberidze DESY, Hamburg, Germany
	The linear accelerator ARES (Accelerator Research Experiment at SINBAD) is a new research facility at DESY. Electron bunches with a maximum repetition rate of 50 Hz are accelerated up to 155 MeV. The facility aims for ultra-stable sub-femtosecond arrival-times and high peak-currents at the experiment, placing high demands on the reference distribution and field regulation of the S-band RF structures. In this paper, we report on the current status of the RF reference generation, facility-wide distribution, and the LLRF systems of the RF structures.
	Poster WEPAB294 [2.394 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB294
About •	paper received ※ 18 May 2021 paper accepted ※ 05 July 2021 issue date ※ 20 August 2021
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WEPAB296	A Klystron Phase Lock Loop for RF System at TPS Booster Ring	controls, cathode, klystron, injection	3354
	F.Y. Chang, M.H. Chang, S.W. Chang, L.J. Chen, F.-T. Chung, Y.D. Li, M.-C. Lin, Z.K. Liu, C.H. Lo, Ch. Wang, M.-S. Yeh, T.-C. Yu NSRRC, Hsinchu, Taiwan
	In TPS booster ring, the DLLRF is used to controlled the ramping gap voltage and also the energy saving module is applied to save power while the ring does not inject beam. But we occurred to have a problem of PI saturation due to a large phase change when the energy saving module working. The energy saving module switches the anode voltage of the klystron from high to low level to decrease the cathode current while the ring does not inject and do the opposite while the ring injects. This action causes a large phase change of the transmitter and leads the PI controller to work in the wrong direction. We add a klystron phase loop to solve this situation.
	Poster WEPAB296 [0.792 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB296
About •	paper received ※ 19 May 2021 paper accepted ※ 01 July 2021 issue date ※ 30 August 2021
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WEPAB298	Design of an Accurate LLRF System for an Array of Two-Gap Resonators	controls, FPGA, distributed, Ethernet	3360
	D.A. Liakin, S.V. Barabin, T. Kulevoy, A.Y. Orlov ITEP, Moscow, Russia
	A particle accelerator based on an array of two-gap resonators requires a control system, which is responsible for precise setup and stabilization of the phase and magnitude of the electromagnetic field in resonators. We develop a cost-effective LLRF system for the array of more than 80 resonators and three different operating frequencies. The design is based on proved solution used for 5-resonators accelerator HILAC (project NICA, Dubna). This paper gives an overview of the basic structure and some specific features of the developing LLRF control system.
	Poster WEPAB298 [0.355 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB298
About •	paper received ※ 18 May 2021 paper accepted ※ 23 June 2021 issue date ※ 30 August 2021
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WEPAB299	Spallation Neutron Source Proton Power Upgrade Low-Level RF Control System Development	controls, operation, cavity, neutron	3363
	M.T. Crofford, J.A. Ball, J.E. Breeding, M.P. Martinez, J.S. Moss, M. Musrock ORNL, Oak Ridge, Tennessee, USA L.R. Doolittle, C. Serrano, V.K. Vytla LBNL, Berkeley, California, USA J. Graham, C.K. Roberts, J.W. Sinclair, Z. Sorrell, S. Whaley ORNL RAD, Oak Ridge, Tennessee, USA
	Funding: * This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract number DE-AC05-00OR22725. The Proton Power Upgrade (PPU) Project is approved for the Spallation Neutron Source at Oak Ridge National Laboratory and will double the proton beam power capability from 1.4 MW to 2.8 MW with 2 MW beam power available to the first target station. A second target station is planned and will utilize the remaining beam power in the future. The proton power increase will be supported with the addition of twenty-eight new superconducting cavities powered by 700 kW peak power klystrons to increase beam energy while increases to the beam current will be done with a combination of existing RF margin, and DTL HPRF upgrades. The original low-level RF control system has proven to be reliable over the past 15 years of operations, but obsolescence issues mandate a replacement system be developed for the PPU project. The replacement system is realized in a µTCA.4 platform using a combination of commercial off-the-shelf boards and custom hardware to support the requirements of PPU. This paper presents the prototype hardware, firmware, and software development activities along with preliminary testing results of the new system.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB299
About •	paper received ※ 18 May 2021 paper accepted ※ 21 June 2021 issue date ※ 11 August 2021
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WEPAB300	Python Based Tools for FRIB LLRF Operation and Management	controls, cavity, EPICS, linac	3367
	S.R. Kunjir, D.G. Morris, S. Zhao FRIB, East Lansing, Michigan, USA
	Funding: This work is supported by the US Department of Energy Office of Science under Cooperative Agreement DE-SC0000661, the State of Michigan and Michigan State University. Some Python based tools have been developed at the Facility for Rare Isotope Beams (FRIB) for the ease of operation and management of the low level radio frequency (LLRF) controllers. Utilizing the rich features in Python, some tasks can be easily applied to a whole segment, one type of cryomodule (CM), a specific cryomodule or individual cavities grouped by a complex custom query. The tasks include, for example, 1) testing interface connections between various sub-systems prior to an operational run; 2) setting, checking and saving/restoring parameters during and after an operational run; 3) updating LLRF controller firmware and software during maintenance. With these tools, routine manual tasks are streamlined to achieve significantly greater efficiency in terms of scalability, time, memory and network resources. Considering channel access security, beam on/off status etc., the strategy of choosing either input/output controller (IOC) or Python for the implementation of certain tasks is also discussed in the paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB300
About •	paper received ※ 18 May 2021 paper accepted ※ 01 July 2021 issue date ※ 24 August 2021
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WEPAB301	Design of an X-Band LLRF System for TEX Test Facility at LNF-INFN	cavity, klystron, insertion, GUI	3371
	L. Piersanti, D. Alesini, M. Bellaveglia, S. Bini, B. Buonomo, F. Cardelli, C. Di Giulio, M. Diomede, A. Falone, G. Franzini, A. Gallo, A. Liedl, S. Pioli, S. Quaglia, L. Sabbatini, M. Scampati, G. Scarselletta, A. Stella INFN/LNF, Frascati, Italy
	Funding: Latino is a project co-funded by Regione Lazio within POR-FESR 2014-2020 program In the framework of LATINO project (Laboratory in Advanced Technologies for INnOvation) funded by Lazio regional government, a TEst stand for X-band (TEX) is being commissioned at Frascati National Laboratories (LNF) of INFN. TEX is born as a collaboration with CERN, aimed at carrying out high power tests of X-band accelerating structure prototypes and waveguide components, and it is of paramount importance in view of the construction of EuPRAXIA@SPARC_LAB facility at LNF. In order to generate, manipulate and measure the RF pulses needed to feed the RF power unit (solid state ScandiNova K400 modulator, CPI 50 MW 50 Hz klystron) an X-band low level RF system has been developed, making use of a commercial S-band (2.856 GHz) Libera digital LLRF (manufactured by Instrumentation Technologies) with a newly designed up/down conversion stage and a reference generation/distribution system, which is able to produce coherent reference frequencies for the American S-band (2.856 GHz) and European X-band (11.994 GHz). In this paper the main features of such systems will be reviewed together with preliminary laboratory measurement results.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB301
About •	paper received ※ 19 May 2021 paper accepted ※ 12 July 2021 issue date ※ 27 August 2021
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WEPAB314	TEX - an X-Band Test Facility at INFN-LNF	controls, klystron, GUI, framework	3406
	S. Pioli, D. Alesini, F.A. Anelli, M. Bellaveglia, S. Bini, B. Buonomo, S. Cantarella, F. Cardelli, G. Catuscelli, R. Ceccarelli, A. Cecchinelli, F. Chiarelli, P. Ciuffetti, R. Clementi, C. Di Giulio, E. Di Pasquale, G. Di Raddo, M. Diomede, A. Esposito, L. Faillace, A. Falone, G. Franzini, A. Gallo, S. Incremona, A. Liedl, D. Pellegrini, G. Piermarini, L. Piersanti, S. Quaglia, R. Ricci, L. Sabbatini, M. Scampati, G. Scarselletta, A. Stella, R. Zarlenga INFN/LNF, Frascati, Italy
	Funding: The LATINO project is co-funded by the Regione Lazio within POR-FESR 2014-2020 European activities (public call "Open Research Infrastructures"). We report the status of the development of an High Power RF Laboratory in X-Band called TEX (TEst-stand for X-Band). TEX is part of the LATINO (Laboratory in Advanced Technologies for INnOvation) initiative that is ongoing at the Frascati National Laboratories (LNF) of the Italian Institute for Nuclear Physics (INFN) that covers many different areas focused on particle accelerator technologies. TEX is a RF test facility based on solid-state K400 modulator from ScandiNova with a 50MW class X-band (11.996 GHz) klystron tube model vkx 8311a operating at 50 Hz. This RF source will operate as resource for test and research programs such as the RF breakdown on RF waveguide components as well as high power testing of accelerating structures for future high gradient linear accelerator such as EuPRAXIA and CLIC. The high power testing will be performed in a dedicated brand-new bunker that has been recently built. RF system, vacuum controls and safety equipments are currently being installed. The first accelerating structure testing is scheduled by beginning 2022. In this document design and tests for all the sub-systems of the facility will be presented and discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB314
About •	paper received ※ 19 May 2021 paper accepted ※ 28 July 2021 issue date ※ 19 August 2021
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THPAB268	Hierarchical Intelligent Real-Time Optimal Control for LLRF Using Time Series Machine Learning Methods and Transfer Learning	controls, cavity, network, simulation	4329
	R. Pirayesh, S. Biedron UNM-ME, Albuquerque, New Mexico, USA S. Biedron, J.A. Diaz Cruz, M. Martínez-Ramón UNM-ECE, Albuquerque, USA J.A. Diaz Cruz SLAC, Menlo Park, California, USA
	Funding: supported by DOE, Office of Science, Office of High Energy Physics, under award number DE-SC0019468, Contract No. DE-AC02-76SF00515, also supported Office of Basic Energy Sciences. ALCF, Element Aero Machine learning (ML) has recently been applied to Low-level RF (LLRF) control systems to keep the voltage and phase of Superconducting Radiofrequency (SRF) cavities stable within 0.01 degree in phase and 0.01% amplitude as constraints. Model predictive control (MPC) uses an optimization algorithm offline to minimize a cost function with constraints on the states and control input. The surrogate model optimally controls the cavities online. Time series deep ML structures including recurrent neural network (RNN) and long short-term memory (LSTM) can model the control input of MPC and dynamics of LLRF as a surrogate model. When the predicted states diverge from the measured states more than a threshold at each time step, the states’ measurements from the cavity fine-tune the surrogate model with transfer learning. MPC does the optimization offline again with the updated surrogate model, and, next, transfer learning fine-tunes the surrogate model with the new data from the optimal control inputs. The surrogate model provides us with a computationally faster and accurate modeling of MPC and LLRF, which in turn results in a more stable control system. Machine learning, Surrogate model, control, LLRF, MPC, Transfer learning
	Poster THPAB268 [0.377 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB268
About •	paper received ※ 16 May 2021 paper accepted ※ 13 July 2021 issue date ※ 18 August 2021
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THPAB271	JLAB LLRF 3.0 Development and Tests	cavity, controls, FPGA, cryomodule	4340
	T.E. Plawski, R. Bachimanchi, S. Higgins, C. Hovater, J. Latshaw, C.I. Mounts, D.J. Seidman, J. Yan JLab, Newport News, Virginia, USA
	The Jefferson Lab LLRF 3.0 system is being developed to replace legacy LLRF systems in the CEBAF accelerator. The new design builds upon 25 years of design and operational RF control experience, and our recent collaboration in the design of the LCLSII LLRF system. The new cavity control algorithm is a fully functional phase and amplitude locked Self Exciting Loop (SEL). This paper discusses the progress of the LLRF 3.0 hardware design, FPGA firmware development, User Datagram Protocol (UDP) operation, and recent LLRF 3.0 system tests on the CEBAF Booster cryomodule in the Upgrade Injector Test Facility (UITF).
	Poster THPAB271 [1.940 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB271
About •	paper received ※ 14 May 2021 paper accepted ※ 06 July 2021 issue date ※ 20 August 2021
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THPAB272	Validation of Two Re-Buncher Cavities under High Beam Loading for LIPAc	cavity, beam-loading, operation, MEBT	4343
	D. Gavela, I. Podadera, F. Toral CIEMAT, Madrid, Spain I. Moya Fusion for Energy, Garching, Germany F. Scantamburlo IFMIF/EVEDA, Rokkasho, Japan
	Funding: Work partially supported by the Spanish Ministry of Science and Innovation under project AIC-A-2011-0654 and FIS2013-40860-R Two re-buncher cavities were installed at the Medium Energy Beam Transport line of the LIPAc accelerator, presently being commissioned at Rokkasho (Japan). They are IH-type cavities with five gaps providing an effective voltage of 350 kV at 175 MHz for a nominal operation of 125 mA CW deuterons at 5 MeV. After full conditioning and beamline integration in Europe, the cavities were installed in the accelerator with special care given to the alignment with respect to the rest of the components. The RF line, cooling circuits, and instrumentation were also mounted. The cavities were operated with an FPGA-based LLRF system. A re-conditioning of the cavities was performed in the first place, followed by tests with a pulsed beam with increasing currents. A maximum pulsed beam current of 100 mA was reached while operating the buncher cavities, under which they reached voltages up to 340 kV and 260 kV respectively. As expected, the beam loading was significant, leading to a series of difficulties and required strategies for a good operation that are discussed in this paper. The effect on the beam dynamics, measured by beam position monitors downstream of the bunchers is also discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB272
About •	paper received ※ 19 May 2021 paper accepted ※ 02 September 2021 issue date ※ 18 August 2021
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THPAB287	Providing Computing Power for High Level Controllers in MicroTCA-based LLRF Systems via PCI Express Extension	controls, software, Ethernet, cavity	4363
	P. Nonn, A. Eichler, S. Pfeiffer, H. Schlarb, J.H.K. Timm DESY, Hamburg, Germany
	It is possible to connect the PCIe bus of a high performance computer to a MicroTCA crate. This allows the software on the computer to communicate with the modules in the crate, as if they were peripherals of the computer. This article will discuss the use of this feature in respect to accelerator control with a focus on High Level Controllers.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB287
About •	paper received ※ 19 May 2021 paper accepted ※ 26 July 2021 issue date ※ 16 August 2021
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THPAB338	Performance of the LLRF System for the Fermilab PIP-II Injector Test	cavity, controls, resonance, cryomodule	4450
	P. Varghese, B.E. Chase, P.M. Hanlet, H. Maniar, D.J. Nicklaus Fermilab, Batavia, Illinois, USA L.R. Doolittle, C. Serrano LBNL, Berkeley, California, USA
	PIP-II IT is a test facility for the PIP-II project where the injector, warm front-end, and the first two superconducting cryomodules are being tested. The 8-cavity half-wave-resonator (HWR) cryomodule operating at 162.5 MHz is followed by the 8-cavity single-spoke resonator(SSR1) cryomodule operating at 325 MHz. The LLRF systems for both cryomodules are based on a common SOC FPGA-based hardware platform. The resonance control systems for the two cryomodules are quite different, the first being a pneumatic system based on helium pressure and the latter a piezo/stepper motor type control. The data acquisition and control system can support both CW and Pulsed mode operations. Beam loading compensation is available which can be used for both manual/automatic control in the LLRF system. The user interfaces include EPICS, Labview, and ACNET. Testing of the RF system has progressed to the point of being ready for a 2 mA beam to be accelerated to 25 MeV. The design and performance of the field control and resonance control system operation with beam are presented in this paper.
	Poster THPAB338 [5.482 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB338
About •	paper received ※ 13 May 2021 paper accepted ※ 27 July 2021 issue date ※ 24 August 2021
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Paper

Title

Other Keywords

Page

MOPAB192

LILac Energy Upgrade to 13 MeV

cavity, linac, proton, controls

651

B. Koubek, S. Altürk, M. Busch, H. Höltermann, J.D. Kaiser, H. Podlech, U. Ratzinger, M. Schuett, M. Schwarz, W. Schweizer, D. Strehl, R. Tiede, C. Trageser
BEVATECH, Frankfurt, Germany
A. Brunzel, P. Nonn, H. Schlarb
DESY, Hamburg, 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

In the frame of the NICA (Nuclotron-based Ion Collider fAcility) ion collider upgrade a new light ion LINAC for protons and ions will be built in collaboration between JINR and BEVATECH GmbH. While ions with a mass-to-charge ratio up to 3 will be fed into the NUCLOTRON ring with an energy of 7 MeV/u, protons are supposed to be accelerated up to an energy of 13 MeV using a third IH structure. This energy upgrade comprises a third IH structure, a dual-use Debuncher cavity as well as an extension of the LLRF control system built on MicroTCA technology.

Poster MOPAB192 [4.914 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB192

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paper received ※ 11 May 2021 paper accepted ※ 31 May 2021 issue date ※ 20 August 2021

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MOPAB290

Machine Learning-Based LLRF and Resonance Control of Superconducting Cavities

cavity, controls, simulation, SRF

920

J.A. Diaz Cruz, S. Biedron, M. Martínez-Ramón
UNM-ECE, Albuquerque, USA
J.A. Diaz Cruz
SLAC, Menlo Park, California, USA
R. Pirayesh
UNM-ME, Albuquerque, New Mexico, USA
S. Sosa
ODU, Norfolk, Virginia, USA

Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of High Energy Physics, under award number DE-SC0019468.
Superconducting radio frequency (SRF) cavities with high loaded quality factors that operate in continuous wave (CW) and low beam loading are sensitive to microphonics-induced detuning. Cavity detuning can result in an increase of operational power and/or in a cavity quench. Such SRF cavities have bandwidths on the order of 10 Hz and detuning requirements can be as tight as 10 Hz. Passive methods to mitigate vibration sources and their impact in the cryomodule/cavity environment are widely used. Active resonance control techniques that use stepper motors and piezoelectric actuators to tune the cavity resonance frequency by compensating for microphonics detuning have been investigated. These control techniques could be further improved by applying Machine Learning (ML), which has shown promising results in other particle accelerator control systems. In this paper, we describe a Low-level RF (LLRF) and resonance control system based on ML methods that optimally and adaptively tunes the control parameters. We present simulations and test results obtained using a low power test bench with a cavity emulator.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB290

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paper received ※ 03 June 2021 paper accepted ※ 11 June 2021 issue date ※ 29 August 2021

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MOPAB334

Status and Recent Development of FAIR Ring RF Systems

cavity, power-supply, operation, status

1037

U. Laier, R. Balß, C. Christoph, M. Frey, P. Hülsmann, H. Klingbeil, H.G. König, D.E.M. Lens, J.S. Schmidt, A. Stuhl, K.G. Thomin, T. Winnefeld
GSI, Darmstadt, Germany
H. Klingbeil
TEMF, TU Darmstadt, Darmstadt, Germany

Funding: GSI Helmholtzzentrum für Schwerionenforschung GmbH
Five different Ring RF Systems are required for the operation of FAIR (Facility for Antiproton and Ion Research). These systems have to operate at frequencies between 310 kHz and 3.2 MHz, with gap voltages up to 40 kVp and duty cycles from 5·10^-4 up to cw. All systems will be realized using inductively loaded (ferrite or magnetic alloy) cavities driven by tetrode-based amplifiers fed by switch-mode power supplies. To stabilize the amplitude, resonance frequency and phase, versatile digital feedback and feedforward control will be used. This contribution will present the latest development on the power part and the LLRF of the four RF systems of the SIS100 (SIS100 Acceleration, SIS100 Bunch Compression, SIS100 Barrier Bucket and SIS100 Longitudinal Feedback) as well as the CR Debuncher system which is part of the Collector Ring. The progress of these systems varies by a large degree. This note will give an overview regarding the status of the design, procurement, realization, testing, optimization, commissioning and preparation for installation of these RF systems.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB334

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paper received ※ 18 May 2021 paper accepted ※ 07 June 2021 issue date ※ 12 August 2021

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MOPAB390

Development of a 166.6 MHz Low-Level RF System by Direct Sampling for High Energy Photon Source

cavity, controls, photon, pick-up

1189

D.B. Li, H.Y. Lin, Q.Y. Wang, P. Zhang
IHEP, Beijing, People’s Republic of China

Funding: This work was supported by High Energy Photon Source, a major national science and technology infrastructure in China.
A digital low-level radio frequency (LLRF) system by direct sampling has been proposed for 166.6 MHz superconducting cavities at High Energy Photon Source (HEPS). The RF field inside the cavities has to be controlled better than ±0.1% (peak to peak) in amplitude and ±0.1 deg (peak to peak) in phase. Considering that the RF frequency is 166.6 MHz, which is well within the analog bandwidth of modern high-speed ADCs and DACs, direct RF sampling and direct digital modulation can be achieved. A digital LLRF system utilizing direct sampling has therefore been developed with embedded experimental physics and industrial control system (EPICS) in the field programmable gate array (FPGA). The performance in the lab has been characterized in a self-closed loop with a residual peak-to-peak noise of ±0.05% in amplitude and ±0.03 deg in phase, which is well below the HEPS specifications. Further tests on a warm 166.6 MHz cavity in the lab are also presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB390

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paper received ※ 17 May 2021 paper accepted ※ 09 June 2021 issue date ※ 30 August 2021

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TUPAB295

Upgrade to the EPICS Control System at the Argonne Wakefield Accelerator Test Facility

controls, EPICS, interface, data-acquisition

2173

W. Liu, J.M. Byrd, D.S. Doran, G. Ha, A.N. Johnson, P. Piot, J.G. Power, J.H. Shao, G. Shen, C. Whiteford, E.E. Wisniewski
ANL, Lemont, Illinois, USA

Funding: US Department of Energy, Office of Science
The Argonne Wakefield Accelerator (AWA) Test Facility has used a completely homebrewed, MS Windows-based control system for the last 20 years. In an effort to modernize the control system and prepare for an active machine learning program, the AWA will work with the Advanced Photon Source (APS) controls group to upgrade its control system to EPICS. The EPICS control system is expected to facilitate collaborations and support the future growth of AWA. An overview of the previous AWA control and data acquisition system is presented, along with a vision and path for completing the EPICS upgrade.

Poster TUPAB295 [1.108 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB295

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paper received ※ 19 May 2021 paper accepted ※ 01 July 2021 issue date ※ 30 August 2021

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TUPAB296

LLRF Upgrade at the Argonne Wakefield Accelerator Test Facility

laser, controls, klystron, pick-up

2176

W. Liu, D.S. Doran, G. Ha, P. Piot, J.G. Power, J.H. Shao, C. Whiteford, E.E. Wisniewski
ANL, Lemont, Illinois, USA
L.R. Doolittle, D. Filippetto, D. Li, S. Paiagua, C. Serrano, V.K. Vytla
LBNL, Berkeley, California, USA

Funding: US Department of Energy, Office of Science
The Argonne Wakefiled Accelerator (AWA) Test Facility designed and operated a homemade LLRF system for the last 20 years. It is based on NI-PXI products that has now become obsolete. The AWA’s LLRF cannot keep up with the increasing stability demands of AWA’s upgraded facility. An overhaul of the system is strongly desired. With the support from DOE-HEP, the AWA is collaborating with Lawrence Berkeley National Laboratory (LBNL)to upgrade its LLRF system with modern instrumentation to meet the growing stability demands. An overview of AWA’s current LLRF system performance is presented together with the upgrade plan and expectations.

Poster TUPAB296 [1.943 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB296

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paper received ※ 19 May 2021 paper accepted ※ 05 July 2021 issue date ※ 26 August 2021

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TUPAB306

Status of Beam-Based Feedback Research and Development for Continuous Wave SRF Linac ELBE

controls, electron, feedback, cavity

2200

A. Maalberg, M. Kuntzsch
HZDR, Dresden, Germany
E. Petlenkov
TalTech, Tallinn, Estonia

The superconducting electron linear accelerator ELBE at Helmholtz-Zentrum Dresden-Rossendorf is a versatile light source operated in continuous wave mode. As the demand on the beam stability increases, the improvement of the beam control schemes currently installed at ELBE becomes highly relevant. This improvement can be achieved by an upgrade of the existing digital MicroTCA.4-based LLRF control scheme by beam-based feedback. By presenting both the design and implementation details of the new control scheme this contribution reports the status of the work in progress.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB306

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paper received ※ 19 May 2021 paper accepted ※ 21 June 2021 issue date ※ 30 August 2021

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WEPAB038

Commissioning of a New X-Band, Low-Noise LLRF System

klystron, cavity, MMI, linac

2683

A.V. Edwards, M. Boronat Arevalo, N. Catalán Lasheras, G. McMonagle
CERN, Meyrin, Switzerland
A.C. Dexter
Cockcroft Institute, Lancaster University, Lancaster, United Kingdom

To increase beam energy in the CLEAR facility at CERN and study the CLIC accelerating structure prototype in operating conditions, the first X-band test facility at CERN was upgraded in 2020. Both, the acquisition and software systems at X-band test stand 1 (Xbox1) were upgraded to exhibit low phase noise which is relevant to klystron based CLIC and to the use of crab cavities in the beam delivery system. The new LLRF uses down-conversion which necessitates a local oscillator which can be produced by two different methods. The first is a PLL, a commonly used technique which has been previously employed at the other X-band facilities at CERN. The second is a novel application of a single sideband up-convertor. The up-convertor system has demonstrated reduced phase noise when compared with the PLL. The commissioning of the new system began in late 2020 with the conditioning of a 50 MW Klystron. Measurements of the quality of the new LLRF will be shown. These will compare the PLL and up-convertor with particular attention on the quality of the phase measurements. Also, a preliminary study of phase shifts in the waveguide network due to temperature changes will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB038

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paper received ※ 13 May 2021 paper accepted ※ 05 July 2021 issue date ※ 20 August 2021

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WEPAB073

An Overview of the Radio-Frequency System for an Inverse Compton X-Ray Source Based on CLIC Technology

klystron, controls, network, laser

2759

T.G. Lucas, O.J. Luiten, P.H.A. Mutsaers, X.F.D. Stragier, H.A. Van Doorn, F.M. van Setten, H.J.M. van den Heuvel, M.L.M.C. van der Sluis
TUE, Eindhoven, The Netherlands

Funding: This project is financed by the "Interreg V programme Flanders-Netherlands" with financial support of the European Fund for Regional Development.
Compact inverse Compton scattering X-ray sources are gaining in popularity as the future of lab-based x-ray sources. Smart*Light is one such facility, under commissioning at Eindhoven University of Technology (TU/e), which is based on high gradient X-band technology originally designed for the Compact Linear Collider (CLIC) and its test stands located at CERN. Critical to the beam quality is the RF system which aims to deliver 10-24 MW RF pulses at repetition rates up to 1 kHz with a high amplitude and phase stability of <0.5\% and <0.65~^° allowing it to adhere to strict synchronicity conditions at the interaction point. This work overviews the design of the high power and low level RF systems for Smart*Light.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB073

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paper received ※ 19 May 2021 paper accepted ※ 23 June 2021 issue date ※ 29 August 2021

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WEPAB294

LLRF Control and Synchronization System of the ARES Facility

gun, laser, experiment, distributed

3347

S. Pfeiffer, J. Branlard, F. Burkart, M. Hoffmann, T. Lamb, F. Ludwig, H. Schlarb, S. Schulz, B. Szczepanski, M. Titberidze
DESY, Hamburg, Germany

The linear accelerator ARES (Accelerator Research Experiment at SINBAD) is a new research facility at DESY. Electron bunches with a maximum repetition rate of 50 Hz are accelerated up to 155 MeV. The facility aims for ultra-stable sub-femtosecond arrival-times and high peak-currents at the experiment, placing high demands on the reference distribution and field regulation of the S-band RF structures. In this paper, we report on the current status of the RF reference generation, facility-wide distribution, and the LLRF systems of the RF structures.

Poster WEPAB294 [2.394 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB294

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paper received ※ 18 May 2021 paper accepted ※ 05 July 2021 issue date ※ 20 August 2021

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WEPAB296

A Klystron Phase Lock Loop for RF System at TPS Booster Ring

controls, cathode, klystron, injection

3354

F.Y. Chang, M.H. Chang, S.W. Chang, L.J. Chen, F.-T. Chung, Y.D. Li, M.-C. Lin, Z.K. Liu, C.H. Lo, Ch. Wang, M.-S. Yeh, T.-C. Yu
NSRRC, Hsinchu, Taiwan

In TPS booster ring, the DLLRF is used to controlled the ramping gap voltage and also the energy saving module is applied to save power while the ring does not inject beam. But we occurred to have a problem of PI saturation due to a large phase change when the energy saving module working. The energy saving module switches the anode voltage of the klystron from high to low level to decrease the cathode current while the ring does not inject and do the opposite while the ring injects. This action causes a large phase change of the transmitter and leads the PI controller to work in the wrong direction. We add a klystron phase loop to solve this situation.

Poster WEPAB296 [0.792 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB296

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paper received ※ 19 May 2021 paper accepted ※ 01 July 2021 issue date ※ 30 August 2021

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WEPAB298

Design of an Accurate LLRF System for an Array of Two-Gap Resonators

controls, FPGA, distributed, Ethernet

3360

D.A. Liakin, S.V. Barabin, T. Kulevoy, A.Y. Orlov
ITEP, Moscow, Russia

A particle accelerator based on an array of two-gap resonators requires a control system, which is responsible for precise setup and stabilization of the phase and magnitude of the electromagnetic field in resonators. We develop a cost-effective LLRF system for the array of more than 80 resonators and three different operating frequencies. The design is based on proved solution used for 5-resonators accelerator HILAC (project NICA, Dubna). This paper gives an overview of the basic structure and some specific features of the developing LLRF control system.

Poster WEPAB298 [0.355 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB298

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paper received ※ 18 May 2021 paper accepted ※ 23 June 2021 issue date ※ 30 August 2021

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WEPAB299

Spallation Neutron Source Proton Power Upgrade Low-Level RF Control System Development

controls, operation, cavity, neutron

3363

M.T. Crofford, J.A. Ball, J.E. Breeding, M.P. Martinez, J.S. Moss, M. Musrock
ORNL, Oak Ridge, Tennessee, USA
L.R. Doolittle, C. Serrano, V.K. Vytla
LBNL, Berkeley, California, USA
J. Graham, C.K. Roberts, J.W. Sinclair, Z. Sorrell, S. Whaley
ORNL RAD, Oak Ridge, Tennessee, USA

Funding: * This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract number DE-AC05-00OR22725.
The Proton Power Upgrade (PPU) Project is approved for the Spallation Neutron Source at Oak Ridge National Laboratory and will double the proton beam power capability from 1.4 MW to 2.8 MW with 2 MW beam power available to the first target station. A second target station is planned and will utilize the remaining beam power in the future. The proton power increase will be supported with the addition of twenty-eight new superconducting cavities powered by 700 kW peak power klystrons to increase beam energy while increases to the beam current will be done with a combination of existing RF margin, and DTL HPRF upgrades. The original low-level RF control system has proven to be reliable over the past 15 years of operations, but obsolescence issues mandate a replacement system be developed for the PPU project. The replacement system is realized in a µTCA.4 platform using a combination of commercial off-the-shelf boards and custom hardware to support the requirements of PPU. This paper presents the prototype hardware, firmware, and software development activities along with preliminary testing results of the new system.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB299

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paper received ※ 18 May 2021 paper accepted ※ 21 June 2021 issue date ※ 11 August 2021

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WEPAB300

Python Based Tools for FRIB LLRF Operation and Management

controls, cavity, EPICS, linac

3367

S.R. Kunjir, D.G. Morris, S. Zhao
FRIB, East Lansing, Michigan, USA

Funding: This work is supported by the US Department of Energy Office of Science under Cooperative Agreement DE-SC0000661, the State of Michigan and Michigan State University.
Some Python based tools have been developed at the Facility for Rare Isotope Beams (FRIB) for the ease of operation and management of the low level radio frequency (LLRF) controllers. Utilizing the rich features in Python, some tasks can be easily applied to a whole segment, one type of cryomodule (CM), a specific cryomodule or individual cavities grouped by a complex custom query. The tasks include, for example, 1) testing interface connections between various sub-systems prior to an operational run; 2) setting, checking and saving/restoring parameters during and after an operational run; 3) updating LLRF controller firmware and software during maintenance. With these tools, routine manual tasks are streamlined to achieve significantly greater efficiency in terms of scalability, time, memory and network resources. Considering channel access security, beam on/off status etc., the strategy of choosing either input/output controller (IOC) or Python for the implementation of certain tasks is also discussed in the paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB300

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paper received ※ 18 May 2021 paper accepted ※ 01 July 2021 issue date ※ 24 August 2021

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WEPAB301

Design of an X-Band LLRF System for TEX Test Facility at LNF-INFN

cavity, klystron, insertion, GUI

3371

L. Piersanti, D. Alesini, M. Bellaveglia, S. Bini, B. Buonomo, F. Cardelli, C. Di Giulio, M. Diomede, A. Falone, G. Franzini, A. Gallo, A. Liedl, S. Pioli, S. Quaglia, L. Sabbatini, M. Scampati, G. Scarselletta, A. Stella
INFN/LNF, Frascati, Italy

Funding: Latino is a project co-funded by Regione Lazio within POR-FESR 2014-2020 program
In the framework of LATINO project (Laboratory in Advanced Technologies for INnOvation) funded by Lazio regional government, a TEst stand for X-band (TEX) is being commissioned at Frascati National Laboratories (LNF) of INFN. TEX is born as a collaboration with CERN, aimed at carrying out high power tests of X-band accelerating structure prototypes and waveguide components, and it is of paramount importance in view of the construction of EuPRAXIA@SPARC_LAB facility at LNF. In order to generate, manipulate and measure the RF pulses needed to feed the RF power unit (solid state ScandiNova K400 modulator, CPI 50 MW 50 Hz klystron) an X-band low level RF system has been developed, making use of a commercial S-band (2.856 GHz) Libera digital LLRF (manufactured by Instrumentation Technologies) with a newly designed up/down conversion stage and a reference generation/distribution system, which is able to produce coherent reference frequencies for the American S-band (2.856 GHz) and European X-band (11.994 GHz). In this paper the main features of such systems will be reviewed together with preliminary laboratory measurement results.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB301

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paper received ※ 19 May 2021 paper accepted ※ 12 July 2021 issue date ※ 27 August 2021

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WEPAB314

TEX - an X-Band Test Facility at INFN-LNF

controls, klystron, GUI, framework

3406

S. Pioli, D. Alesini, F.A. Anelli, M. Bellaveglia, S. Bini, B. Buonomo, S. Cantarella, F. Cardelli, G. Catuscelli, R. Ceccarelli, A. Cecchinelli, F. Chiarelli, P. Ciuffetti, R. Clementi, C. Di Giulio, E. Di Pasquale, G. Di Raddo, M. Diomede, A. Esposito, L. Faillace, A. Falone, G. Franzini, A. Gallo, S. Incremona, A. Liedl, D. Pellegrini, G. Piermarini, L. Piersanti, S. Quaglia, R. Ricci, L. Sabbatini, M. Scampati, G. Scarselletta, A. Stella, R. Zarlenga
INFN/LNF, Frascati, Italy

Funding: The LATINO project is co-funded by the Regione Lazio within POR-FESR 2014-2020 European activities (public call "Open Research Infrastructures").
We report the status of the development of an High Power RF Laboratory in X-Band called TEX (TEst-stand for X-Band). TEX is part of the LATINO (Laboratory in Advanced Technologies for INnOvation) initiative that is ongoing at the Frascati National Laboratories (LNF) of the Italian Institute for Nuclear Physics (INFN) that covers many different areas focused on particle accelerator technologies. TEX is a RF test facility based on solid-state K400 modulator from ScandiNova with a 50MW class X-band (11.996 GHz) klystron tube model vkx 8311a operating at 50 Hz. This RF source will operate as resource for test and research programs such as the RF breakdown on RF waveguide components as well as high power testing of accelerating structures for future high gradient linear accelerator such as EuPRAXIA and CLIC. The high power testing will be performed in a dedicated brand-new bunker that has been recently built. RF system, vacuum controls and safety equipments are currently being installed. The first accelerating structure testing is scheduled by beginning 2022. In this document design and tests for all the sub-systems of the facility will be presented and discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB314

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paper received ※ 19 May 2021 paper accepted ※ 28 July 2021 issue date ※ 19 August 2021

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THPAB268

Hierarchical Intelligent Real-Time Optimal Control for LLRF Using Time Series Machine Learning Methods and Transfer Learning

controls, cavity, network, simulation

4329

R. Pirayesh, S. Biedron
UNM-ME, Albuquerque, New Mexico, USA
S. Biedron, J.A. Diaz Cruz, M. Martínez-Ramón
UNM-ECE, Albuquerque, USA
J.A. Diaz Cruz
SLAC, Menlo Park, California, USA

Funding: supported by DOE, Office of Science, Office of High Energy Physics, under award number DE-SC0019468, Contract No. DE-AC02-76SF00515, also supported Office of Basic Energy Sciences. ALCF, Element Aero
Machine learning (ML) has recently been applied to Low-level RF (LLRF) control systems to keep the voltage and phase of Superconducting Radiofrequency (SRF) cavities stable within 0.01 degree in phase and 0.01% amplitude as constraints. Model predictive control (MPC) uses an optimization algorithm offline to minimize a cost function with constraints on the states and control input. The surrogate model optimally controls the cavities online. Time series deep ML structures including recurrent neural network (RNN) and long short-term memory (LSTM) can model the control input of MPC and dynamics of LLRF as a surrogate model. When the predicted states diverge from the measured states more than a threshold at each time step, the states’ measurements from the cavity fine-tune the surrogate model with transfer learning. MPC does the optimization offline again with the updated surrogate model, and, next, transfer learning fine-tunes the surrogate model with the new data from the optimal control inputs. The surrogate model provides us with a computationally faster and accurate modeling of MPC and LLRF, which in turn results in a more stable control system.
Machine learning, Surrogate model, control, LLRF, MPC, Transfer learning

Poster THPAB268 [0.377 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB268

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paper received ※ 16 May 2021 paper accepted ※ 13 July 2021 issue date ※ 18 August 2021

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THPAB271

JLAB LLRF 3.0 Development and Tests

cavity, controls, FPGA, cryomodule

4340

T.E. Plawski, R. Bachimanchi, S. Higgins, C. Hovater, J. Latshaw, C.I. Mounts, D.J. Seidman, J. Yan
JLab, Newport News, Virginia, USA

The Jefferson Lab LLRF 3.0 system is being developed to replace legacy LLRF systems in the CEBAF accelerator. The new design builds upon 25 years of design and operational RF control experience, and our recent collaboration in the design of the LCLSII LLRF system. The new cavity control algorithm is a fully functional phase and amplitude locked Self Exciting Loop (SEL). This paper discusses the progress of the LLRF 3.0 hardware design, FPGA firmware development, User Datagram Protocol (UDP) operation, and recent LLRF 3.0 system tests on the CEBAF Booster cryomodule in the Upgrade Injector Test Facility (UITF).

Poster THPAB271 [1.940 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB271

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paper received ※ 14 May 2021 paper accepted ※ 06 July 2021 issue date ※ 20 August 2021

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THPAB272

Validation of Two Re-Buncher Cavities under High Beam Loading for LIPAc

cavity, beam-loading, operation, MEBT

4343

D. Gavela, I. Podadera, F. Toral
CIEMAT, Madrid, Spain
I. Moya
Fusion for Energy, Garching, Germany
F. Scantamburlo
IFMIF/EVEDA, Rokkasho, Japan

Funding: Work partially supported by the Spanish Ministry of Science and Innovation under project AIC-A-2011-0654 and FIS2013-40860-R
Two re-buncher cavities were installed at the Medium Energy Beam Transport line of the LIPAc accelerator, presently being commissioned at Rokkasho (Japan). They are IH-type cavities with five gaps providing an effective voltage of 350 kV at 175 MHz for a nominal operation of 125 mA CW deuterons at 5 MeV. After full conditioning and beamline integration in Europe, the cavities were installed in the accelerator with special care given to the alignment with respect to the rest of the components. The RF line, cooling circuits, and instrumentation were also mounted. The cavities were operated with an FPGA-based LLRF system. A re-conditioning of the cavities was performed in the first place, followed by tests with a pulsed beam with increasing currents. A maximum pulsed beam current of 100 mA was reached while operating the buncher cavities, under which they reached voltages up to 340 kV and 260 kV respectively. As expected, the beam loading was significant, leading to a series of difficulties and required strategies for a good operation that are discussed in this paper. The effect on the beam dynamics, measured by beam position monitors downstream of the bunchers is also discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB272

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paper received ※ 19 May 2021 paper accepted ※ 02 September 2021 issue date ※ 18 August 2021

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THPAB287

Providing Computing Power for High Level Controllers in MicroTCA-based LLRF Systems via PCI Express Extension

controls, software, Ethernet, cavity

4363

P. Nonn, A. Eichler, S. Pfeiffer, H. Schlarb, J.H.K. Timm
DESY, Hamburg, Germany

It is possible to connect the PCIe bus of a high performance computer to a MicroTCA crate. This allows the software on the computer to communicate with the modules in the crate, as if they were peripherals of the computer. This article will discuss the use of this feature in respect to accelerator control with a focus on High Level Controllers.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB287

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paper received ※ 19 May 2021 paper accepted ※ 26 July 2021 issue date ※ 16 August 2021

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THPAB338

Performance of the LLRF System for the Fermilab PIP-II Injector Test

cavity, controls, resonance, cryomodule

4450

P. Varghese, B.E. Chase, P.M. Hanlet, H. Maniar, D.J. Nicklaus
Fermilab, Batavia, Illinois, USA
L.R. Doolittle, C. Serrano
LBNL, Berkeley, California, USA

PIP-II IT is a test facility for the PIP-II project where the injector, warm front-end, and the first two superconducting cryomodules are being tested. The 8-cavity half-wave-resonator (HWR) cryomodule operating at 162.5 MHz is followed by the 8-cavity single-spoke resonator(SSR1) cryomodule operating at 325 MHz. The LLRF systems for both cryomodules are based on a common SOC FPGA-based hardware platform. The resonance control systems for the two cryomodules are quite different, the first being a pneumatic system based on helium pressure and the latter a piezo/stepper motor type control. The data acquisition and control system can support both CW and Pulsed mode operations. Beam loading compensation is available which can be used for both manual/automatic control in the LLRF system. The user interfaces include EPICS, Labview, and ACNET. Testing of the RF system has progressed to the point of being ready for a 2 mA beam to be accelerated to 25 MeV. The design and performance of the field control and resonance control system operation with beam are presented in this paper.

Poster THPAB338 [5.482 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB338

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paper received ※ 13 May 2021 paper accepted ※ 27 July 2021 issue date ※ 24 August 2021

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