IPAC2022 - List of Keywords (LLRF)

Paper	Title	Other Keywords	Page
TUPOST008	Digital Low-Level RF System for the CERN Linac3 Accelerator	cavity, linac, controls, operation	853
	D. Valuch, R. Alemany-Fernández, Y. Brischetto, S.J. Faeroe, G. Piccinini, M.E. Soderen CERN, Meyrin, Switzerland
	A major consolidation of the aging RF system of the CERN Linac3, the ion source for the whole CERN accelerator chain, started during the Long Shutdown II. The main changes were an upgrade of the analogue Low-Level RF system (LLRF) and replacement of the 350 kW tube amplifiers by a solid-state equivalent. The state-of-the-art digital LLRF system enabled new sophisticated features in field manipulations, significantly increased the operational flexibility and improved operational reliability and availability. The paper presents the new architecture, a low noise master clock generator, digital signal processing with direct sampling of the RF signals, pulse parameter measurement or cavity resonance control.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST008
About •	Received ※ 27 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 15 June 2022
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TUPOST012	Sirius Storage Ring RF Plant Identification	controls, cavity, storage-ring, low-level-rf	865
	D. Daminelli, F.K.G. Hoshino, A.P.B. Lima LNLS, Campinas, Brazil M. Souza UNICAMP, Campinas, São Paulo, Brazil
	The design configuration of the Sirius Light Source RF System is based on two superconducting RF cavities and eight 65 kW solid-state amplifiers operating at 500 MHz. The current configuration, based on a 7-cell normal conducting PETRA cavity, was initially planned for commissioning and initial tests of the beamlines. A digital low-level RF (DLLRF) system based on ALBA topology has been operating since 2019. Sirius is currently operating in decay mode for beamline tests with 100 mA stored current. During the commissioning, several studies were carried out to increase the stored current with stable beam. This paper presents a study using parametric data-driven models to identify the Storage Ring RF plant, aiming to optimize the DLLRF PI control parameters.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST012
About •	Received ※ 08 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 01 July 2022
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TUPOST014	Sirius Storage Ring RF System Status Update	cavity, operation, storage-ring, cryogenics	872
	A.P.B. Lima, D. Daminelli, M. Hoffmann Wallner, F.K.G. Hoshino LNLS, Campinas, Brazil I. Carvalho de Almeida, R.H.A. Farias CNPEM, Campinas, SP, Brazil
	Sirius’s nominal operation phase consists of two 500 MHz CESR-B type superconducting cavities, each being driven by four 65 kW solid-state amplifiers, and a passive superconducting third harmonic cavity. Currently a normal conducting 7-cell PETRA cavity is being used along with two 65 kW RF amplifiers and was recently able to achieve 100 mA stored current. The performance of the storage ring RF system and the updated installation plans update are presented and discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST014
About •	Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 23 June 2022
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TUPOST015	Commissioning and First Results of an X-Band LLRF System for TEX Test Facility at LNF-INFN	MMI, klystron, GUI, network	876
	L. Piersanti, D. Alesini, M. Bellaveglia, S. Bini, B. Buonomo, F. Cardelli, C. Di Giulio, E. Di Pasquale, M. Diomede, L. Faillace, A. Falone, G. Franzini, A. Gallo, G. Giannetti, A. Liedl, D. Moriggi, S. Pioli, S. Quaglia, L. Sabbatini, M. Scampati, G. Scarselletta, A. Stella, S. Tocci, L. Zelinotti LNF-INFN, 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, the commissioning of the TEst stand for X-band (TEX) facility has started in 2021 at Frascati National Laboratories of INFN. Born as a collaboration with CERN to test high gradient accelerating structures, during 2022 TEX aims at feeding the first EuPRAXIA@SPARC_LAB X-band structure prototype. During 2021 the commissioning has been successfully carried out up to 48 MW. The power unit is driven by an X-band low level RF system, that employs a commercial S-band (2.856 GHz) Libera digital LLRF (manufactured by Instrumentation Technologies), with an up/down conversion stage and a reference generation and distribution system able to produce coherent frequencies for the American S-band and European X-band (11.994 GHz), both designed and realized at LNF. The performance of the system, with a particular focus on amplitude and phase resolution, together with klystron and driver amplifier jitter measurements, will be reviewed in this paper. Moreover, considerations on its suitability and main limitations in view of EuPRAXIA@SPARC_LAB project will be discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST015
About •	Received ※ 20 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 28 June 2022
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TUPOST017	PEG Contribution to the LLRF System for Superconducting Elliptical Cavities of ESS Accelerator Linac	cavity, controls, hardware, electron	884
	W. Cichalewski, G.W. Jabłoński, K. Klys, D.R. Makowski, A. Mielczarek, A. Napieralski, P. Perek, P. Plewinski TUL-DMCS, Łódź, Poland A. Abramowicz, K. Czuba, M.G. Grzegrzółka, K. Oliwa, I. Rutkowski, W. Wierba Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland P.R. Bartoszek, K. Chmielewski, K. Kostrzewa, T. Kowalski, D. Rybka, M. Sitek, J. Szewiński, Z. Wojciechowski NCBJ, Świerk/Otwock, Poland M. Jensen ESS, Lund, Sweden A.J. Johansson, A.M. Svensson Lund University, Lund, Sweden
	The LLRF (Low-Level Radio Frequency) system optimizes energy transfer from the superconducting resonator to the accelerating beam. At ESS, one LLRF system regulates a single cavity. This digital system’s HW platform is the MTCA.4 standard. The system has been co-designed by ESS, Lund University, and the PEG (Polish Electronic Group) consortium. The PEG is also responsible for the system components design, evaluation, and production (like Local Oscillator Rear transition module, piezo tuner driver RTM, RTM carrier board, and others). The PEG delivers a HW/SW cavity simulator, an LLRF system test-stand, and provides necessary integration and installation services required for complete system preparation for the linac commissioning and operation phase. The paper summarizes the PEG work on the development and preparation of the LLRF systems for the ESS elliptical structures. The efforts concerning hardware and software components prototyping and evaluation are discussed. Moreover, we present the current status of the project, including components mass production, integration, and installation work.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST017
About •	Received ※ 08 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 19 June 2022 — Issue date ※ 20 June 2022
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TUPOST018	Long Pulse Operation of the E-XFEL Cryomodule	cavity, operation, controls, FEL	888
	W. Cichalewski TUL-DMCS, Łódź, Poland J.K. Sekutowicz DESY, Hamburg, Germany
	The CW operation becomes more attractive mode of beam and RF operation, even for infrastructures initially developed as pulsed experiments. Compared to the short (single ms) pulse the CW or long pulse (LP) operation allows for a more relaxed bunch scheme and enables higher bunch quantities during the experiment run. The Long Pulse operation scenario is one of the possible EXFEL modes of work in the future. LLRF systems that work in CW (and LP) are in operation worldwide. Most of them are dedicated to single cavity control. The XFEL dedicated system is capable of multicavity cryomodules vector-sum operation. In such a configuration switching from short-pulse operation into long-pulse with the existing limitations from the allowed cryo heat load level, average input power per coupler (and others) can be extremely challenging. For this setup the support from the dynamic resonance control system is essential. This paper summarizes efforts towards the successful vector-sum operation of the X-FEL type cryomodule in the LP operation mode. Modifications to the original LLRF setup together with challenges of narrow bandwidth operation in moderate and high gradients are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST018
About •	Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 21 June 2022 — Issue date ※ 23 June 2022
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TUPOST021	The CERN SPS Low Level RF: The Beam-Control	controls, cavity, proton, hardware	895
	A. Spierer, P. Baudrenghien, J. Egli, G. Hagmann, P. Kuzmanović, I. Stachon, M. Sumiński, T. Włostowski CERN, Meyrin, Switzerland
	The Super Proton Synchrotron (SPS) Low Level RF (LLRF) has been completely upgraded during the CERN long shutdown (LS2, 2019-2020). The old NIM and VME based, mainly analog system has been replaced with modern digital electronics implemented on a MicroTCA platform. The architecture has also been reviewed, with synchronization between RF stations now resting on the White Rabbit (WR) deterministic link. This paper is the first of a series of three on the SPS LLRF upgrade. It covers the Beam-Control part, that is responsible for the generation of the RF reference frequency from a measurement of the magnetic field, and beam phase and radial position. It broadcasts this frequency word to the RF stations, via a White Rabbit network. The paper presents the architecture, gives details on the signal processing, firmware, hardware and software. Finally, results from the first year of beam commissioning are presented (2021).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST021
About •	Received ※ 07 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 05 July 2022
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TUPOST022	The CERN SPS Low Level RF: Lead Ions Acceleration	cavity, acceleration, injection, controls	899
	P. Baudrenghien, J. Egli, G. Hagmann, A. Spierer, T. Włostowski CERN, Meyrin, Switzerland
	This paper is the third of a series of three on the Super Proton Synchrotron (SPS) Low Level RF (LLRF). Its focus is the upgrade concerned with the acceleration of Lead ions for injection into the LHC. Lead ions are far from relativistic at injection into the SPS. Therefore, the classic acceleration scheme at constant harmonic number (h=4620) does not work as the RF frequency swing does not fit within the cavity bandwidth. Fixed Frequency Acceleration (FFA) is therefore used. The upgraded LLRF uses a completely new implementation of the FFA, based on a Numerically Controlled Oscillator (NCO) implemented as an FPGA IP in the Controller of each cavity. In addition, the 2022 scheme for LHC ions filling calls for slip stacking of two families of bunches, 100 ns spacing, to generate a 50 ns spacing after interleaving. The paper presents the key components for FFA and ions slip stacking as implemented in the new system, together with successful first tests performed in Autumn 2021.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST022
About •	Received ※ 08 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 24 June 2022
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TUPOST023	The CERN SPS Low level RF: The Cavity-Controller	cavity, controls, feedback, proton	903
	G. Hagmann, P. Baudrenghien, J. Egli, A. Spierer, M. Sumiński, T. Włostowski CERN, Meyrin, Switzerland
	This paper is the second of a series of three on the Super Proton Synchrotron (SPS) Low Level RF (LLRF) upgrade. It covers the 200MHz Cavity-Controller part, that is responsible for the regulation of the accelerating field in a single SPS cavity. When the SPS is used as Large Hadron Collider (LHC) proton injector, the issue is the high beam loading that must be compensated to guarantee longitudinal stability and constant parameters over the bunch train. That calls for strong One-Turn Delay Feedback (OTFB) and Feed-Forward (FFWD). The SPS is also accelerating Lead ions (Pb). There the issue is Frequency-Modulation (FM) and Amplitude-Modulation (AM) over the turn (so called Fixed Frequency Acceleration - FFA) plus RF gymnastics for the new ions slip-stacking. The paper reviews the functional requirements, presents the block diagram, then gives details on the signal processing, firmware and hardware. Finally results from the first year of beam commissioning are presented (2021).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST023
About •	Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 19 June 2022
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TUPOST024	A New Beam Loading Compensation and Blowup Control System Using Multi-Harmonic Digital Feedback Loops in the CERN Proton Synchrotron Booster	cavity, controls, feedback, operation	907
	D. Barrientos, S.C.P. Albright, M.E. Angoletta, A. Findlay, M. Jaussi, J.C. Molendijk CERN, Meyrin, Switzerland
	As part of the LHC Injectors Upgrade, the CERN Proton Synchrotron Booster (PSB) has been upgraded with new wide-band Finemet cavities and a renovated Low-Level Radio Frequency system with digital cavity controllers implemented in FPGAs. Each controller synchronously receives the computed revolution frequency, used to generate 16 harmonic references. These are then used to IQ demodulate the voltage gap and modulate the 16 RF drive signals each controlled through a Cartesian feedback loop (with individual voltage and phase control). The sum of these digital drive signals is then sent to the cavities. In addition, a configurable blow-up system providing a sinusoidal or custom noise pattern can be used to excite the beam. An embedded network analyzer allows studying the stability of the feedback loops of the individual harmonics. The 16 harmonic feedback loops have been successfully operated during 2021, allowing to reduce the beam induced voltage and control the longitudinal emittance of the beam. In this paper we present the system architecture as well as the performance of the complete cavity controller during operation in the PSB.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST024
About •	Received ※ 23 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 28 June 2022
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TUPOST025	Beam Commissioning of the New Digital Low-Level RF System for CERN’s AD	MMI, operation, timing, proton	911
	M.E. Angoletta, S.C.P. Albright, D. Barrientos, A. Findlay, M. Jaussi, A. Rey, M. Sumiński CERN, Meyrin, Switzerland
	CERN’s Antiproton Decelerator (AD) has been re-furbished to provide reliable operation for the Extra Low ENergy Antiproton ring (ELENA). In particular, AD was equipped with a new digital Low-Level RF (LLRF) system that was successfully commissioned during the summer 2021. The new AD LLRF system has routinely captured and decelerated more than 3·10⁷ antiprotons from 3.5 GeV/c to 100 MeV/c in successive steps, referred to as RF segments, interleaved by cooling periods. The LLRF system implements the frequency program from Btrain data received over optical fiber. Beam phase/radial and cavity amplitude/phase feedback loops are operated during each RF segment. An extraction synchronization loop is triggered on the extraction RF segment to transfer a single bunch of antiprotons to ELENA. Extensive diagnostics features are available and operational modes such as bunched beam cooling and bunch rotation have been successfully deployed. The LLRF parameters can be different for each RF segment and are controlled by a dedicated application. This paper gives an overview of the AD LLRF beam commissioning results obtained and challenges overcome. Hints on future steps are also provided.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST025
About •	Received ※ 25 May 2022 — Accepted ※ 15 June 2022 — Issue date ※ 17 June 2022
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TUPOST027	Machine Learning-Based Tuning of Control Parameters for LLRF System of Superconducting Cavities	cavity, controls, simulation, SRF	915
	J.A. Diaz Cruz, S. Biedron 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
	The multiple systems involved in the operation of particle accelerators use diverse control systems to reach the desired operating point for the machine. Each system needs to tune several control parameters to achieve the required performance. Traditional Low-Level RF (LLRF) systems are implemented as proportional-integral feedback loops, whose gains need to be optimized. In this paper, we explore Machine Learning (ML) as a tool to improve a traditional LLRF controller by tuning its gains using a Neural Network (NN). We present the data production scheme and a control parameter optimization using a NN. The NN training is performed using the THETA supercomputer.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST027
About •	Received ※ 14 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 20 June 2022
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TUPOPT061	Status and Commissioning of the First X-Band RF Source of the TEX Facility	klystron, GUI, MMI, controls	1148
	F. Cardelli, D. Alesini, M. Bellaveglia, S. Bini, M. Ceccarelli, C. Di Giulio, A. Falone, G. Franzini, A. Gallo, L. Piersanti, L. Sabbatini INFN/LNF, Frascati, Italy B. Buonomo, G. Catuscelli, R. Ceccarelli, A. Cecchinelli, R. Clementi, E. Di Pasquale, A. Liedl, D. Moriggi, G. Piermarini, S. Pioli, S. Quaglia, L.A. Rossi, M. Scampati, G. Scarselletta, S. Strabioli, S. Tocci, R. Zarlenga LNF-INFN, Frascati, Italy
	In 2021 started the commissioning of the TEX (Test stand for X-band) facility at the Frascati National laboratories of INFN. This facility has been founded in the framework of the LATINO (Laboratory in Advanced Technologies for INnOvation) project. The current facility layout includes an high power X-band (11.994 GHz) RF source, realized in collaboration with CERN, which will be used for validation and development of the X-band RF high gradient technology in view of the EuPRAXIA@SPARC_LAB project. The RF source is based on a CPI VKX8311 Klystron and a solid state ScandiNova k400 modulator to generate a maximum RF output power of 50 MW at 50 Hz, that will be mainly used for accelerating structure conditioning and waveguide components testing. In this paper the layout, the installation, commissioning and stability measurements of this source are described in detail. The test stand will be soon operative and ready to test the first X-band accelerating structure prototype.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT061
About •	Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 10 July 2022
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TUPOPT066	KEK LUCX Facility Laser-to-RF&RF-to-RF Stability Study and Optimization	laser, feedback, gun, timing	1167
	K. Popov Sokendai, Ibaraki, Japan A. Aryshev, N. Terunuma, J. Urakawa KEK, Ibaraki, Japan
	KEK LUCX facility* is a linear accelerator devoted to the beam instrumentation R&Ds for present and future accelerator systems and colliders including ILC. According to the ILC TDR, it is necessary to achieve RF-gun Laser-to-RF&RF-to-RF phase stability of 0.35°(RMS) and amplitude stability of 0.07%(RMS) with implementation of the Digital LLRF feedback based on commercially available FPGA board and digital trigger system. As the first step to achieve ILC stability level at KEK-LUCX facility, present Laser-to-RF&RF-to-RF phase and amplitude jitters were measured using time- and frequency-domain techniques. After that, jitter influence on beam parameters after RF-gun and main solenoid magnet was simulated with ASTRA tracking code* and results were cross-checked during LUCX facility beam operation. Finally, stable digital trigger system and digital LLRF feedback based on SINAP EVG&EVR and RedPitaya SIGNALlab-250 modules were implemented. This report demonstrates the results of Laser-to-RF&RF-to-RF phase and amplitude jitter measurements cross-checked with ASTRA simulation and real beam parameters measurements before and after LUCX facility stabilization. References A. Aryshev et al., Appl. Phys. Lett. 111, 033508 (2017). International Linear Collider Reference Design Report, ILC-REPORT-2007-001, 2007. **https://www.desy.de/~mpyflo/
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT066
About •	Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 03 July 2022
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TUPOTK026	ESS Elliptical Cryomodules Tests at Lund Test Stand	cavity, cryomodule, operation, vacuum	1261
	C.G. Maiano, E. Asensi Conejero, N. Elias, P. Goudket, W. Hees, P. Pierini, L. Sagliano, F. Schlander, M.Y. Wang ESS, Lund, Sweden D. Bocian, W. Gaj, P. Halczynski, M. Sienkiewicz, F.D. Skalka, J. Swierblewski, K.M. Wartak, M. Wartak IFJ-PAN, Kraków, Poland
	We present an overview and description of the elliptical cryomodules test activities at Lund Test Stand 2. During 2021 the test facility was commissioned with one prototype, and four series medium beta modules have now been successfully tested at ESS in Lund. This activity allowed the joint ESS and IFJ PAN team to develop all the procedures and the necessary automated tools for the different phases of the site acceptance test campaign (e.g. incoming inspections, coupler conditioning, cooldown strategies, tuning to resonance and electromagnetic/cryogenic performance verification). During the initial test period techniques for diagnostics of limiting mechanisms have been developed and improved up to a consolidated and mature state for the rest of the test campaign. Tests results and the initial statistics is presented and commented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK026
About •	Received ※ 07 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 16 June 2022
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TUPOMS049	Digital LLRF for the Canadian Light Source	cavity, booster, controls, operation	1538
	P. Solans, F. Pérez, A. Salom ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain D.R. Beauregard, C.J. Boyle, J.M. Patel, H. Shaker, J. Stampe CLS, Saskatoon, Saskatchewan, Canada
	The Canadian Light Source, at the University of Saskatchewan, is a 3rd generation synchrotron light source located in the city of Saskatoon, Canada. The facility comprises a 250 MeV LINAC, a full energy booster and a 2.9 GeV storage ring. The radiofrequency system in the booster consist of two 5-cell cavities feed with a single SSPA. The analogue LLRF for the booster has been recently replaced by a digital LLRF based in the ALBA design with a Picodigitizer, a stand-alone commercial solution provided by Nutaq. Also, the firmware of the new DLLRF is configurable to allow operation with a superconducting cavity feed with one amplifier, thus providing the possibility to replace the CLS SR LLRF as well. The main hardware components, the basic firmware functionalities and the commissioning measurements of the new DLLRF for the CLS booster will be presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS049
About •	Received ※ 08 June 2022 — Accepted ※ 11 June 2022 — Issue date ※ 30 June 2022
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WEOYSP3	Operation Experience with SESAME RF System	cavity, operation, injection, controls	1636
	D.S. Foudeh, A.I. Kurdi, N.Kh. Sawai SESAME, Allan, Jordan
	SESAME RF system has been in operation since 2017 where the operational electron beam current has been increased from 100mA to 300mA since then. The higher operational beam current together with the need to have longer beam lifetime to reduce number of injections per day required higher forward RF power, On the other hand; more attention needed to be paid to monitor and tackle the current driven High Order Modes and to respect the limitation on the forward RF power coming from the solid state amplifiers. In this paper we describe the RF system and report on the challenges we faced in addition to the operational experience we had with the RF system and solid state amplifiers.
	Slides WEOYSP3 [4.207 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEOYSP3
About •	Received ※ 03 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 07 July 2022
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WEPOPT055	Linac3, LEIR and PS Performance with Ions in 2021 and Prospects for 2022	linac, operation, cavity, injection	1983
	N. Biancacci, S.C.P. Albright, R. Alemany-Fernández, D. Alves, M.E. Angoletta, D. Barrientos, H. Bartosik, G. Bellodi, S.B. Bertolo, D. Bodart, M. Bozzolan, H. Damerau, F.D.L. Di Lorenzo, A. Frassier, D. Gamba, A. Huschauer, S. Jensen, V. Kain, T. Koevener, G. Kotzian, D. Küchler, A. Lasheen, G. Le Godec, T.E. Levens, N. Madysa, E. Mahner, O. Marqversen, C.M. Mastrostefano, P.D. Meruga, C. Mutin, M. O’Neil, G. Piccinini, R. Scrivens, P.S. Solvang, D. Valuch, F.M. Velotti, R. Wegner, C. Wetton, M. Zampetakis CERN, Meyrin, Switzerland
	CERN accelerators underwent a period of long shutdown from the end of 2018 to 2020. During this time frame, significant hardware and software upgrades have been put in place to increase the performance of both proton and ion accelerator chains in the High Luminosity LHC era. In the context of the CERN lead ion chain, 2021 has been mainly devoted to restore the injectors’ performance and to successfully prove the slip-stacking technique in SPS. In this paper we summarise the key milestones of the ion beam commissioning and the achieved beam performance for the Linac 3 (including the source), LEIR and PS accelerators, together with an outlook on 2022 operation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT055
About •	Received ※ 03 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 17 June 2022
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WEPOTK012	Commissioning the New LLRF System of the CERN PS Booster	cavity, operation, injection, MMI	2060
	S.C.P. Albright, M.E. Angoletta, D. Barrientos, A. Findlay, M. Jaussi, J.C. Molendijk CERN, Meyrin, Switzerland
	The PS Booster (PSB) is the first synchrotron in the injection chain for protons. The beams produced for the LHC and various fixed target experiments cover a very large parameter space. Over the Long Shutdown 2 (LS2), the PSB was heavily upgraded as part of the LHC Injectors Upgrade (LIU) project. The low-level RF systems now drive the new Finemet-loaded cavities, control RF synchronisation for the new injection mechanism, and cope with the increased injection and extraction energies. The Finemet cavities provide exceptional flexibility, allowing an arbitrary distribution of voltage at different revolution frequency harmonics, but at the cost of significant broadband impedance. The new injection mechanism allows bunch-to-bucket multi-turn injection, which significantly reduces the amount of beam loss at the start of the cycle. The longitudinal beam production schema for each beam-type was developed based on simulations during LS2, and then adapted during the setting-up phase to suit the final operational configuration. This paper discusses the commissioning of the new LLRF, and the consequences of the LIU upgrades on the production of various beams.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK012
About •	Received ※ 25 May 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 07 July 2022
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THPOST007	Slow-Control Loop to Stabilize the RF Power of the FLUTE Electron Gun	controls, cavity, electron, gun	2449
	M.-D. Noll, A. Böhm, J. Jelonek, I. Križnar, O. Manzhura, A.-S. Müller, R. Ruprecht, M. Schuh, N.J. Smale KIT, Karlsruhe, Germany
	The linear accelerator FLUTE (Far Infrared Linac and Test Experiment) at KIT serves as a test facility for accelerator research and for the generation of ultra-intense coherent THz radiation. To achieve stable THz photon energy and optimal beam trajectory, the energy of the electrons emitted from the RF photo-injector must be stable. The accelerating voltage of the RF cavity has been shown to be a significant influencing factor. Here, we report on the development of a slow closed-loop feedback system to stabilize the RF power and thus the accelerating voltage in the RF photo-injector cavity. With this closed-loop feedback system the relative standard deviation of the RF power in the cavity can be improved by 8.5 %.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST007
About •	Received ※ 08 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 24 June 2022
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THPOST016	Development Progress of HEPS LINAC	linac, MMI, emittance, simulation	2472
	C. Meng, N. Gan, D.Y. He, X. He, Y. Jiao, J.Y. Li, J.D. Liu, Y.M. Peng, H. Shi, G. Shu, S.C. Wang, O. Xiao, J.R. Zhang, Z.D. Zhang, Z.S. Zhou IHEP, Beijing, People’s Republic of China X.H. Lu, X.J. Nie IHEP CSNS, Guangdong Province, People’s Republic of China
	The High Energy Photon Source (HEPS) is a synchrotron radiation source of ultrahigh brightness and under construction in China. Its accelerator system is comprised of a 6-GeV storage ring, a full energy booster, a 500-MeV Linac and three transfer lines. The Linac is a S-band normal conducting electron linear accelerator with available bunch charge up to 10 nC. The Linac installation has been finished at the end of May this year. The system joint debugging and device conditioning of the accelerating units, the power supplies, et al., are in progress. The beam commissioning will start in September 2022. This paper presents the status of the HEPS Linac and detailed introduction of the beam commissioning simulations and preparations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST016
About •	Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 09 July 2022
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Paper

Title

Other Keywords

Page

TUPOST008

Digital Low-Level RF System for the CERN Linac3 Accelerator

cavity, linac, controls, operation

853

D. Valuch, R. Alemany-Fernández, Y. Brischetto, S.J. Faeroe, G. Piccinini, M.E. Soderen
CERN, Meyrin, Switzerland

A major consolidation of the aging RF system of the CERN Linac3, the ion source for the whole CERN accelerator chain, started during the Long Shutdown II. The main changes were an upgrade of the analogue Low-Level RF system (LLRF) and replacement of the 350 kW tube amplifiers by a solid-state equivalent. The state-of-the-art digital LLRF system enabled new sophisticated features in field manipulations, significantly increased the operational flexibility and improved operational reliability and availability. The paper presents the new architecture, a low noise master clock generator, digital signal processing with direct sampling of the RF signals, pulse parameter measurement or cavity resonance control.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST008

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Received ※ 27 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 15 June 2022

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TUPOST012

Sirius Storage Ring RF Plant Identification

controls, cavity, storage-ring, low-level-rf

865

D. Daminelli, F.K.G. Hoshino, A.P.B. Lima
LNLS, Campinas, Brazil
M. Souza
UNICAMP, Campinas, São Paulo, Brazil

The design configuration of the Sirius Light Source RF System is based on two superconducting RF cavities and eight 65 kW solid-state amplifiers operating at 500 MHz. The current configuration, based on a 7-cell normal conducting PETRA cavity, was initially planned for commissioning and initial tests of the beamlines. A digital low-level RF (DLLRF) system based on ALBA topology has been operating since 2019. Sirius is currently operating in decay mode for beamline tests with 100 mA stored current. During the commissioning, several studies were carried out to increase the stored current with stable beam. This paper presents a study using parametric data-driven models to identify the Storage Ring RF plant, aiming to optimize the DLLRF PI control parameters.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST012

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Received ※ 08 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 01 July 2022

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TUPOST014

Sirius Storage Ring RF System Status Update

cavity, operation, storage-ring, cryogenics

872

A.P.B. Lima, D. Daminelli, M. Hoffmann Wallner, F.K.G. Hoshino
LNLS, Campinas, Brazil
I. Carvalho de Almeida, R.H.A. Farias
CNPEM, Campinas, SP, Brazil

Sirius’s nominal operation phase consists of two 500 MHz CESR-B type superconducting cavities, each being driven by four 65 kW solid-state amplifiers, and a passive superconducting third harmonic cavity. Currently a normal conducting 7-cell PETRA cavity is being used along with two 65 kW RF amplifiers and was recently able to achieve 100 mA stored current. The performance of the storage ring RF system and the updated installation plans update are presented and discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST014

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Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 23 June 2022

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TUPOST015

Commissioning and First Results of an X-Band LLRF System for TEX Test Facility at LNF-INFN

MMI, klystron, GUI, network

876

L. Piersanti, D. Alesini, M. Bellaveglia, S. Bini, B. Buonomo, F. Cardelli, C. Di Giulio, E. Di Pasquale, M. Diomede, L. Faillace, A. Falone, G. Franzini, A. Gallo, G. Giannetti, A. Liedl, D. Moriggi, S. Pioli, S. Quaglia, L. Sabbatini, M. Scampati, G. Scarselletta, A. Stella, S. Tocci, L. Zelinotti
LNF-INFN, 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, the commissioning of the TEst stand for X-band (TEX) facility has started in 2021 at Frascati National Laboratories of INFN. Born as a collaboration with CERN to test high gradient accelerating structures, during 2022 TEX aims at feeding the first EuPRAXIA@SPARC_LAB X-band structure prototype. During 2021 the commissioning has been successfully carried out up to 48 MW. The power unit is driven by an X-band low level RF system, that employs a commercial S-band (2.856 GHz) Libera digital LLRF (manufactured by Instrumentation Technologies), with an up/down conversion stage and a reference generation and distribution system able to produce coherent frequencies for the American S-band and European X-band (11.994 GHz), both designed and realized at LNF. The performance of the system, with a particular focus on amplitude and phase resolution, together with klystron and driver amplifier jitter measurements, will be reviewed in this paper. Moreover, considerations on its suitability and main limitations in view of EuPRAXIA@SPARC_LAB project will be discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST015

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Received ※ 20 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 28 June 2022

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TUPOST017

PEG Contribution to the LLRF System for Superconducting Elliptical Cavities of ESS Accelerator Linac

cavity, controls, hardware, electron

884

W. Cichalewski, G.W. Jabłoński, K. Klys, D.R. Makowski, A. Mielczarek, A. Napieralski, P. Perek, P. Plewinski
TUL-DMCS, Łódź, Poland
A. Abramowicz, K. Czuba, M.G. Grzegrzółka, K. Oliwa, I. Rutkowski, W. Wierba
Warsaw University of Technology, Institute of Electronic Systems, Warsaw, Poland
P.R. Bartoszek, K. Chmielewski, K. Kostrzewa, T. Kowalski, D. Rybka, M. Sitek, J. Szewiński, Z. Wojciechowski
NCBJ, Świerk/Otwock, Poland
M. Jensen
ESS, Lund, Sweden
A.J. Johansson, A.M. Svensson
Lund University, Lund, Sweden

The LLRF (Low-Level Radio Frequency) system optimizes energy transfer from the superconducting resonator to the accelerating beam. At ESS, one LLRF system regulates a single cavity. This digital system’s HW platform is the MTCA.4 standard. The system has been co-designed by ESS, Lund University, and the PEG (Polish Electronic Group) consortium. The PEG is also responsible for the system components design, evaluation, and production (like Local Oscillator Rear transition module, piezo tuner driver RTM, RTM carrier board, and others). The PEG delivers a HW/SW cavity simulator, an LLRF system test-stand, and provides necessary integration and installation services required for complete system preparation for the linac commissioning and operation phase. The paper summarizes the PEG work on the development and preparation of the LLRF systems for the ESS elliptical structures. The efforts concerning hardware and software components prototyping and evaluation are discussed. Moreover, we present the current status of the project, including components mass production, integration, and installation work.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST017

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Received ※ 08 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 19 June 2022 — Issue date ※ 20 June 2022

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TUPOST018

Long Pulse Operation of the E-XFEL Cryomodule

cavity, operation, controls, FEL

888

W. Cichalewski
TUL-DMCS, Łódź, Poland
J.K. Sekutowicz
DESY, Hamburg, Germany

The CW operation becomes more attractive mode of beam and RF operation, even for infrastructures initially developed as pulsed experiments. Compared to the short (single ms) pulse the CW or long pulse (LP) operation allows for a more relaxed bunch scheme and enables higher bunch quantities during the experiment run. The Long Pulse operation scenario is one of the possible EXFEL modes of work in the future. LLRF systems that work in CW (and LP) are in operation worldwide. Most of them are dedicated to single cavity control. The XFEL dedicated system is capable of multicavity cryomodules vector-sum operation. In such a configuration switching from short-pulse operation into long-pulse with the existing limitations from the allowed cryo heat load level, average input power per coupler (and others) can be extremely challenging. For this setup the support from the dynamic resonance control system is essential. This paper summarizes efforts towards the successful vector-sum operation of the X-FEL type cryomodule in the LP operation mode. Modifications to the original LLRF setup together with challenges of narrow bandwidth operation in moderate and high gradients are discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST018

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Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 21 June 2022 — Issue date ※ 23 June 2022

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TUPOST021

The CERN SPS Low Level RF: The Beam-Control

controls, cavity, proton, hardware

895

A. Spierer, P. Baudrenghien, J. Egli, G. Hagmann, P. Kuzmanović, I. Stachon, M. Sumiński, T. Włostowski
CERN, Meyrin, Switzerland

The Super Proton Synchrotron (SPS) Low Level RF (LLRF) has been completely upgraded during the CERN long shutdown (LS2, 2019-2020). The old NIM and VME based, mainly analog system has been replaced with modern digital electronics implemented on a MicroTCA platform. The architecture has also been reviewed, with synchronization between RF stations now resting on the White Rabbit (WR) deterministic link. This paper is the first of a series of three on the SPS LLRF upgrade. It covers the Beam-Control part, that is responsible for the generation of the RF reference frequency from a measurement of the magnetic field, and beam phase and radial position. It broadcasts this frequency word to the RF stations, via a White Rabbit network. The paper presents the architecture, gives details on the signal processing, firmware, hardware and software. Finally, results from the first year of beam commissioning are presented (2021).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST021

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Received ※ 07 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 05 July 2022

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TUPOST022

The CERN SPS Low Level RF: Lead Ions Acceleration

cavity, acceleration, injection, controls

899

P. Baudrenghien, J. Egli, G. Hagmann, A. Spierer, T. Włostowski
CERN, Meyrin, Switzerland

This paper is the third of a series of three on the Super Proton Synchrotron (SPS) Low Level RF (LLRF). Its focus is the upgrade concerned with the acceleration of Lead ions for injection into the LHC. Lead ions are far from relativistic at injection into the SPS. Therefore, the classic acceleration scheme at constant harmonic number (h=4620) does not work as the RF frequency swing does not fit within the cavity bandwidth. Fixed Frequency Acceleration (FFA) is therefore used. The upgraded LLRF uses a completely new implementation of the FFA, based on a Numerically Controlled Oscillator (NCO) implemented as an FPGA IP in the Controller of each cavity. In addition, the 2022 scheme for LHC ions filling calls for slip stacking of two families of bunches, 100 ns spacing, to generate a 50 ns spacing after interleaving. The paper presents the key components for FFA and ions slip stacking as implemented in the new system, together with successful first tests performed in Autumn 2021.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST022

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Received ※ 08 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 24 June 2022

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TUPOST023

The CERN SPS Low level RF: The Cavity-Controller

cavity, controls, feedback, proton

903

G. Hagmann, P. Baudrenghien, J. Egli, A. Spierer, M. Sumiński, T. Włostowski
CERN, Meyrin, Switzerland

This paper is the second of a series of three on the Super Proton Synchrotron (SPS) Low Level RF (LLRF) upgrade. It covers the 200MHz Cavity-Controller part, that is responsible for the regulation of the accelerating field in a single SPS cavity. When the SPS is used as Large Hadron Collider (LHC) proton injector, the issue is the high beam loading that must be compensated to guarantee longitudinal stability and constant parameters over the bunch train. That calls for strong One-Turn Delay Feedback (OTFB) and Feed-Forward (FFWD). The SPS is also accelerating Lead ions (Pb). There the issue is Frequency-Modulation (FM) and Amplitude-Modulation (AM) over the turn (so called Fixed Frequency Acceleration - FFA) plus RF gymnastics for the new ions slip-stacking. The paper reviews the functional requirements, presents the block diagram, then gives details on the signal processing, firmware and hardware. Finally results from the first year of beam commissioning are presented (2021).

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST023

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Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 19 June 2022

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TUPOST024

A New Beam Loading Compensation and Blowup Control System Using Multi-Harmonic Digital Feedback Loops in the CERN Proton Synchrotron Booster

cavity, controls, feedback, operation

907

D. Barrientos, S.C.P. Albright, M.E. Angoletta, A. Findlay, M. Jaussi, J.C. Molendijk
CERN, Meyrin, Switzerland

As part of the LHC Injectors Upgrade, the CERN Proton Synchrotron Booster (PSB) has been upgraded with new wide-band Finemet cavities and a renovated Low-Level Radio Frequency system with digital cavity controllers implemented in FPGAs. Each controller synchronously receives the computed revolution frequency, used to generate 16 harmonic references. These are then used to IQ demodulate the voltage gap and modulate the 16 RF drive signals each controlled through a Cartesian feedback loop (with individual voltage and phase control). The sum of these digital drive signals is then sent to the cavities. In addition, a configurable blow-up system providing a sinusoidal or custom noise pattern can be used to excite the beam. An embedded network analyzer allows studying the stability of the feedback loops of the individual harmonics. The 16 harmonic feedback loops have been successfully operated during 2021, allowing to reduce the beam induced voltage and control the longitudinal emittance of the beam. In this paper we present the system architecture as well as the performance of the complete cavity controller during operation in the PSB.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST024

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Received ※ 23 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 28 June 2022

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TUPOST025

Beam Commissioning of the New Digital Low-Level RF System for CERN’s AD

MMI, operation, timing, proton

911

M.E. Angoletta, S.C.P. Albright, D. Barrientos, A. Findlay, M. Jaussi, A. Rey, M. Sumiński
CERN, Meyrin, Switzerland

CERN’s Antiproton Decelerator (AD) has been re-furbished to provide reliable operation for the Extra Low ENergy Antiproton ring (ELENA). In particular, AD was equipped with a new digital Low-Level RF (LLRF) system that was successfully commissioned during the summer 2021. The new AD LLRF system has routinely captured and decelerated more than 3·10⁷ antiprotons from 3.5 GeV/c to 100 MeV/c in successive steps, referred to as RF segments, interleaved by cooling periods. The LLRF system implements the frequency program from Btrain data received over optical fiber. Beam phase/radial and cavity amplitude/phase feedback loops are operated during each RF segment. An extraction synchronization loop is triggered on the extraction RF segment to transfer a single bunch of antiprotons to ELENA. Extensive diagnostics features are available and operational modes such as bunched beam cooling and bunch rotation have been successfully deployed. The LLRF parameters can be different for each RF segment and are controlled by a dedicated application. This paper gives an overview of the AD LLRF beam commissioning results obtained and challenges overcome. Hints on future steps are also provided.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST025

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Received ※ 25 May 2022 — Accepted ※ 15 June 2022 — Issue date ※ 17 June 2022

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TUPOST027

Machine Learning-Based Tuning of Control Parameters for LLRF System of Superconducting Cavities

cavity, controls, simulation, SRF

915

J.A. Diaz Cruz, S. Biedron
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

The multiple systems involved in the operation of particle accelerators use diverse control systems to reach the desired operating point for the machine. Each system needs to tune several control parameters to achieve the required performance. Traditional Low-Level RF (LLRF) systems are implemented as proportional-integral feedback loops, whose gains need to be optimized. In this paper, we explore Machine Learning (ML) as a tool to improve a traditional LLRF controller by tuning its gains using a Neural Network (NN). We present the data production scheme and a control parameter optimization using a NN. The NN training is performed using the THETA supercomputer.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST027

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Received ※ 14 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 20 June 2022

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TUPOPT061

Status and Commissioning of the First X-Band RF Source of the TEX Facility

klystron, GUI, MMI, controls

1148

F. Cardelli, D. Alesini, M. Bellaveglia, S. Bini, M. Ceccarelli, C. Di Giulio, A. Falone, G. Franzini, A. Gallo, L. Piersanti, L. Sabbatini
INFN/LNF, Frascati, Italy
B. Buonomo, G. Catuscelli, R. Ceccarelli, A. Cecchinelli, R. Clementi, E. Di Pasquale, A. Liedl, D. Moriggi, G. Piermarini, S. Pioli, S. Quaglia, L.A. Rossi, M. Scampati, G. Scarselletta, S. Strabioli, S. Tocci, R. Zarlenga
LNF-INFN, Frascati, Italy

In 2021 started the commissioning of the TEX (Test stand for X-band) facility at the Frascati National laboratories of INFN. This facility has been founded in the framework of the LATINO (Laboratory in Advanced Technologies for INnOvation) project. The current facility layout includes an high power X-band (11.994 GHz) RF source, realized in collaboration with CERN, which will be used for validation and development of the X-band RF high gradient technology in view of the EuPRAXIA@SPARC_LAB project. The RF source is based on a CPI VKX8311 Klystron and a solid state ScandiNova k400 modulator to generate a maximum RF output power of 50 MW at 50 Hz, that will be mainly used for accelerating structure conditioning and waveguide components testing. In this paper the layout, the installation, commissioning and stability measurements of this source are described in detail. The test stand will be soon operative and ready to test the first X-band accelerating structure prototype.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT061

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Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 10 July 2022

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TUPOPT066

KEK LUCX Facility Laser-to-RF&RF-to-RF Stability Study and Optimization

laser, feedback, gun, timing

1167

K. Popov
Sokendai, Ibaraki, Japan
A. Aryshev, N. Terunuma, J. Urakawa
KEK, Ibaraki, Japan

KEK LUCX facility* is a linear accelerator devoted to the beam instrumentation R&Ds for present and future accelerator systems and colliders including ILC. According to the ILC TDR**, it is necessary to achieve RF-gun Laser-to-RF&RF-to-RF phase stability of 0.35°(RMS) and amplitude stability of 0.07%(RMS) with implementation of the Digital LLRF feedback based on commercially available FPGA board and digital trigger system. As the first step to achieve ILC stability level at KEK-LUCX facility, present Laser-to-RF&RF-to-RF phase and amplitude jitters were measured using time- and frequency-domain techniques. After that, jitter influence on beam parameters after RF-gun and main solenoid magnet was simulated with ASTRA tracking code*** and results were cross-checked during LUCX facility beam operation. Finally, stable digital trigger system and digital LLRF feedback based on SINAP EVG&EVR and RedPitaya SIGNALlab-250 modules were implemented. This report demonstrates the results of Laser-to-RF&RF-to-RF phase and amplitude jitter measurements cross-checked with ASTRA simulation and real beam parameters measurements before and after LUCX facility stabilization.
References
*A. Aryshev et al., Appl. Phys. Lett. 111, 033508 (2017).
**International Linear Collider Reference Design Report, ILC-REPORT-2007-001, 2007.
***https://www.desy.de/~mpyflo/

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT066

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Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 03 July 2022

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TUPOTK026

ESS Elliptical Cryomodules Tests at Lund Test Stand

cavity, cryomodule, operation, vacuum

1261

C.G. Maiano, E. Asensi Conejero, N. Elias, P. Goudket, W. Hees, P. Pierini, L. Sagliano, F. Schlander, M.Y. Wang
ESS, Lund, Sweden
D. Bocian, W. Gaj, P. Halczynski, M. Sienkiewicz, F.D. Skalka, J. Swierblewski, K.M. Wartak, M. Wartak
IFJ-PAN, Kraków, Poland

We present an overview and description of the elliptical cryomodules test activities at Lund Test Stand 2. During 2021 the test facility was commissioned with one prototype, and four series medium beta modules have now been successfully tested at ESS in Lund. This activity allowed the joint ESS and IFJ PAN team to develop all the procedures and the necessary automated tools for the different phases of the site acceptance test campaign (e.g. incoming inspections, coupler conditioning, cooldown strategies, tuning to resonance and electromagnetic/cryogenic performance verification). During the initial test period techniques for diagnostics of limiting mechanisms have been developed and improved up to a consolidated and mature state for the rest of the test campaign. Tests results and the initial statistics is presented and commented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK026

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Received ※ 07 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 16 June 2022

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TUPOMS049

Digital LLRF for the Canadian Light Source

cavity, booster, controls, operation

1538

P. Solans, F. Pérez, A. Salom
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
D.R. Beauregard, C.J. Boyle, J.M. Patel, H. Shaker, J. Stampe
CLS, Saskatoon, Saskatchewan, Canada

The Canadian Light Source, at the University of Saskatchewan, is a 3rd generation synchrotron light source located in the city of Saskatoon, Canada. The facility comprises a 250 MeV LINAC, a full energy booster and a 2.9 GeV storage ring. The radiofrequency system in the booster consist of two 5-cell cavities feed with a single SSPA. The analogue LLRF for the booster has been recently replaced by a digital LLRF based in the ALBA design with a Picodigitizer, a stand-alone commercial solution provided by Nutaq. Also, the firmware of the new DLLRF is configurable to allow operation with a superconducting cavity feed with one amplifier, thus providing the possibility to replace the CLS SR LLRF as well. The main hardware components, the basic firmware functionalities and the commissioning measurements of the new DLLRF for the CLS booster will be presented in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS049

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Received ※ 08 June 2022 — Accepted ※ 11 June 2022 — Issue date ※ 30 June 2022

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WEOYSP3

Operation Experience with SESAME RF System

cavity, operation, injection, controls

1636

D.S. Foudeh, A.I. Kurdi, N.Kh. Sawai
SESAME, Allan, Jordan

SESAME RF system has been in operation since 2017 where the operational electron beam current has been increased from 100mA to 300mA since then. The higher operational beam current together with the need to have longer beam lifetime to reduce number of injections per day required higher forward RF power, On the other hand; more attention needed to be paid to monitor and tackle the current driven High Order Modes and to respect the limitation on the forward RF power coming from the solid state amplifiers. In this paper we describe the RF system and report on the challenges we faced in addition to the operational experience we had with the RF system and solid state amplifiers.

Slides WEOYSP3 [4.207 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEOYSP3

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Received ※ 03 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 07 July 2022

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WEPOPT055

Linac3, LEIR and PS Performance with Ions in 2021 and Prospects for 2022

linac, operation, cavity, injection

1983

N. Biancacci, S.C.P. Albright, R. Alemany-Fernández, D. Alves, M.E. Angoletta, D. Barrientos, H. Bartosik, G. Bellodi, S.B. Bertolo, D. Bodart, M. Bozzolan, H. Damerau, F.D.L. Di Lorenzo, A. Frassier, D. Gamba, A. Huschauer, S. Jensen, V. Kain, T. Koevener, G. Kotzian, D. Küchler, A. Lasheen, G. Le Godec, T.E. Levens, N. Madysa, E. Mahner, O. Marqversen, C.M. Mastrostefano, P.D. Meruga, C. Mutin, M. O’Neil, G. Piccinini, R. Scrivens, P.S. Solvang, D. Valuch, F.M. Velotti, R. Wegner, C. Wetton, M. Zampetakis
CERN, Meyrin, Switzerland

CERN accelerators underwent a period of long shutdown from the end of 2018 to 2020. During this time frame, significant hardware and software upgrades have been put in place to increase the performance of both proton and ion accelerator chains in the High Luminosity LHC era. In the context of the CERN lead ion chain, 2021 has been mainly devoted to restore the injectors’ performance and to successfully prove the slip-stacking technique in SPS. In this paper we summarise the key milestones of the ion beam commissioning and the achieved beam performance for the Linac 3 (including the source), LEIR and PS accelerators, together with an outlook on 2022 operation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT055

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Received ※ 03 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 17 June 2022

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WEPOTK012

Commissioning the New LLRF System of the CERN PS Booster

cavity, operation, injection, MMI

2060

S.C.P. Albright, M.E. Angoletta, D. Barrientos, A. Findlay, M. Jaussi, J.C. Molendijk
CERN, Meyrin, Switzerland

The PS Booster (PSB) is the first synchrotron in the injection chain for protons. The beams produced for the LHC and various fixed target experiments cover a very large parameter space. Over the Long Shutdown 2 (LS2), the PSB was heavily upgraded as part of the LHC Injectors Upgrade (LIU) project. The low-level RF systems now drive the new Finemet-loaded cavities, control RF synchronisation for the new injection mechanism, and cope with the increased injection and extraction energies. The Finemet cavities provide exceptional flexibility, allowing an arbitrary distribution of voltage at different revolution frequency harmonics, but at the cost of significant broadband impedance. The new injection mechanism allows bunch-to-bucket multi-turn injection, which significantly reduces the amount of beam loss at the start of the cycle. The longitudinal beam production schema for each beam-type was developed based on simulations during LS2, and then adapted during the setting-up phase to suit the final operational configuration. This paper discusses the commissioning of the new LLRF, and the consequences of the LIU upgrades on the production of various beams.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK012

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Received ※ 25 May 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 07 July 2022

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THPOST007

Slow-Control Loop to Stabilize the RF Power of the FLUTE Electron Gun

controls, cavity, electron, gun

2449

M.-D. Noll, A. Böhm, J. Jelonek, I. Križnar, O. Manzhura, A.-S. Müller, R. Ruprecht, M. Schuh, N.J. Smale
KIT, Karlsruhe, Germany

The linear accelerator FLUTE (Far Infrared Linac and Test Experiment) at KIT serves as a test facility for accelerator research and for the generation of ultra-intense coherent THz radiation. To achieve stable THz photon energy and optimal beam trajectory, the energy of the electrons emitted from the RF photo-injector must be stable. The accelerating voltage of the RF cavity has been shown to be a significant influencing factor. Here, we report on the development of a slow closed-loop feedback system to stabilize the RF power and thus the accelerating voltage in the RF photo-injector cavity. With this closed-loop feedback system the relative standard deviation of the RF power in the cavity can be improved by 8.5 %.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST007

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Received ※ 08 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 24 June 2022

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THPOST016

Development Progress of HEPS LINAC

linac, MMI, emittance, simulation

2472

C. Meng, N. Gan, D.Y. He, X. He, Y. Jiao, J.Y. Li, J.D. Liu, Y.M. Peng, H. Shi, G. Shu, S.C. Wang, O. Xiao, J.R. Zhang, Z.D. Zhang, Z.S. Zhou
IHEP, Beijing, People’s Republic of China
X.H. Lu, X.J. Nie
IHEP CSNS, Guangdong Province, People’s Republic of China

The High Energy Photon Source (HEPS) is a synchrotron radiation source of ultrahigh brightness and under construction in China. Its accelerator system is comprised of a 6-GeV storage ring, a full energy booster, a 500-MeV Linac and three transfer lines. The Linac is a S-band normal conducting electron linear accelerator with available bunch charge up to 10 nC. The Linac installation has been finished at the end of May this year. The system joint debugging and device conditioning of the accelerating units, the power supplies, et al., are in progress. The beam commissioning will start in September 2022. This paper presents the status of the HEPS Linac and detailed introduction of the beam commissioning simulations and preparations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST016

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Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 09 July 2022

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