In this contribution, an overview of the injector complex design for the electron-positron Future Circular Collider (FCC) will be given and a summary of the injector parameters will also be presented, focusing on the most challenging ones for the different injector subsystems. Furthermore, since the FCC is designed to operate at the extreme end of the parameters, a positron source with a high...
Recent progress of LLRF systems in several accelerator facilities at KEK (SuperKEKB Ring, PF/PF-AR Ring, LINAC, cERL, STF etc.) will be reported.
Presentation of the work the JLAB LLRF engineering staff since 2019.
The current major projects at Fermilab include PIP-II – an 800 MEV superconducting LINAC, LBNF (long baseline neutrino facility), DUNE(deep underground neutrino experiment), the Muon g-2 and the Mu2e experiment and several accelerator upgrade projects preparing for the higher intensity proton beam with the commissioning of the PIP-II Linac. PIP-II has entered the construction phase while the...
Many accelerator projects are going on in China, ranging from small-scale cyclotrons for medical treatments, 4th generation synchrotron radiations, to CW X-ray superconducting free-electron lasers. These projects place high demands on low-level RF (LLRF) systems with different requirements on reliability, RF field stability, and multi-mode operability. Super active research and developments on...
This presentation will highlight the LLRF developments at the Spallation Neutron Source at Oak Ridge National Laboratory.
This is the lab talk, which covers all LLRF topics in a summary of all facilities operated at PSI (SwissFEL, SLS, HIPA, Proscan).
The presentation will provide highlights from LBNL of the most relevant developments in LLRF at this lab.
Diagnosis and supervision of particle accelerators is mostly a manual task, requiring deep insight by human operators. The usage of machine learning and data analysis has the potential to enhance the controllability and the diagnosis capability.
However, applications like longitudinal phase-space estimation, automatic control optimization, or anomaly detection can be used only when the...
The application of machine learning to accelerators has been a dinner table discussion amongst members of the community with an ever increasing list of application spaces. ML has successfully been applied to the improvement of diagnostics, on-line modeling, anomaly detection, and postmortem data analysis. When it comes to accelerator RF systems, machine learning has been of most interest for...
The Electron-Ion Collider (EIC), to be constructed at Brookhaven National Laboratory (BNL), is a roughly 10 year project to design and construct a facility to collide polarized high energy electron beams with polarized proton and heavy ion beams at center of mass energies from 20 GeV to 140 GeV and luminosity up to 10^34 cm^(-2s-1). The project is a partnership between BNL and the Thomas...
Besides the realization of the LLRF systems for the new heavy-ion synchrotron SIS100 and the storage rings CR and HESR, the FAIR project at GSI also includes an upgrade of the LLRF systems of the existing accelerator rings such as SIS18 and ESR. Although each accelerator and each type of RF system has its own specific requirements, the basic underlying concept and topology is the same for all...
The Advanced Photon Source Upgrade (APS-U) will replace the more than 25 year old storage ring with a multibend achromat lattice. To alleviate beam lifetime and emittance concerns, the new storage ring will include a passive superconducting bunch-lengthening cavity whose voltage will be regulated via slow cavity tuning control. The reduction of the synchrotron tune will make the beam more...
The LIGHT (Linac for Image-Guided Hadron Therapy) linac is designed to produce proton beams up to 230 MeV for cancer therapy. The machine consists of three different kinds of accelerators: RFQ (Radio-Frequency Quadrupole), SCDTL (Side Coupled Drift Tube Linac) and CCL (Coupled Cavity Linac). These accelerating structures operate with RF power at 750 MHz (RFQ) and 3 GHz (SCDTL, CCL) which is...
Any cavity controller for a distributed system needs a Phase Reference Line (PRL) signal from which to define phases of a cavity field measurement. The LCLS-II PRL system at SLAC provides bidirectional (forward and reverse) phase references at 1300 MHz to each rack of the LLRF system. The PRL controller embedded with the Master Oscillator (MO) locks the average phase of the two directions to...
FLASH was the first FEL in the world to provide ultrashort pulses of radiation in extreme ultraviolet and soft X-ray range, first launched in 2005. The FLASH2020+ plan is to upgrade the existing FEL lines, by implementing tunable undulators and extending the maximum electron beam energy to 1.35 GeV. The upgrade plan was also a perfect opportunity to completely rebuild the RF reference...
The Super Proton Synchrotron (SPS) Digital LLRF 200 MHz system at CERN
was redesigned in 2020, using a fixed-frequency
clock provided by the White Rabbit network instead of the usual RF clock. This triggered the development of WR hardware with sufficient performance (approx. 100 fs rms jitter above 100 Hz and 13 ps/1 degree end-to-end phase stability). WR is also used in the SPS to...
The required phase synchronization for the European Spallation Source proton linac LLRF and Beam Diagnostics systems is: 0.1° for short term (during 3.5 ms pulse), 0.1° for long term between adjacent outputs, and 2.0° for long term (hours to days) between any two points at both frequencies of 352 MHz and 704 MHz. The phase reference distribution system consists of a Phase Reference Line (PRL),...
I will review several characteristics of low level RF (LLRF) control problems in accelerators and discuss control design methods that are well suited to these problem classes. The methods, and their key features are: i) Iterative learning control, which adapts to correct persistent disturbances in repetitive or pulsed operations; ii) Robust control with uncertainty quantification, which...
Developing Low Level Radio Frequency (LLRF) systems for accelerators requires teams with skills in a variety of areas such as beam dynamics, feedback theory, analogue/digital electronics, firmware/software engineering. This fascinating field suffers from a lack of diversity, mirroring the situation in the various accelerator facilities and research centers. For example, the number of women...
- PSI welcome talk [H. Braun]
- Organization and splitting into four groups [M. Stoll]
Currently ALS is undergoing an upgrade to ALS-U to produce 100 times
brighter soft X-ray light. The LLRF system for Accumulator Ring (AR) is
composed of two identical LLRF stations, for driving RF amplifiers. The
closed loop RF amplitude and phase stability is measured as $< 0.1\%$ and $<
0.1 ^\circ$ respectively, using the non-IQ digital down conversion together
with analog up/down...
One of the crucial control systems of any particle accelerator is the Low Level Radio Frequency (LLRF). The purpose of a LLRF is to control the amplitude and phase of the field inside the accelerating cavity.
The LLRF is a subsystem of the CEA control domain for the SARAF-LINAC instrumentation and Seven Solutions has designed, developed, manufactured and tested the system based on CEA...
Incremental upgrades of the legacy low level RF (LLRF) equipment—50 years for the Los Alamos Neutron Science Center (LANSCE)—involves challenges and problems not seen with new and total replacement opportunities. The digital LLRF upgrade at LANSCE has deployed 30 of the 53 required systems as of September 2022. This paper describes the performance of the digital upgrade, current status, and...
Recent studies showed that the transverse feedback system noise floor in the Large Hadron Collider (LHC) must be reduced by at least factor of two in order to operate the machine with large beam-beam tune shift as foreseen in the High Luminosity (HL) LHC. Also, the future feedback system foreseen to suppress the LHC Crab Cavity noise relies on improved noise performance of the beam position...
What is the firmware framework? What it should provide and why you want to have it.
Why you want to have an open source framework and open source firmware?
What is needed to make collaboration possible?
What is our idea for the firmware framework.
Licensing.
Over the past ten years, two digital LLRF systems (SwissFEL, HIPA) with FPGA based digital signal processing (DSP) have been developed at PSI and the third for SLS-2 is underway. Other accelerator systems such as beam diagnostics also use FPGA platforms for their DSP. Even though there are large differences in the applications even between the LLRF systems, many similarities in the under...
SwissFEL LLRF system was well designed with precise RF detection, reliable amplitude and phase feedback, and high degree automation. After the start of user operation, new requirements on robustness and reproducibility have been raised for LLRF. Efforts have been spent to consolidate the LLRF system. We implemented lookup-table-based algorithms for the fast setup of klystrons for desired...
For the SLS-2 project and the 500 MHz RF upgrades, the LLRF will be renewed and the previously analog system is going to be replaced by a digital one. The new system is built into two separated chassis, an analog frontend and a CompactPCI Serial based digital backend interconnected with coaxial cables. The custom design analog frontend implements two up- and eight down-conversion channels 50...
At PSI, the high intensity proton accelerator (HIPA) delivers a proton beam of 590 MeV energy at a current of up to 2.4 mA. The RF cavities are operated in CW mode at a frequency of 50 MHz. The initial system was built about 30 years ago with the technology at that time which was predominantly analogue. With the modern replacement of the analogue system, the cavity operation and maintenance...
CompactPCI Serial has been selected as one of the Next Processing Platforms (NPP) for development of future electronic systems at PSI. In this contribution, we describe the new platform and the pilot application for the Swiss Light Source (SLS) LLRF upgrade. We detail Hardware/Firmware/Software architectures, present automated testing procedures, as well as share the hands-on experience gained...
A new 16 channel LLRF front end was developed at PSI for the two X-band RF stations at SwissFEL.
This poster summarizes operational experience and performance achieved with new direct up-conversion LLRF front end. In addition, comparison between the dual conversion to the new direct conversion front end is given.
ALBA is a 3rd generation synchrotron light source located in Cerdanyola del Vallès (Barcelona, Spain). The facility comprises a 3 GeV electron storage ring (SR), injected from a 110 MeV Linac through a full energy booster synchrotron. The RF system consists of six normal conducting cavities in the storage ring, fed with IOT based transmitters that are able to provide up to 3 MV to the...
Originally, the LLRF control software, developed for the accelerators at DESY (XFEL, FLASH,...), was exclusively based on DOOCS. The development of the ChimeraTK framework enables the LLRF control applications to use other control systems than DOOCS (i.e. EPICS, OPC-UA), as well. Recently, EPICS-based LLRF control applications have been implemented at LLRF control systems outside of...
The two cyclotrons at the High Intensity Proton Accelerator (HIPA) at PSI are equipped with eight high-power CW RF cavities at 50 MHz and one flat-top cavity at 150 MHz with input power levels up to 500 kW.
The purpose of the startup sequencer is to establish continuous (CW) high power RF operation as safe, fast and reliable as possible from both cold and warm cavity initial states. Precise...
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...
CNAO is one of the six hadrontherapy centers able to treat cancer with proton beams and carbon ions. It is a synchrotron with a diameter of 77 meters, equipped with a LINAC as the injector. The stability of the RF in the LINAC being fundamental for the quality of the beam injected into the ring impelled CNAO to decide to upgrade the actual analogic LINAC LLRF to a digital one.
This...
For the new PETRA IV project at DESY a new LLRF system based on MicroTCA.4 is foreseen. It will be used to control 24 cavities at 500MHz and 24 cavities at 1.5GHz. In this contribution we will present the setup of a first prototype of the LLRF system for the single cavity LLRF system operating at 500MHz continuous wave.
There are many stages in the LLRF and RF system development process for any new accelerator that can take advantage of hardware emulation of the high power RF system and RF cavities. LLRF development, bench testing, control system development and testing of installed systems must happen well before SRF cavities are available for test. The PIP-II Linac has three frequencies of SRF cavities,...
The first version of digital low level RF (DLLRF) for the Diamond Light Source storage ring and booster was developed with ALBA Synchrotron. Six systems have been built so far. Two of them are in routine operation controlling two normal conducting HOM-damped cavities in the Diamond storage ring. A third system is being used for cavity testing in the RF test facility. The fourth system is...
Accelerator low-level RF (LLRF) systems have demanding requirements on signal distribution circuity. The RF feedback control paths from the cavity are not corrected for error and demand a high level of attention to performance. This chassis allows the frequency dependent (805 MHz or 201.25 MHz) circuits to be separated from the modular frequency independent digital low level RF system. The...
During the last few years, the LLRF systems of all CERN small synchrotrons (PSB, LEIR, AD, ELENA) have been upgraded to a fixed frequency clock scheme. As a result, the beam profiles obtained from the digitization of pick-up signals will have a different number of samples as the revolution frequency varies. In this work, we present a method to reconstruct the time-domain signal of the bunch...
Commissioning of the LLRF systems of CERN accelerators consists of a number of time-consuming procedures, involving calibration and fine-tuning of numerous parameters. In the recent years, a system of Python scripts was developed to automate the setting up of the LLRF of the LHC and the SPS. Targeted at RF experts, the scripts provide high-level interface to the underlying physical system,...
Polish Free Electron Laser PolFEL is a new facility located in the National Centre for Nuclear Research in Swierk (Otwock, Poland). PolFEL will be based on the 200 MeV linear superconducting electron accelerator made of the TESLA type cavities, targeting VUV, IR and THZ wavelengths. The accelerator will operate in the single cavity regulation mode using solid state amplifiers. It will be able...
The goal of a LLRF system is to control an actual RF cavity with beam. While digital simulations have a place, having an analog circuit to stand in for the cavity can be tremendously helpful in validating hardware+firmware+software under development. A wide range of cavity emulators have been developed in collaboration with SLAC, and LBNL. Cavity emulators are typically based on quartz...
The Fermilab 650 STC (Spoke resonator Test Cave) is used as a horizontal test facility for the PIP-II 650 MHz Low Beta(LB) and HB superconducting cavities provided by INFN(Italy) and RRCAT(India). The cavities are 5-cell elliptical doublet type with betas of 0.61 and 0.9.Testing of two HB cavities has been completed and testing with a LB cavity is in progress. Coupler thermal testing, tuner...
The Fermilab 650 MHz Cryomodule Test Stand is a facility for independently testing HB/LB 650 MHz and SSR2 (325 MHz) cryomodules without beam. The first cryomodule tested will be the HB 650 which consists of six cavities. The LLRF system is built with the same LLRF controller as the LCLS-II project with mostly identical firmware and software components allowing for the small differences in...
Sampling the RF signals is a challenging problem for the modern LLRF Control System. One of the analog-to-the digital conversion problems is the clock jitter's influence on the output signal. As clock jitter impact increases with the input signal frequency, it is primarily a problem in precise RF systems, where signal frequencies are high. This issue can be minimized by lowering the input...
The Korean 4th Generation Storage Ring (4GSR) project is being under construction with the plan of commissioning at the end of 2027. The beam energy of this facility is 4 GeV, and a 500 MHz EU- HOM-damped normal cavity will be adopted to generate the ultra-low emittance beam of 58 pm rad with the beam current of 400 mA. This paper covers the design considerations of the low level RF (LLRF)...
An essential requirement for ESS is to assure a precise phase synchronization of LLRF and Beam Diagnostics systems, operating at 352.21 MHz and 704.42 MHz. The long-term required phase accuracy is 0.1° between adjacent outputs and 2.0° between any two points.
The phase synchronization system consists mainly of a Master Oscillator (MO) in the Klystron Gallery and a Phase Reference Line (PRL)...
In the framework of the BESSY-VSR upgrade, the beam injection from the booster to the storage ring has to be modified in order to inject shorter bunches. For this purpose, a new PETRA-type 5 cell cavity has been installed in the booster ring and a second one is to be installed. These two new normal conducting 500MHz cavities are to be powered by two already installed and tested 80kW Solid...
REGAE is a facility for UED experiments (ultrafast electron diffraction) based on a normal conducting S-band gun and buncher cavity. Their RF regulation is performed by a single cavity controller, implemented by an FPGA firmware and operating at 125 MHz. With a variant of the Struck SIS8300-KU controller board that is equipped with 250 MSps ADCs we were able to increase the frequency of the...
A new powerful longitudinal diagnostics system is being developed for the two CERN’s antiproton machines, the Antiproton Decelerator (AD) and the Extra Low Energy Antiproton ring (ELENA).
The system is based upon a fast computer, fully integrated in CERN’s controls infrastructure, with high processing power and hosting a Linux server running real-time software for online data analysis. Its...
The PolFEL is a Polish Free-Electron Laser project under construction at National Centre for Nuclear Research in Świerk. An essential requirement for the PolFEL is to assure a precise phase synchronization of LLRF and Beam Diagnostics systems operating at 1300 MHz.
The synchronization system consists of a phase synchronization system and the timing system. The phase synchronization system...
The Sirepo platform is designed to offer GUIs for popular simulation codes used in the accelerator space, along with integration with a JupyterLab Python environment. This includes srw, radia, elegant, and warp, mad-x, opal, and synergia, as well as ongoing development for an online controls and fault detection interface. This open-source platform is available through sirepo.com, as well as a...
The linear accelerator (LINAC) at the Los Alamos Neutron Science Center (LANSCE) consists of Pre-buncher, Main-Buncher, low-energy beam transport (LEBT), four 201.25-MHz Drift Tube Linacs (DTLs) and forty-four 805-MHz Coupled Cavity Linacs(CCLs). As a part of the upcoming LANSCE Modernization project, low-level RF (LLRF) systems of four 201-MHz DTLs and twenty-six 805-MHz SCLs are digitized....
LCLS-II is currently in its commissioning phase at SLAC. It is an X-ray FEL driven by a CW superconducting LINAC. The beam injector plays a crucial role in the overall performance of the accelerator, and is critical to the final electron beam performance parameters. The LCLS-II injector comprises of a 185.7 MHz VHF copper gun cavity, and a 1.3 GHz two-cell L-band copper buncher cavity. The...
The superconducting cavity vertical test stand at DESY is going to be updated with the MTCA.4 based system. The digital self exited loop (SEL) LLRF controller has been developed to fulfill the requirements for the controller to drive the cavity with high QL up to 1e10 and high cavity detuning up to 10kHz. In order to test the SEL controller, additionally the real-time cavity simulator has been...
The Facility for Rare Isotope Beams (FRIB) opened for full user operation in May 2022 and is currently prototyping a 644 MHz superconducting (SC) cavity and cryomodule for an energy upgrade of the accelerator to 400 MeV/u. The low level radio frequency (LLRF) controllers in operation are based on Xilinx Spartan 6 field programmable gate array (FPGA) and support frequencies up to 322 MHz. With...
The preparation of the LLRF Control equipment of the SeaLab project for the commissioning is going on. The current hardware configuration comprises gun and booster cavities under server PC control and the standalone transverse deflecting cavity controller. The ongoing infrastructure works, i.e. cabling traces termination/patch panels connection, network installation and power lines...
The High Repetition rate Electron Scattering (HiRES) accelerator at LBNL uses a CW, normal-conducting RF electron gun and bunching cavity to deliver high-stability, high repetition rate electron pulses for scientific applications, such as ultrafast electron diffraction (UED) and FELs. Beyond-state-of-art stability is required for the electron beam energy in order to achieve femtosecond...
Compact particle accelerators are increasingly needed in medical, industrial, and defense settings. Such an accelerator requires a highly efficient, lightweight, and space-efficient footprint; this leverages particularly unique requirements on RF, power, and thermal budgets. RadiaSoft has been working with SLAC on developing the LLRF system for a structure consisting of 26 pairs of...
LCLS-II is an X-Ray Free Electron Laser (XFEL) com-
missioned in 2022, being the first Continuous Wave (CW)
hard XFEL in the world to come into operation. To accel-
erate the electron beam to an energy of 4 GeV, 280 TESLA
type superconducting RF (SRF) cavities are used. A Loaded
Q (𝑄𝐿 ) of 4×10^7 is used to drive the cavities at a power level
of a few kilowatts. For this 𝑄𝐿 , the RF...
Author:
James Latshaw
PIP-II Resonance Control System
J. Latshaw, B. Chase, C. Hovater, R. Bachimanchi, T. Plawski,
Thomas Jefferson National Accelerator Facility,
Newport News, VA 23606, USA
June 30, 2022
Abstract
The PIP-II Resonance Control System has the goal of providing the electronics to mechanically tune four superconducting cavities as directed by two RF control stations...
The stability and convergence of an Iterative Learning Controller (ILC) may be assessed in time domain, by actually iterating the equations for a variety of inputs, or by finding the eigenvalues (lambda) of the iterated system (lambda-domain), or by forming the Z-transform and applying analogues of the Nyquist criteria. Two often-used criteria are (i) Asymptotic Convergence (AC) of the...
The Canadian Light Source (CLS) operates a single-cell CESR-B superconducting RF cavity system in the 2.9 GeV storage ring, powered by a 310 kW klystron. After the successful implementation of ALBA’s digital low-level radio frequency system (DLLRF) in the dual cavity booster ring at CLS, plans are in place to test the same system in the storage ring RF. The DLLRF also leaves open future...
The Electron-Ion Collider (EIC), to be constructed at Brookhaven National Laboratory (BNL), is a roughly 10 year project to design and construct a facility to collide high energy polarized electron beams with polarized proton and heavy ion beams at center of mass energies from 20 GeV to 140 GeV and luminosity up to 1034 cm-2s-1. The project is a partnership between BNL and the Thomas Jefferson...
The Electron-Ion Collider (EIC), to be constructed at Brookhaven National Laboratory (BNL), is a roughly 10 year project to design and construct a facility to collide polarized high energy electron beams with polarized proton and heavy ion beams at center of mass energies from 20 GeV to 140 GeV and luminosity up to 1034 cm-2s-1. The project is a partnership between BNL and the Thomas...
Medaustron is a cancer treatment facility with ion therapy. It is based on a synchrotron accelerator with proton and carbon beams. The treatment has been successfully running since 2016, treating about 400 patients a year. Even at this young age of the facility, though, there are problems arising regarding the sustainability of the current system as some of the components are nearing end of...
The commissioning of the ESS linac is ongoing and the five first normal conductive (NC) cavities have recently been operated with beam. An overview of the LLRF systems in use, first commissioning results with initial beam, and experiences are presented. The initial Piezo compensation tests obtained at the Medium Beta cavity test stand is also presented.
PIP-II IT is a test facility for the PIP-II project where the injector, warm front-end and the first two superconducting cryomodules were tested. The warm front-end consists of an Ion source, an RFQ and three buncher cavities. The superconducting cryomodules consist of an 8-cavity half-wave-resonator(HWR) cryomodule operating at 162.5 MHz followed by an 8-cavity single-spoke resonator(SSR1)...
SRF cavities are characterized by low energy loses derived from their extremely high intrinsic quality factor. In accelerators geared towards new applications such as new light source linacs, such cavities are operated with extremely high loaded quality factor due to the negligible beam loading involved. In those particular cases, the bandwidth of RF systems is very narrow, so they become much...
The JLAB LLRF 3.0 system has been developed and is replacing the 30-year-old LLRF systems in the CEBAF accelerator. The LLRF system builds upon 25 years of design and operational RF control experience (digital and analog), and our recent collaboration in the design of the LCLS-II LLRF system. The new system also incorporates a cavity control algorithm using a fully functional phase and...
Magnetic alloy (MA) cavities are employed in the J-PARC RCS. The wideband response of the MA cavity enables the dual harmonic rf operation for the bunch shape control, which mitigates the space charge effects, while the wake voltage in a single MA cavity consists of several harmonics. Multiharmonic beam loading compensation is required for high intensity beam acceleration. We decided to employ...
Before AI and neural nets, the excitement was about iterative learning control (ILC): the idea to train robots to perform repetitive tasks, or train a system to reject quasi-periodic disturbances. The excitement waned after the discovery of “bad learning transients” in systems which satisfy the ILC asymptotic convergence stability criteria. The transients may be of long duration, persisting...
In this contribution I will describe a method for determining cavity detuning in the CW storage ring RF systems. This method uses a vector network analyzer integrated in the LLRF system to determine the reflection coefficient versus frequency at the cavity feed port. Resulting measurement can then be fitted to extract cavity center frequency as well as other parameters of interest. The major...
For pump-probe experiments, where the FEL photon pulses interact together with an external laser, a highly temporal stability is mandatory. The longitudinal beam-based feedback system at the European XFEL stabilizes the arrival time, measured by a bunch arrival time monitor (BAM). To compensate fast arrival time fluctuations of the bunch trains, the energy in front of a bunch compression...
