Novel Approaches for Forecasting of Beam Interruptions in Particle Accelerator
S. Li, A. Adelmann, J. Snuverink
PSI, Villigen PSI, Switzerland
The beam interruptions (i.e. interlocks) of particle accelerators, despite being necessary safety measures, lead to abrupt operational changes and a substantial loss of beam time. Novel data-driven time series classification approaches are applied in the High-Intensity Proton Accelerator complex of Paul Scherrer Institut, in order to forecast interlock events thus decrease beam time loss. The forecasting is performed through binary classification of single timestamps as well as windows of multivariate time series, with methods ranging from linear Lasso models based on statistical Two Sample Test, to deep learning model that generates Recurrence Plots followed by Convolutional Neural Network*. The "beam time saved" in any given time interval, a continuous evaluation metric, is established with preliminary experiments showing that interlocks could be circumvented by reducing the beam current. The models have been integrated with EPICS, and the best-performing interlock-to-stable classifier on real-time data potentially increases 5 min beam time per day for the users. * Li S, Zacharias M, Snuverink J, et al. A novel approach for classification and forecasting of time series in particle accelerators[J]. Information, 2021, 12(3): 121.
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New X-Rays Diagnostics at ESRF: The X-BPMs and the Halo-Monitor
125
E. Buratin, K.B. Scheidt
ESRF, Grenoble, France
Two new X-ray diagnostics have been installed in the Front-Ends of the Storage Ring of the ESRF’s Extremely Brilliant Source (EBS) recently. Two independent optical X-BPMs at 23m distance from their bending magnet source-point are giving extremely useful additional information on the vertical beam stability in comparison to the e-BPMs data. A vertical beam Halo-monitor allows to measure permanently and quantitatively the level the electron density at large distance (1-3mm) from the beam core, in a non-destructive manner.
New Measurements Using Libera-Spark Electronics at ESRF: The High Quality Phase-Monitor and the Single-Electron
129
E. Buratin, N. Benoist, P.B. Borowiec, G. Denat, J. Jacob, K.B. Scheidt, F. Taoutaou
ESRF, Grenoble, France
Several new diagnostics have been installed and exploited at the ESRF’s new Extremely Brilliant Source (EBS) in 2022. A Libera-Spark BPM device has been implemented to measure the phase of Booster and EBS rings, with high resolution and up to turn-by-turn rate. In the Storage Ring we achieved irrefutably the control, injection and measurement of single electron(s) with the use of transfer-line screens, the visible-light extraction system and a low-cost photo-multiplier tube, combined with the commercial Spark Beam Loss Monitor. Further planned developments, like the TCPC technique, on this are on-going and will be essential to verify that our Booster cleaning process reaches a level of zero-electron bunch pollution in EBS.
Novel Beam Excitation System Based on Software-Defined Radio
133
P.J. Niedermayer, R. Singh
GSI, Darmstadt, Germany
Funding:This project has received funding from the European Union’s Horizon 2020 Research and Innovation programme under GA No 101004730. A signal generator for transverse excitation of stored particle beams is developed and commissioned at GSI SIS18. Thereby a novel approach using a software-defined radio system and the open-source GNU Radio ecosystem is taken. This allows for a low cost yet highly flexible setup for creating customizable and tuneable excitation spectra. Due to its open-source nature, it has the potential for long term maintainability and integrability into the accelerator environment. Furthermore, this opens up the possibility to easily share algorithms for the generation of waveforms across accelerator facilities. As a first application, the device is used to control the coherence and amplitude of transverse oscillations by excitation in the vicinity of betatron sidebands. It enables measurement of beam parameters like tune and chromaticity. On a longer term, it will be used for more complex tasks such as beam shaping, extraction and automated parameter scans towards these complex processes.
Beam Polarization Measurements with the Revised Compton Polarimeter at ELSA
137
M.T. Switka, K. Desch, D. Elsner
ELSA, Bonn, Germany
W. Hillert
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
The Compton Polarimeter at the ELSA 3.2 GeV storage ring has been designed to measure the polarization degree of the stored electron beam by analyzing the profile of the back-scattered gamma-beam with a silicon microstrip detector. Utilizing a scattering asymmetry from interaction with circularly polarized laser light, the electron beam polarization is determined from the vertical shift of the gamma-beam’s center of gravity in respect to the handedness of the laser light. The installation of a new laser source and silicon strip detector has improved the polarimeter’s performance significantly. Additionally, the profile analysis could be enhanced by using a Pearson type peak function fit. The analyzing power was determined through the observation of the Sokolov-Ternov effect and a statistical measurement accuracy of 2 % could be obtained within 5 minutes of measurement time. The polarimeter resolves the expected spin dynamical effects occurring in the storage ring and has shown to be a robust and reliable measurement system for operation with the GaAs source for polarized electrons.
S. Mazzoni, W. Andreazza, E. Balci, D. Belohrad, E. Bravin, N.S. Chritin, J.C. Esteban Felipe, T. Lefèvre, M. Martin Nieto, M. Palm
CERN, Meyrin, Switzerland
The Beam Rate of Neutrals (BRAN) is a monitor that provides a relative luminosity measurement for the four LHC experiments. BRANs are used during operations as a tool to find and optimise collision and to cross-check experiments luminosity monitors. While each LHC experiments is equipped with BRANs, in this contribution we will focus on the new monitors installed for ATLAS and CMS that will replace the current ageing gas chambers during LHC run 3. These will also serve as as prototypes for the future High Luminosity LHC monitors that will need to sustain an even higher collision rate. A description of the BRAN as well as the first results obtained during the LHC Run 3 start-up will be presented.
Beam-Based Calibration of Sextupole Magnet Displacement with Betatron Tune Shift
192
S. Takano, T. Fujita, K. Fukami, H. Maesaka, M. Masaki, K. Soutome, M. Takao, T. Watanabe
JASRI, Hyogo, Japan
K. Fukami, T. Hiraiwa, H. Maesaka, K. Soutome, S. Takano, H. Tanaka, T. Watanabe
RIKEN SPring-8 Center, Hyogo, Japan
K. Ueshima
QST, Sendai, Miyagi, Japan
The alignment of sextupole magnets is one of the critical issues for the upcoming 4th generation light sources and future colliders. The alignment error of magnets and the beam offsets in sextupoles should be within a few 10 µm rms to ensure enough dynamic aperture for stable operation and minimize deterioration of beam quality. Considering that the quadrupole field in a sextupole is proportional to the displacement (normal Q for horizontal and skew Q for vertical), we propose a beam-based calibration (BBC) method to measure the sextupole centers by observing the betatron tune shift. The magnetic center is the point where the tune does not change regardless of the sextupole field strength. The key is increasing the XY coupling to obtain a tune shift large enough for the vertical calibration. We studied experimentally the feasibility of the sextupole BBC at SPring-8 and successfully demonstrated the principle for both horizontal and vertical calibration. The tune shift was monitored by bunch-by-bunch feedback electronics with approximately 1e-5 resolution. The measurement resolution of the sextupole center was approximately 10 µm std., which was sufficient for our requirement.
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Acceleration, Transport and Diagnostic of Protons from Laser-Matter Interaction
G. Petringa, G.A.P. Cirrone
INFN/LNS, Catania, Italy
Laser-generated radiation represent one of the frontiers of the acceleration techniques. When a TW level, fs duration laser is focused in small spot size, the radiation pressure triggers physics processes able to accelerate ions with intensities of the order of E9-E11 particles/steradians. Laser driven ion acceleration has several applications. The development of laser-accelerated proton irradiation systems was proposed by many research group. The Czech pillar of ELI site, includes the ’ELIMED’ beamline, devoted to exploring medical applications of laser-driven proton beams. Radioisotope production is another potential medical application, but many other are of interest such as high-resolution proton radiography, nuclear reactions and the development of laser-driven high-brightness injectors. All these applications require the detectors and diagnostic systems able to detect these high intense beams. In this talk an overview on the last approaches of laser-driven ion acceleration and diagnostic will be presented. Advanced solutions on detectors development will be presented with a critical discussion on the current limitations and potential future achievable progresses.
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LHC Schottky Spectrum from Macro-Particle Simulations
308
C. Lannoy, D. Alves, N. Mounet
CERN, Meyrin, Switzerland
C. Lannoy, T. Pieloni
EPFL, Lausanne, Switzerland
K. Łasocha
Jagiellonian University, Kraków, Poland
We introduce a method for building Schottky spectra from macro-particle simulations performed with the PyHEADTAIL code, applied to LHC beam conditions. In this case, the use of a standard Fast Fourier Transform (FFT) algorithm to recover the spectral content of the beam becomes computationally intractable memory-wise, because of the relatively short bunch length compared to the large revolution period. This would imply having to handle an extremely large amount of data for performing the FFT. To circumvent this difficulty, a semi-analytical method was developed to compute efficiently the Fourier transform. The spectral content of the beam is calculated on the fly along with the macro-particle simulation and stored in a compact manner, independently from the number of particles, thus allowing the processing of one million macro-particles in the LHC, over 10’000 revolutions, in a few hours, on a regular computer. The simulated Schottky spectrum is then compared against theoretical formulas and measurements of Schottky signals previously obtained with lead ion beams in the LHC.
First RF Phase Scans at the European Spallation Source
313
Y. Levinsen, R.A. Baron, E.M. Donegani, M. Eshraqi, A. Garcia Sosa, H. Hassanzadegan, B. Jones, N. Milas, R. Miyamoto, D. Noll, I. Vojskovic, R.H. Zeng
ESS, Lund, Sweden
M. Akhyani
EPFL, Lausanne, Switzerland
I. Bustinduy
ESS Bilbao, Zamudio, Spain
F. Grespan
INFN/LNL, Legnaro (PD), Italy
The installation and commissioning of the European Spallation Source is currently underway at full speed, with the goal to be ready for first neutron production by end of 2024. This year we accelerated protons through the first DTL tank. This included the RFQ, 3 buncher cavities in the medium energy beam transport as well as the DTL tank itself as RF elements. At the end of the DTL tank we had a Faraday cup acting as the effective beam stop. This marks the first commissioning when RF matching is required for beam transport. In this paper we discuss the phase scan measurements and analysis of the buncher cavities and the first DTL tank.
Beam Characterization of Slow Extraction Measurement at GSI-SIS18 for Transverse Emittance Exchange Experiments
318
J. Yang, P. Boutachkov, P. Forck, T. Milosic, R. Singh, S. Sorge
GSI, Darmstadt, Germany
Funding:This project has received funding from the European Union’s Horizon 2020 Research and Innovation programme under GA No 101004730. The quality of slowly, typically several seconds, extracted beams from the GSI synchrotron SIS18 is characterized with respect to the temporal beam stability, the so-called spillμstructure on the 100 µs scale. A pilot experiment was performed utilizing transverse emittance exchange to reduce the beam size in the extraction plane, and the improvement of spillμstructure was found. Important beam instrumentation comprises an Ionization Profile Monitor for beam profile measurement inside the synchrotron and a plastic scintillator at the external transfer line for ion counting with up to several 106 particles per second and 20 µs time slices. The performant data acquisition systems, including a scaler and a fast Time-to-Digital Converter (TDC), allow for determining the spill quality. The application of the TDC in the measurement and related MAD-X simulations are discussed.
Deep Neural Network for Beam Profile Classification in Synchrotron
323
M. Piekarski
NSRC SOLARIS, Kraków, Poland
Funding:The presented work has been achieved in collaboration with AGH University of Science and Technology in Kraków as a part of a PhD thesis. The main goal of NSRC SOLARIS is to provide scientific community with high quality synchrotron light. To achieve this, it is necessary to constantly monitor many subsystems responsible for beam stability and to analyze data about the beam itself from various diagnostic beamlines. In this work a deep neural network for transverse beam profile classification is proposed. Main task of the system is to automatically assess and classify transverse beam profiles based solely on the evaluation of the beam image from the Pinhole diagnostic beamline at SOLARIS. At the present stage, a binary assignment of each profile is performed: stable beam operation or unstable beam operation / no beam. Base model architecture consists of a pre-trained convolutional neural network followed by a densely-connected classifier and the system reaches accuracy at the level of 90%. The model and the results obtained so far are discussed, along with plans for future development.
High Accuracy Measurement of the Absolute Energy by Synchrotron Radiation Interferometry with Relativistic Electrons
P. Klag, P. Achenbach
KPH, Mainz, Germany
Funding:Supported by DFG (PO 256/7-1) Supported by the European Union’s Horizon 2020 programme, No 824093 The Mainz Microtron is an electron accelerator, which delivers electron energies up to 1.6 GeV, with a small spread of the energy <13keV. Besides a small energy spread, the high quality of the beam allows producing high coherent synchrotron radiation. The light from two spatially separated and movable light sources (undulators) can be superimposed to render an interference pattern. The ideal applications are high accuracy absolute energy measurements of the relativistic electrons. Experiments have been carried out at 180 MeV and 195 MeV. The radiation lies in the optical range where also Fresnel Diffraction patterns occur, which features allow very precise alignment control.
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Experimental Single Electron 6d Tracking in IOTA (remote contribution)
A.L. Romanov
Fermilab, Batavia, Illinois, USA
Funding:This work is supported by the U.S. Department of Energy under contract No. DE-AC02-07CH11359 This talk focuses on the upcoming first ever direct 6-dimensional tracking of a single electron in a storage ring with the goal to enable a new class of beam diagnostic technologies. This will allow high precision characterization of a single-particle dynamics. This works builds off previous experimental 3-dimensional tracking of the dynamics of a single electron in the Fermilab Integrable Optics Test Accelerator (IOTA)*. At IOTA, we will detect single photons randomly emitted by an electron over many turns to precisely reconstruct its trajectory. State of the art technologies of photon detection have temporal and spatial resolution sufficient for the high-precision tracking if coupled with advanced analysis algorithms. Complete tracking of a point-like object will enable the first measurements of single-particle dynamical properties, including dynamical invariants, amplitude-dependent oscillation frequencies, and chaotic behavior. These single-particle measurements will be employed for long-term tracking simulations, training of AI/ML algorithms, and ultimately for precise predictions of dynamics in present and future accelerators. * A. Romanov et al., ’Experimental 3-dimensional tracking of the dynamics of a single electron in the Fermilab Integrable Optics Test Accelerator,’ J. Instrum., vol. 16, P12009, Dec 2021
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Upgraded CMS Fast Beam Condition Monitor for LHC Run 3 Online Luminosity and Beam Induced Background Measurements
540
J.M. Wańczyk
CERN, Meyrin, Switzerland
The fast Beam Condition Monitor (BCM1F) for the CMS experiment at the LHC was upgraded for precision luminosity measurement in the demanding conditions foreseen for LHC Run3. BCM1F has been rebuilt with new silicon diodes, produced on the CMS Phase 2 Outer Tracker PS silicon wafers. The mechanical structure was adapted to include a 3D printed titanium circuit for active cooling of BCM1F sensors. The assembly and qualification of the detector quadrants were followed by the integration with Pixel Luminosity Telescope and Beam Conditions Monitor for Losses on a common carbon fibre carriage. This carriage was installed inside the CMS behind the Pixel detector, 1.9 m from the Interaction Point. BCM1F will provide a real-time luminosity measurement as well as a measurement of the beam-induced background, by exploiting the arrival time information of the hits with a sub-bunch crossing precision. Moreover, regular beam overlap scans at CMS were introduced during Run 2, enabling an independent and non-destructive transverse profile measurement for LHC Operators. The paper describes the improved BCM1F detector design, its commissioning and performance during the beginning of Run 3 operation.
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