| Paper | Title | Other Keywords | Page |
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| MOPOST042 | Using Dynamic Indicators for Probing Single-Particle Stability in Circular Accelerators | lattice, alignment, dynamic-aperture, simulation | 168 |
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| Computing the long-term behaviour of single-particle motion is a numerically intensive process, as it requires a large number of initial conditions to be tracked for a large number of turns to probe their stability. A possibility to reduce the computational resources required is to provide indicators that can efficiently detect chaotic motion, which are considered precursors to unbounded motion. These indicators could allow skilful selection of a set of initial conditions that could then be considered for long-term tracking. The chaotic nature of each orbit can be assessed by using fast-converging dynamic indicators, such as the Fast Lyapunov Indicator (FLI), the Reversibility Error Method (REM), and the Smallest and Global Alignment Index (SALI and GALI). These indicators are widely used in the field of Celestial Mechanics, but not so widespread in Accelerator Physics. They have been applied both to a modulated Hénon map, as a toy model, as well as to realistic lattices of the High-Luminosity LHC. In this paper, we discuss the results of detailed numerical studies, focusing on their performance in detecting chaotic motions. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST042 | ||
| About • | Received ※ 07 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 02 July 2022 | ||
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| MOPOPT017 | Terahertz Sampling Rates with Photonic Time-Stretch for Electron Beam Diagnostics | photon, electron, laser, data-acquisition | 263 |
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Funding: Supported by the Helmholtz Program-Oriented Funding (PoF), research program Matter and Technologies (Detector Technology and System), ANR-DFG ULTRASYNC funding program, CEMPI LABEX and Wavetech CPER. To understand the underlying complex beam diagnostic often large numbers of single-shot measurements must be acquired continuously over a long time with extremely high temporal resolution. Photonic time-stretch is a measurement method that is able to overcome speed limitations of con- ventional digitizers and enable continuous ultra-fast single- shot terahertz spectroscopy with refresh rates of trillions of consecutive frames. In this contribution, a novel ultra- fast data sampling system based on photonic time-stretch is presented and the performance is discussed. THERESA (TeraHErtz REadout SAmpling) is a data acquisition system based on the recent ZYNQ-RFSoC family. THERESA has been developed with an analog bandwidth up to 20 GHz and a sampling rate up to 90 GS/s. When combined with the photonic time-stretch setup, the system will be able to sample a THz signal with an unprecedented frame rate of 8 TS/s. Continuous acquisition for long observation times will open up new possibilities in the detection of rare events in accelerator physics. |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT017 | ||
| About • | Received ※ 08 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 05 July 2022 | ||
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| TUPOST029 | Small Talk on AT | interface, factory, controls, lattice | 918 |
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| Tracy 3 ’ was implemented by the 3rd author by pursuing a first principles approach, aka Hamiltonian dynamics for an on-line modeel to guide the ALS and LBL comissioning in the early 1990s. with its origin as a Hamiltonian based pascal online model used 90 ’ is the core of today’s accelerator tool box. These Hamiltonians have not been changed. Soft- ware design has evolved since then: C++ and in particular its standardisation C++11 and C++2xa. In this paper we out- line our strategy of modernisation of tracy: reorganisation of the beam dynamics library in cleanly designed modules, using well proven open-source libraries (GSL, armadillo) and so on. Furthermore, Python and Matlab Interfaces based on modern tools are being pursued. We report on the in- terface design, the status of modernisation. This project has been renamed to thor-scsi-lib and is available at Github. Collaboration’s welcome. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST029 | ||
| About • | Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 28 June 2022 | ||
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| TUPOST035 | BOLINA, a Suite for High Level Beam Optimization: First Experimental Results on the Adige Injection Beamline of SPES | diagnostics, database, EPICS, controls | 933 |
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| A high-level software BOLINA (Beam Orbit for LINear Accelerators) has been designed to fully characterise and automatically correct the ion beams trajectory, to help operators during the beam transport with an easily scalable suite for LINACs. Currently, the high-level software, interfaced with an EPICS control system, automatically manages accelerator devices to preserve the beam quality, including beam-based alignment and, if needed, dispersion-free steering software. The suite has been developed to satisfy and commutate the software easily on different machine, using interceptive /not interceptive diagnostics. The software was designed for ELI-np and now is under test at Legnaro National Laboratories of INFN using the installed accelerators complex. In particular, BOLINA has been successfully tested on the Adige Injector 1+ beamline of the SPES Project where the system response matrix is measured on interceptive beam diagnostic by varying both electrostatic and magnetic steerers. This paper describes results and strategies to reduce trajectory residuals close to the diagnostic resolutions and their effectiveness to prepare the commissioning of LINACs. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST035 | ||
| About • | Received ※ 12 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 16 June 2022 | ||
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| TUPOST059 | PyEmittance: A General Python Package for Particle Beam Emittance Measurements with Adaptive Quadrupole Scans | emittance, quadrupole, simulation, experiment | 1003 |
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| The emittance of a particle beam is a critically important parameter for many particle accelerator applications. Its measurements guide the initial tuning of an accelerator and are typically done using quadrupole or wire scans. Quadrupole scans are time-intensive, and it can be difficult to determine scan values that provide a good emittance measurement. To address this issue, we describe an adaptive quadrupole scan method that automates the determination of the scan range. With a given initial set of scanning values, our method adapts the range to capture the waist of the beam, and returns the Twiss parameters and a measure of the beam matching at the measurement screen. With the added capability to repeat beam size measurements when needed, this method provides a reliable measurement of the emittance even with sub-optimal initial conditions. To efficiently integrate these measurements into Python-based machine learning optimizations, the method was developed into a Python package, PyEmittance, at the SLAC National Accelerator Laboratory. We present the experimental tests of PyEmittance as performed at the Linac Coherent Light Source (LCLS) and the Facility for Advanced Accelerator Experimental Test (FACET-II). | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST059 | ||
| About • | Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 17 June 2022 | ||
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| TUPOPT028 | THz Undulator Radiation Based on Super-Radiant Technique at Chiang Mai University | undulator, radiation, electron, simulation | 1067 |
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| A linear accelerator system at the PBP-CMU Electron Linac Laboratory is used as an electron source for generating coherent THz radiation and MIR-FEL. To achieve high power THz radiation, the super-radiant technique using pre-bunched electrons and undulator magnet is utilized. In this study, we investigate the generation of such radiation with comparable properties as the FEL. The beamline composes of a 180-degree magnetic bunch compressor, a 2 m-electromagnet undulator, quadrupole magnets and diagnostic devices. This work includes the undulator design and investigation on properties of electron beam and THz radiation. Based-on the results of beam dynamic study, the optimized electron beams have an energy in a range of 10-16 MeV, a bunch charge of 100 pC, and a bunch length of 300 fs. The radiation with frequency covering from 0.5 to 3 THz yields a peak power of 5.21 MW at 1.15 THz. This information was used as an initial parameter for undulator design by using the CST-EM Studio software. It has 19.5 periods with a period length of 100 mm. The design results show that the maximum magnetic field is 0.2317 T. The results of this study are used as the guideline for construction of the undulator and the THz-FEL beamline. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT028 | ||
| About • | Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 27 June 2022 | ||
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| TUPOPT063 | Vsystem to EPICS Control System Transition at the ISIS Accelerators | controls, EPICS, interface, hardware | 1156 |
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| The ISIS Neutron and Muon Source at Rutherford Appleton Laboratory is a pulsed source used for research in material and life sciences. A linac and synchrotron accelerate protons to produce neutrons in two spallation targets. The accelerators are currently operated using commercial Vsystem control software. A transition to the EPICS control system is underway, with the end goal of a containerised system preferring the pvAccess protocol. We report the progress of this transition, which is being done without disrupting ISIS operations. We describe a bidirectional interface between Vsystem and EPICS that enables the two control systems to co-exist and interact. This allows us to decouple the transition of controls UI from the associated hardware. Automated conversion of the binary-format Vsystem control screens has been developed that replicates the current interface in EPICS, allowing minimal retraining of operators. We also outline the development of EPICS interfaces to standard and unique-to-ISIS hardware, reuse of and managing continuity of existing long-term data archiving, the development of EPICS interfaces to standard and unique-to-ISIS hardware, and migration of alerts. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT063 | ||
| About • | Received ※ 25 May 2022 — Accepted ※ 13 June 2022 — Issue date ※ 16 June 2022 | ||
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| TUPOMS016 | A Pipeline for Orchestrating Machine Learning and Controls Applications | simulation, controls, operation, framework | 1439 |
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| Machine learning and artificial intelligence are becoming widespread paradigms in control of complex processes. Operation of accelerator facilities is not an exception, with a number of advances having happened over the last years. In the domain of intelligent control of accelerator facilities, the research has mostly been focused on feasibility demonstration of ML-based agents, or application of ML-based agents to a well-defined problem such as parameter tuning. The main challenge on the way to a more holistic AI-based operation, in our opinion, is of engineering nature and is related to the need of significant reduction of the amount of human intervention. The areas where such intervention is still significant are: training and tuning of ML models; scheduling and orchestrating of multiple intelligent agents; data stream handling; configuration management; and software testing and verification requiring advanced simulation environment. We have developed a software framework which attempts to address all these issues. The design and implementation of this system will be presented, together with application examples for the PETRA III storage ring. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS016 | ||
| About • | Received ※ 09 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 25 June 2022 | ||
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| TUPOMS022 | Cooling Challenges in a NEG-Coated Vacuum Chamber of a Light Source | vacuum, simulation, radiation, synchrotron | 1456 |
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| In a light Source, unused synchrotron radiation is being distributed along the walls of the chambers. Due to the small conductance of the chambers, vacuum pumping is based on the distributed concept, and then non-evaporable getter (NEG) coating is extensively used. The vacuum chambers are made of copper alloys tube, and cooling circuits are welded to the chamber to remove the heat load from the radiation generated. Filler metal is used to create a brazed joint between the water cooling pipe and the vacuum chamber body. The thermal conductivity of the fillers is less than the vacuum chamber body. Moreover, the water velocity in the cooling pipe must be taken into account in thermal calculations. In this paper, we study and investigate the effects of the filler metal and the cooling water velocity in cooling the chambers. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS022 | ||
| About • | Received ※ 20 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 28 June 2022 | ||
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| THPOTK026 | Development and Test of a Program for Automatic Conditioning of Room Temperature Cavities | cavity, experiment, rfq, interface | 2823 |
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| The conditioning of room temperature cavities is a time-consuming process that can take several weeks and requires the supervision of experienced experimenters. To simplify this process for future cavities, a program is currently being developed at the IAP Frankfurt that will simplify the experimenter’s work and eventually take it over completely. This paper describes the basic setup of the program so far, as well as the tests performed on different cavities so far. In addition, an outlook for the next development steps and their application is given. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK026 | ||
| About • | Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 16 June 2022 | ||
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| THPOTK057 | ESS RFQ Experimental Modal Analysis | rfq, experiment, damping, cavity | 2907 |
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| The European Spallation Source-ESS, which is currently under construction and commissioning at Lund, Sweden is a neutron source that consists of a 2 GeV linear accelerator (LINAC) accelerating a proton beam to a solid Tungsten (W) target. The proton beam is produced by the Ion Source (ISRC) and transported through the Low Energy Beam Transport (LEBT) to the Radio Frequency Quadrupole (RFQ) that will then focus, bunch and accelerate it to 3.6 MeV. The RFQ beam commissioning started in October 2021, following the RF conditioning phase in summer 2021. This current work presents an experimental modal analysis performed on RFQ including the comparative analysis with the modal finite element simulation using the ANSYS software suite. Measurements were performed using accelerometer sensors connected to a data acquisition system excited with an impact hammer. Geophones were used in parallel to the modal measurements in order to monitor the seismic background of the accelerator tunnel. Acquired data were post-processed and analysed with dedicated software, juxtaposed with simulated results in order to determine the resonance frequencies, structural deformation patterns (mode shapes) and error margin between experimental and simulated results. | |||
| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK057 | ||
| About • | Received ※ 07 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 17 June 2022 | ||
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| THPOTK062 | Thermal Modeling and Benchmarking of Crystalline Laser Amplifiers | laser, simulation, experiment, ECR | 2921 |
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Funding: This work is supported by the US Department of Energy, Office of High Energy Physics under Award Numbers DE-SC0020931 and DE-AC02-05CH11231. Ti:sapphire crystals constitute the lasing medium of a class of lasers valued for their wide tunability and ultra-short, ultra-high intensity pulses. When operated at high power and high repetition rate (1kHz), such lasers experience multiple effects that can degrade performance. In particular, thermal gradients induce a spatial variation in the index of refraction, hence thermal lensing*. Using the open-source finite-element code FEniCS***, we solve the relevant partial differential equations to obtain a quantitative measure of the disruptive effects of thermal gradients on beam quality. We present thermal simulations of a pump laser illuminating a Ti:sapphire crystal. From these simulations we identify the radial variation in the refractive index, and hence the extent of thermal lensing. In addition, we present analytic models used to estimate the effect of thermal gradients on beam quality. This work generalizes to other types of crystal amplifiers. * S. Cho, et al., Appl. Phys. Express, 11:092701, 2018. ** M. Born & E. Wolf, Principles of Optics, Cambridge Univ. Press, 1980. *** The FEniCS computing platform, https://fenicsproject.org |
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| DOI • | reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK062 | ||
| About • | Received ※ 13 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 17 June 2022 | ||
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