IPAC2021 - Classification: MC5: Beam Dynamics and EM Fields / D11 Code Developments and Simulation Techniques

Paper	Title	Page
MOPAB028	Using Machine Learning to Improve Dynamic Aperture Estimates	134
	F.F. Van der Veken, M. Giovannozzi, E.H. Maclean CERN, Geneva, Switzerland C.E. Montanari Bologna University, Bologna, Italy G. Valentino University of Malta, Information and Communication Technology, Msida, Malta
	The dynamic aperture (DA) is an important concept in the study of nonlinear beam dynamics. Several analytical models used to describe the evolution of DA as a function of time, and to extrapolate to realistic time scales that would not be reachable otherwise due to computational limitations, have been successfully developed. Even though these models have been quite successful in the past, the fitting procedure is rather sensitive to several details. Machine Learning (ML) techniques, which have been around for decades and have matured into powerful tools ever since, carry the potential to address some of these challenges. In this paper, two applications of ML approaches are presented and discussed in detail. Firstly, ML has been used to efficiently detect outliers in the DA computations. Secondly, ML techniques have been applied to improve the fitting procedures of the DA models, thus improving their predictive power.
	Poster MOPAB028 [1.764 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB028
About •	paper received ※ 18 May 2021 paper accepted ※ 25 May 2021 issue date ※ 12 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPAB059	Tools for Use of Generalized Gradient Expansions in Accelerator Simulations	253
	M. Borland, R.R. Lindberg, R. Soliday, A. Xiao ANL, Lemont, Illinois, USA
	Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. A common assumption in simulation of accelerators is that the magnets can be approximated using a hard-edge model, perhaps with some edge effects implemented in an impulse approximation. This is usually a good assumption but ignores details of the longitudinal variation of the magnetic fields, which makes it straightforward to implement symplectic tracking. Use of generalized gradient expansions* provides an alternative approach that can suppress numerical deficiencies that may be present in computed or measured 3D field maps. However, the computation of the expansions is not particularly straightforward. In this note, we describe several recently-developed tools that make this process fairly painless and allow tracking with such expansions in the program ELEGANT*. We show several examples of using the tools for simulations related to the Advanced Photon Source Upgrade. M. Venturini et al., NIM A 427, 387 (1999). ** M. Borland, Advanced Photon Source LS-287, September 2000
	Poster MOPAB059 [4.311 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB059
About •	paper received ※ 17 May 2021 paper accepted ※ 26 May 2021 issue date ※ 18 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPAB070	mbtrack2, a Collective Effect Library in Python	282
	A. Gamelin, W. Foosang, R. Nagaoka SOLEIL, Gif-sur-Yvette, France
	This article introduces mbtrack2, a collective effect library written in python3. The idea behind mbtrack2 is to build a coherent object-oriented framework to work on collective effects in synchrotrons. mbtrack2 is composed of different modules allowing to easily write scripts for single bunch or multi-bunch tracking using MPI parallelization in a transparent way. The base of the tracking model of mbtrack2 is inspired by mbtrack, a C multi-bunch tracking code initially developed at SOLEIL. In addition, many tools to prepare or analyse tracking simulations are included. R. Nagaoka, R. Bartolini, and J. Rowland, Studies of Collective Effects in SOLEIL and Diamond Using the Multiparticle Tracking Codes SBTRACK and MBTRACK, in Proc. PAC’09, 2009.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB070
About •	paper received ※ 17 May 2021 paper accepted ※ 06 July 2021 issue date ※ 16 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPAB203	Electromagnetic Simulations of a Novel Proton Linac Using VSim on HPC	1887
	S.I. Sosa Guitron, S. Biedron, T.B. Bolin UNM-ECE, Albuquerque, USA J.R. Cary Tech-X, Boulder, Colorado, USA M.S. Curtin, B. Hartman, T. Pressnall, D.A. Swenson Ion Linac Systems, Inc., Albuquerque, USA
	Funding: This work is supported by the U.S. Department of Energy, award number DE-SC0019468; It used resources of the Argonne Leadership Computing Facility, contract DE-AC02-06CH11357, and from Element Aero. We discuss electromagnetic simulations of accelerating structures in a high performance computing (HPC) system. Our overarching goal is to resolve the linac operation in a large ensemble of initial beam conditions. This requires a symbiotic relation between the electromagnetic solver and HPC. The linac is being developed by Ion Linac Systems to produce a low-energy, high-current, proton beam. We use VSim, an electromagnetic solver and PIC software developed by Tech-X to determine the electromagnetic fundamental mode of operation of the accelerating structures and discuss its implementation at the THETA supercomputer in the Argonne Leadership Computing Facility.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB203
About •	paper received ※ 20 May 2021 paper accepted ※ 17 June 2021 issue date ※ 10 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPAB209	The Particle Tracking Code Fixfield	1905
	J.-B. Lagrange STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	FixField is a code developed to track particles in Fixed Field alternating gradient Accelerators (FFAs). This paper discusses the structure and features of the code.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB209
About •	paper received ※ 19 May 2021 paper accepted ※ 02 July 2021 issue date ※ 25 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPAB215	Novel Non-Linear Particle Tracking Approach Employing Lie Algebraic Theory in the TensorFlow Environment	1920
	J. Frank, M. Arlandoo, P. Goslawski, J. Li, T. Mertens, M. Ries, L. Vera Ramirez HZB, Berlin, Germany
	With this paper we present first results for encoding Lie transformations as computational graphs in Tensorflow that are used as layers in a neural network. By implementing a recursive differentiation scheme and employing Lie algebraic arguments we were able to reproduce the diagrams for well known lattice configurations. We track through simple optical lattices that are encountered as the main constituents of accelerators and demonstrate the flexibility and modularity our approach offers. The neural network can represent the optical lattice with predefined coefficients allowing for particle tracking for beam dynamics or can learn from experimental data to fine-tune beam optics.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB215
About •	paper received ※ 12 May 2021 paper accepted ※ 31 August 2021 issue date ※ 21 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPAB266	Periodic Transient Beam Loading Effects Predicted by a Semi-Analytical Method	2086
	T.L. He, Z.H. Bai, G. Feng, W. Li, W.W. Li, G. Liu, L. Wang, H. Xu, S.C. Zhang USTC/NSRL, Hefei, Anhui, People’s Republic of China
	In this paper, we improve a semi-analytical method, which can be not only used for bunch lengthening under equilibrium conditions, but also applied to the prediction of a periodic transient beam loading effect. This periodic transient is induced by the presence of the passive harmonic cavity and might be encountered under specific conditions for a ultra-low emittance storage ring with a higher beam current.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB266
About •	paper received ※ 16 May 2021 paper accepted ※ 21 June 2021 issue date ※ 24 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPAB024	Release of Crystal Routine for Multi-Turn Proton Simulations within SixTrack v5	2648
	M. D’Andrea, A. Mereghetti, D. Mirarchi, V.K.B. Olsen, S. Redaelli CERN, Geneva, Switzerland
	Crystal collimation is studied as a possible scheme to further improve the efficiency of ion collimation at the High Luminosity Large Hadron Collider (HL-LHC), as well as for possible applications in the CERN program of Physics Beyond Colliders. This concept relies on the use of bent crystals that can deflect high-energy halo particles at large angles, of the order of tens of urad. In order to reproduce key experimental results of crystal collimation tests and predict the performance of this system when applied to present and future machines, a dedicated simulation routine was developed. This routine is capable of modeling both coherent and incoherent interactions of beam particles with crystal collimators, and is fully integrated into the magnetic tracking and collimator modeling provided by the single-particle tracking code SixTrack. This paper describes the implementation of the routine in the latest version of SixTrack and its most recent improvements, in particular regarding the treatment of the crystal miscut angle.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB024
About •	paper received ※ 19 May 2021 paper accepted ※ 23 June 2021 issue date ※ 14 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPAB105	Simulating Electron Impact Ionization Using a General Particle Tracer (GPT) Custom Element	2843
	J.T. Yoskowitz, G.A. Krafft ODU, Norfolk, Virginia, USA J.M. Grames JLab, Newport News, Virginia, USA G.R. Montoya Soto Universidad de Guanajuato, División de Ciencias e Ingenierías, León, Mexico C.A. Valerio ECFM-UAS, Culiacan, Sinaloa, Mexico S.B. van der Geer Pulsar Physics, Eindhoven, The Netherlands
	Funding: U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177, Consejo Nacional de Ciencia y Tecnología (CONACYT). A new C++ custom element has been developed with the framework of General Particle Tracer (GPT) to simulate electron impact ionization of residual gas molecules. The custom element uses Monte-Carlo routines to determine both the ion production rate and the secondary electron kinetic energy based on user-defined gas densities and theoretical values for the ionization cross section and the secondary electron differential cross section. It then uses relativistic kinematics to track the secondary electron, the scattered electron, and the newly formed ion after ionization. The ion production rate and the secondary electron energy distribution determined by the custom element have been benchmarked against theoretical calculations and against simulations made using the simulation package IBSimu. While the custom element was originally built for particle accelerator simulations, it is readily extensible to other applications. The custom element will be described in detail and examples of applications at the Thomas Jefferson National Accelerator Facility will be presented for ion production in a DC high voltage photo-gun.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB105
About •	paper received ※ 20 May 2021 paper accepted ※ 25 June 2021 issue date ※ 19 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPAB203	RFQ Beam Dynamics Optimization Using Machine Learning	3100
	D. Koser, J.M. Conrad, L.H. Waites, D. Winklehner MIT, Cambridge, Massachusetts, USA A. Adelmann, M. Frey, S. Mayani PSI, Villigen PSI, Switzerland
	To efficiently inject a high-current H²⁺ beam into the 60 MeV driver cyclotron for the proposed IsoDAR project in neutrino physics, a novel direct-injection scheme is planned to be implemented using a compact radio-frequency quadrupole (RFQ) as a pre-buncher, being partially inserted into the cyclotron yoke. To optimize the RFQ beam dynamics design, machine learning approaches were investigated for creating a surrogate model of the RFQ. The required sample datasets are generated by standard beam dynamics simulation tools like PARMTEQM and RFQGen or more sophisticated PIC simulations. By reducing the computational complexity of multi-objective optimization problems, surrogate models allow to perform sensitivity studies and an optimization of the crucial RFQ beam output parameters like transmission and emittances. The time to solution might be reduced by up to several orders of magnitude. Here we discuss different methods of surrogate model creation (polynomial chaos expansion and neural networks) and identify present limitations of surrogate model accuracy.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB203
About •	paper received ※ 20 May 2021 paper accepted ※ 01 July 2021 issue date ※ 30 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPAB214	Realistic Simulations of Stray Field Impact on Low Energy Transfer Lines	3130
	V. Rodin, S. Padden, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom A. Farricker, S. Padden, V. Rodin, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom J. Resta-López UVEG, Burjasot (Valencia), Spain
	Funding: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 721559. Low energy (~100 keV) facilities working with antiprotons, heavy ions, or charged molecules may experience severe beam transport instabilities caused by field imperfections. For example, long (~10 m), unshielded beamlines will not be able to transfer particles due to the natural Earth magnetic field or stray fields from closely located experiments. Currently, only a limited number of simulation codes allow a simplified representation of such field errors, limiting capabilities for beam delivery optimization. In this contribution, a new simulation approach is presented that can provide detailed insight into 4D beam transport. It illustrates the impact of imperfections and stray fields on beam stability and quality through simulations of two antiproton experiments located in the Antimatter Factory (AD) at CERN in Geneva, Switzerland. Magnetic field imperfections are examined in two different ways, providing greater flexibility and an opportunity to benchmark all outcomes. Simulation performance is analyzed as a function of the level of detail and efficiency.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB214
About •	paper received ※ 19 May 2021 paper accepted ※ 12 July 2021 issue date ※ 18 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPAB215	Simulation of Intra-Beam Scattering in PyHEADTAIL	3134
	V. Rodin, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom A. Oeftiger GSI, Darmstadt, Germany V. Rodin, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: This project has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No 721559 High-intensity beams in low-energy synchrotrons are subject to space charge as well as intra-beam scattering (IBS). Accurate modelling of both effects becomes essential when the transverse emittances and minimum bunch length are determined through heating processes and resonances induced by machine errors. To date, only very few tools available to the general public allow to simultaneously study space charge and IBS in self-consistent simulations. In this contribution, we present our recent development of an IBS module for PyHEADTAIL, an open-source 6D multi-particle tracking tool, which already includes various 2.5D and 3D space-charge models based on the self-consistent particle-in-cell algorithm. A simulation example of high-intensity bunch rotation demonstrates the joint impact of applied heating effects. Our model is based on the Martini and Bjorken-Mitingwa theories. Benchmarks of our implementation against IBS modules provided in the MAD-X and JSPEC codes are shown.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB215
About •	paper received ※ 23 May 2021 paper accepted ※ 14 July 2021 issue date ※ 13 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB129	Beam Dynamics Simulations in a High-Gradient X-Band Photoinjector	4013
	W.H. Tan, P. Piot Northern Illinois University, DeKalb, Illinois, USA G. Chen, S.V. Kuzikov Euclid TechLabs, Solon, Ohio, USA G. Chen IIT, Chicago, Illinois, USA G. Ha, C.-J. Jing ANL, Lemont, Illinois, USA C.-J. Jing Euclid Beamlabs, Bolingbrook, USA
	A high-gradient X-band (11.7-GHz) photoinjector was recently developed by Euclid Techlabs and is in its commissioning phase at the Argonne Wakefield Accelerator (AWA). This contribution discuss the beam-dynamics modeling of the photoinjector system comprising an RF gun and linac section. We especially discuss beam-dynamics optimization of setup for an integrated proof-of-principle experiments. We also discuss the use of such a photoinjector as a witness-bunch source for a future high-gradient collinear-wakefield accelerator experiments at the AWA. * S. V. Kuzikov, et al. these proceedings.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB129
About •	paper received ※ 20 May 2021 paper accepted ※ 14 July 2021 issue date ※ 31 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB134	Development and Analysis of Software for the Numerical Simulation of Field Emission Electron Sources	4024
	N.S. Kakorin, K.A. Nikiforov Saint Petersburg State University, Saint Petersburg, Russia N.V. Egorov St. Petersburg State University, St. Petersburg, Russia
	Funding: The reported study was funded by RFBR, project number 20-07-01086. The open-source DAISI C++ package (Design of Accelerators, optImizations and SImulations) is extended with the ability to simulate the operation of electron sources in the field emission mode, with the user-defined initial distribution of emitted electrons velocities, as a model parameter, and with the automated calculation of current-voltage characteristics. Particles injection scheme is suggested. Computational experiments are performed for silicon carbide field emission electron source nanostructure with bimodal energy spectrum, revealed from experimental study, and comparative analysis with Maxwell distribution is presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB134
About •	paper received ※ 20 May 2021 paper accepted ※ 27 July 2021 issue date ※ 17 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB174	T-BMT Spin Resonance Tracker Code for He3 with Six Snakes	4101
	V.H. Ranjbar, H. Huang, Y. Luo, F. Méot, V. Ptitsyn BNL, Upton, New York, USA G.H. Hoffstaetter, D. Sagan Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA F. Lin, V.S. Morozov JLab, Newport News, Virginia, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy . Polarization lifetime for He3 using two and six snakes are studied using the T-BMT Spin Resonance Tracker code. This code integrates a reduced spinor form of the T-BMT equation including only several spin resonances and the kinematics of synchrotron motion. It was previously benchmarked against RHIC polarization lifetime under the two snake system . Phys. Rev.Accel. Beams 22 (2019) 9, 091001
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB174
About •	paper received ※ 20 May 2021 paper accepted ※ 02 July 2021 issue date ※ 28 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB186	Review of Proton Linac Beam Dynamic Simulation Code	4137
	X.Y. Feng, J. Peng IHEP CSNS, Guangdong Province, People’s Republic of China
	CSNS-II project design a linac accelerates 40 mA H⁻ beam from 3.8 MeV to 300 MeV, which should not only overcome the space-charge effect at low energy but also have high efficiency at high energy. Therefore, lots of simulation studies should be done on a variety of codes. Each of them has its own characteristics. For example, MAD can easily match quadrupole fast while it couldn’t do the multiparticle calculation. This paper will introduce some common and efficient code used to design linac and study beam dynamic performance.
	Poster THPAB186 [0.880 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB186
About •	paper received ※ 17 May 2021 paper accepted ※ 08 July 2021 issue date ※ 11 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB189	New Techniques to Compute the Linear Tune	4142
	G. Russo, M. Giovannozzi CERN, Geneva, Switzerland G. Franchetti GSI, Darmstadt, Germany
	Tune determination in numerical simulations is an essential aspect of nonlinear beam dynamics studies. In particular, because it allows probing whether an initial condition is close to resonance, and it enables assessment of the stability of the orbit, i.e. whether the motion is regular or chaotic. In this paper, results of recently developed techniques to obtain accurate tune computation from numerical simulation data are presented and discussed in detail.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB189
About •	paper received ※ 18 May 2021 paper accepted ※ 26 July 2021 issue date ※ 19 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB190	Optimising and Extending a Single-Particle Tracking Library for High Parallel Performance	4146
	M. Schwinzerl, H. Bartosik, R. De Maria, G. Iadarola, K. Paraschou CERN, Geneva, Switzerland A. Oeftiger GSI, Darmstadt, Germany M. Schwinzerl KFUG/IMSC, Graz, Austria
	SixTrackLib is a library for performing beam-dynamics simulations on highly parallel computing devices such as shared memory multi-core processors or graphical processing units (GPUs). Its single-particle approach fits very well with parallel implementations with reasonable baseline performance, making such a library an interesting building block for various use cases, including simulations covering collective effects. We describe optimizations to improve their performance on SixTrackLib’s main target platforms and the associated performance gains. Finally, we outline the implemented technical interfaces and extensions that allow SixTrackLib to be used in a wider range of applications and studies.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB190
About •	paper received ※ 18 May 2021 paper accepted ※ 14 July 2021 issue date ※ 16 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB191	Physics-Enhanced Reinforcement Learning for Optimal Control	4150
	A.N. Ivanov, I.V. Agapov, A. Eichler, S. Tomin DESY, Hamburg, Germany
	We propose an approach for incorporating accelerator physics models into reinforcement learning agents. The proposed approach is based on the Taylor mapping technique for simulation of the particle dynamics. The resulting computational graph is represented as a polynomial neural network and embedded into the traditional reinforcement learning agents. The application of the model is demonstrated in a nonlinear simulation model of beam transmission. The comparison of the approach with the traditional numerical optimization as well as neural networks based agents demonstrates better convergence of the proposed technique.
	Poster THPAB191 [0.846 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB191
About •	paper received ※ 11 May 2021 paper accepted ※ 29 July 2021 issue date ※ 24 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB192	Continuous Beam Dynamics Simulation in COMSOL Multiphysics	4153
	D. Popov, O. Karamyshev, I.D. Lyapin, V. Malinin JINR/DLNP, Dubna, Moscow region, Russia
	The classic way of beam dynamics simulation in a cyclotron is to separate it into many different stages from the ion source to the extraction (or even further), this was absolutely necessary to fit the calculations into any reasonable time in a cost of influence of some operation devices from one stage, on beam dynamics of another (next or previous mostly) stage. We’ve managed to perform beam dynamics from ion source through a solenoid to the center region in a single model in COMSOL, using several fields simultaneously: external magnetic (the magnet), calculated magnetic (the solenoid) and alternating and stationary electric fields in the center region.
	Poster THPAB192 [1.233 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB192
About •	paper received ※ 19 May 2021 paper accepted ※ 23 June 2021 issue date ※ 17 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB197	Enhancing Efficiency of Multi-Objective Neural-Network-Assisted Nonlinear Dynamics Lattice Optimization via 1-D Aperture Objectives & Objective Focusing	4156
	Y. Hidaka, D.A. Hidas, F. Plassard, T.V. Shaftan, G.M. Wang BNL, Upton, New York, USA
	Funding: This work is supported by U.S. DOE under Contract No. DE-SC0012704. Mutli-objective optimizers such as multi-objective genetic algorithm (MOGA) have been quite popular in discovering desirable lattice solutions for accelerators. However, even these successful algorithms can become ineffective as the dimension and range of the search space increase due to exponential growth in the amount of exploration required to find global optima. This difficulty is even more exacerbated by the resource-intensive and time-consuming tendency for the evaluations of nonlinear beam dynamics. Lately the use of surrogate models based on neural network has been drawing attention to alleviate this problem. Following this trend, to further enhance the efficiency of nonlinear lattice optimization for storage rings, we propose to replace typically used objectives with those that are less time-consuming and to focus on a single objective constructed from multiple objectives, which can maximize utilization of the trained models through local optimization and objective gradient extraction. We demonstrate these enhancements using a NSLS-II upgrade lattice candidate as an example.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB197
About •	paper received ※ 20 May 2021 paper accepted ※ 23 June 2021 issue date ※ 10 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB199	Studies of Longitudinal Beam Losses at LHC Injection	4164
	L.E. Medina Medrano, T. Argyropoulos, R. Calaga, H. Timko CERN, Geneva, Switzerland
	Funding: Research supported by the HL-LHC project. Due to higher beam intensities, the required rf power in the High-Luminosity LHC (HL-LHC) era is expected to be at the limit of the available rf power. To mitigate potential limitations of the rf system, the injection voltage can be reduced at the expense of beam losses. In this paper, the average and bunch-by-bunch losses are estimated from Run 2 beam intensity measurements in the SPS before extraction and in the LHC after injection. Macro-particle simulations are performed with CERN’s Beam Longitudinal Dynamics code to reproduce the observed SPS-to-LHC capture and LHC flat-bottom losses. First estimates of injection losses for the HL-LHC at different injection voltages and injection energy errors are discussed.
	Poster THPAB199 [2.428 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB199
About •	paper received ※ 18 May 2021 paper accepted ※ 28 July 2021 issue date ※ 14 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB200	Cavity Control Modelling for SPS-to-LHC Beam Transfer Studies	4168
	L.E. Medina Medrano, T. Argyropoulos, P. Baudrenghien, H. Timko CERN, Geneva, Switzerland
	Funding: Research supported by the HL-LHC project. To accurately simulate injection losses in the LHC and the High-Luminosity LHC era, a realistic beam distribution model at SPS extraction is needed. To achieve this, the beam-loading compensation by the SPS cavity controller has to be included, as it modulates the bunch positions with respect to the rf buckets. This dynamic cavity control model also allows generating a more realistic beam halo, from which the LHC injection losses will mainly originate. In this paper, the implementation of the present SPS cavity controller in CERN’s Beam Longitudinal Dynamics particle tracking code is described. Just like in the machine, the feedback and feedforward controls are included in the simulation model, as well as the generator-beam-cavity interaction. Benchmarking against measurements of the generated beam distributions at SPS extraction are presented.
	Poster THPAB200 [4.164 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB200
About •	paper received ※ 18 May 2021 paper accepted ※ 27 July 2021 issue date ※ 26 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB201	A Machine Learning Technique for Dynamic Aperture Computation	4172
	B. Dalena, M. Ben Ghali CEA-IRFU, Gif-sur-Yvette, France
	Currently, dynamic aperture calculations of high-energy hadron colliders are performed through computer simulations, which are both a resource-heavy and time-costly processes. The aim of this study is to use a reservoir computing machine learning model in order to achieve a faster extrapolation of dynamic aperture values. A recurrent echo-state network (ESN) architecture is used as a basis for this work. Recurrent networks are better fitted to extrapolation tasks while the reservoir echo-state structure is computationally effective. Model training and validation is conducted on a set of "seeds" corresponding to the simulation results of different machine configurations. Adjustments in the model architecture, manual metric and data selection, hyper-parameters tuning and the introduction of new parameters enabled the model to reliably achieve good performance on examining testing sets.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB201
About •	paper received ※ 14 May 2021 paper accepted ※ 22 July 2021 issue date ※ 02 September 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB202	Problem and Solution with the Longitudinal Tracking of the ORBIT Code	4176
	L.H. Zhang, J.Y. Tang IHEP, Beijing, People’s Republic of China Y.K. Chen IHEP CSNS, Guangdong Province, People’s Republic of China L.H. Zhang University of Chinese Academy of Sciences, Beijing, People’s Republic of China
	The ORBIT code has been widely used for beam dynamics simulations including injection and acceleration in high-intensity hadron synchrotrons. When the ORBIT’s 1D longitudinal tracking was employed for the acceleration process in CSNS/RCS, the longitudinal emittance in eV-s was found decreasing substantially during acceleration, though the adiabatic condition is still met during this process. This is against the Liouville theorem that predicts the preservation of the emittance during acceleration. The recent machine study in the accelerator and the simulations with a self-made code demonstrate that the longitudinal emittance is almost invariant, which further indicates that the ORBIT longitudinal tracking might be incorrect. A detailed check-over in the ORBIT code source finds that the longitudinal finite difference equation used in the code is erroneous when applied to an acceleration process. The new code format PyORBIT has the same problem. After the small secondary factor is included in the code, ORBIT can produce results keeping the longitudinal emittance invariant. This paper presents some details about the study.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB202
About •	paper received ※ 14 May 2021 paper accepted ※ 01 July 2021 issue date ※ 21 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB203	Update of the Tracking Code RF-Track	4180
	A. Latina CERN, Geneva, Switzerland
	During the last couple of years, the RF-Track particle tracking code has seen a tremendous increase in the number of its applications: medical linacs, compact injector electron guns, and positron sources are among the main ones. Following a work of consolidation of its internal structure, new simulation capabilities have been introduced, together with several new effects: arbitrary orientation of elements in space, full element overlap, short- and long-range wakefields, and laser-beam interaction through Compton scattering are the most significant ones. In this paper, some of these new features are presented and discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB203
About •	paper received ※ 14 May 2021 paper accepted ※ 02 August 2021 issue date ※ 01 September 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB204	End-to-End RMS Envelope Model of the ISAC-I Linac	4183
	O. Shelbaya, R.A. Baartman, O.K. Kester TRIUMF, Vancouver, Canada
	A full end-to-end simulation of the ISAC-I linear accelerator has been built in the first order envelope code TRANSOPTR. This enables the fast tracking of rms sizes and correlations for a 6-dimensional hyperellipsoidal beam distribution defined around a Frenet-Serret reference particle frame, for which the equations guiding envelope evolution are numerically solved through a model of the machine’s electromagnetic potentials. Further, the adopted formalism enables the direct integration of energy gain via time-dependent accelerating potentials, without resorting to transit-time factors.
	Poster THPAB204 [0.627 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB204
About •	paper received ※ 18 May 2021 paper accepted ※ 08 July 2021 issue date ※ 31 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB206	Validating pyORBIT for Modeling Beam Dynamics in the IOTA Ring	4190
	R. Li UW-Madison/PD, Madison, Wisconsin, USA J.-F. Ostiguy, T. Sen Fermilab, Batavia, Illinois, USA
	Funding: Supported by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics. The Integrable Optics Test Accelerator (IOTA) ring is a new Fermilab facility dedicated to beam physics experiments, currently operating with 150 MeV electrons. Space charge effects are expected to be significant when it operates with 2.5 MeV protons. In this contribution, we present results of a suite of validation tests of PyORBIT, a PICstyle space charge code. Single particle dynamics of quasiintegrable optics using an octupole string in IOTA is compared with MADX, and shown to be in good agreement. Requirements for the convergence of space charge computations are systematically established and when possible, tests involving space charge are compared with theoretical predictions.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB206
About •	paper received ※ 19 May 2021 paper accepted ※ 08 July 2021 issue date ※ 12 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB207	Beam Dynamics Simulation about the Dual Harmonic System by PyORBIT	4194
	H.Y. Liu, X.Y. Feng, L. Huang, M.T. Li, X.H. Lu IHEP CSNS, Guangdong Province, People’s Republic of China S. Wang, S.Y. Xu IHEP, Beijing, People’s Republic of China
	The space charge effect is a strong limitation in high-intensity accelerators, especially for low- and medium-energy proton synchrotrons. And for CSNS-II, the number of particles in the RCS is 3.9·10¹³ ppp, which is five times of CSNS. To mitigate the effects of the strong space charge effect, CSNS-II/RCS (Rapid Cycling Synchrotron) will use a dual harmonic system to increase the bunching factor during the injection and the initial acceleration phase. For studying the beam dynamics involved in a dual harmonic RF system, PyORBIT is used as the major simulation code, which is developed at SNS to simulate beam dynamics in accumulation rings and synchrotrons. We modified parts of the code to make it applicable to the beam dynamic in RCS. This paper includes the major code modification of the Dual Harmonic RF system and some benchmark results. The preliminary simulation results of the dual-harmonic system in CSNS-II/RCS simulated by the particle tracking code PyORBIT will also be discussed.
	Poster THPAB207 [0.354 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB207
About •	paper received ※ 16 May 2021 paper accepted ※ 05 July 2021 issue date ※ 11 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB209	Tracking Complex Re-Circulating Machines with PLACET2	4197
	R.A.J. Costa, A. Latina CERN, Geneva, Switzerland
	We present the latest version of the multi-particle tracking package PLACET2. This software was designed to track multiple electron bunches through re-circulating machines with complex topologies, such as the recombination complex of the Compact Linear Collider (CLIC), energy-recovery linacs such as the Large Hadron-Electron Collider (LHeC), racetracks and others. This update also expands the capabilities of PLACET2 to track heavier particles such as muons. In addition to simulation, PLACET2 was also developed to allow beamline optimization scans, evaluating beam properties and tuning the beamline parameters at runtime either standalone or accessing the optimization tools present in the Octave and Python packages, with which it interfaces. This paper presents and benchmarks PLACET2’s latest features, such as coherent and incoherent synchrotron radiation, long and short wakefields and power extraction.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB209
About •	paper received ※ 18 May 2021 paper accepted ※ 13 July 2021 issue date ※ 27 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB214	Recent BDSIM Related Developments and Modeling of Accelerators	4208
	L.J. Nevay, A. Abramov, S.E. Alden, S.T. Boogert, G. D’Alessandro, S.M. Gibson, H. Lefebvre, W. Shields, S.D. Walker JAI, Egham, Surrey, United Kingdom A. Abramov, G. D’Alessandro, C. Hernalsteens CERN, Meyrin, Switzerland E. Gnacadja, C. Hernalsteens, E. Ramoisiaux, R. Tesse ULB, Bruxelles, Belgium S. Liu DESY, Hamburg, Germany
	Funding: This work is supported by the STFC (UK) grants: JAI ST/P00203X/1, HL-LHC-UK1 ST/N001583/1, HL-LHC-UK2 ST/T001925/1, and ST/P003028/1. Beam Delivery Simulation (BDSIM) is a program based on Geant4 that creates 3D radiation transport models of accelerators from a simple optical description in a vastly reduced time frame with great flexibility. It also uses ROOT and CLHEP to create a single simulation model that can accurately track all particle species in an accelerator to predict and understand beam losses, secondary radiation, dosimetric quantities and their origin. BDSIM provides a library of scalable generic geometry for a variety of applications. Our Python package, Pyg4ometry, allows rapid preparation and conversion of geometries for BDSIM and other radiation transport simulations including FLUKA. We present a broad overview of BDSIM developments related to a variety of experiments at several facilities. We present a model of the forward experiment FASER at the LHC, CERN where the geometry is composited from multiple sources using Pyg4ometry. The analysis of particle history is presented as well as production mechanisms. We also present the application of recently introduced laser interactions in Geant4 to Compton photons from a laserwire diagnostic at the ATF2.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB214
About •	paper received ※ 20 May 2021 paper accepted ※ 19 July 2021 issue date ※ 22 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB217	Lightsource Unified Modeling Environment (LUME), a Start-to-End Simulation Ecosystem	4212
	C.E. Mayes, A.L. Edelen, P. Fuoss, J.R. Garrahan, A. Halavanau, F. Ji, J. Krzywiński, W. Lou, N.R. Neveu, H.H. Slepicka SLAC, Menlo Park, California, USA J.C. E, C. Fortmann-Grote EuXFEL, Schenefeld, Germany C.M. Gulliford, D. Sagan Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA L. Gupta University of Chicago, Chicago, Illinois, USA A. Huebl, R. Lehé LBNL, Berkeley, USA
	SLAC is developing the Lightsource Unified Modeling Environment (LUME) for efficient modeling of X-ray free electron laser (XFEL) performance. This project takes a holistic approach starting with the simulation of the electron beams, to the production of the photon pulses, to their transport through the optical components of the beamline, to their interaction with the samples and the simulation of the detectors, and finally followed by the analysis of simulated data. LUME leverages existing, well-established simulation codes, and provides standard interfaces to these codes via open-source Python packages. Data are exchanged in standard formats based on openPMD and its extensions. The platform is built with an open, well-documented architecture so that science groups around the world can contribute specific experimental designs and software modules, advancing both their scientific interests and a broader knowledge of the opportunities provided by the exceptional capabilities of X-ray FELs.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB217
About •	paper received ※ 20 May 2021 paper accepted ※ 20 July 2021 issue date ※ 19 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB221	Multi-Objective Optimization with ACE3P and IMPACT	4223
	D.A. Bizzozero, J. Qiang LBNL, Berkeley, California, USA L. Ge, Z. Li, C.-K. Ng, L. Xiao SLAC, Menlo Park, California, USA
	Funding: This work is supported by the Director of the Office of Science of the US Department of Energy under contracts DE-AC02-05-CH11231 and DE-AC02-76-SF00515. Photo injector design is an important consideration in the construction of next-generation accelerators. In current injector optimization, components (e.g. RF cavities) are individually shape-optimized for performance subject to requirements such as peak surface field, shunt impedance, and resonant frequency. Once these component shapes are determined, beam dynamics simulations optimize the injector lattice by adjusting parameters such as the amplitude and phase of the driving fields. However, this form of beam dynamics optimization is restricted by the fixed geometry and field profile of the components. To optimize accelerator design more generally, a coupled optimization of the cavity shape and beam parameters is required. For this coupled optimization problem, we have created an integrated ACE3P-IMPACT workflow. Within this workflow, component geometries are adjusted, field modes are computed with Omega3P (a module in the ACE3P suite), and beam dynamics are simulated with IMPACT-T. This workflow is encapsulated into a multi-objective optimization algorithm using the DEAP* and libEnsemble** Python libraries to yield a Pareto-optimal set of solutions for a simple injector model. * F.-A. Fortin et al, DEAP: Evolutionary Algorithms Made Easy, J Mach Learn Res, 13, 2171-2175, July 2012 ** S. Hudson et al, libEnsemble User Manual, Argonne National Laboratory, Rev 0.7.1, 2020
	Poster THPAB221 [1.842 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB221
About •	paper received ※ 19 May 2021 paper accepted ※ 02 August 2021 issue date ※ 14 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB227	MACH-B: Fast Multipole Method Approaches in Particle Accelerator Simulations for the Computational and Intensity Frontiers	4237
	M.H. Langston, R. Lethin, P.D. Letourneau, J. Wei Reservoir Labs, New York, USA M.J. Morse Courant Institute of Mathematical Sciences, New York University, New York, USA
	Funding: U.S. Department of Energy DOE SBIR Phase I Project DE-SC0020934 The MACH-B (Multipole Accelerator Codes for Hadron Beams) project is developing a Fast Multipole Method (FMM*)-based tool for higher fidelity modeling of particle accelerators for high-energy physics within the next generation of Fermilab’s Synergia simulation package. MACH-B incorporates (1) highly-scalable, high-performance and generally-applicable FMM-based algorithms to accurately model space-charge effects in high-intensity hadron beams and (2) boundary integral approaches to handle singular effects near the beam pipe using advanced quadratures. MACH-B will allow for more complex beam dynamics simulations that more accurately capture bunch effects and predict beam loss. Further, by introducing an abstraction layer to hide FMM implementation and parallelization complexities, MACH-B removes one of the key impediments to the adoption of FMMs by the accelerator physics community. * J. Amundson et al. "Synergia: An accelerator modeling tool with 3-D space charge". J.C.P. 211.1 (2006) 229-248. ** L. Greengard. "Fast algorithms for classical physics". Science (Aug 1994) 909-914.
	Poster THPAB227 [0.984 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB227
About •	paper received ※ 19 May 2021 paper accepted ※ 14 July 2021 issue date ※ 27 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB228	Study on Laser Modulator for Electron Beam Density Modulation	4241
	K. Kan, M. Gohdo, J. Yang, Y. Yoshida ISIR, Osaka, Japan
	Ultrashort electron beams are essential for light sources and time-resolved measurements. Laser modulation using an undulator and pulsed near infrared light is expected for attosecond density modulation of electron beam. In this study, simulation of laser modulation using undulator with period length of 6.6 mm and optical pulse with a wavelength of 800 nm was performed by ELEGANT* code. Simulation results of laser modulation for electron beam with an energy of 32.5 MeV will be presented from a view point of the density modulation. * M. Borland, elegant: A Flexible SDDS-Compliant Code for Accelerator Simulation, Advanced Photon Source LS-287, September 2000.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB228
About •	paper received ※ 19 May 2021 paper accepted ※ 28 July 2021 issue date ※ 16 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB229	Energy-Binning Fast Multipole Method for Electron Injector Simulations	4244
	S.A. Schmid, H. De Gersem, E. Gjonaj TEMF, TU Darmstadt, Darmstadt, Germany
	In a high brilliance electron injector, small beam energy and large charge density give rise to strong space charge effects. Furthermore, a large relative energy spread during the beam generation modifies the space charge interaction between different regions of the particle bunch. Therefore, modeling the phase space evolution in an electron injector requires a numerically efficient particle tracking code that can handle space charge interactions of spatially and energetically strongly inhomogeneous particle distributions. We implemented an energy-binning scheme for a meshless fast multipole method (FMM). The energy-binning approximates the momentum distribution of the beam by assigning particles to adaptive tree structures defined at different Lorentz frames. Based on the tree structures, the FMM computes a hierarchical approximation for the space charge interaction of the particle bunch. We use the energy-binning FMM to simulate the beam generation in the photoinjector of the European XFEL developed at DESY-PITZ. Furthermore, we present numerical convergence and performance studies and compare the simulation results to direct particle-particle methods.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB229
About •	paper received ※ 19 May 2021 paper accepted ※ 12 July 2021 issue date ※ 25 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB236	First Order Analytic Approaches to Modelling the Vertical Excursion Fixed Field Alternating Gradient Accelerator	4262
	M.E. Topp-Mugglestone, S.L. Sheehy JAI, Oxford, United Kingdom J.-B. Lagrange, S. Machida STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
	Whilst the Vertical Excursion Fixed Field Alternating Gradient Accelerator (VFFA) remains a promising solution to a number of problems at the frontiers of accelerator physics, the optics of this type of machine are still poorly understood. Current designers are forced to rely on brute-force numerical tracking codes, with optimisation dependent on time-consuming parameter scans. With an aim to both improve understanding of this machine, as well as to develop tools for rapid design and optimisation of VFFA lattices, first steps towards an analytic approach based on a linearised Hamiltonian formalism have been developed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB236
About •	paper received ※ 13 May 2021 paper accepted ※ 14 July 2021 issue date ※ 10 August 2021
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Using Machine Learning to Improve Dynamic Aperture Estimates

134

F.F. Van der Veken, M. Giovannozzi, E.H. Maclean
CERN, Geneva, Switzerland
C.E. Montanari
Bologna University, Bologna, Italy
G. Valentino
University of Malta, Information and Communication Technology, Msida, Malta

The dynamic aperture (DA) is an important concept in the study of nonlinear beam dynamics. Several analytical models used to describe the evolution of DA as a function of time, and to extrapolate to realistic time scales that would not be reachable otherwise due to computational limitations, have been successfully developed. Even though these models have been quite successful in the past, the fitting procedure is rather sensitive to several details. Machine Learning (ML) techniques, which have been around for decades and have matured into powerful tools ever since, carry the potential to address some of these challenges. In this paper, two applications of ML approaches are presented and discussed in detail. Firstly, ML has been used to efficiently detect outliers in the DA computations. Secondly, ML techniques have been applied to improve the fitting procedures of the DA models, thus improving their predictive power.

Poster MOPAB028 [1.764 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB028

About •

paper received ※ 18 May 2021 paper accepted ※ 25 May 2021 issue date ※ 12 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPAB059

Tools for Use of Generalized Gradient Expansions in Accelerator Simulations

253

M. Borland, R.R. Lindberg, R. Soliday, A. Xiao
ANL, Lemont, Illinois, USA

Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357.
A common assumption in simulation of accelerators is that the magnets can be approximated using a hard-edge model, perhaps with some edge effects implemented in an impulse approximation. This is usually a good assumption but ignores details of the longitudinal variation of the magnetic fields, which makes it straightforward to implement symplectic tracking. Use of generalized gradient expansions* provides an alternative approach that can suppress numerical deficiencies that may be present in computed or measured 3D field maps. However, the computation of the expansions is not particularly straightforward. In this note, we describe several recently-developed tools that make this process fairly painless and allow tracking with such expansions in the program ELEGANT**. We show several examples of using the tools for simulations related to the Advanced Photon Source Upgrade.
* M. Venturini et al., NIM A 427, 387 (1999).
** M. Borland, Advanced Photon Source LS-287, September 2000

Poster MOPAB059 [4.311 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB059

About •

paper received ※ 17 May 2021 paper accepted ※ 26 May 2021 issue date ※ 18 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPAB070

mbtrack2, a Collective Effect Library in Python

282

A. Gamelin, W. Foosang, R. Nagaoka
SOLEIL, Gif-sur-Yvette, France

This article introduces mbtrack2, a collective effect library written in python3. The idea behind mbtrack2 is to build a coherent object-oriented framework to work on collective effects in synchrotrons. mbtrack2 is composed of different modules allowing to easily write scripts for single bunch or multi-bunch tracking using MPI parallelization in a transparent way. The base of the tracking model of mbtrack2 is inspired by mbtrack, a C multi-bunch tracking code initially developed at SOLEIL*. In addition, many tools to prepare or analyse tracking simulations are included.
* R. Nagaoka, R. Bartolini, and J. Rowland, Studies of Collective Effects in SOLEIL and Diamond Using the Multiparticle Tracking Codes SBTRACK and MBTRACK, in Proc. PAC’09, 2009.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB070

About •

paper received ※ 17 May 2021 paper accepted ※ 06 July 2021 issue date ※ 16 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPAB203

Electromagnetic Simulations of a Novel Proton Linac Using VSim on HPC

1887

S.I. Sosa Guitron, S. Biedron, T.B. Bolin
UNM-ECE, Albuquerque, USA
J.R. Cary
Tech-X, Boulder, Colorado, USA
M.S. Curtin, B. Hartman, T. Pressnall, D.A. Swenson
Ion Linac Systems, Inc., Albuquerque, USA

Funding: This work is supported by the U.S. Department of Energy, award number DE-SC0019468; It used resources of the Argonne Leadership Computing Facility, contract DE-AC02-06CH11357, and from Element Aero.
We discuss electromagnetic simulations of accelerating structures in a high performance computing (HPC) system. Our overarching goal is to resolve the linac operation in a large ensemble of initial beam conditions. This requires a symbiotic relation between the electromagnetic solver and HPC. The linac is being developed by Ion Linac Systems to produce a low-energy, high-current, proton beam. We use VSim, an electromagnetic solver and PIC software developed by Tech-X to determine the electromagnetic fundamental mode of operation of the accelerating structures and discuss its implementation at the THETA supercomputer in the Argonne Leadership Computing Facility.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB203

About •

paper received ※ 20 May 2021 paper accepted ※ 17 June 2021 issue date ※ 10 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPAB209

The Particle Tracking Code Fixfield

1905

J.-B. Lagrange
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

FixField is a code developed to track particles in Fixed Field alternating gradient Accelerators (FFAs). This paper discusses the structure and features of the code.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB209

About •

paper received ※ 19 May 2021 paper accepted ※ 02 July 2021 issue date ※ 25 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPAB215

Novel Non-Linear Particle Tracking Approach Employing Lie Algebraic Theory in the TensorFlow Environment

1920

J. Frank, M. Arlandoo, P. Goslawski, J. Li, T. Mertens, M. Ries, L. Vera Ramirez
HZB, Berlin, Germany

With this paper we present first results for encoding Lie transformations as computational graphs in Tensorflow that are used as layers in a neural network. By implementing a recursive differentiation scheme and employing Lie algebraic arguments we were able to reproduce the diagrams for well known lattice configurations. We track through simple optical lattices that are encountered as the main constituents of accelerators and demonstrate the flexibility and modularity our approach offers. The neural network can represent the optical lattice with predefined coefficients allowing for particle tracking for beam dynamics or can learn from experimental data to fine-tune beam optics.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB215

About •

paper received ※ 12 May 2021 paper accepted ※ 31 August 2021 issue date ※ 21 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPAB266

Periodic Transient Beam Loading Effects Predicted by a Semi-Analytical Method

2086

T.L. He, Z.H. Bai, G. Feng, W. Li, W.W. Li, G. Liu, L. Wang, H. Xu, S.C. Zhang
USTC/NSRL, Hefei, Anhui, People’s Republic of China

In this paper, we improve a semi-analytical method, which can be not only used for bunch lengthening under equilibrium conditions, but also applied to the prediction of a periodic transient beam loading effect. This periodic transient is induced by the presence of the passive harmonic cavity and might be encountered under specific conditions for a ultra-low emittance storage ring with a higher beam current.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB266

About •

paper received ※ 16 May 2021 paper accepted ※ 21 June 2021 issue date ※ 24 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPAB024

Release of Crystal Routine for Multi-Turn Proton Simulations within SixTrack v5

2648

M. D’Andrea, A. Mereghetti, D. Mirarchi, V.K.B. Olsen, S. Redaelli
CERN, Geneva, Switzerland

Crystal collimation is studied as a possible scheme to further improve the efficiency of ion collimation at the High Luminosity Large Hadron Collider (HL-LHC), as well as for possible applications in the CERN program of Physics Beyond Colliders. This concept relies on the use of bent crystals that can deflect high-energy halo particles at large angles, of the order of tens of urad. In order to reproduce key experimental results of crystal collimation tests and predict the performance of this system when applied to present and future machines, a dedicated simulation routine was developed. This routine is capable of modeling both coherent and incoherent interactions of beam particles with crystal collimators, and is fully integrated into the magnetic tracking and collimator modeling provided by the single-particle tracking code SixTrack. This paper describes the implementation of the routine in the latest version of SixTrack and its most recent improvements, in particular regarding the treatment of the crystal miscut angle.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB024

About •

paper received ※ 19 May 2021 paper accepted ※ 23 June 2021 issue date ※ 14 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPAB105

Simulating Electron Impact Ionization Using a General Particle Tracer (GPT) Custom Element

2843

J.T. Yoskowitz, G.A. Krafft
ODU, Norfolk, Virginia, USA
J.M. Grames
JLab, Newport News, Virginia, USA
G.R. Montoya Soto
Universidad de Guanajuato, División de Ciencias e Ingenierías, León, Mexico
C.A. Valerio
ECFM-UAS, Culiacan, Sinaloa, Mexico
S.B. van der Geer
Pulsar Physics, Eindhoven, The Netherlands

Funding: U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177, Consejo Nacional de Ciencia y Tecnología (CONACYT).
A new C++ custom element has been developed with the framework of General Particle Tracer (GPT) to simulate electron impact ionization of residual gas molecules. The custom element uses Monte-Carlo routines to determine both the ion production rate and the secondary electron kinetic energy based on user-defined gas densities and theoretical values for the ionization cross section and the secondary electron differential cross section. It then uses relativistic kinematics to track the secondary electron, the scattered electron, and the newly formed ion after ionization. The ion production rate and the secondary electron energy distribution determined by the custom element have been benchmarked against theoretical calculations and against simulations made using the simulation package IBSimu. While the custom element was originally built for particle accelerator simulations, it is readily extensible to other applications. The custom element will be described in detail and examples of applications at the Thomas Jefferson National Accelerator Facility will be presented for ion production in a DC high voltage photo-gun.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB105

About •

paper received ※ 20 May 2021 paper accepted ※ 25 June 2021 issue date ※ 19 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPAB203

RFQ Beam Dynamics Optimization Using Machine Learning

3100

D. Koser, J.M. Conrad, L.H. Waites, D. Winklehner
MIT, Cambridge, Massachusetts, USA
A. Adelmann, M. Frey, S. Mayani
PSI, Villigen PSI, Switzerland

To efficiently inject a high-current H²⁺ beam into the 60 MeV driver cyclotron for the proposed IsoDAR project in neutrino physics, a novel direct-injection scheme is planned to be implemented using a compact radio-frequency quadrupole (RFQ) as a pre-buncher, being partially inserted into the cyclotron yoke. To optimize the RFQ beam dynamics design, machine learning approaches were investigated for creating a surrogate model of the RFQ. The required sample datasets are generated by standard beam dynamics simulation tools like PARMTEQM and RFQGen or more sophisticated PIC simulations. By reducing the computational complexity of multi-objective optimization problems, surrogate models allow to perform sensitivity studies and an optimization of the crucial RFQ beam output parameters like transmission and emittances. The time to solution might be reduced by up to several orders of magnitude. Here we discuss different methods of surrogate model creation (polynomial chaos expansion and neural networks) and identify present limitations of surrogate model accuracy.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB203

About •

paper received ※ 20 May 2021 paper accepted ※ 01 July 2021 issue date ※ 30 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPAB214

Realistic Simulations of Stray Field Impact on Low Energy Transfer Lines

3130

V. Rodin, S. Padden, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
A. Farricker, S. Padden, V. Rodin, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
J. Resta-López
UVEG, Burjasot (Valencia), Spain

Funding: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 721559.
Low energy (~100 keV) facilities working with antiprotons, heavy ions, or charged molecules may experience severe beam transport instabilities caused by field imperfections. For example, long (~10 m), unshielded beamlines will not be able to transfer particles due to the natural Earth magnetic field or stray fields from closely located experiments. Currently, only a limited number of simulation codes allow a simplified representation of such field errors, limiting capabilities for beam delivery optimization. In this contribution, a new simulation approach is presented that can provide detailed insight into 4D beam transport. It illustrates the impact of imperfections and stray fields on beam stability and quality through simulations of two antiproton experiments located in the Antimatter Factory (AD) at CERN in Geneva, Switzerland. Magnetic field imperfections are examined in two different ways, providing greater flexibility and an opportunity to benchmark all outcomes. Simulation performance is analyzed as a function of the level of detail and efficiency.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB214

About •

paper received ※ 19 May 2021 paper accepted ※ 12 July 2021 issue date ※ 18 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPAB215

Simulation of Intra-Beam Scattering in PyHEADTAIL

3134

V. Rodin, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
A. Oeftiger
GSI, Darmstadt, Germany
V. Rodin, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: This project has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No 721559
High-intensity beams in low-energy synchrotrons are subject to space charge as well as intra-beam scattering (IBS). Accurate modelling of both effects becomes essential when the transverse emittances and minimum bunch length are determined through heating processes and resonances induced by machine errors. To date, only very few tools available to the general public allow to simultaneously study space charge and IBS in self-consistent simulations. In this contribution, we present our recent development of an IBS module for PyHEADTAIL, an open-source 6D multi-particle tracking tool, which already includes various 2.5D and 3D space-charge models based on the self-consistent particle-in-cell algorithm. A simulation example of high-intensity bunch rotation demonstrates the joint impact of applied heating effects. Our model is based on the Martini and Bjorken-Mitingwa theories. Benchmarks of our implementation against IBS modules provided in the MAD-X and JSPEC codes are shown.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB215

About •

paper received ※ 23 May 2021 paper accepted ※ 14 July 2021 issue date ※ 13 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB129

Beam Dynamics Simulations in a High-Gradient X-Band Photoinjector

4013

W.H. Tan, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
G. Chen, S.V. Kuzikov
Euclid TechLabs, Solon, Ohio, USA
G. Chen
IIT, Chicago, Illinois, USA
G. Ha, C.-J. Jing
ANL, Lemont, Illinois, USA
C.-J. Jing
Euclid Beamlabs, Bolingbrook, USA

A high-gradient X-band (11.7-GHz) photoinjector was recently developed by Euclid Techlabs and is in its commissioning phase at the Argonne Wakefield Accelerator (AWA). This contribution discuss the beam-dynamics modeling of the photoinjector system comprising an RF gun and linac section. We especially discuss beam-dynamics optimization of setup for an integrated proof-of-principle experiments. We also discuss the use of such a photoinjector as a witness-bunch source for a future high-gradient collinear-wakefield accelerator experiments at the AWA.
* S. V. Kuzikov, et al. these proceedings.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB129

About •

paper received ※ 20 May 2021 paper accepted ※ 14 July 2021 issue date ※ 31 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB134

Development and Analysis of Software for the Numerical Simulation of Field Emission Electron Sources

4024

N.S. Kakorin, K.A. Nikiforov
Saint Petersburg State University, Saint Petersburg, Russia
N.V. Egorov
St. Petersburg State University, St. Petersburg, Russia

Funding: The reported study was funded by RFBR, project number 20-07-01086.
The open-source DAISI C++ package (Design of Accelerators, optImizations and SImulations) is extended with the ability to simulate the operation of electron sources in the field emission mode, with the user-defined initial distribution of emitted electrons velocities, as a model parameter, and with the automated calculation of current-voltage characteristics. Particles injection scheme is suggested. Computational experiments are performed for silicon carbide field emission electron source nanostructure with bimodal energy spectrum, revealed from experimental study, and comparative analysis with Maxwell distribution is presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB134

About •

paper received ※ 20 May 2021 paper accepted ※ 27 July 2021 issue date ※ 17 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB174

T-BMT Spin Resonance Tracker Code for He3 with Six Snakes

4101

V.H. Ranjbar, H. Huang, Y. Luo, F. Méot, V. Ptitsyn
BNL, Upton, New York, USA
G.H. Hoffstaetter, D. Sagan
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
F. Lin, V.S. Morozov
JLab, Newport News, Virginia, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy .
Polarization lifetime for He3 using two and six snakes are studied using the T-BMT Spin Resonance Tracker code. This code integrates a reduced spinor form of the T-BMT equation including only several spin resonances and the kinematics of synchrotron motion. It was previously benchmarked against RHIC polarization lifetime under the two snake system *.
* Phys. Rev.Accel. Beams 22 (2019) 9, 091001

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB174

About •

paper received ※ 20 May 2021 paper accepted ※ 02 July 2021 issue date ※ 28 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB186

Review of Proton Linac Beam Dynamic Simulation Code

4137

X.Y. Feng, J. Peng
IHEP CSNS, Guangdong Province, People’s Republic of China

CSNS-II project design a linac accelerates 40 mA H⁻ beam from 3.8 MeV to 300 MeV, which should not only overcome the space-charge effect at low energy but also have high efficiency at high energy. Therefore, lots of simulation studies should be done on a variety of codes. Each of them has its own characteristics. For example, MAD can easily match quadrupole fast while it couldn’t do the multiparticle calculation. This paper will introduce some common and efficient code used to design linac and study beam dynamic performance.

Poster THPAB186 [0.880 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB186

About •

paper received ※ 17 May 2021 paper accepted ※ 08 July 2021 issue date ※ 11 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB189

New Techniques to Compute the Linear Tune

4142

G. Russo, M. Giovannozzi
CERN, Geneva, Switzerland
G. Franchetti
GSI, Darmstadt, Germany

Tune determination in numerical simulations is an essential aspect of nonlinear beam dynamics studies. In particular, because it allows probing whether an initial condition is close to resonance, and it enables assessment of the stability of the orbit, i.e. whether the motion is regular or chaotic. In this paper, results of recently developed techniques to obtain accurate tune computation from numerical simulation data are presented and discussed in detail.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB189

About •

paper received ※ 18 May 2021 paper accepted ※ 26 July 2021 issue date ※ 19 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB190

Optimising and Extending a Single-Particle Tracking Library for High Parallel Performance

4146

M. Schwinzerl, H. Bartosik, R. De Maria, G. Iadarola, K. Paraschou
CERN, Geneva, Switzerland
A. Oeftiger
GSI, Darmstadt, Germany
M. Schwinzerl
KFUG/IMSC, Graz, Austria

SixTrackLib is a library for performing beam-dynamics simulations on highly parallel computing devices such as shared memory multi-core processors or graphical processing units (GPUs). Its single-particle approach fits very well with parallel implementations with reasonable baseline performance, making such a library an interesting building block for various use cases, including simulations covering collective effects. We describe optimizations to improve their performance on SixTrackLib’s main target platforms and the associated performance gains. Finally, we outline the implemented technical interfaces and extensions that allow SixTrackLib to be used in a wider range of applications and studies.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB190

About •

paper received ※ 18 May 2021 paper accepted ※ 14 July 2021 issue date ※ 16 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB191

Physics-Enhanced Reinforcement Learning for Optimal Control

4150

A.N. Ivanov, I.V. Agapov, A. Eichler, S. Tomin
DESY, Hamburg, Germany

We propose an approach for incorporating accelerator physics models into reinforcement learning agents. The proposed approach is based on the Taylor mapping technique for simulation of the particle dynamics. The resulting computational graph is represented as a polynomial neural network and embedded into the traditional reinforcement learning agents. The application of the model is demonstrated in a nonlinear simulation model of beam transmission. The comparison of the approach with the traditional numerical optimization as well as neural networks based agents demonstrates better convergence of the proposed technique.

Poster THPAB191 [0.846 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB191

About •

paper received ※ 11 May 2021 paper accepted ※ 29 July 2021 issue date ※ 24 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB192

Continuous Beam Dynamics Simulation in COMSOL Multiphysics

4153

D. Popov, O. Karamyshev, I.D. Lyapin, V. Malinin
JINR/DLNP, Dubna, Moscow region, Russia

The classic way of beam dynamics simulation in a cyclotron is to separate it into many different stages from the ion source to the extraction (or even further), this was absolutely necessary to fit the calculations into any reasonable time in a cost of influence of some operation devices from one stage, on beam dynamics of another (next or previous mostly) stage. We’ve managed to perform beam dynamics from ion source through a solenoid to the center region in a single model in COMSOL, using several fields simultaneously: external magnetic (the magnet), calculated magnetic (the solenoid) and alternating and stationary electric fields in the center region.

Poster THPAB192 [1.233 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB192

About •

paper received ※ 19 May 2021 paper accepted ※ 23 June 2021 issue date ※ 17 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB197

Enhancing Efficiency of Multi-Objective Neural-Network-Assisted Nonlinear Dynamics Lattice Optimization via 1-D Aperture Objectives & Objective Focusing

4156

Y. Hidaka, D.A. Hidas, F. Plassard, T.V. Shaftan, G.M. Wang
BNL, Upton, New York, USA

Funding: This work is supported by U.S. DOE under Contract No. DE-SC0012704.
Mutli-objective optimizers such as multi-objective genetic algorithm (MOGA) have been quite popular in discovering desirable lattice solutions for accelerators. However, even these successful algorithms can become ineffective as the dimension and range of the search space increase due to exponential growth in the amount of exploration required to find global optima. This difficulty is even more exacerbated by the resource-intensive and time-consuming tendency for the evaluations of nonlinear beam dynamics. Lately the use of surrogate models based on neural network has been drawing attention to alleviate this problem. Following this trend, to further enhance the efficiency of nonlinear lattice optimization for storage rings, we propose to replace typically used objectives with those that are less time-consuming and to focus on a single objective constructed from multiple objectives, which can maximize utilization of the trained models through local optimization and objective gradient extraction. We demonstrate these enhancements using a NSLS-II upgrade lattice candidate as an example.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB197

About •

paper received ※ 20 May 2021 paper accepted ※ 23 June 2021 issue date ※ 10 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB199

Studies of Longitudinal Beam Losses at LHC Injection

4164

L.E. Medina Medrano, T. Argyropoulos, R. Calaga, H. Timko
CERN, Geneva, Switzerland

Funding: Research supported by the HL-LHC project.
Due to higher beam intensities, the required rf power in the High-Luminosity LHC (HL-LHC) era is expected to be at the limit of the available rf power. To mitigate potential limitations of the rf system, the injection voltage can be reduced at the expense of beam losses. In this paper, the average and bunch-by-bunch losses are estimated from Run 2 beam intensity measurements in the SPS before extraction and in the LHC after injection. Macro-particle simulations are performed with CERN’s Beam Longitudinal Dynamics code to reproduce the observed SPS-to-LHC capture and LHC flat-bottom losses. First estimates of injection losses for the HL-LHC at different injection voltages and injection energy errors are discussed.

Poster THPAB199 [2.428 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB199

About •

paper received ※ 18 May 2021 paper accepted ※ 28 July 2021 issue date ※ 14 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB200

Cavity Control Modelling for SPS-to-LHC Beam Transfer Studies

4168

L.E. Medina Medrano, T. Argyropoulos, P. Baudrenghien, H. Timko
CERN, Geneva, Switzerland

Funding: Research supported by the HL-LHC project.
To accurately simulate injection losses in the LHC and the High-Luminosity LHC era, a realistic beam distribution model at SPS extraction is needed. To achieve this, the beam-loading compensation by the SPS cavity controller has to be included, as it modulates the bunch positions with respect to the rf buckets. This dynamic cavity control model also allows generating a more realistic beam halo, from which the LHC injection losses will mainly originate. In this paper, the implementation of the present SPS cavity controller in CERN’s Beam Longitudinal Dynamics particle tracking code is described. Just like in the machine, the feedback and feedforward controls are included in the simulation model, as well as the generator-beam-cavity interaction. Benchmarking against measurements of the generated beam distributions at SPS extraction are presented.

Poster THPAB200 [4.164 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB200

About •

paper received ※ 18 May 2021 paper accepted ※ 27 July 2021 issue date ※ 26 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB201

A Machine Learning Technique for Dynamic Aperture Computation

4172

B. Dalena, M. Ben Ghali
CEA-IRFU, Gif-sur-Yvette, France

Currently, dynamic aperture calculations of high-energy hadron colliders are performed through computer simulations, which are both a resource-heavy and time-costly processes. The aim of this study is to use a reservoir computing machine learning model in order to achieve a faster extrapolation of dynamic aperture values. A recurrent echo-state network (ESN) architecture is used as a basis for this work. Recurrent networks are better fitted to extrapolation tasks while the reservoir echo-state structure is computationally effective. Model training and validation is conducted on a set of "seeds" corresponding to the simulation results of different machine configurations. Adjustments in the model architecture, manual metric and data selection, hyper-parameters tuning and the introduction of new parameters enabled the model to reliably achieve good performance on examining testing sets.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB201

About •

paper received ※ 14 May 2021 paper accepted ※ 22 July 2021 issue date ※ 02 September 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB202

Problem and Solution with the Longitudinal Tracking of the ORBIT Code

4176

L.H. Zhang, J.Y. Tang
IHEP, Beijing, People’s Republic of China
Y.K. Chen
IHEP CSNS, Guangdong Province, People’s Republic of China
L.H. Zhang
University of Chinese Academy of Sciences, Beijing, People’s Republic of China

The ORBIT code has been widely used for beam dynamics simulations including injection and acceleration in high-intensity hadron synchrotrons. When the ORBIT’s 1D longitudinal tracking was employed for the acceleration process in CSNS/RCS, the longitudinal emittance in eV-s was found decreasing substantially during acceleration, though the adiabatic condition is still met during this process. This is against the Liouville theorem that predicts the preservation of the emittance during acceleration. The recent machine study in the accelerator and the simulations with a self-made code demonstrate that the longitudinal emittance is almost invariant, which further indicates that the ORBIT longitudinal tracking might be incorrect. A detailed check-over in the ORBIT code source finds that the longitudinal finite difference equation used in the code is erroneous when applied to an acceleration process. The new code format PyORBIT has the same problem. After the small secondary factor is included in the code, ORBIT can produce results keeping the longitudinal emittance invariant. This paper presents some details about the study.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB202

About •

paper received ※ 14 May 2021 paper accepted ※ 01 July 2021 issue date ※ 21 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB203

Update of the Tracking Code RF-Track

4180

A. Latina
CERN, Geneva, Switzerland

During the last couple of years, the RF-Track particle tracking code has seen a tremendous increase in the number of its applications: medical linacs, compact injector electron guns, and positron sources are among the main ones. Following a work of consolidation of its internal structure, new simulation capabilities have been introduced, together with several new effects: arbitrary orientation of elements in space, full element overlap, short- and long-range wakefields, and laser-beam interaction through Compton scattering are the most significant ones. In this paper, some of these new features are presented and discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB203

About •

paper received ※ 14 May 2021 paper accepted ※ 02 August 2021 issue date ※ 01 September 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB204

End-to-End RMS Envelope Model of the ISAC-I Linac

4183

O. Shelbaya, R.A. Baartman, O.K. Kester
TRIUMF, Vancouver, Canada

A full end-to-end simulation of the ISAC-I linear accelerator has been built in the first order envelope code TRANSOPTR. This enables the fast tracking of rms sizes and correlations for a 6-dimensional hyperellipsoidal beam distribution defined around a Frenet-Serret reference particle frame, for which the equations guiding envelope evolution are numerically solved through a model of the machine’s electromagnetic potentials. Further, the adopted formalism enables the direct integration of energy gain via time-dependent accelerating potentials, without resorting to transit-time factors.

Poster THPAB204 [0.627 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB204

About •

paper received ※ 18 May 2021 paper accepted ※ 08 July 2021 issue date ※ 31 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB206

Validating pyORBIT for Modeling Beam Dynamics in the IOTA Ring

4190

R. Li
UW-Madison/PD, Madison, Wisconsin, USA
J.-F. Ostiguy, T. Sen
Fermilab, Batavia, Illinois, USA

Funding: Supported by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
The Integrable Optics Test Accelerator (IOTA) ring is a new Fermilab facility dedicated to beam physics experiments, currently operating with 150 MeV electrons. Space charge effects are expected to be significant when it operates with 2.5 MeV protons. In this contribution, we present results of a suite of validation tests of PyORBIT, a PICstyle space charge code. Single particle dynamics of quasiintegrable optics using an octupole string in IOTA is compared with MADX, and shown to be in good agreement. Requirements for the convergence of space charge computations are systematically established and when possible, tests involving space charge are compared with theoretical predictions.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB206

About •

paper received ※ 19 May 2021 paper accepted ※ 08 July 2021 issue date ※ 12 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB207

Beam Dynamics Simulation about the Dual Harmonic System by PyORBIT

4194

H.Y. Liu, X.Y. Feng, L. Huang, M.T. Li, X.H. Lu
IHEP CSNS, Guangdong Province, People’s Republic of China
S. Wang, S.Y. Xu
IHEP, Beijing, People’s Republic of China

The space charge effect is a strong limitation in high-intensity accelerators, especially for low- and medium-energy proton synchrotrons. And for CSNS-II, the number of particles in the RCS is 3.9·10¹³ ppp, which is five times of CSNS. To mitigate the effects of the strong space charge effect, CSNS-II/RCS (Rapid Cycling Synchrotron) will use a dual harmonic system to increase the bunching factor during the injection and the initial acceleration phase. For studying the beam dynamics involved in a dual harmonic RF system, PyORBIT is used as the major simulation code, which is developed at SNS to simulate beam dynamics in accumulation rings and synchrotrons. We modified parts of the code to make it applicable to the beam dynamic in RCS. This paper includes the major code modification of the Dual Harmonic RF system and some benchmark results. The preliminary simulation results of the dual-harmonic system in CSNS-II/RCS simulated by the particle tracking code PyORBIT will also be discussed.

Poster THPAB207 [0.354 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB207

About •

paper received ※ 16 May 2021 paper accepted ※ 05 July 2021 issue date ※ 11 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB209

Tracking Complex Re-Circulating Machines with PLACET2

4197

R.A.J. Costa, A. Latina
CERN, Geneva, Switzerland

We present the latest version of the multi-particle tracking package PLACET2. This software was designed to track multiple electron bunches through re-circulating machines with complex topologies, such as the recombination complex of the Compact Linear Collider (CLIC), energy-recovery linacs such as the Large Hadron-Electron Collider (LHeC), racetracks and others. This update also expands the capabilities of PLACET2 to track heavier particles such as muons. In addition to simulation, PLACET2 was also developed to allow beamline optimization scans, evaluating beam properties and tuning the beamline parameters at runtime either standalone or accessing the optimization tools present in the Octave and Python packages, with which it interfaces. This paper presents and benchmarks PLACET2’s latest features, such as coherent and incoherent synchrotron radiation, long and short wakefields and power extraction.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB209

About •

paper received ※ 18 May 2021 paper accepted ※ 13 July 2021 issue date ※ 27 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB214

Recent BDSIM Related Developments and Modeling of Accelerators

4208

L.J. Nevay, A. Abramov, S.E. Alden, S.T. Boogert, G. D’Alessandro, S.M. Gibson, H. Lefebvre, W. Shields, S.D. Walker
JAI, Egham, Surrey, United Kingdom
A. Abramov, G. D’Alessandro, C. Hernalsteens
CERN, Meyrin, Switzerland
E. Gnacadja, C. Hernalsteens, E. Ramoisiaux, R. Tesse
ULB, Bruxelles, Belgium
S. Liu
DESY, Hamburg, Germany

Funding: This work is supported by the STFC (UK) grants: JAI ST/P00203X/1, HL-LHC-UK1 ST/N001583/1, HL-LHC-UK2 ST/T001925/1, and ST/P003028/1.
Beam Delivery Simulation (BDSIM) is a program based on Geant4 that creates 3D radiation transport models of accelerators from a simple optical description in a vastly reduced time frame with great flexibility. It also uses ROOT and CLHEP to create a single simulation model that can accurately track all particle species in an accelerator to predict and understand beam losses, secondary radiation, dosimetric quantities and their origin. BDSIM provides a library of scalable generic geometry for a variety of applications. Our Python package, Pyg4ometry, allows rapid preparation and conversion of geometries for BDSIM and other radiation transport simulations including FLUKA. We present a broad overview of BDSIM developments related to a variety of experiments at several facilities. We present a model of the forward experiment FASER at the LHC, CERN where the geometry is composited from multiple sources using Pyg4ometry. The analysis of particle history is presented as well as production mechanisms. We also present the application of recently introduced laser interactions in Geant4 to Compton photons from a laserwire diagnostic at the ATF2.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB214

About •

paper received ※ 20 May 2021 paper accepted ※ 19 July 2021 issue date ※ 22 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB217

Lightsource Unified Modeling Environment (LUME), a Start-to-End Simulation Ecosystem

4212

C.E. Mayes, A.L. Edelen, P. Fuoss, J.R. Garrahan, A. Halavanau, F. Ji, J. Krzywiński, W. Lou, N.R. Neveu, H.H. Slepicka
SLAC, Menlo Park, California, USA
J.C. E, C. Fortmann-Grote
EuXFEL, Schenefeld, Germany
C.M. Gulliford, D. Sagan
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
L. Gupta
University of Chicago, Chicago, Illinois, USA
A. Huebl, R. Lehé
LBNL, Berkeley, USA

SLAC is developing the Lightsource Unified Modeling Environment (LUME) for efficient modeling of X-ray free electron laser (XFEL) performance. This project takes a holistic approach starting with the simulation of the electron beams, to the production of the photon pulses, to their transport through the optical components of the beamline, to their interaction with the samples and the simulation of the detectors, and finally followed by the analysis of simulated data. LUME leverages existing, well-established simulation codes, and provides standard interfaces to these codes via open-source Python packages. Data are exchanged in standard formats based on openPMD and its extensions. The platform is built with an open, well-documented architecture so that science groups around the world can contribute specific experimental designs and software modules, advancing both their scientific interests and a broader knowledge of the opportunities provided by the exceptional capabilities of X-ray FELs.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB217

About •

paper received ※ 20 May 2021 paper accepted ※ 20 July 2021 issue date ※ 19 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB221

Multi-Objective Optimization with ACE3P and IMPACT

4223

D.A. Bizzozero, J. Qiang
LBNL, Berkeley, California, USA
L. Ge, Z. Li, C.-K. Ng, L. Xiao
SLAC, Menlo Park, California, USA

Funding: This work is supported by the Director of the Office of Science of the US Department of Energy under contracts DE-AC02-05-CH11231 and DE-AC02-76-SF00515.
Photo injector design is an important consideration in the construction of next-generation accelerators. In current injector optimization, components (e.g. RF cavities) are individually shape-optimized for performance subject to requirements such as peak surface field, shunt impedance, and resonant frequency. Once these component shapes are determined, beam dynamics simulations optimize the injector lattice by adjusting parameters such as the amplitude and phase of the driving fields. However, this form of beam dynamics optimization is restricted by the fixed geometry and field profile of the components. To optimize accelerator design more generally, a coupled optimization of the cavity shape and beam parameters is required. For this coupled optimization problem, we have created an integrated ACE3P-IMPACT workflow. Within this workflow, component geometries are adjusted, field modes are computed with Omega3P (a module in the ACE3P suite), and beam dynamics are simulated with IMPACT-T. This workflow is encapsulated into a multi-objective optimization algorithm using the DEAP* and libEnsemble** Python libraries to yield a Pareto-optimal set of solutions for a simple injector model.
* F.-A. Fortin et al, DEAP: Evolutionary Algorithms Made Easy, J Mach Learn Res, 13, 2171-2175, July 2012
** S. Hudson et al, libEnsemble User Manual, Argonne National Laboratory, Rev 0.7.1, 2020

Poster THPAB221 [1.842 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB221

About •

paper received ※ 19 May 2021 paper accepted ※ 02 August 2021 issue date ※ 14 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB227

MACH-B: Fast Multipole Method Approaches in Particle Accelerator Simulations for the Computational and Intensity Frontiers

4237

M.H. Langston, R. Lethin, P.D. Letourneau, J. Wei
Reservoir Labs, New York, USA
M.J. Morse
Courant Institute of Mathematical Sciences, New York University, New York, USA

Funding: U.S. Department of Energy DOE SBIR Phase I Project DE-SC0020934
The MACH-B (Multipole Accelerator Codes for Hadron Beams) project is developing a Fast Multipole Method (FMM**)-based tool for higher fidelity modeling of particle accelerators for high-energy physics within the next generation of Fermilab’s Synergia* simulation package. MACH-B incorporates (1) highly-scalable, high-performance and generally-applicable FMM-based algorithms to accurately model space-charge effects in high-intensity hadron beams and (2) boundary integral approaches to handle singular effects near the beam pipe using advanced quadratures. MACH-B will allow for more complex beam dynamics simulations that more accurately capture bunch effects and predict beam loss. Further, by introducing an abstraction layer to hide FMM implementation and parallelization complexities, MACH-B removes one of the key impediments to the adoption of FMMs by the accelerator physics community.
* J. Amundson et al. "Synergia: An accelerator modeling tool with 3-D space charge". J.C.P. 211.1 (2006) 229-248.
** L. Greengard. "Fast algorithms for classical physics". Science (Aug 1994) 909-914.

Poster THPAB227 [0.984 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB227

About •

paper received ※ 19 May 2021 paper accepted ※ 14 July 2021 issue date ※ 27 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB228

Study on Laser Modulator for Electron Beam Density Modulation

4241

K. Kan, M. Gohdo, J. Yang, Y. Yoshida
ISIR, Osaka, Japan

Ultrashort electron beams are essential for light sources and time-resolved measurements. Laser modulation using an undulator and pulsed near infrared light is expected for attosecond density modulation of electron beam. In this study, simulation of laser modulation using undulator with period length of 6.6 mm and optical pulse with a wavelength of 800 nm was performed by ELEGANT* code. Simulation results of laser modulation for electron beam with an energy of 32.5 MeV will be presented from a view point of the density modulation.
* M. Borland, elegant: A Flexible SDDS-Compliant Code for Accelerator Simulation, Advanced Photon Source LS-287, September 2000.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB228

About •

paper received ※ 19 May 2021 paper accepted ※ 28 July 2021 issue date ※ 16 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB229

Energy-Binning Fast Multipole Method for Electron Injector Simulations

4244

S.A. Schmid, H. De Gersem, E. Gjonaj
TEMF, TU Darmstadt, Darmstadt, Germany

In a high brilliance electron injector, small beam energy and large charge density give rise to strong space charge effects. Furthermore, a large relative energy spread during the beam generation modifies the space charge interaction between different regions of the particle bunch. Therefore, modeling the phase space evolution in an electron injector requires a numerically efficient particle tracking code that can handle space charge interactions of spatially and energetically strongly inhomogeneous particle distributions. We implemented an energy-binning scheme for a meshless fast multipole method (FMM). The energy-binning approximates the momentum distribution of the beam by assigning particles to adaptive tree structures defined at different Lorentz frames. Based on the tree structures, the FMM computes a hierarchical approximation for the space charge interaction of the particle bunch. We use the energy-binning FMM to simulate the beam generation in the photoinjector of the European XFEL developed at DESY-PITZ. Furthermore, we present numerical convergence and performance studies and compare the simulation results to direct particle-particle methods.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB229

About •

paper received ※ 19 May 2021 paper accepted ※ 12 July 2021 issue date ※ 25 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPAB236

First Order Analytic Approaches to Modelling the Vertical Excursion Fixed Field Alternating Gradient Accelerator

4262

M.E. Topp-Mugglestone, S.L. Sheehy
JAI, Oxford, United Kingdom
J.-B. Lagrange, S. Machida
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

Whilst the Vertical Excursion Fixed Field Alternating Gradient Accelerator (VFFA) remains a promising solution to a number of problems at the frontiers of accelerator physics, the optics of this type of machine are still poorly understood. Current designers are forced to rely on brute-force numerical tracking codes, with optimisation dependent on time-consuming parameter scans. With an aim to both improve understanding of this machine, as well as to develop tools for rapid design and optimisation of VFFA lattices, first steps towards an analytic approach based on a linearised Hamiltonian formalism have been developed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB236

About •

paper received ※ 13 May 2021 paper accepted ※ 14 July 2021 issue date ※ 10 August 2021

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)