A-2 Modeling of Current and Future Machines
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Normal Form Approach to and Nonlinear Optics Analysis of the IOTA Ring  
  • B. Erdelyi
    Northern Illinois University, DeKalb, Illinois, USA
  The IOTA ring is the realization as an accelerator system of a nonlinear, completely integrable Hamiltonian. Normal form methods allow analysis of one-turn maps of rings, exposing global information about the dynamics, including amplitude dependent tune shifts and resonance strengths. Since mapping the phase space of particle dynamics in IOTA is important to gain insight and offer practical ways to optimize for intensity frontier beam physics, this talk will summarize our group’s results, the advantages, difficulties, and limitations of normal form analysis of the IOTA nonlinear optics.  
slides icon Slides SAPAG01 [3.747 MB]  
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Design and Simulation of High Momentum Acceptance Gantries for Ion Beam Therapy  
  • A.M. Huggins
    HHU, Duesseldorf, Germany
  • L.N. Brouwer
    LBNL, Berkeley, USA
  • W. Wan
    ShanghaiTech University, Shanghai, People’s Republic of China
  One challenge of proton beam therapy is the shear size of its equipment. A proton gantry that rotates a beamline about a patient is typically about 10 meters in diameter, heavy and expensive. One approach to reduce size and cost of gantries is their miniaturization by the application of superconducting (SC) magnets in the beamline. SC magnets, however, have difficulties to quickly adapt their field when the beam energy is changed. Achromatic beamline designs with high momentum acceptance based on superconducting magnets can lead to compact gantries that still allow rapid beam application which is an important clinical requirement. In a collaborative effort LBNL, Varian Medical Systems and PSI have developed the Alternating Gradient Canted-Cosine-Theta (AG-CCT), a curved version of the CCT design that includes alternating quadrupole and sextupole components to build an achromat. The AG-CCT reaches a momentum acceptance of approx. 20 % dp/p while preserving beam profiles within clinical specification. Another design, conceived by LBNL and Varian, achieves momentum acceptance over the entire clinical beam energy range (70-225 MeV), called the fixed-field achromat. The beam optics principles of the two achromats and an optimized associated gantry beamline design is the main focus of the presented work, as well as putting these in context of clinical requirements and economic constraints.  
slides icon Slides SUPAF01 [2.886 MB]  
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Lightsource Unified Modeling Environment (LUME), a Start-to-End Simulation Framework for Electrons and Photons  
  • C.E. Mayes
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  Since first light at LCLS, there has been continuous invention of new operating modes, introduction of new optical elements, and apid improvement in detectors. While these improvements have led to new experiments with much greater scientific impacts, their transfer to user operations has often taken several experimental runs (many months to years). The integration of these technical advances into scientific programs would be greatly accelerated by a modeling tool that allowed for quantitative assessment of the impact on scientific programs of facility improvements. To this end, SLAC is developing the Lightsource Unified Modeling Environment (LUME) for unified modeling of X-ray free electron laser (XFEL) performance. This modeling tool will be built in several stages with an initial focus on quantitative prediction of critical parameters of the X-ray pulses delivered to experimental stations. This initial development will be followed by incorporation of X-ray-sample interaction and detector performance. This project will take a holistic approach starting with the simulation of the electron beams, to the production of the photon pulses and their transport through the optical components of the beamline, their interaction with the samples and the simulation of the detectors, followed by the analysis of simulated data. LUME will leverage existing, well-established codes [Astra, Bmad, Elegant, Genesis, Impact for electrons, Genesis 1.3 for FEL simulation, and the "Synchrotron Radiation Workshop" (SRW) for X-ray optics] that will be driven and configured by a coherent high-level framework. The high-level framework will build on the Simex platform being developed by the European Cluster of Advanced Laser Light Sources (EUCALL). The platform will be 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  
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SUPAG05 Muon Background Studies for Beam Dump Operation of the K12 Beam Line at CERN 93
  • M.S. Rosenthal, D. Banerjee, J. Bernhard, M. Brugger, N. Charitonidis, B. Döbrich, L. Gatignon, A. Gerbershagen, E. Montbarbon, B. Rae, M.W.U. Van Dijk
    CERN, Geneva, Switzerland
  • T. Spadaro
    INFN/LNF, Frascati, Italy
  In the scope of the Physics Beyond Colliders study at CERN a future operation of the NA62 experiment in beam dump mode is discussed, enabling the search for dark sector particles, e.g. heavy neutral leptons, dark photons and axions. For this purpose, the 400 GeV/c primary proton beam, extracted from the SPS, will be dumped on a massive dump collimator located in the front end of the K12 beam line. Muons originating from interactions and decays form a potential background for this kind of experiment. To reduce this background, magnetic sweeping within the beam line is employed. In this contribution, the muon production and transport has been investigated with the simulation framework G4beamline. The high computational expense of the muon production has been reduced by implementing sampling methods and parametrizations to estimate the amount of high-energy muons and efficiently study optimizations of the magnetic field configuration. These methods have been benchmarked with measured data, showing a good qualitative agreement. Finally, first studies to reduce the muon background by adapting the magnetic field configuration are presented, promising a potential background reduction by a factor four.  
slides icon Slides SUPAG05 [1.885 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ICAP2018-SUPAG05  
About • paper received ※ 19 October 2018       paper accepted ※ 28 January 2019       issue date ※ 26 January 2019  
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Seamless Beam and Radiation Transport Simulations of IBA Proteus Systems Using BDSIM  
  • R. Tesse, A. Dubus, E. Gnacadja, C. Hernalsteens, N. Pauly
    ULB - FSA - SMN, Bruxelles, Belgium
  • S.T. Boogert, L.J. Nevay, W. Shields
    JAI, Egham, Surrey, United Kingdom
  • C. Hernalsteens
    IBA, Louvain-la-Neuve, Belgium
  The precise modeling of proton therapy systems is challenging and requires simulation tools that have capabilities in both beam transport and in the detailed description of particle-matter interactions. Current separate simulations such as those of optical codes or Monte-Carlo transport through discrete elements show their limitations due to the very strict requirements on beam quality at the isocenter. This is particularly relevant with the development of compact systems where the coupling between the components is dominant. For such systems the design of the concrete shielding, which has a large impact on the total cost of the system, is of primary importance. Beam Delivery Simulation (BDSIM) allows the seamless simulation of the transport of particles in a beamline and its surrounding environment. A complete 3D model is built using Geant4, CLHEP and ROOT to provide an extensive insight into beam loss, its interaction and subsequent radiation. This capability is applied to the IBA eye treatment proton therapy machine and to the IBA Proteus One compact system. We discuss the validation of both models against experimental data. In particular, we use it to predict lateral profiles and energy spectra using a detailed geometry of the eye-treatment beam forming nozzle. For the Proteus One system, we present results on the activation of the concrete shielding of the system estimated for a period of 20 years of operation obtained for the first time using end-to-end simulations of the transport of protons in the beamline and their interactions with the environment.  
slides icon Slides SUPAG11 [16.647 MB]  
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Computation and Measurement of Geometric and Chromatic Aberrations is Critical for the Optimal Design and Use of Aberration Corrected Electron Microscopes, and for Quantitative Understanding of Images  
  • R.M. Tromp
    IBM T. J. Watson Center, Yorktown Heights, New York, USA
  Computation and measurement of geometric and chromatic aberrations is critical for the optimal design and use of aberration corrected electron microscopes, and for quantitative understanding of images obtained with such instruments. Here, I will focus on the correction of spherical and chromatic aberrations of a cathode lens instrument (i.e. Low Energy Electron Microscope ’LEEM- or Photo Electron Emission Microscope ’ PEEM) using catadioptrics, i.e. a combination of electron lenses (dioptrics) and an electron mirror (catoptrics). First-order properties calculated with high precision using Munro’s Electron Beam Software’s MIRDA package are in excellent with detailed experimental results. Theoretical maps of C3 vs Cc as a function of the applied potentials then provide a deterministic method to dial in the desired mirror properties at will. Now it is necessary to measure the resultant aberrations of the full system. Unfortunately, the experimental methods developed for TEM and STEM are not applicable in LEEM/PEEM for a variety of reasons. Spherical aberration (plus defocus and astigmatism) can be measured using so-called micro-spot real-space Low Energy Electron Diffraction, or by measuring image shift as a function of beam tilt. Measuring chromatic aberration is more troublesome as it conventionally requires that defocus be measured as a function of gun voltage. However, the use of magnetic prism arrays to separate in- and outgoing path in LEEM results in changing alignment conditions when gun voltage is changed. However, a novel method first demonstrated using ray-tracing simulations enables us to measure chromatic aberration, even at fixed gun voltage. The chromatically corrected system behaves like a simple (but adjustable) achromat, comparable to the crown/flint optical achromat invented by Chester Moore Hall around 1730.  
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Muon g-2: An Interplay of Beam Dynamics and HEP  
  • M.J. Syphers
    Northern Illinois University, DeKalb, Illinois, USA
  The Fermilab experiment E989, Muon g-2, unites particle beam physics with a high energy physics experiment in a unique way. The close interplay of the understanding of particle beam dynamics and the preparation of the beam properties for the experimental measurement is tantamount to the reduction of systematic errors in the determination of the anomalous magnetic moment of the muon to unprecedented precision. The precision of the g-2 measurement will be increased by a factor of four over the most recent case (BNL, E821) mostly due to the increased statistics offered by the higher proton flux delivered by the Fermilab accelerators. However, it is possible that even further gains can be made through a better understanding of the muon beam being delivered to the g-2 Storage Ring. Several effects come into play that can contribute to systematic errors and for which detailed calculations and modeling of the incoming muon beam properties will aid in interpreting the results.  Various correlations of spin and momentum, spin and position along the bunch, etc., will become important to understand during the analysis of the experiment’s data sets. While orders of magnitude of these types of effects are straightforward to estimate, detailed calculations and experimental verification of beam properties will be necessary to contribute to the sub-ppm accuracy of the g-2 measurement.  
slides icon Slides MOPAF01 [19.478 MB]  
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MOPAG01 Plasma Wakefield Start to End Acceleration Simulations From Photocathode to FEL With Simulated Density Profiles 154
  • A. Marocchino
    INFN/LNF, Frascati (Roma), Italy
  Plasma Wakefield acceleration is a promising new acceleration technique that profit by a charged bunch, e.g. an electron bunch, to break the neutrality of a plasma channel to produce a wake where a trailing bunch is eventually accelerated. The quest to achieve extreme gradient conserving high brightness has prompted to a variety of new approaches and techniques. Most of the proposed schemes are however limited to the only plasma channel, assuming in the vast majority of cases, ideal scenarios (e.g. ideal bi-gaussian bunches and uniform density plasma channels). Realistic start-to-end simulations from the photocathode to a FEL via a plasma accelerating section are a fundamental step to further investigate realistic scheme possibilities, the underlying physics and future applications. To remove ideal simplifications, the SPARC_LAB simulation team is simulating bunches from the photo-cathode and tracking them all the way to the plasma. Similarly, the density profiles, where bunches evolve and accelerate, are calculated with a magneto-hydrodynamic code. The density profile is imported into the particle in cell codes used to calculate the particle evolution within the plasma section. The use of a multitude of codes, involving different architectures, physical units and programming languages, made necessary the definition of code interfacing and pipe-processes to ensure a proper pipeline of tools that are traditionally used in different fields are do not often come across. By combining the different numerical codes (particle tracker, particle in cell, magneto-hydrodynamics and FEL codes) we could propose a first realistic start-to-end simulation from the photo-cathode to a FEL lasering for a possible upcoming Italian PWFA-FEL facility. Such a work is conducted with a great focus on code reliability and data reproducibility. The Italian PWFA experimental team uses a capillary to control and tailor the plasma density profile, we could perform preliminary code comparison and  
slides icon Slides MOPAG01 [34.540 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ICAP2018-MOPAG01  
About • paper received ※ 16 October 2018       paper accepted ※ 24 October 2018       issue date ※ 26 January 2019  
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TUPAF08 A Full Field-Map Modeling of Cornell-BNL CBETA 4-Pass Energy Recovery Linac 186
  • F. Méot, S.J. Brooks, D. Trbojevic, N. Tsoupas
    BNL, Upton, Long Island, New York, USA
  • J.A. Crittenden
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy
The Cornell-BNL Electron Test Accelerator (CBETA) is a four-pass, 150 MeV energy recovery linac (ERL), now in construction at Cornell. A single fixed-field alternating gradient (FFAG) beam line recirculates the four energies, 42, 78, 114 and 150 MeV. The return loop is comprised of 107 quadrupole-doublet cells, built using Halbach permanent magnet technology. Spreader and combiner sections (4 independent beam lines each) connect the 36 MeV linac to the FFAG loop. We present here a start-to-end simulation of the 4-pass ERL, entirely, and exclusively, based on the use of magnetic field maps to model the magnets and correctors. There are paramount reasons for that and this is discussed, detailed outcomes are presented, together with comparisons with regular beam transport (mapping based) techniques.
slides icon Slides TUPAF08 [2.568 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ICAP2018-TUPAF08  
About • paper received ※ 23 October 2018       paper accepted ※ 07 December 2018       issue date ※ 26 January 2019  
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TUPAF09 Multi Pass Energy Recovery Linac Design With a Single Fixed Field Magnet Return Line 191
  • D. Trbojevic, J.S. Berg, S.J. Brooks, F. Méot, N. Tsoupas
    BNL, Upton, Long Island, New York, USA
  • W. Lou
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  We present a new approach of the Energy Recovery Linac Design for the future projects: PERLE (Powerful Energy Recovery Linac for Experiments), LHeC/FCCeH and eR- HIC. The concept uses superconducting linacs and a single xed eld beam line with multiple energy passes of electron beams. This represents an update to the existing CBETA (Cornell University Brookhaven National Laboratory ERL Test Accelerator) where the superconducting linac uses a single xed eld magnet beam line with four energy passes during acceleration and four passes during the energy recov- ery. To match the single xed eld beam line to the linac the CBETA uses the spreaders and combiners on both sides of the linac, while the new concept eliminates them. The arc cells from the single xed eld beam line are connected to the linac with adiabatic transition arcs wher cells increase in length. The orbits of di erent energies merge into a sin- gle orbit through the interleaved linac within the straight sections as in the CBETA project. The betatron functions from the arcs are matched to the linac. The time of ight of di erent electron energies is corrected for the central orbits by additional correction magnet controlled induced beam oscillations.  
slides icon Slides TUPAF09 [3.935 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ICAP2018-TUPAF09  
About • paper received ※ 22 October 2018       paper accepted ※ 27 January 2019       issue date ※ 26 January 2019  
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TUPAF10 Experience With CBETA Online Modeling Tools 196
  • C.M. Gulliford, A.C. Bartnik, J. Dobbins, D. Sagan
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • J.S. Berg
    BNL, Upton, Long Island, New York, USA
  • A. Nunez-delPrado
    UCF, Orlando, USA
  Funding: NYSERDA, the New York StateEnergy Research and Development Agency
The Cornell-Brookhaven CBETA machine is a four pass Energy Recovery Linac (ERL) with a Non-scaling Fixed-Field Alternating gradient (NS-FFA) arc. For online modeling of single particle dynamics in CBETA, a customized version of the Tao program, which is based upon the Bmad toolkit, has been developed. This online program, called CBETA-V, is interfaced to CBETA’s EPICS control system. This paper describes the online modeling system and initial experience during machine running.
slides icon Slides TUPAF10 [4.227 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-ICAP2018-TUPAF10  
About • paper received ※ 17 October 2018       paper accepted ※ 28 January 2019       issue date ※ 26 January 2019  
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Advanced Design and Simulation of Fixed-Field Accelerators  
  • C. Johnstone
    Fermilab, Batavia, Illinois, USA
  • M. Berz, K. Makino
    MSU, East Lansing, Michigan, USA
  • P. Snopok
    Illinois Institute of Technology, Chicago, Illlinois, USA
  Funding: Work supported by Fermi Research Alliance, LLC under contract no. DE-AC02-07CH11359
The development of new types of accelerators that allow wide choices of parameters, promote complicated fields, and often need to efficiently handle very large emittance beams requires the availability of new simulation environments to design and accurately predict operation. This is particularly true of Fixed-field accelerators, FFAs, which apply arbitrary-order fields - both alternating gradient, strong focusing - but also weak-focusing cyclotrons. This is especially applicable at medium-to-high energy combined with high intensity (mA currents). Synchrotron and cyclotron codes are generally inadequate to simulate accurately the performance of these strong-focusing fixed-field accelerators, particularly the new breed of non-scaling machines which have difficult, high-order fringe-field and edge-angle effects. One well-supported code, COSY INFINITY (COSY) is particularly suitable for accurate, high-order descriptions of accelerators. New tools have been developed in COSY INFINITY to address and accurately represent complex fixed-field machines in both a sector and spiral sector footprint. A description, application, and comparison of these tools with fields from magnet lattice design is presented.
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