TUPLM —  Tuesday Poster Session-Lake Michigan   (03-Sep-19   16:30—18:00)
Paper Title Page
TUPLM01 Experimental Studies of Resonance Structure Dynamics With Space Charge -1
SUPLM04   use link to see paper's listing under its alternate paper code  
  • L. Dovlatyan, T.M. Antonsen, B.L. Beaudoin, S. Bernal, I. Haber, D.F. Sutter, G.D. Wyche
    UMD, College Park, Maryland, USA
  Funding: Funding for this project is provided by DOE-HEP award #DE-SC0010301
Space charge is one of the fundamental limitations for next generation high intensity circular accelerators. It can lead to halo growth as well as beam loss, and affect resonance structure in ways not completely understood. We employ the University of Maryland Electron Ring (UMER), a circular 10 keV storage machine, to experimentally study the structure of betatron resonances for beams of varying degrees of space charge intensity. Experimental techniques such as tune scans and frequency maps are employed. Results are also compared to computer simulations using the WARP code.
A Study of Quadrupole Error Correction in RF Photoinjectors  
SUPLM14   use link to see paper's listing under its alternate paper code  
  • P.E. Denham, F.W. Cropp V, J. Giner Navarro, P. Musumeci
    UCLA, Los Angeles, USA
  Machining errors in solenoids and radiofrequency couplers in electron guns often lead to unwanted quadrupole moments that are long in focal length and arbitrarily rotated. These moments lead to correlations in the beam distribution which can be corrected by a compensation quadrupole. It is shown here that the correlations induced by weak quadrupole moments can be exactly cancelled with a skew quadrupole corrector (SQC) placed inside a solenoid following the electron gun. The result is a block diagonalized beam matrix. Simulation is shown to agree with experiment.  
TUPLM03 Adjoint Approach to Accelerator Lattice Design -1
  • T.M. Antonsen, B.L. Beaudoin, L. Dovlatyan, I. Haber
    UMD, College Park, Maryland, USA
  Funding: Supported by USDoE DESC0010301
Accelerator lattices are designed using computer codes that solve the equations of motion for charged particles in both prescribed and self-consistent fields. These codes are run in a mode in which particles enter a lattice region, travel for a finite distance, and have their coordinates recorded to assess various figures of merit (FoMs). The lattice is then optimized by varying the positions and strengths of the focusing elements. This optimization is done in a high dimensional parameter space, requiring multiple simulations of the particle trajectories to determine the dependence of the confinement on the many parameters. Sophisticated algorithms for this optimization are being introduced. However, the process is still time consuming. We propose to alter the design process using "adjoint" techniques [*]. Incorporation of an "adjoint" calculation of the trajectories and self-fields can, in several runs, determine the gradient in parameter space of a given FoM with respect to all lattice parameters. It includes naturally self-fields and can be embedded in existing codes such as WARP or Vorpal. The theoretical basis for the method and several applications will be presented.
* T. Antonsen, D. Chernin, J. Petillo, Adjoint Approach to Beam Optics Sensitivity Based on Hamiltonian Particle Dynamics, 2018 arXiv:1807.07898, Physics of Plasmas 26, 013109 (2019).
Phase Retrieval of OAM FEL Beams Using Sequential Intensity and Edge-Diffraction Measurements  
SUPLM05   use link to see paper's listing under its alternate paper code  
  • P. Liu, H. Hao, Y.K. Wu, J. Yan
    FEL/Duke University, Durham, North Carolina, USA
  Orbital angular momentum (OAM) beams have been widely used in many fields. In the visible regime, numerous methods have been developed to generate his kind of beam, while in the X-ray and gamma-ray regime, the generation of OAM beams remains challenging. The possibility of using free electron lasers (FEL) for the high energy OAM generation has been extensively explored in recent years. To characterize the generated OAM beams, phase retrieval is a good method. Here, we present a phase retrieval algorithm for OAM beams without using any conventional optics and thus can be possibly used beyond the visible regime. This algorithm is based on free-space-propagated and edge-diffracted beam intensity profiles, which are sequentially sampled by using a CCD camera at several longitudinal locations. The dependence on the initial input phase is investigated using a set of pure OAM modes and mixed OAM modes with different mixing ratio. The phase of these modes can be successfully retrieved with a weak dependence on the choice of the initial phase.  
Beam Transport for an Offset Anode Operation Mode for DC Guns  
  • O.H. Rahman, J. Skaritka, E. Wang
    BNL, Upton, New York, USA
  • J.P. Biswaspresenter
    Stony Brook University, Stony Brook, USA
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
An offset anode operation mode for DC gun has been investigated at Brookhaven National Lab. This scheme requires the anode to be transversely offset from the electrostatic center for the cathode, while keeping the laser spot at the center of the cathode. The beam transport from the cathode to out of the gun requires a transverse kicker in the DC gap and then subsequent correctors to bring the beam back on axis. In this paper, we describe various components, including the anode offsetting mechanism required for transporting the beam out of the gun and show beam dynamics results for different configurations of the optics.
poster icon Poster TUPLM05 [0.869 MB]  
TUPLM07 First Experimental Observations of the Plasma-Cascade Instability in the CeC PoP Accelerator -1
  • I. Petrushina
    SUNY SB, Stony Brook, New York, USA
  • Y.C. Jing, V. Litvinenko, J. Ma, I. Pinayev, G. Wang, Y.H. Wu
    BNL, Upton, New York, USA
  • V. Litvinenko
    Stony Brook University, Stony Brook, USA
  • K. Shih
    SBU, Stony Brook, New York, USA
  Preservation of the beam quality is important for attaining the desirable properties of the beam. Collective effects can produce an instability severely degrading beam emittance, momentum spread and creating filamentation of the beam. Microbunching instability for beams traveling along a curved trajectory, and space charge driven parametric transverse instabilities are well-known and in-depth studied. However, none of the above include a microbunching longitudinal instability driven by modulations of the transverse beam size. This phenomenon was observed for the first time during the commissioning of the CeC PoP experiment. Based on the dynamics of this instability we named it a Plasma-Cascade Instability (PCI). PCI can strongly intensify longitudinal micro-bunching originating from the beam’s shot noise, and even saturate it. Resulting random density and energy microstructures in the beam can become a serious problem for generating high quality electron beams. On the other hand, such instability can drive novel high-power sources of broadband radiation. In this paper we present our experimental observations of the PCI and the supporting results of the numerical simulations.  
poster icon Poster TUPLM07 [17.389 MB]  
TUPLM08 Experimental Studies of Single Invariant Quasi-Integrable Nonlinear Optics at IOTA -1
SUPLM19   use link to see paper's listing under its alternate paper code  
  • N. Kuklev, Y.K. Kim
    University of Chicago, Chicago, Illinois, USA
  • S. Nagaitsev, A.L. Romanov, A. Valishev
    Fermilab, Batavia, Illinois, USA
  Funding: Work supported by National Science Foundation award PHY-1549132, the Center for Bright Beams. Fermi Research Alliance operates Fermilab under Contract DE-AC02-07CH11359 with the US Dept. of Energy.
The Integrable Optics Test Accelerator is a research electron and proton storage ring recently commissioned at the Fermilab Accelerator Science and Technology facility. Its research program is focused on testing novel techniques for improving beam stability and quality, notably the concept of non-linear integrable optics. In this paper, we report on run 1 results of experimental studies of a quasi-integrable transverse focusing system with one invariant of motion, a Henon-Heiles type system implemented with octupole magnets. Good agreement with simulations is demonstrated on key parameters of achievable tune spread, dynamic aperture, and invariant conservation. We also outline current simulation and hardware improvement efforts for run 2, planned for fall of 2019.
TUPLM09 A Fast Method to Evaluate Transverse Coupled-Bunch Stability at Non-Zero Chromaticity -1
  • R.R. Lindberg
    ANL, Lemont, Illinois, USA
  Funding: Supported by U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357
We present a dispersion relation that gives the complex growth rate for coupled-bunch instabilities at arbitrary chromaticity in terms of its value at zero chromaticity. We compare predictions of the theory to elegant tracking simulations, and show that there are two distinct regimes to stability depending upon whether the zero chromaticity growth rate is smaller or larger than the chromatic tune shift over the bunch. We derive an approximate expression that is easily solved numerically, and furthermore indicate how the formalism can be extended to describe arbitrary longitudinal potentials.
TUPLM11 Beam-Beam Damping of the Ion Instability -1
  • M. Blaskiewicz
    BNL, Upton, New York, USA
  Funding: Work Supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Beam-Beam damping of the Ion Instability The electron storage ring of the proposed electron ion collider at BNL has bunch charges as large as 50 nC and bunch spacings as small as 10 ns. For molecules like CO a dangerous buildup of positive ions is possible and a significant fraction of these ions can survive allowable clearing gaps. The instability is thus multi-turn and the weak damping required to stop the ion instabilty with an ideal clearing gap is ineffective here. The beam-beam force is highly nonlinear and a potent source of tune spread. Simulations employing several macro-particles per electron bunch and several ion macroparticles are used to estimate maximum gas densities for some common molecules. A simplified model is introduced and compared with simulations.
TUPLM12 Method for a Multiple Square Well Model to Study Transverse Mode Coupling Instability -1
SUPLM18   use link to see paper's listing under its alternate paper code  
  • M.A. Balcewicz, Y. Hao
    FRIB, East Lansing, Michigan, USA
  • M. Blaskiewicz
    BNL, Upton, New York, USA
  In the high intensity limit it can become difficult to simulate intense beams sufficiently within a short time scale due to collective effects. Semi-Analytic methods such as the Square Well Model*/AirBag Square Well** (SWM/ABS) exist to estimate collective effects within a short time scale. SWM/ABS discretizes the longitudinal confining potential into a single square well enforcing linearity for the case of linear transverse optics. A method is proposed here to extend the Square Well Method multiple square wells. This method preserves linearity properties that make it easily solvable within a short time scale as well as including nonlinear effects from the longitudinal potential shape.
*M. Blaskiewicz PRSTAB 1, 044201. 1998
**A. Burov PRAB 22, 034202. 2019
poster icon Poster TUPLM12 [1.818 MB]  
TUPLM13 Two-Energy Storage-Ring Electron Cooler for Relativistic Ion Beams -1
SUPLM07   use link to see paper's listing under its alternate paper code  
  • B. Dhital, J.R. Delayen, G.A. Krafft
    ODU, Norfolk, Virginia, USA
  • J.R. Delayen, Y.S. Derbenev, D. Douglas, G.A. Krafft, F. Lin, V.S. Morozov, Y. Zhang
    JLab, Newport News, Virginia, USA
  An electron beam based cooling system for the ion beam is one of the commonly used approaches. The proposed two’energy storage-ring electron cooler consists of damping and cooling sections at markedly different energies connected by an energy recovering superconducting RF structure. The parameters in the cooling and damping sections are adjusted for optimum cooling of a stored ion beam and for optimum damping of the electron beam respectively. This paper briefly describes a two cavities model along with a third cavity model to accelerate and decelerate the electron beam in two energy storage ring. Based on our assumed value of equilibrium emittance shows that these models give a bunch length of the order of cm and energy spread of the order of 〖10〗-5 in the cooling section which are required parameters for the better cooling. Numerical calculations along with elegant simulation are presented.  
Progress on Tunable Bunch Train Generation Using Emittance Exchange and Transverse Wiggler  
  • G. Ha, M.E. Conde, J.G. Power, J.H. Shao, E.E. Wisniewski
    ANL, Lemont, Illinois, USA
  Funding: This work is supported by the U.S. Department of Energy Offices of HEP and BES, under Contract No. DE-AC02-06CH11357. It is also funded by Argonne LDRD.
A tunable bunch train is usually generated from the energy-to-density modulation conversion using R56 of chicane. Although the amplitude of the modulation, longitudinal chirp, and R56 of chicane provide a tunability of bunch train properties, its tuning is not easy since it changes the beamline condition significantly (e.g. RF power, linac phase, bending angle etc). Recently, Argonne Wakefield Accelerator (AWA) group proposed a new scheme to generate a tunable train using emittance exchange (EEX) beamline with a transverse wiggler. An EEX beamline provides the exchange of transverse and longitudinal phase spaces. This exchange significantly improves the capability and quality of longitudinal phase space control due to the lack of correlations during the manipulation and the easiness of the transverse control of the beam. In this scheme, we generate a transverse momentum modulation using a transverse wiggler, and convert this modulation to a longitudinal density modulation. Wiggler gap and quadrupole strength control the bunch train properties such as frequency, bandwidth, and pulse length. We present progress of the proof-of-principle experiment planned at AWA facility.
TUPLM15 Arbitrary Transverse Profile Shaping using Transverse Wigglers -1
  • G. Ha, M.E. Conde, J.G. Power
    ANL, Lemont, Illinois, USA
  Funding: This work is supported by the U.S. Department of Energy, Offices of HEP and BES, under Contract No. DE-AC02-06CH11357.
Argonne Wakefield Accelerator (AWA) group demonstrated arbitrary longitudinal shaping capability of thee emittance exchange (EEX) beamline in 2016. Several different transverse masks were used to shape the beam transversely, and the transmission through the mask was around 40%. The masking is one of the easiest ways to control the profile, but this low transmission would make significant drop of the beam quality due to a higher charge requirement in the gun, and it can make thermal issues for high repetition rate or high intensity beams. At the same time, it only controls the profile not a 2D phase space. We recently proposed a scheme to generate a tunable bunch train using a EEX beamline with a transverse wiggler. This wiggler provides a sinusoidal magnetic field which makes a sinusoidal modulation on the transverse phase space. If the beam passes series of transverse wigglers with different period and strength, one can make arbitrary correlation on the horizontal position and momentum. It opens up totally new way to control all longitudinal properties including arbitrary current profile shaping without charge loss. In this poster, we present the concept of the work and plan.
TUPLM16 Double-Horn Suppression in EEX Based Bunch Compression -1
  • J. Seok, M. Chung
    UNIST, Ulsan, Republic of Korea
  • M.E. Conde, G. Ha, J.G. Power
    ANL, Lemont, Illinois, USA
  Nonlinearities on the longitudinal phase space in-duce a double-horn current profile when the bunch is compressed strongly. Since this double-horn can de-grade the performance of FELs due to the CSR it makes, the suppression of the double-horn is one of important beam dynamics issues. Emittance exchange (EEX) can be interesting option for this issue due to its longitudinal controllability. Since EEX exchanges the longitudinal phase space and transverse phase space, higher order magnets such as octupole can control the nonlinearity. In this paper, we present simulation re-sults on the suppression of the double-horn current profile using EEX based bunch compression. We use a double EEX beamline installed at the Argonne Wake-field Accelerator facility for the simulation.  
Optimization of JLEIC Luminosity Performance Without On-Energy Cooling  
  • Y. Zhang
    JLab, Newport News, Virginia, USA
  Funding: Work is supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics, and Office of High Energy Physics under Contracts DE-AC05-06OR23177 and DE-SC0018370.
Jefferson Lab electron-ion collider (JLEIC) is designed to reach high luminosity for physics program. An challenging R&D for JLEIC is development of advanced cooling technologies. Here we present schemes for optimizing JLEIC integrated luminosity performance without cooling of ion beams during collisions.
TUPLM18 Improving Energy Resolution and Compensating Chromatic Aberration With a TM010 Microwave Cavity -1
  • C.J.R. Duncan
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • P. Cueva, J.M. Maxson, D.A. Muller
    Cornell University, Ithaca, New York, USA
  Funding: National Science Foundation under Award OIA-1549132, the Center for Bright Beams
The intrinsic energy spread of electron sources limits the achievable resolution of electron microscopes in both spectroscopic and spatially resolved measurements. We propose that the TM010 mode of a single radio frequency (RF) cavity be used to dramatically reduce this energy spread in a pulsed beam. We show with analytic approximations, confirmed in simulations, that the non-linear time-energy correlations that develop in an electron gun can be undone by the RF cavity running near-crest. We derive an expression that gives the required RF field strength as a function of accelerating voltage. We explore multiple applications, including EELS and SEM. By pulsing a photocathode with commercially available, high repetition-rate lasers, our scheme could yield competitive energy spread reduction at higher currents when compared with monochromated continuous-wave sources for electron microscopes.
Realizing Self-Consistent Distributions at the Spallation Neutron Source  
  • N.J. Evans
    ORNL RAD, Oak Ridge, Tennessee, USA
  • T.V. Gorlov, J.A. Holmes
    ORNL, Oak Ridge, Tennessee, USA
  Funding: DOE Office of Science, Basic Energy Science, Accelerator and Detector Research Program and UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy
We define a self-consistent distribution as an elliptical, uniform charge distribution with phase space correlations such that both properties are maintained through any linear transport, including the distribution’s own linear space charge force. The K-V distribution being the most well known example. *Danilov et al. gave a procedure for constructing self-consistent distributions. Further they showed how a particular example of a so-called rotating distribution could be painted into a real ring using a transverse painting system like that in Oak Ridge’s Spallation Neutron Source(SNS). I will report on the progress of experiments to paint such a distribution into the SNS accumulator ring, and progress in understanding the impact these beams may have on future high power accelerators.
*Danliov et al, "Self-consistent time dependent two dimensional and three dimensional space charge distributions with linear force", Phys. Rev. ST Accel. Beams 6, 094202
TUPLM20 Generation of High-Charge Magnetized Electron Beams Consistent With JLEIC Electron Cooling Requirements -1
SUPLM21   use link to see paper's listing under its alternate paper code  
  • A.T. Fetterman, P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  • S.V. Benson, F.E. Hannon, S. Wang
    JLab, Newport News, Virginia, USA
  • D.J. Crawford, D.R. Edstrom, P. Piot, J. Ruan
    Fermilab, Batavia, Illinois, USA
  Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear physics under contract DE-AC05-06OR23177 and DE-AC02-07CH11359.
The proposed Jefferson Lab Electron-Ion Collider (JLEIC), currently under design, relies on electron cooling in order to achieve the desired luminosity. This includes an electron beam with >55 Mev, 3.2 nC bunches that cools hadron beams with energies up to 100 GeV. To enhance the cooling, the electron beam must be magnetized with a specific eigen-emittance partition. This paper explores the use of the Fermilab Accelerator Science and Technology (FAST) facility to demonstrate the generation of an electron beam with parameters consistent with those required in the JLEIC high-energy cooler. We demonstrate via simulations the generation of the required electron-beam parameters and perform a preliminary experiment to validate FAST capabilities to produce such beams.
TUPLM21 Optical Stochastic Cooling Program at Fermilab’s Integrable Optics Test Accelerator -1
  • J.D. Jarvis, S. Chattopadhyay, V.A. Lebedev, H. Piekarz, P. Piot, A.L. Romanov, J. Ruan
    Fermilab, Batavia, Illinois, USA
  • S. Chattopadhyay, P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  Funding: Fermi National Accelerator Laboratory is operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
Beam cooling enables an increase of peak and average luminosities and significantly expands the discovery potential of colliders. Optical Stochastic Cooling (OSC) is a high-bandwidth cooling technique that will advance the present state-of-the-art, stochastic-cooling rate by more than three orders of magnitude. A proof-of-principle demonstration with protons or heavy ions involves prohibitive costs, risks and technological challenges; however, exploration of OSC with electrons is a cost-effective alternative for studying the beam-cooling physics, optical systems and diagnostics. The ability to demonstrate OSC was a key requirement in the design of Fermilab’s Integrable Optics Test Accelerator (IOTA) ring. The IOTA program will explore the physics and technology of OSC in amplified and non-amplified configurations. We also plan to investigate the cooling and manipulation of a single electron stored in the ring. The OSC apparatus is currently being fabricated, and installation will begin in the fall of 2019. In this contribution, we will describe the IOTA OSC program, the upcoming passive-OSC experimental runs and ongoing preparations for an amplified-OSC experiment
TUPLM22 Off Axis Dependence of Current Dependent Coherent Tune Shifts in the UMER Ring -1
  • D.F. Sutter, B.L. Beaudoin, L. Dovlatyan
    UMD, College Park, Maryland, USA
  Funding: Work supported by U. S. Department of Energy grant number DESC00010301
The University of Maryland Electron Ring (UMER) was built to explore space charge effects in the extreme - beyond the space charge limit of most existing storage rings. At the nominal operating kinetic energy of 10 keV, the beam is also non relativistic. We have experimentally verified that the current dependent coherent tune shift obeys the Laslett formula over a wide current range for a cylindrical geometry and non penetrating magnetic fields when the beam is on axis; i.e. the average closed orbit displacement around the ring is essentially zero.* In the current experiment this measurement is extended to the change in current dependent coherent tune shift as the average closed orbit is moved off axis. It can be displaced over approximately ±10 mm of the vacuum pipe diameter of 50 mm without loss of beam. Because the 36 bending magnets in UMER are very short, we treat each of them as a local kick and then increment each by a calculated small amount to achieve the desired, global closed orbit displacement. Experimental results are compared to predictions by Zotter and others.
* D. für Sutter, M.Cornacchia, et al, "Current dependent tune shifts in the University of Maryland electron ring", NAPAC 2013.
TUPLM24 Electron Heating by Ions in Cooling Rings -1
  • H. Zhao, M. Blaskiewicz
    BNL, Upton, New York, USA
  Hadron beam cooling at high energy is a critical technique for Electron-Ion Colliders (EIC). We consider using an electron storage ring for the EIC at BNL. For such a cooler, the electron beam quality plays an important role since it directly determines the cooling rate. Besides the effects of IBS, space charge and synchrotron damping, which are calculable with well known methods, the heating effect by ions also needs to be carefully considered in electron beam dynamics. In this paper, we present an analytical model to calculate the heating rate by ions and give some example calculations. In addition, this model was benchmarked by applying it on the IBS calculation.
* Work supported by States Department of Energy
TUPLM25 Connecting Gas-Scattering Lifetime and Ion Instabilities -1
  • B. Podobedov, M. Blaskiewicz
    BNL, Upton, New York, USA
  Recently there is a renewed interest in fast ion instability (FII) which is of concern for future low-emittance electron storage rings, such as MBA light sources and colliders, i.e. eRHIC. While analytical theories and numerical codes exist to model the effect, due to various assumptions and limitations, accurate experimental verification is often desirable. Unfortunately, one of the most critical parameters for FII (as well as the classical "trapped-ion" instability), the residual ion concentration, is usually the most uncertain. Vacuum gauges and residual gas analyzers (RGAs) provide some useful data, but they are often not accurate enough, and, more importantly, they cannot directly probe the ion concentration along the beam orbit. In this paper we show how one could use gas-scattering lifetime measurements to infer the residual gas concentration suitable for ion instability experiment modelling.  
TUPLM26 Progress Toward a Laser Amplifier for Optical Stochastic Cooling -1
SUPLM22   use link to see paper's listing under its alternate paper code  
  • A.J. Dick, P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  • M.B. Andorf
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  Optical Stochastic Cooling (OSC) is a method of beam cooling using optical frequencies which compresses the phase space of the beam by correcting the deviation of each particle’s momentum. A particle bunch passing through an undulator produces radiation which is amplified and provides the corrective energy kick. In this project, we are testing a method of amplifying synchrotron radiation (SR) for the eventual use in OSC. The SR is amplified by passing through a highly-doped Chromium:Zinc Selenide (Cr:ZnSe) crystal which is pumped by a Thulium fiber laser. The SR will be produced by one of the bending magnets of the Advanced Photon Source. The first step is to detect and measure the power of SR using a photo-diode. The gain is then determined by measuring the radiation amplified after the single-pass through the crystal. This serves as a preliminary step to investigate the performance of the amplification of beam-induced radiation fields. The planned experiment is an important step towards achieving active OSC in a proof-of-principle demonstration in IOTA.  
Beam Dynamics Effects Due to Non-Cylindrical-Symmetric RF Field at the AWA Facility  
SUPLM01   use link to see paper's listing under its alternate paper code  
  • T. Xu, P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  • M.E. Conde, G. Ha, J.G. Power, J.H. Shao
    ANL, Lemont, Illinois, USA
  • P. Piot
    Fermilab, Batavia, Illinois, USA
  The Argonne Wakefield Accelerator (AWA) is supporting an array of experiments with increasing demand on the ability to generate brighter beams. One impeding element to generate low-emittance beams comes from the non-axisymmetric nature of the RF field in the AWA linac. Deviation from the axisymmetry arises from the input couplers and generally lead to a transverse emittance dilution via a head-tail effect of the beam. Numerical tracking in a 3D model is performed with IMPACT-T to investigate the impact of these 3D effects and their possible mitigation for the case of AWA nominal round-beam operation and for the asymmetric-emittance ("flat beam") generation.  
TUPLM29 Current Status and Prospects of FRIB Machine Protection System -1
  • Z. Li, D. Chabot, S. Cogan, S.M. Lidia
    FRIB, East Lansing, Michigan, USA
  Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661
The Facility for Rare Isotope Beams (FRIB) is designed to accelerate beam up to 400 kW power with kinetic energy ≥ 200 MeV/u. Fast response of the machine protection system is critical for FRIB beam commissioning and operation to prevent damage to equipment. The beam commissioning of the first linac segment, including fifteen cryomodules, has been completed. Four ion species were accelerated to a beam energy of 20.3 MeV/u with duty factors from 0.05 percent to continuous wave. The peak beam current exceeded 10 percent of the final requirements. This paper summarizes the status of the machine protection system deployed in the production, Machine interlock response time of ~8 μs was achieved. Incentives for future development include being able to achieve smooth and reliable beam operation, faster machine protection response time and real time data analysis of failure mode.
poster icon Poster TUPLM29 [2.064 MB]  
Reaching Low Emittance in Synchrotron Light Sources by Using Complex Bends  
TUZBB2   use link to access more material from this paper's primary paper code  
  • G.M. Wang, J. Choi, O.V. Chubar, Y. Hidaka, T.V. Shaftan, S.K. Sharma, V.V. Smaluk, C.J. Spataro, T. Tanabe
    BNL, Upton, New York, USA
  • N.A. Mezentsev
    BINP SB RAS, Novosibirsk, Russia
  All modern projects of low-emittance synchrotrons follow Multi-Bend Achromat approach*. The low emittance is realized by arranging small horizontal beta-function and dispersion in the bending magnets, the number of which varies from 4 to 9 magnets per cell. We propose an alternative way to reach low emittance by use of a lattice element that we call "Complex Bend"**, instead of regular dipole magnets. The Complex Bend is a new concept of bending magnet consisting of a number of dipole poles interleaved with strong alternate focusing so as to maintain the beta-function and dispersion oscillating at very low values. The details of Complex Bend, considerations regarding the choice of optimal parameters, thoughts for its practical realization and use in low-emittance lattices, are discussed.
* MBA: http://citeseerx.ist.psu.edu/viewdoc/download?doi=
** Complex Bend: Phys. Rev. Accel. Beams 21, 100703 (2018)
slides icon Slides TUPLM30 [8.348 MB]  
Transverse Ion Beam Emittance Growth Due to Low Frequency Instabilities in Microwave Ion Source Plasma  
SUPLM10   use link to access more material from this paper's primary paper code  
TUZBB5   use link to access more material from this paper's primary paper code  
  • C. Mallick, M. Bandyopadhyay, R. Kumar
    Institute for Plasma Research, Bhat, Gandhinagar, India
  The ion source is accompanied by the generation of low frequency (LF) plasma instabilities (PI). Its signature is also visible in high current heavy ion beam required for any accelerator. These LFs affect the profile of the ion beam in transverse phase-space. These issues are investigated in detail by measuring the emittance of beam. Beam oscillations are extracted from the transverse emittance data by taking Fast Fourier Transform (FFT) of it. PI frequencies are identified in the measured electromagnetic emission from the plasma, in which these frequencies appeared as sidebands around pump frequency 2.45 GHz. The PI components i.e.,ion acoustic (IA) and ion cyclotron (IC) waves are also visible in the FFT spectra. Low and high frequency oscillations in the beam are 476 kHz and ~1.3 MHz respectively. These two groups of frequencies also exist within the PI induced IA (238 - 873 kHz) and IC (1.29 - 1.3 MHz) frequency ranges. The measured emittance (rms-normalized) in horizontal and vertical phase-space varies from 0.002-0.098 𝜋 mm mrad and 0.004-0.23 𝜋 mm mrad respectively. PI induced beam oscillation is the reason behind such broad transverse emittance growth.
’S. Kumar et al.,Phys. Rev. Accel. Beams 21, 093402 (2018)’
’R. D’Arcy et al., Nucl. Instrum. Methods Phys. Res. A 815 7(2016)’
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slides icon Slides TUPLM31 [5.911 MB]  
Nonlinear Tune-Shift Measurements in the Integrable Optics Test Accelerator  
SUPLM11   use link to access more material from this paper's primary paper code  
TUZBB6   use link to access more material from this paper's primary paper code  
  • S. Szustkowski, S. Chattopadhyay
    Northern Illinois University, DeKalb, Illinois, USA
  • S. Chattopadhyay, A.L. Romanov, A. Valishev
    Fermilab, Batavia, Illinois, USA
  • N. Kuklev
    University of Chicago, Chicago, Illinois, USA
  Funding: US Department of Energy, Office of High Energy Physics, General Accelerator Research and Development (GARD) Program
The first experimental run of Fermilab’s Integrable Optics Test Accelerator (IOTA) ring aimed at testing the concept of nonlinear integrable beam optics. In this report we present the preliminary results of the studies of a nonlinear focusing system with two invariants of motion realized with the special elliptic-potential magnet. The key measurement of this experiment was the horizontal and vertical betatron tune shift as a function of transverse amplitude. A vertical kicker strength was varied to change the betatron amplitude for several values of the nonlinear magnet strength. The turn-by-turn positions of the 100 MeV electron beam at twenty-one beam position monitors around the ring were captured and used for the analysis of phase-space trajectories.
slides icon Slides TUPLM32 [12.880 MB]  
TUPLM33 Optimization of Beam Parameters for UEM with Photo-Emission S-Band RF Gun and Alpha Magnet -1
SUPLM24   use link to see paper's listing under its alternate paper code  
  • H.R. Lee, P. Buaphad, I.G. Jeong, Y. Joo, Y. Kim
    University of Science and Technology of Korea (UST), Daejeon, Republic of Korea
  • P. Buaphad, I.G. Jeong, Y. Joo, Y. Kim
    KAERI, Jeongeup-si, Republic of Korea
  • B.L. Cho
    KRISS, Daejeon, Republic of Korea
  • M.Y. Han, J.Y. Lee, S.H. Lee
    Korea Atomic Energy Research Institute (KAERI), Daejeon, Republic of Korea
  • H. Suk
    GIST, Gwangju, Republic of Korea
  Ultrafast Electron Microscopy (UEM) is a powerful tool to observe ultrafast dynamical processes in sample materials at the atomic level. By collaborating with KRISS and GIST, the future accelerator R&D team at KAERI has been developing a UEM facility based on a photo-emission S-band (=2856 MHz) RF gun. Recently, we have added an alpha magnet in the beamline layout of the UEM to improve beam qualities such as emittance, divergence, energy spread, and bunch length. To achieve high spatial and time resolutions, we have been optimizing those beam parameters and other machine parameters by performing numerous ASTRA and ELEGANT code simulations. In this paper, we describe our ASTRA and ELEGANT code optimizations to obtain high-quality beam parameters for the UEM facility with a photo-emission S-band RF gun and an alpha magnet.  
poster icon Poster TUPLM33 [0.967 MB]  
GPU-Accelerated Simulation of Spin-Polarized Electron Beams  
  • I.A. Zilberter, B.M. Cowan
    Tech-X, Boulder, Colorado, USA
  Accurate simulation of spin precession and orbital dynamics is critical in the design of the next generation of spin-polarized particle accelerators, such as the proposed Electron-Ion Collider. In this paper we will present an extension to the spin tracking code GPUSpinTrack* that allows for the rapid simulation of electron beams on graphics processors. We evaluate the accuracy and computational efficiency of electron tracking through the EIC rapid-cycling synchrotron as well as though individual lattice elements, and discuss the implementation of synchrotron radiation. A performance comparison with the ZGOUBI tracking code is also presented.
* D.T. Abell, D. Meiser, V.H. Ranjbar, and D.P. Barber. "Accurate and efficient spin integration for particle accelerators." Phys. Rev. ST Accel. Beams 18, 024001 (2015)
High-Performance Magnetostatic Solvers  
  • B.M. Cowan, M. de Messieres
    Tech-X, Boulder, Colorado, USA
  New particle accelerator designs rely on magnets of ever-increasing complexity for beam optics. With both complicated geometries and nonlinear materials, the problem of computing magnetic fields becomes computationally demanding. Here, we present a new tool to compute magnetostatic fields that can handle the largest problems. We demonstrate second-order accuracy for figures of merit as well as the ability to scale to large numbers of degrees of freedom. We show results for upcoming accelerator magnet designs.
Support provided by U.S. Department of Energy grant DE-SC0018515.
TUPLM36 Temperature Measurements of the NSLS-II Vacuum Components -1
  • A. Blednykh, G. Bassi, C. Hetzel, B.N. Kosciuk, D. Padrazo Jr, T.V. Shaftan, V.V. Smaluk, G.M. Wangpresenter
    BNL, Upton, New York, USA
  This paper is dedicated to the analysis of our recent experience from ramp-up of operating current at NSLS-II from 25 mA at the end of commissioning in 2014 to 475 mA achieved in studies today. To approach the design level of the ring intensity we had to solve major problems in overheating of the chamber components. Since the beginning of the NSLS-II commissioning, the temperature of the vacuum components has been monitored by the Resistance Temperature Detectors located predominantly outside of the vacuum chamber and attached to the chamber body. A couple of vacuum components were designed with the possibility for internal temperature measurements under the vacuum as diagnostic assemblies. Temperature map helps us to control overheating of the vacuum components around the ring especially during the current ramp-up. The average current of 475mA has been achieved with two main 500MHz RF cavities and w/o any harmonic cavities. In this paper we discuss the heating results for a 15ps bunch length (at low current) of the following vacuum components: Large Aperture BPM, Small Aperture BPM, Bellows, Flanges, Ceramics Chambers and Stripline Kickers.  
poster icon Poster TUPLM36 [3.741 MB]  
TUPLM37 High Energy Beam Transport Along the 68-m LANSCE 1L Beamline to Optimize Neutron Production -1
  • P.K. Roy, E.L. Kerstiens, R.J. Macek, C. Pillai, C.E. Taylor
    LANL, Los Alamos, New Mexico, USA
  Funding: *Work supported by the United States Department of Energy, National Nuclear Security Agency, under contract DE-AC52-06NA25396.
An 800 MeV 100 µA proton beam is delivered to the Lujan Center, one of five user facilities at the LANSCE linear accelerator center, to generate an intense beam of pulsed neutrons. The Lujan Center beam transport line, known as 1L beamline, is over 68 meters in length, starting from the ROWS01. The beamline is consisted with bending and focusing elements before it reaches the end of the 1L beam optics system, where the beam spot size is nominally 1.5 cm (RMS). The Mark IV target assembly has been designed to optimize the neutron production for the 1L target in the Lujan center to improve the flux and resolution. As part of the safety review of this design, it becomes necessary to know the beam intensity and size on the new target. Using the new measurements of the beamline, calculated beam sizes using the LANL version of the beam envelope code TRANSPORT and CERN code MAD-X are compared. The input beam parameters for the codes were extracted from ORBIT analysis of the proton storage ring beam. Beam envelope measurements were made at various locations throughout the beamline using wire scanners. The predicted beam envelopes and measured data agree within expected errors.
poster icon Poster TUPLM37 [5.004 MB]