NAPAC2019 - List of Keywords (quadrupole)

Paper	Title	Other Keywords	Page
MOPLM03	Correlations Between Beta Beating and APS-U Single Particle Dynamics Performance	lattice, focusing, sextupole, simulation	95
	Y.P. Sun 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. In the optimizations and evaluations process of the Advanced Photon Source upgrade (APS-U) lattice, it was observed that there are negative correlations between beta beating and APS-U single particle dynamics performance (such as dynamic acceptance and local momentum acceptance). These correlations are not always present due to different reasons. In this paper, a systematic simulation study is performed to understand the correlations between beta beating and APS-U single particle dynamics performance. Relatively high beta beatings are generated to reveal these effects.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLM03
About •	paper received ※ 31 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPLM04	First Attempts at Applying Machine Learning to ALS Storage Ring Stabilization	experiment, storage-ring, emittance, operation	98
	S.C. Leemann, Ph. Amstutz, W.E. Byrne, M.P. Ehrlichman, T. Hellert, A. Hexemer, S. Liu, M. Marcus, C.N. Melton, H. Nishimura, G. Penn, F. Sannibale, D.A. Shapiro, C. Sun, D. Ushizima, M. Venturini LBNL, Berkeley, USA
	Funding: This research is funded by the US Department of Energy (BES & ASCR Programs), and supported by the Director of the Office of Science of the US Department of Energy under Contract No. DEAC02-05CH11231. The ALS storage ring operates multiple feedbacks and feed-forwards during user operations to ensure that various source properties such as beam position, beam angle, and beam size are maintained constant. Without these active corrections, strong perturbations of the electron beam would result from constantly varying ID gaps and phases. An important part of the ID gap/phase compensation requires recording feed-forward tables. While recording such tables takes a lot of time during dedicated machine shifts, the resulting compensation data is imperfect due to machine drift both during and after recording of the table. Since it is impractical to repeat recording feed-forward tables on a more frequent basis, we have decided to employ Machine Learning techniques to improve ID compensation in order to stabilize electron beam properties at the source points.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLM04
About •	paper received ※ 26 August 2019 paper accepted ※ 31 August 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPLO04	Progress in Time-Resolved MeV Transmission Electron Microscopy at UCLA	electron, cavity, alignment, detector	243
	P.E. Denham UCLA, Los Angeles, USA
	We describe here two new enhancements developed for the time-resolved microscope at the UCLA PEGASUS Lab based on the use of a radiofrequency photoinjector as an ultrafast electron source and permanent magnet quadrupoles as electron lenses. The first enhancement is a flexible optical column design including hybrid-style stronger focusing quadrupoles, yielding a 60% magnification increase, and a collimator to improve imaging contrast. This new optical system will have the ability to switch between real-space imaging and diffraction pattern imaging with variable magnification. The second enhancement is a high-frequency (X-band) cavity downstream from the (S-band) photoinjector to reduce the beam energy spread. These enhancements are crucial for improving contrast and image quality. In addition, a pulse-wire alignment method to fiducialize the quadrupole positions to better than 20-um precision is used to reduce the aberrations induced by misalignment and achieve spatial resolution at the 20 nm-level.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLO04
About •	paper received ※ 28 August 2019 paper accepted ※ 04 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPLO07	MEMS Based Multibeam Ion Linacs	acceleration, laser, extraction, ion-source	249
	T. Schenkel, G. Giesbrecht, Q. Ji, A. Persaud, P.A. Seidl LBNL, Berkeley, California, USA K. Afridi, A. Lal, D. Ni, S. Sinha Cornell University, Ithaca, New York, USA
	Funding: Work at LBNL was conducted under the auspices of the US DOE (DE-AC0205CH11231) and supported by ArpaE. Device fab at the Cornell Nano Fab facility was supported by NSF (Grant 384 No.ECCS-1542081). We report on the development of multi-beam RF linear ion accelerators that are formed from stacks o low cost wafers. Wafers are prepared using MEMS techniques. We have demonstrated acceleration of ions in a 3x3 beamlet array with ion currents in the 0.1 mA range and acceleration at the 10 keV in lattice of RF (13 MHz) acceleration units and electrostatic quadrupoles. We will describe the status and plans for scaling to 10x10 beams, ion currents >1 mA and ion energies >100 keV in a compact, low cost setup for applications in materials processing. [1] P. A. Seidl, et al., Rev. Sci. Instr. 89, 053302 (2018); doi: 10.1063/1.5023415
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLO07
About •	paper received ※ 27 August 2019 paper accepted ※ 16 November 2020 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPLO09	A Pulsed, Current Regulated Magnet Power Supply for Small Magnets	injection, controls, operation, timing	252
	G.D. Wyche, B.L. Beaudoin, L. Dovlatyan, D.F. Sutter UMD, College Park, Maryland, USA
	Funding: Work supported by U. S. Department of Energy grant number DESC00010301 The University of Maryland Electron Ring (UMER) has two pulsed quadrupoles in the injection section that must be current regulated to the same precision as the other DC quadrupoles in the ring, as well as accurately synchro-nized to the ring operating cycle. To meet this need, a practical pulsed current, regulated power supply has been designed and built using a commercial power operational amplifier for output, standard operational amplifiers for feedback control and monitoring, and matched resistor pairs to produce the desired transfer function of 10 Volts to 6 Amperes. For other applications the circuit can be modified to produce a range of transfer functions by varying the appropriate resistor pair ratios. Output pulse width and timing are generated by a standardized TTL pulse from the control system that gates the output of the amplifier. Installed safety circuitry detects the absence of a proper control pulse, an open circuit or shorted output, and measures and returns to the control system the actual operating amplitude of the current pulse. In this paper we present the design, implementation, and operational results of the prototyped pulsed current source.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLO09
About •	paper received ※ 28 August 2019 paper accepted ※ 04 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPLO13	Field Quality Analysis of Interaction Region Quadrupoles for JLEIC	electron, collider, interaction-region, operation	259
	G.L. Sabbi LBNL, Berkeley, California, USA B.R. Gamage, T.J. Michalski, V.S. Morozov, R. Rajput-Ghoshal, M. Wiseman JLab, Newport News, Virginia, USA Y.M. Nosochkov, M.K. Sullivan SLAC, Menlo Park, California, USA
	Funding: Work supported by the US Department of Energy Office of Science. The JLEIC physics goals of high luminosity and a full acceptance detector result in significant design challenges for the Interaction Region quadrupoles. Key requirements include large aperture, high field, compact transverse and longitudinal dimensions, and tight control of the field errors. In this paper, we present and discuss field quality estimates for the IR Quadrupoles of both electron and ion beamlines, obtained by integrating experience from pre-vious projects with realistic designs consistent with the specific requirements of the JLEIC collider.
	Poster MOPLO13 [0.847 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLO13
About •	paper received ※ 27 August 2019 paper accepted ※ 06 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUZBA2	Electron Ion Collider Machine Detector Interface	electron, detector, hadron, collider	335
	B. Parker, E.C. Aschenauer, A. Kiselev, C. Montag, R.B. Palmer, V. Ptitsyn, F.J. Willeke, H. Witte BNL, Upton, New York, USA M. Diefenthaler, Y. Furletova, T.J. Michalski, V.S. Morozov, D. Romanov, A. Seryi, R. Yoshida JLab, Newport News, Virginia, USA C. Hyde ODU, Norfolk, Virginia, USA M.K. Sullivan SLAC, Menlo Park, California, USA
	This presentation summarizes the physics requirements as they translate into accelerator requirements at the machine-detector interface. Unique aspects of the Interaction Region and detector acceptance – unique to an Electron Ion Collider – are summarized. Designs of both site-specific concepts are outlined.
	Slides TUZBA2 [13.525 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUZBA2
About •	paper received ※ 29 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUZBA4	Interaction Region Magnets for Future Electron-Ion Collider at Jefferson Lab	electron, solenoid, interaction-region, collider	345
	R. Rajput-Ghoshal, C. Hutton, F. Lin, T.J. Michalski, V.S. Morozov, M. Wiseman JLab, Newport News, Virginia, USA
	The Jefferson Lab Electron Ion Collider (JLEIC) is a proposed new machine for nuclear physics research. It uses the existing CEBAF accelerator as a full energy injector to deliver 3 to 12 GeV electrons into a new electron collider ring. An all new ion accelerator and collider complex will deliver up to 200 GeV protons. The machine has luminosity goals of 10³⁴ cm^-2 ses⁻¹. The whole detector region including forward detection covers about 80 meters of the JLEIC complex. The interaction region design has recently been optimized to accommodate 200 GeV proton energy using conventional NbTi superconducting magnet technology. This paper will describe the requirements and preliminary designs for both the ion and electron beam magnets in the most complex 32 m long interaction region (IR) around the interaction point (IP). The interaction region has over thirty-seven superconducting magnets operating at 4.5K; these include dipoles, quadrupoles, skew-quadrupoles, solenoids, horizontal and vertical correctors and higher order multipole magnets. The paper will also discuss the electromagnetic interaction between these magnets.
	Slides TUZBA4 [6.444 MB]
	Poster TUZBA4 [1.549 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUZBA4
About •	paper received ※ 27 August 2019 paper accepted ※ 31 August 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUZBA5	Algorithms Used in Action and Phase Jump Analysis to Estimate Corrections to Quadrupole Errors in the Interaction Regions of the LHC	lattice, software, interaction-region, experiment	349
	J.F. Cardona UNAL, Bogota D.C, Colombia
	Action and phase jump analysis has been used to estimate corrector strengths in the high luminosity interaction regions of the LHC. It has been proven that these corrections are effective to eliminate the beta-beating that is generated in those important regions and that propagates around the ring. More recently, it was also shown that the beta-beating at the interaction point can also be suppressed by combining k-modulation measurements with action and phase jump analysis. Applying this technique to the re-commissioning of the LHC in 2021 requires a good knowledge of the software developed for action and phase jump analysis over the years. In this paper a detailed description is made of all the modules that are part of this software and the corresponding algorithms.
	Slides TUZBA5 [0.431 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUZBA5
About •	paper received ※ 22 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUZBB2	Reaching Low Emittance in Synchrotron Light Sources by Using Complex Bends	lattice, emittance, dipole, focusing	352
	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=10.1.1.495.2446&rep=rep1&type=pdf ** Complex Bend: Phys. Rev. Accel. Beams 21, 100703 (2018)
	Slides TUZBB2 [7.894 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUZBB2
About •	paper received ※ 01 September 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPLM01	Experimental Studies of Resonance Structure Dynamics With Space Charge	resonance, space-charge, experiment, simulation	372
	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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM01
About •	paper received ※ 26 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPLM03	Adjoint Approach to Accelerator Lattice Design	lattice, focusing, simulation, plasma	376
	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).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM03
About •	paper received ※ 23 August 2019 paper accepted ※ 13 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPLM16	Double-Horn Suppression in EEX Based Bunch Compression	octupole, simulation, controls, emittance	407
	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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM16
About •	paper received ※ 03 September 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPLS08	Analysis of Allison Scanner Phase Portraits Using Action-Phase Coordinates	MEBT, optics, ECR, focusing	467
	C.J. Richard NSCL, East Lansing, Michigan, USA J.-P. Carneiro, L.R. Prost, A.V. Shemyakin Fermilab, Batavia, Illinois, USA
	Allison scanners provide detailed information on the beam transverse phase space. An effective way for analyzing the beam distribution from these measurements is to use action-phase coordinates, where beam propagation in a linear lattice is reduced to advancing the phase. This report presents such analysis for measurements performed with a 2.1 MeV, 5 mA H⁻ beam in the MEBT of the PIP2IT test accelerator at Fermilab. In part, with the choice of calculating the Twiss parameters over the high intensity portion of the beam, the beam core is found to be phase-independent with intensity decreasing exponentially with action, while the beam tails exhibit a clear phase dependence that is stable over the beam line.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLS08
About •	paper received ※ 27 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPLS12	Final Design of NEG-Coated Aluminum Vacuum Chambers & Stainless Steel Keyhole Vacuum Chambers for the APS-U Storage Ring	vacuum, storage-ring, photon, radiation	480
	A. McElderry, B. Billett, J.A. Carter, K.J. Wakefield ANL, Lemont, Illinois, USA
	Funding: Argonne National Laboratory’s work was supported by the U.S. Department of Energy, Office of Science under contract DE-AC02-06CH11357. The APS-Upgrade storage ring features a diverse group of vacuum chambers which includes eight NEG (non-evaporable getter) coated aluminum chambers and two copper coated stainless steel keyhole-shaped chambers per sector (40 total). Each chamber contains a 22 mm diameter electron beam aperture; the keyhole chambers also include a photon extraction antechamber. The chambers vary in length of approximately 289 ’ 792 mm and fit within the narrow envelope of quadrupole and sextupole magnets. Each design is a balance of functionality, manufacturability, and installation space. An innovative CAD skeleton model system and ray tracing layout accurately determined synchrotron radiation heat loads on built-in photon absorbers and the internal envelope of the keyhole antechamber. Chamber designs were optimized using thermal-structural FEA for operating and bakeout conditions. The group of chambers require complex manufacturing processes including EDM, explosion-bonded metals, furnace brazing, and welding with minimal space. This paper describes the design process and manufacturing plan for these vacuum chambers including details about FEA, fabrication plans, and cooling/bakeout strategies.
	Poster TUPLS12 [2.581 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLS12
About •	paper received ※ 27 August 2019 paper accepted ※ 02 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPLH10	Fabrication Progress of a Superconducting Helical Undulator with Superimposed Focusing Gradient for High Efficiency Tapered X-Ray FELs	undulator, FEL, vacuum, focusing	509
	S.M. Lynam, R.B. Agustsson, I.I. Gadjev, A.Yu. Smirnov RadiaBeam, Santa Monica, California, USA F.H. O’Shea Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
	Funding: This work is supported by DOE grant no. DE-SC0017072, "Superconducting Helical Undulator with Superimposed Focusing Gradient for High Efficiency Tapered X-Ray FELs" The Advanced Gradient Undulator (AGU) represents a potentially significant advancement in x-ray conversion efficiency for x-ray FELs. This increase in efficiency would have broad implications on the capabilities of x-ray light sources. To achieve this high conversion efficiency, the inner diameter of the undulator coil is a mere 7mm, even with the use of superconducting coils. To accommodate the beamline at the Advanced Photon Source this yields in a chamber with a wall thickness of 0.5mm fabricated from Aluminum. With a period of 2cm and a conductor position tolerance of <100 µm over a length of >80cm at 4.2K, the engineering and fabrication challenges for the undulator alone are substantial. We will discuss these fabrication challenges and present solutions to meet the tolerances required for desired performance, and provide an update on current progress of the construction of a section of the AGU insertion device.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLH10
About •	paper received ※ 28 August 2019 paper accepted ※ 16 November 2020 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPLO01	Dual-Function Electron Ring-Ion Booster Design for JLEIC High-Energy Option	booster, electron, collider, lattice	529
	J.L. Martinez Marin, B. Mustapha ANL, Lemont, Illinois, USA L.K. Spentzouris Illinois Institute of Technology, Chicago, Illinois, USA
	Funding: This work was supported by the U.S. DOE, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357 for ANL and by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. As part of the alternative design approach for the Jeffer-son Laboratory Electron-Ion Collider (JLEIC) ion com-plex, the electron storage ring (e-ring) is consolidated to also serve as a large booster for the ions. The goal of reaching 16 GeV/u or higher for all ions using only room-temperature magnets forces the re-design of the e-ring because of magnetic field and lattice limitations. The new design is challenging due to several imposed constraints: (1) use of room-temperature magnets, (2) avoiding transi-tion crossing, and (3) maintaining the size and shape of the original e-ring design as much as possible. A design study is presented for a 16 GeV/u large ion booster after analyzing different alternatives that use: (1) combined-function magnets, (2) large quadrupoles or (3) quadrupole doublets in the lattice design. This design boosts the injection energy to the collider ring from 8 GeV (proton-equivalent) in the original baseline design to 16 GeV/u for all ions which is beneficial for the high-energy option of JLEIC of 200 GeV or higher. A scheme for adapting the new large ion booster design to also serve as electron storage ring is presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLO01
About •	paper received ※ 28 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPLO15	Multipole Effects on Dynamic Aperture in JLEIC Ion Collider Ring	multipole, collider, electron, detector	559
	B.R. Gamage, F. Lin, T.J. Michalski, V.S. Morozov, R. Rajput-Ghoshal, M. Wiseman JLab, Newport News, Virginia, USA Y. Cai, Y.M. Nosochkov, M.K. Sullivan SLAC, Menlo Park, California, USA G.L. Sabbi LBNL, Berkeley, California, USA
	Funding: This material is based upon work supported by the U.S. DoE under Contracts No. DE-AC05-06OR23177, DE-AC02-76SF00515, and DEAC03-76SF00098. In a collider, stronger focusing at the interaction point (IP) for low beta-star and high luminosity produces large beams at final focusing quadrupoles (FFQs). To achieve the high luminosity requirement in the Jefferson Lab Electron-Ion Collider (JLEIC), the interaction region (IR) beta functions peak at 4.2 km in downstream FFQs. These large beta functions and FFQ multipoles reduce the dynamic aperture (DA) of the ring. A study of the multipole effects on the DA was performed to determine limits on multipoles, and to include a multipole compensation scheme to increase the DA and beam lifetime.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLO15
About •	paper received ※ 28 August 2019 paper accepted ※ 04 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEZBA3	No Beam-Loss Quadrupole Scan for Transverse Phase Space Measurements	linac, emittance, cryomodule, beam-losses	650
	K. Fukushima, T. Maruta, P.N. Ostroumov, T. Yoshimoto FRIB, East Lansing, Michigan, USA
	Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661, the State of Michigan and Michigan State University. Facility for Rare Isotope Beams (FRIB) at Michigan State University is based on a high power heavy ion linac and beam commissioning is under way. For evaluation of beam Twiss parameters and rms emittance, we routinely use multiple profile measurements while the strength of an upstream quadrupole is varied. The change of the quadrupole strength results in a beam mismatch downstream of the profile monitor which can cause beam losses. This is not acceptable in a high energy beamline. To avoid this transverse mismatch, we developed a beam matching procedure by optimization of quadrupoles’ setting downstream of the profile monitor. Using this procedure we were able to eliminate beam losses during the quadrupole scan, and evaluate beam Twiss parameters and rms emittance. Examples of using this procedure in the folding segment of the FRIB linac will be reported.
	Slides WEZBA3 [7.964 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEZBA3
About •	paper received ※ 27 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPLS03	Analytical Expression for a N-Turn Trajectory in the Presence of Quadrupole Magnetic Errors	betatron, experiment, simulation, lattice	772
	Y. Rodriguez Garcia, J.F. Cardona UNAL, Bogota D.C, Colombia Y. Rodriguez Garcia UAN, Bogotá D.C., Colombia
	The action and phase jump method is a technique, based on the use of turn-by-turn experimental data in a circular accelerator, to find and measure local sources of magnetic errors through abrupt changes in the values of action and phase. At this moment, this method uses at least one pair of adjacent BPMs (Beam Position Monitors) to estimate the action and phase at one particular position in the accelerator. In this work, we propose a theoretical expression to describe the trajectory of a charged particle for an arbitrary number of turns when a magnetic error is present in the accelerator. This expression might help to estimate action and phase at one particular position of the accelerator using only one BPM in contrast to the current method that needs at least two BPMs.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLS03
About •	paper received ※ 26 August 2019 paper accepted ※ 03 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPLH04	Beam Envelope Reconstruction for FRIB-FS1 Transport Line Using Beam Position Monitors	linac, MMI, diagnostics, emittance	810
	T. Yoshimoto, S. Cogan, J.L. Crisp, K. Fukushima, S.M. Lidia, T. Maruta, P.N. Ostroumov, A.S. Plastun, T. Zhang, Q. Zhao FRIB, East Lansing, Michigan, USA
	Funding: This work is supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661, the State of Michigan and Michigan State University. The Facility for Rare Isotope Beam (FRIB) includes a heavy ion superconducting (SC) linac. Recently we completed beam commissioning of the Linac Segment 1 (LS1) and 45° bend section of the Folding Segment 1 (FS1). Four ion species, 40Ar⁹⁺, 20Ne⁶⁺, 86Kr¹⁷⁺ and 129Xe²⁶⁺ were successfully accelerated to a beam energy of 20.3 MeV/u. We explored the possibility of non-invasive beam diagnostics for online beam envelope monitoring based on beam quadrupole moments derived from Beam Position Monitors (BPMs). In future operations, various ion beam species will be accelerated and minimization of beam tuning time is critical. To address this requirement, it is beneficial to use BPMs to obtain beam Twiss parameters instead of wire scanners. This paper reports the results of BPM-based beam Twiss parameters evolution in the FS1. R. E. Shafer, "Laser Diagnostic for High Current H beams", Proc. 1998 Beam Instrumentation Workshop (Stanford). A.I.P. Conf. Proceedings, (451), 191.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLH04
About •	paper received ※ 27 August 2019 paper accepted ※ 16 November 2020 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPLE07	Transfer Matrix Classification with Artificial Neural Network	network, dipole, framework, software	898
	Y.P. Sun 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. Standard neural network algorithms are developed for classification and regression applications. In this paper, the details of the neural network algorithms are presented, together with several applications. Artificial neural network is trained to classify multi-class transfer matrix of different types of particle accelerator components. It is shown that with a fully-connected feedforward neural network, it is possible to get high accuracy of 99% on training data, validation data and test data.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLE07
About •	paper received ※ 30 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THXBA2	Analysis of Beam Position Monitor Requirements with Bayesian Gaussian Regression	optics, undulator, brightness, emittance	912
	Y. Li, R.S. Rainer BNL, Upton, New York, USA W.X. Cheng ANL, Lemont, Illinois, USA Y. Hao FRIB, East Lansing, Michigan, USA
	Funding: This research is supported by U.S. Department of Energy under Contract No. DE-SC0012704, and the NSF under Cooperative Agreement PHY-1102511. With a Bayesian Gaussian regression approach, a systematic method for analyzing a storage ring’s beam position monitor (BPM) system requirements has been developed. The ultimate performance of a ring-based accelerator, based on brightness or luminosity, is determined not only by global parameters, but also by local beam properties at some particular points of interest (POI). BPMs used for monitoring the beam properties, however, can not be located at these points. Therefore, the underlying and fundamental purpose of a BPM system is to predict whether the beam properties at POIs reach their desired values. The prediction process is a regression problem with BPM readings as the training data, but containing random noise. A Bayesian Gaussian regression approach can determine the probability distribution of the predictive errors, which can be used to conversely analyze the BPM system requirements. This approach is demonstrated by using turn-by-turn data to reconstruct a linear optics model, and predict the brightness degradation for a ring-based light source. The quality of BPMs was found to be more important than their quantity in mitigating predictive errors.
	Slides THXBA2 [3.205 MB]
	Poster THXBA2 [7.083 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THXBA2
About •	paper received ※ 16 August 2019 paper accepted ※ 04 September 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THZBA3	Status of Beam Commissioning in FRIB Driver Linac	MMI, MEBT, emittance, cryomodule	951
	T. Maruta, S. Cogan, K. Fukushima, M. Ikegami, S.H. Kim, S.M. Lidia, G. Machicoane, F. Marti, D.G. Morris, P.N. Ostroumov, A.S. Plastun, J.T. Popielarski, J. Wei, T. Xu, T. Yoshimoto, T. Zhang, Q. Zhao, S. Zhao FRIB, East Lansing, Michigan, USA
	Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661, the State of Michigan and Michigan State University. The beam commissioning of linac segment 1 (LS1) composed of fifteen cryomodules consisting of total 10⁴ superconducting (SC) resonators and 36 SC solenoids was successfully completed. Four ion beam species, Ne, Ar, Kr and Xe were successfully accelerated up to 20.3 MeV/u. The FRIB driver linac in its current configuration became the highest energy continuous wave hadron linac. We will report a detailed study of beam dynamics in the LS1 prior to and after stripping with a carbon foil.
	Slides THZBA3 [11.377 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THZBA3
About •	paper received ※ 04 September 2019 paper accepted ※ 20 November 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THZBB6	Error Minimization in Transverse Phase-Space Measurements Using Quadrupole and Solenoid Scans	focusing, emittance, solenoid, linac	971
	C.Y. Wong NSCL, East Lansing, Michigan, USA S.M. Lund FRIB, East Lansing, Michigan, USA
	Quadrupole and solenoid scans are common techniques where a series of beam profile measurements are taken under varying excitation of the linear focusing elements to unfold second-order phase-space moments of the beam at an upstream location. Accurate knowledge of the moments is crucial to machine tuning and understanding the underlying beam dynamics. The scans have many sources of errors including measurement errors, field errors and misalignments. The impact of these uncertainties on the moment measurement is often not analyzed. This study proposes a scheme motivated by linear algebra error bounds that can efficiently select a set of scan parameters to minimize the errors in measured initial moments. The results are verified via a statistical error analysis. These techniques are being applied at the Facility for Rare Isotope Beams (FRIB). We find that errors in initial moments can be large under conventional scans but are greatly reduced using the procedures described.
	Slides THZBB6 [2.153 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THZBB6
About •	paper received ※ 04 September 2019 paper accepted ※ 04 December 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

FRXBA4	Maximizing 2-D Beam Brightness Using the Round to Flat Beam Transformation in the Ultralow Charge Regime	emittance, cathode, electron, laser	986
	F.W. Cropp V, P.E. Denham, J. Giner Navarro, E.T. Liu, P. Musumeci UCLA, Los Angeles, USA N. Burger, L. Phillips PBPL, Los Angeles, USA A.L. Edelen, C. Emma SLAC, Menlo Park, California, USA
	Funding: This work is supported by the United States National Science Foundation award PHY-1549132 (the Center for Bright Beams) We seek to maximize the 2-D beam brightness in an RF photoinjector operating in an ultralow charge (<1 pC) regime by implementing the FBT. Particle tracking simulations suggest that in one dimension, normalized projected emittances smaller than 5 nm can be obtained at the UCLA Pegasus facility with up to 100 fC beam charge. A tunable magnetic field is put on the cathode. Three skew quadrupoles are used to block-diagonalize the beam matrix and recover the vastly different eigenemittances as the projected emittances. Emittance measurement routines, including grid-based, pepperpot-based and quad scan routines, have been developed for on-line calculation of the 4-D beam matrix and its eigenemittances. Preliminary measurements are in agreement with simulations and indicate emittance ratios larger than 10 depending on the laser spot size on the cathode. Fine tuning the quadrupole gradients for the FBT has a significant effect on the 2-D beam brightness. We have made concrete steps toward computer minimization and machine learning optimization of the quadrupole gradients in order to remove the canonical angular momentum from the beam and achieve the target normalized projected emittances.
	Slides FRXBA4 [3.059 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-FRXBA4
About •	paper received ※ 28 August 2019 paper accepted ※ 05 December 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

MOPLM03

Correlations Between Beta Beating and APS-U Single Particle Dynamics Performance

lattice, focusing, sextupole, simulation

95

Y.P. Sun
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.
In the optimizations and evaluations process of the Advanced Photon Source upgrade (APS-U) lattice, it was observed that there are negative correlations between beta beating and APS-U single particle dynamics performance (such as dynamic acceptance and local momentum acceptance). These correlations are not always present due to different reasons. In this paper, a systematic simulation study is performed to understand the correlations between beta beating and APS-U single particle dynamics performance. Relatively high beta beatings are generated to reveal these effects.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLM03

About •

paper received ※ 31 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019

Export •

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

MOPLM04

First Attempts at Applying Machine Learning to ALS Storage Ring Stabilization

experiment, storage-ring, emittance, operation

98

S.C. Leemann, Ph. Amstutz, W.E. Byrne, M.P. Ehrlichman, T. Hellert, A. Hexemer, S. Liu, M. Marcus, C.N. Melton, H. Nishimura, G. Penn, F. Sannibale, D.A. Shapiro, C. Sun, D. Ushizima, M. Venturini
LBNL, Berkeley, USA

Funding: This research is funded by the US Department of Energy (BES & ASCR Programs), and supported by the Director of the Office of Science of the US Department of Energy under Contract No. DEAC02-05CH11231.
The ALS storage ring operates multiple feedbacks and feed-forwards during user operations to ensure that various source properties such as beam position, beam angle, and beam size are maintained constant. Without these active corrections, strong perturbations of the electron beam would result from constantly varying ID gaps and phases. An important part of the ID gap/phase compensation requires recording feed-forward tables. While recording such tables takes a lot of time during dedicated machine shifts, the resulting compensation data is imperfect due to machine drift both during and after recording of the table. Since it is impractical to repeat recording feed-forward tables on a more frequent basis, we have decided to employ Machine Learning techniques to improve ID compensation in order to stabilize electron beam properties at the source points.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLM04

About •

paper received ※ 26 August 2019 paper accepted ※ 31 August 2019 issue date ※ 08 October 2019

Export •

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

MOPLO04

Progress in Time-Resolved MeV Transmission Electron Microscopy at UCLA

electron, cavity, alignment, detector

243

P.E. Denham
UCLA, Los Angeles, USA

We describe here two new enhancements developed for the time-resolved microscope at the UCLA PEGASUS Lab based on the use of a radiofrequency photoinjector as an ultrafast electron source and permanent magnet quadrupoles as electron lenses. The first enhancement is a flexible optical column design including hybrid-style stronger focusing quadrupoles, yielding a 60% magnification increase, and a collimator to improve imaging contrast. This new optical system will have the ability to switch between real-space imaging and diffraction pattern imaging with variable magnification. The second enhancement is a high-frequency (X-band) cavity downstream from the (S-band) photoinjector to reduce the beam energy spread. These enhancements are crucial for improving contrast and image quality. In addition, a pulse-wire alignment method to fiducialize the quadrupole positions to better than 20-um precision is used to reduce the aberrations induced by misalignment and achieve spatial resolution at the 20 nm-level.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLO04

About •

paper received ※ 28 August 2019 paper accepted ※ 04 September 2019 issue date ※ 08 October 2019

Export •

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

MOPLO07

MEMS Based Multibeam Ion Linacs

acceleration, laser, extraction, ion-source

249

T. Schenkel, G. Giesbrecht, Q. Ji, A. Persaud, P.A. Seidl
LBNL, Berkeley, California, USA
K. Afridi, A. Lal, D. Ni, S. Sinha
Cornell University, Ithaca, New York, USA

Funding: Work at LBNL was conducted under the auspices of the US DOE (DE-AC0205CH11231) and supported by ArpaE. Device fab at the Cornell Nano Fab facility was supported by NSF (Grant 384 No.ECCS-1542081).
We report on the development of multi-beam RF linear ion accelerators that are formed from stacks o low cost wafers. Wafers are prepared using MEMS techniques. We have demonstrated acceleration of ions in a 3x3 beamlet array with ion currents in the 0.1 mA range and acceleration at the 10 keV in lattice of RF (13 MHz) acceleration units and electrostatic quadrupoles. We will describe the status and plans for scaling to 10x10 beams, ion currents >1 mA and ion energies >100 keV in a compact, low cost setup for applications in materials processing.
[1] P. A. Seidl, et al., Rev. Sci. Instr. 89, 053302 (2018); doi: 10.1063/1.5023415

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLO07

About •

paper received ※ 27 August 2019 paper accepted ※ 16 November 2020 issue date ※ 08 October 2019

Export •

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

MOPLO09

A Pulsed, Current Regulated Magnet Power Supply for Small Magnets

injection, controls, operation, timing

252

G.D. Wyche, B.L. Beaudoin, L. Dovlatyan, D.F. Sutter
UMD, College Park, Maryland, USA

Funding: Work supported by U. S. Department of Energy grant number DESC00010301
The University of Maryland Electron Ring (UMER) has two pulsed quadrupoles in the injection section that must be current regulated to the same precision as the other DC quadrupoles in the ring, as well as accurately synchro-nized to the ring operating cycle. To meet this need, a practical pulsed current, regulated power supply has been designed and built using a commercial power operational amplifier for output, standard operational amplifiers for feedback control and monitoring, and matched resistor pairs to produce the desired transfer function of 10 Volts to 6 Amperes. For other applications the circuit can be modified to produce a range of transfer functions by varying the appropriate resistor pair ratios. Output pulse width and timing are generated by a standardized TTL pulse from the control system that gates the output of the amplifier. Installed safety circuitry detects the absence of a proper control pulse, an open circuit or shorted output, and measures and returns to the control system the actual operating amplitude of the current pulse. In this paper we present the design, implementation, and operational results of the prototyped pulsed current source.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLO09

About •

paper received ※ 28 August 2019 paper accepted ※ 04 September 2019 issue date ※ 08 October 2019

Export •

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

MOPLO13

Field Quality Analysis of Interaction Region Quadrupoles for JLEIC

electron, collider, interaction-region, operation

259

G.L. Sabbi
LBNL, Berkeley, California, USA
B.R. Gamage, T.J. Michalski, V.S. Morozov, R. Rajput-Ghoshal, M. Wiseman
JLab, Newport News, Virginia, USA
Y.M. Nosochkov, M.K. Sullivan
SLAC, Menlo Park, California, USA

Funding: Work supported by the US Department of Energy Office of Science.
The JLEIC physics goals of high luminosity and a full acceptance detector result in significant design challenges for the Interaction Region quadrupoles. Key requirements include large aperture, high field, compact transverse and longitudinal dimensions, and tight control of the field errors. In this paper, we present and discuss field quality estimates for the IR Quadrupoles of both electron and ion beamlines, obtained by integrating experience from pre-vious projects with realistic designs consistent with the specific requirements of the JLEIC collider.

Poster MOPLO13 [0.847 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLO13

About •

paper received ※ 27 August 2019 paper accepted ※ 06 September 2019 issue date ※ 08 October 2019

Export •

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

TUZBA2

Electron Ion Collider Machine Detector Interface

electron, detector, hadron, collider

335

B. Parker, E.C. Aschenauer, A. Kiselev, C. Montag, R.B. Palmer, V. Ptitsyn, F.J. Willeke, H. Witte
BNL, Upton, New York, USA
M. Diefenthaler, Y. Furletova, T.J. Michalski, V.S. Morozov, D. Romanov, A. Seryi, R. Yoshida
JLab, Newport News, Virginia, USA
C. Hyde
ODU, Norfolk, Virginia, USA
M.K. Sullivan
SLAC, Menlo Park, California, USA

This presentation summarizes the physics requirements as they translate into accelerator requirements at the machine-detector interface. Unique aspects of the Interaction Region and detector acceptance – unique to an Electron Ion Collider – are summarized. Designs of both site-specific concepts are outlined.

Slides TUZBA2 [13.525 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUZBA2

About •

paper received ※ 29 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019

Export •

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

TUZBA4

Interaction Region Magnets for Future Electron-Ion Collider at Jefferson Lab

electron, solenoid, interaction-region, collider

345

R. Rajput-Ghoshal, C. Hutton, F. Lin, T.J. Michalski, V.S. Morozov, M. Wiseman
JLab, Newport News, Virginia, USA

The Jefferson Lab Electron Ion Collider (JLEIC) is a proposed new machine for nuclear physics research. It uses the existing CEBAF accelerator as a full energy injector to deliver 3 to 12 GeV electrons into a new electron collider ring. An all new ion accelerator and collider complex will deliver up to 200 GeV protons. The machine has luminosity goals of 10³⁴ cm^-2 ses⁻¹. The whole detector region including forward detection covers about 80 meters of the JLEIC complex. The interaction region design has recently been optimized to accommodate 200 GeV proton energy using conventional NbTi superconducting magnet technology. This paper will describe the requirements and preliminary designs for both the ion and electron beam magnets in the most complex 32 m long interaction region (IR) around the interaction point (IP). The interaction region has over thirty-seven superconducting magnets operating at 4.5K; these include dipoles, quadrupoles, skew-quadrupoles, solenoids, horizontal and vertical correctors and higher order multipole magnets. The paper will also discuss the electromagnetic interaction between these magnets.

Slides TUZBA4 [6.444 MB]

Poster TUZBA4 [1.549 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUZBA4

About •

paper received ※ 27 August 2019 paper accepted ※ 31 August 2019 issue date ※ 08 October 2019

Export •

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

TUZBA5

Algorithms Used in Action and Phase Jump Analysis to Estimate Corrections to Quadrupole Errors in the Interaction Regions of the LHC

lattice, software, interaction-region, experiment

349

J.F. Cardona
UNAL, Bogota D.C, Colombia

Action and phase jump analysis has been used to estimate corrector strengths in the high luminosity interaction regions of the LHC. It has been proven that these corrections are effective to eliminate the beta-beating that is generated in those important regions and that propagates around the ring. More recently, it was also shown that the beta-beating at the interaction point can also be suppressed by combining k-modulation measurements with action and phase jump analysis. Applying this technique to the re-commissioning of the LHC in 2021 requires a good knowledge of the software developed for action and phase jump analysis over the years. In this paper a detailed description is made of all the modules that are part of this software and the corresponding algorithms.

Slides TUZBA5 [0.431 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUZBA5

About •

paper received ※ 22 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019

Export •

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

TUZBB2

Reaching Low Emittance in Synchrotron Light Sources by Using Complex Bends

lattice, emittance, dipole, focusing

352

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=10.1.1.495.2446&rep=rep1&type=pdf
** Complex Bend: Phys. Rev. Accel. Beams 21, 100703 (2018)

Slides TUZBB2 [7.894 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUZBB2

About •

paper received ※ 01 September 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019

Export •

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

TUPLM01

Experimental Studies of Resonance Structure Dynamics With Space Charge

resonance, space-charge, experiment, simulation

372

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.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM01

About •

paper received ※ 26 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019

Export •

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

TUPLM03

Adjoint Approach to Accelerator Lattice Design

lattice, focusing, simulation, plasma

376

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).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM03

About •

paper received ※ 23 August 2019 paper accepted ※ 13 September 2019 issue date ※ 08 October 2019

Export •

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

TUPLM16

Double-Horn Suppression in EEX Based Bunch Compression

octupole, simulation, controls, emittance

407

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.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM16

About •

paper received ※ 03 September 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019

Export •

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

TUPLS08

Analysis of Allison Scanner Phase Portraits Using Action-Phase Coordinates

MEBT, optics, ECR, focusing

467

C.J. Richard
NSCL, East Lansing, Michigan, USA
J.-P. Carneiro, L.R. Prost, A.V. Shemyakin
Fermilab, Batavia, Illinois, USA

Allison scanners provide detailed information on the beam transverse phase space. An effective way for analyzing the beam distribution from these measurements is to use action-phase coordinates, where beam propagation in a linear lattice is reduced to advancing the phase. This report presents such analysis for measurements performed with a 2.1 MeV, 5 mA H⁻ beam in the MEBT of the PIP2IT test accelerator at Fermilab. In part, with the choice of calculating the Twiss parameters over the high intensity portion of the beam, the beam core is found to be phase-independent with intensity decreasing exponentially with action, while the beam tails exhibit a clear phase dependence that is stable over the beam line.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLS08

About •

paper received ※ 27 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019

Export •

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

TUPLS12

Final Design of NEG-Coated Aluminum Vacuum Chambers & Stainless Steel Keyhole Vacuum Chambers for the APS-U Storage Ring

vacuum, storage-ring, photon, radiation

480

A. McElderry, B. Billett, J.A. Carter, K.J. Wakefield
ANL, Lemont, Illinois, USA

Funding: Argonne National Laboratory’s work was supported by the U.S. Department of Energy, Office of Science under contract DE-AC02-06CH11357.
The APS-Upgrade storage ring features a diverse group of vacuum chambers which includes eight NEG (non-evaporable getter) coated aluminum chambers and two copper coated stainless steel keyhole-shaped chambers per sector (40 total). Each chamber contains a 22 mm diameter electron beam aperture; the keyhole chambers also include a photon extraction antechamber. The chambers vary in length of approximately 289 ’ 792 mm and fit within the narrow envelope of quadrupole and sextupole magnets. Each design is a balance of functionality, manufacturability, and installation space. An innovative CAD skeleton model system and ray tracing layout accurately determined synchrotron radiation heat loads on built-in photon absorbers and the internal envelope of the keyhole antechamber. Chamber designs were optimized using thermal-structural FEA for operating and bakeout conditions. The group of chambers require complex manufacturing processes including EDM, explosion-bonded metals, furnace brazing, and welding with minimal space. This paper describes the design process and manufacturing plan for these vacuum chambers including details about FEA, fabrication plans, and cooling/bakeout strategies.

Poster TUPLS12 [2.581 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLS12

About •

paper received ※ 27 August 2019 paper accepted ※ 02 September 2019 issue date ※ 08 October 2019

Export •

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

TUPLH10

Fabrication Progress of a Superconducting Helical Undulator with Superimposed Focusing Gradient for High Efficiency Tapered X-Ray FELs

undulator, FEL, vacuum, focusing

509

S.M. Lynam, R.B. Agustsson, I.I. Gadjev, A.Yu. Smirnov
RadiaBeam, Santa Monica, California, USA
F.H. O’Shea
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

Funding: This work is supported by DOE grant no. DE-SC0017072, "Superconducting Helical Undulator with Superimposed Focusing Gradient for High Efficiency Tapered X-Ray FELs"
The Advanced Gradient Undulator (AGU) represents a potentially significant advancement in x-ray conversion efficiency for x-ray FELs. This increase in efficiency would have broad implications on the capabilities of x-ray light sources. To achieve this high conversion efficiency, the inner diameter of the undulator coil is a mere 7mm, even with the use of superconducting coils. To accommodate the beamline at the Advanced Photon Source this yields in a chamber with a wall thickness of 0.5mm fabricated from Aluminum. With a period of 2cm and a conductor position tolerance of <100 µm over a length of >80cm at 4.2K, the engineering and fabrication challenges for the undulator alone are substantial. We will discuss these fabrication challenges and present solutions to meet the tolerances required for desired performance, and provide an update on current progress of the construction of a section of the AGU insertion device.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLH10

About •

paper received ※ 28 August 2019 paper accepted ※ 16 November 2020 issue date ※ 08 October 2019

Export •

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

TUPLO01

Dual-Function Electron Ring-Ion Booster Design for JLEIC High-Energy Option

booster, electron, collider, lattice

529

J.L. Martinez Marin, B. Mustapha
ANL, Lemont, Illinois, USA
L.K. Spentzouris
Illinois Institute of Technology, Chicago, Illinois, USA

Funding: This work was supported by the U.S. DOE, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357 for ANL and by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
As part of the alternative design approach for the Jeffer-son Laboratory Electron-Ion Collider (JLEIC) ion com-plex, the electron storage ring (e-ring) is consolidated to also serve as a large booster for the ions. The goal of reaching 16 GeV/u or higher for all ions using only room-temperature magnets forces the re-design of the e-ring because of magnetic field and lattice limitations. The new design is challenging due to several imposed constraints: (1) use of room-temperature magnets, (2) avoiding transi-tion crossing, and (3) maintaining the size and shape of the original e-ring design as much as possible. A design study is presented for a 16 GeV/u large ion booster after analyzing different alternatives that use: (1) combined-function magnets, (2) large quadrupoles or (3) quadrupole doublets in the lattice design. This design boosts the injection energy to the collider ring from 8 GeV (proton-equivalent) in the original baseline design to 16 GeV/u for all ions which is beneficial for the high-energy option of JLEIC of 200 GeV or higher. A scheme for adapting the new large ion booster design to also serve as electron storage ring is presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLO01

About •

paper received ※ 28 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019

Export •

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

TUPLO15

Multipole Effects on Dynamic Aperture in JLEIC Ion Collider Ring

multipole, collider, electron, detector

559

B.R. Gamage, F. Lin, T.J. Michalski, V.S. Morozov, R. Rajput-Ghoshal, M. Wiseman
JLab, Newport News, Virginia, USA
Y. Cai, Y.M. Nosochkov, M.K. Sullivan
SLAC, Menlo Park, California, USA
G.L. Sabbi
LBNL, Berkeley, California, USA

Funding: This material is based upon work supported by the U.S. DoE under Contracts No. DE-AC05-06OR23177, DE-AC02-76SF00515, and DEAC03-76SF00098.
In a collider, stronger focusing at the interaction point (IP) for low beta-star and high luminosity produces large beams at final focusing quadrupoles (FFQs). To achieve the high luminosity requirement in the Jefferson Lab Electron-Ion Collider (JLEIC), the interaction region (IR) beta functions peak at 4.2 km in downstream FFQs. These large beta functions and FFQ multipoles reduce the dynamic aperture (DA) of the ring. A study of the multipole effects on the DA was performed to determine limits on multipoles, and to include a multipole compensation scheme to increase the DA and beam lifetime.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLO15

About •

paper received ※ 28 August 2019 paper accepted ※ 04 September 2019 issue date ※ 08 October 2019

Export •

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

WEZBA3

No Beam-Loss Quadrupole Scan for Transverse Phase Space Measurements

linac, emittance, cryomodule, beam-losses

650

K. Fukushima, T. Maruta, P.N. Ostroumov, T. Yoshimoto
FRIB, East Lansing, Michigan, USA

Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661, the State of Michigan and Michigan State University.
Facility for Rare Isotope Beams (FRIB) at Michigan State University is based on a high power heavy ion linac and beam commissioning is under way. For evaluation of beam Twiss parameters and rms emittance, we routinely use multiple profile measurements while the strength of an upstream quadrupole is varied. The change of the quadrupole strength results in a beam mismatch downstream of the profile monitor which can cause beam losses. This is not acceptable in a high energy beamline. To avoid this transverse mismatch, we developed a beam matching procedure by optimization of quadrupoles’ setting downstream of the profile monitor. Using this procedure we were able to eliminate beam losses during the quadrupole scan, and evaluate beam Twiss parameters and rms emittance. Examples of using this procedure in the folding segment of the FRIB linac will be reported.

Slides WEZBA3 [7.964 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEZBA3

About •

paper received ※ 27 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019

Export •

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

WEPLS03

Analytical Expression for a N-Turn Trajectory in the Presence of Quadrupole Magnetic Errors

betatron, experiment, simulation, lattice

772

Y. Rodriguez Garcia, J.F. Cardona
UNAL, Bogota D.C, Colombia
Y. Rodriguez Garcia
UAN, Bogotá D.C., Colombia

The action and phase jump method is a technique, based on the use of turn-by-turn experimental data in a circular accelerator, to find and measure local sources of magnetic errors through abrupt changes in the values of action and phase. At this moment, this method uses at least one pair of adjacent BPMs (Beam Position Monitors) to estimate the action and phase at one particular position in the accelerator. In this work, we propose a theoretical expression to describe the trajectory of a charged particle for an arbitrary number of turns when a magnetic error is present in the accelerator. This expression might help to estimate action and phase at one particular position of the accelerator using only one BPM in contrast to the current method that needs at least two BPMs.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLS03

About •

paper received ※ 26 August 2019 paper accepted ※ 03 September 2019 issue date ※ 08 October 2019

Export •

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

WEPLH04

Beam Envelope Reconstruction for FRIB-FS1 Transport Line Using Beam Position Monitors

linac, MMI, diagnostics, emittance

810

T. Yoshimoto, S. Cogan, J.L. Crisp, K. Fukushima, S.M. Lidia, T. Maruta, P.N. Ostroumov, A.S. Plastun, T. Zhang, Q. Zhao
FRIB, East Lansing, Michigan, USA

Funding: This work is supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661, the State of Michigan and Michigan State University.
The Facility for Rare Isotope Beam (FRIB) includes a heavy ion superconducting (SC) linac. Recently we completed beam commissioning of the Linac Segment 1 (LS1) and 45° bend section of the Folding Segment 1 (FS1). Four ion species, 40Ar⁹⁺, 20Ne⁶⁺, 86Kr¹⁷⁺ and 129Xe²⁶⁺ were successfully accelerated to a beam energy of 20.3 MeV/u. We explored the possibility of non-invasive beam diagnostics for online beam envelope monitoring based on beam quadrupole moments derived from Beam Position Monitors (BPMs)*. In future operations, various ion beam species will be accelerated and minimization of beam tuning time is critical. To address this requirement, it is beneficial to use BPMs to obtain beam Twiss parameters instead of wire scanners. This paper reports the results of BPM-based beam Twiss parameters evolution in the FS1.
* R. E. Shafer, "Laser Diagnostic for High Current H beams", Proc. 1998 Beam Instrumentation Workshop (Stanford). A.I.P. Conf. Proceedings, (451), 191.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLH04

About •

paper received ※ 27 August 2019 paper accepted ※ 16 November 2020 issue date ※ 08 October 2019

Export •

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

WEPLE07

Transfer Matrix Classification with Artificial Neural Network

network, dipole, framework, software

898

Y.P. Sun
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.
Standard neural network algorithms are developed for classification and regression applications. In this paper, the details of the neural network algorithms are presented, together with several applications. Artificial neural network is trained to classify multi-class transfer matrix of different types of particle accelerator components. It is shown that with a fully-connected feedforward neural network, it is possible to get high accuracy of 99% on training data, validation data and test data.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLE07

About •

paper received ※ 30 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019

Export •

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

THXBA2

Analysis of Beam Position Monitor Requirements with Bayesian Gaussian Regression

optics, undulator, brightness, emittance

912

Y. Li, R.S. Rainer
BNL, Upton, New York, USA
W.X. Cheng
ANL, Lemont, Illinois, USA
Y. Hao
FRIB, East Lansing, Michigan, USA

Funding: This research is supported by U.S. Department of Energy under Contract No. DE-SC0012704, and the NSF under Cooperative Agreement PHY-1102511.
With a Bayesian Gaussian regression approach, a systematic method for analyzing a storage ring’s beam position monitor (BPM) system requirements has been developed. The ultimate performance of a ring-based accelerator, based on brightness or luminosity, is determined not only by global parameters, but also by local beam properties at some particular points of interest (POI). BPMs used for monitoring the beam properties, however, can not be located at these points. Therefore, the underlying and fundamental purpose of a BPM system is to predict whether the beam properties at POIs reach their desired values. The prediction process is a regression problem with BPM readings as the training data, but containing random noise. A Bayesian Gaussian regression approach can determine the probability distribution of the predictive errors, which can be used to conversely analyze the BPM system requirements. This approach is demonstrated by using turn-by-turn data to reconstruct a linear optics model, and predict the brightness degradation for a ring-based light source. The quality of BPMs was found to be more important than their quantity in mitigating predictive errors.

Slides THXBA2 [3.205 MB]

Poster THXBA2 [7.083 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THXBA2

About •

paper received ※ 16 August 2019 paper accepted ※ 04 September 2019 issue date ※ 08 October 2019

Export •

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

THZBA3

Status of Beam Commissioning in FRIB Driver Linac

MMI, MEBT, emittance, cryomodule

951

T. Maruta, S. Cogan, K. Fukushima, M. Ikegami, S.H. Kim, S.M. Lidia, G. Machicoane, F. Marti, D.G. Morris, P.N. Ostroumov, A.S. Plastun, J.T. Popielarski, J. Wei, T. Xu, T. Yoshimoto, T. Zhang, Q. Zhao, S. Zhao
FRIB, East Lansing, Michigan, USA

Funding: Work supported by the U.S. Department of Energy Office of Science under Cooperative Agreement DE-SC0000661, the State of Michigan and Michigan State University.
The beam commissioning of linac segment 1 (LS1) composed of fifteen cryomodules consisting of total 10⁴ superconducting (SC) resonators and 36 SC solenoids was successfully completed. Four ion beam species, Ne, Ar, Kr and Xe were successfully accelerated up to 20.3 MeV/u. The FRIB driver linac in its current configuration became the highest energy continuous wave hadron linac. We will report a detailed study of beam dynamics in the LS1 prior to and after stripping with a carbon foil.

Slides THZBA3 [11.377 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THZBA3

About •

paper received ※ 04 September 2019 paper accepted ※ 20 November 2019 issue date ※ 08 October 2019

Export •

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

THZBB6

Error Minimization in Transverse Phase-Space Measurements Using Quadrupole and Solenoid Scans

focusing, emittance, solenoid, linac

971

C.Y. Wong
NSCL, East Lansing, Michigan, USA
S.M. Lund
FRIB, East Lansing, Michigan, USA

Quadrupole and solenoid scans are common techniques where a series of beam profile measurements are taken under varying excitation of the linear focusing elements to unfold second-order phase-space moments of the beam at an upstream location. Accurate knowledge of the moments is crucial to machine tuning and understanding the underlying beam dynamics. The scans have many sources of errors including measurement errors, field errors and misalignments. The impact of these uncertainties on the moment measurement is often not analyzed. This study proposes a scheme motivated by linear algebra error bounds that can efficiently select a set of scan parameters to minimize the errors in measured initial moments. The results are verified via a statistical error analysis. These techniques are being applied at the Facility for Rare Isotope Beams (FRIB). We find that errors in initial moments can be large under conventional scans but are greatly reduced using the procedures described.

Slides THZBB6 [2.153 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-THZBB6

About •

paper received ※ 04 September 2019 paper accepted ※ 04 December 2019 issue date ※ 08 October 2019

Export •

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

FRXBA4

Maximizing 2-D Beam Brightness Using the Round to Flat Beam Transformation in the Ultralow Charge Regime

emittance, cathode, electron, laser

986

F.W. Cropp V, P.E. Denham, J. Giner Navarro, E.T. Liu, P. Musumeci
UCLA, Los Angeles, USA
N. Burger, L. Phillips
PBPL, Los Angeles, USA
A.L. Edelen, C. Emma
SLAC, Menlo Park, California, USA

Funding: This work is supported by the United States National Science Foundation award PHY-1549132 (the Center for Bright Beams)
We seek to maximize the 2-D beam brightness in an RF photoinjector operating in an ultralow charge (<1 pC) regime by implementing the FBT. Particle tracking simulations suggest that in one dimension, normalized projected emittances smaller than 5 nm can be obtained at the UCLA Pegasus facility with up to 100 fC beam charge. A tunable magnetic field is put on the cathode. Three skew quadrupoles are used to block-diagonalize the beam matrix and recover the vastly different eigenemittances as the projected emittances. Emittance measurement routines, including grid-based, pepperpot-based and quad scan routines, have been developed for on-line calculation of the 4-D beam matrix and its eigenemittances. Preliminary measurements are in agreement with simulations and indicate emittance ratios larger than 10 depending on the laser spot size on the cathode. Fine tuning the quadrupole gradients for the FBT has a significant effect on the 2-D beam brightness. We have made concrete steps toward computer minimization and machine learning optimization of the quadrupole gradients in order to remove the canonical angular momentum from the beam and achieve the target normalized projected emittances.

Slides FRXBA4 [3.059 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-FRXBA4

About •

paper received ※ 28 August 2019 paper accepted ※ 05 December 2019 issue date ※ 08 October 2019

Export •

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