NAPAC2019 - List of Keywords (dipole)

Paper	Title	Other Keywords	Page
MOPLO14	From Start to Finish: Using 3D Printing Techniques to Build CBETA	permanent-magnet, experiment, collider, lattice	263
	G.J. Mahler, S.J. Brooks, S.M. Trabocchi BNL, Upton, New York, USA
	Funding: NYSERDA contract with BNL The extensive use of a simple 3D printer allowed for fast prototyping and development of many components used to build CBETA.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLO14
About •	paper received ※ 14 August 2019 paper accepted ※ 31 August 2019 issue date ※ 08 October 2019
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MOPLO20	Quench Performance and Field Quality of the 15 T Nb₃Sn Dipole Demonstrator MDPCT1 in the First Test Run	ion-effects, collider, magnet-design, hadron	282
	A.V. Zlobin, E.Z. Barzi, J.R. Carmichael, G. Chlachidze, J. DiMarco, V.V. Kashikhin, S. Krave, I. Novitski, C.R. Orozco, S. Stoynev, T. Strauss, M.A. Tartaglia, D. Turrioni Fermilab, Batavia, Illinois, USA
	Funding: Work is supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy U.S. Magnet Development Program (US-MDP) is developing high-field accelerator magnets for a post-LHC hadron collider. In June 2019 Fermilab has tested a new Nb₃Sn dipole model, which produced a world record field of 14.1 T at 4.5 K. The magnet design is based on 60 mm aperture 4-layer shell-type coils, graded between the inner and outer layers. The Rutherford cable in the two innermost layers consists of 28 strands 1.0 mm in diameter and the cable in the two outermost layers 40 strands 0.7 mm in diameter. Both cables were fabricated at Fermilab using RRP Nb₃Sn composite wires produced by Bruker-OST. An innovative mechanical structure based on aluminum clamps and a thick stainless-steel skin was developed to preload brittle Nb₃Sn coils and support large Lorentz forces. The maximum field for this design is limited by 15 T due to mechanical considerations. The first magnet assembly was done with lower coil pre-load to achieve 14 T and minimize the risk of coil damage during assembly. The 15 T dipole demonstrator design and the first results of magnet cold tests including quench performance and magnetic measurements are presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLO20
About •	paper received ※ 27 August 2019 paper accepted ※ 03 September 2019 issue date ※ 08 October 2019
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TUZBB2	Reaching Low Emittance in Synchrotron Light Sources by Using Complex Bends	lattice, emittance, quadrupole, 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
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TUZBB3	Precise Beam Velocity Matching for the Experimental Demonstration of Ion Cooling With a Bunched Electron Beam	electron, factory, beam-cooling, acceleration	356
	S. Seletskiy, M. Blaskiewicz, K.A. Drees, A.V. Fedotov, W. Fischer, D.M. Gassner, R.L. Hulsart, D. Kayran, J. Kewisch, K. Mernick, R.J. Michnoff, T.A. Miller, G. Robert-Demolaize, V. Schoefer, H. Song, P. Thieberger, P. Wanderer BNL, Upton, New York, USA
	The first ever electron cooling based on the RF acceleration of electron bunches was experimentally demonstrated on April 5, 2019 at the Low Energy RHIC Electron Cooler (LEReC) at BNL. The critical step in obtaining successful cooling of the Au ion bunches in the RHIC cooling sections was the accurate matching of average longitudinal velocities of electron and ion beams corresponding to a relative error of less than 5·10^-4 in the e-beam momentum. Since the electron beam kinetic energy is just 1.6 MeV, measuring the absolute e-beam energy with sufficient accuracy and eventually achieving the electron-ion velocity matching was a nontrivial task. In this paper we describe our experience with measuring and setting the e-beam energy at LEReC.
	Slides TUZBB3 [1.340 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUZBB3
About •	paper received ※ 26 August 2019 paper accepted ※ 31 August 2019 issue date ※ 08 October 2019
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TUPLM09	A Fast Method to Evaluate Transverse Coupled-Bunch Stability at Non-Zero Chromaticity	synchrotron, wakefield, betatron, simulation	387
	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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM09
About •	paper received ※ 25 August 2019 paper accepted ※ 01 September 2019 issue date ※ 08 October 2019
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TUPLM22	Off Axis Dependence of Current Dependent Coherent Tune Shifts in the UMER Ring	experiment, space-charge, electron, storage-ring	422
	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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM22
About •	paper received ※ 29 August 2019 paper accepted ※ 04 September 2019 issue date ※ 08 October 2019
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TUPLH03	Double-Bend Achromat Beamline for Injection Into a High-Power Superconducting Electron Linac	solenoid, electron, gun, cavity	494
	C.H. Boulware, T.L. Grimm, R. Hipple Niowave, Inc., Lansing, Michigan, USA S.M. Lund FRIB, East Lansing, Michigan, USA V.S. Morozov JLab, Newport News, Virginia, USA
	To take advantage of the high duty cycle operation of superconducting electron linacs, commercial systems use thermionic cathode electron guns that fill every RF bucket with an electron bunch. In continuous operation, the exit energy is limited when compared to pulsed systems. Bunch length and energy spread at the exit of the gun are incompatible with low losses in the superconducting cavity. A solenoid double-bend achromatic beamline is in operation at Niowave which allows energy and bunch length filtering of the beam leaving the gun before injection into the superconducting cavity. This system uses two solenoids and two dipoles to produce a round beam, using the edge angles of the dipoles to balance the focusing effects in the two transverse planes. The design allows beam filtering on the symmetry plane where the dispersion is maximum. Additionally, the bend angle moves the electron gun off the high-energy beam axis, allowing multiple-pass operation of the superconducting booster. This contribution will discuss the beam optics design of the double-bend achromat along with the design of the magnets and beam chambers and the operational experience with the system.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLH03
About •	paper received ※ 28 August 2019 paper accepted ※ 02 September 2019 issue date ※ 08 October 2019
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WEPLM02	Finding Beam Loss Locations in a Linac with Oscillating Dipole Correctors	linac, DTL, betatron, radiation	663
	A.V. Shemyakin, K. Seiya Fermilab, Batavia, Illinois, USA R. Prakash RRCAT, Indore, India
	Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics The paper proposes a method of finding the beam loss locations in a linac. If the beam is scraped at an aperture limitation, moving its centroid with two dipole correctors located upstream and oscillating in sync produces a line at the corresponding frequency in spectra of current-sensitive devices downstream of the loss point. The phase of this signal contains information about the location of the beam loss. Similar lines appear also in the position signals of Beam Position Monitors (BPMs). The phases of the BPM position lines change monotonically (within each 2π) along the linac and can be used a reference system. The phase of the loss signal compared with this reference system pinpoints the beam loss location, assuming that longitudinal coordinates of the BPMs are known. If the correctors deflection amplitudes and the phase offset between their waveforms are chosen optimally and well calibrated, the same measurement provides values of the β-function and the betatron phase advance at the BPM locations. Optics measurements of this type can be made parasitically, with negligible effect on the emittance, if a long measurement time is acceptable.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM02
About •	paper received ※ 27 August 2019 paper accepted ※ 19 November 2019 issue date ※ 08 October 2019
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WEPLM73	Bunker Testing of FRIB Cryomodules	cavity, cryomodule, solenoid, SRF	765
	W. Chang, S. Caton, A. Ganshyn, W. Hartung, S.H. Kim, B. Laumer, H. Maniar, J.T. Popielarski, K. Saito, M. Xu, T. Xu, C. Zhang, S. Zhao FRIB, East Lansing, Michigan, USA
	The FRIB superconducting driver Linac requires 10⁴ quarter-wave resonators (QWRs, β = 0.041, 0.085), 220 half-wave resonators (HWRs, β = 0.29, 0.53), and 74 superconducting solenoid packages. Resonators and solenoids are assembled into cryomodules; 4 accelerating and 2 matching cryomodule types are required. Each cryomodule undergoes cryogenic and RF testing in a bunker prior to installation in the tunnel. The cryomodule test verifies operation of the cavities, couplers, tuners, solenoid packages, magnetic shield, and thermal shield at 4.3 K and 2 K. All of the required cryomodules for β = 0.041, 0.085, and 0.29 have been tested and certified. As of May 2019, five of the β = 0.53 cryomodules have been certified; the remaining modules are being assembled or are in the queue for testing. Cryomodule test results will be presented, including cavity performance (accelerating gradient, field emission X-rays, multipacting conditioning); solenoid package operation (current, current-lead cooling flow rate); and cryomodule heat load (static and dynamic).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM73
About •	paper received ※ 06 September 2019 paper accepted ※ 16 November 2020 issue date ※ 08 October 2019
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WEPLO18	Numerical Study of Coherent Radiation from Induced Plasma Dipole Oscillation by Detuned Laser Pulses	plasma, laser, radiation, simulation	874
	P.C. Castillo, S.D. Rodriguez, D.A. Wan SUNY Farmingdale State College, State University of New York, Farmingdale, New York, USA B. Gross City College of The City University of New York, New York, USA M.S. Hur, S. Kylychbekov, H.S. Song UNIST, Ulsan, Republic of Korea D.G. Lee SBU, Stony Brook, New York, USA K. Yu BNL, Upton, New York, USA
	The study of intense laser-plasma interactions is a growing field of both theoretical and applied research. This research focuses on simulating the cross/self-interactions between high-intense short laser pulses and an initial target for preliminary ionization. Unlike our previous studies of laser-matter interaction over preformed plasma, we will explore the injection of laser pulses to induce background plasma driven by the self-guided laser wakefield mechanism, which is used to perturb the plasma for induced dipole oscillations followed by radiation. Inducing a cylindrical spatial plasma column within the laser beam radius regime, it is expected that a stable spatially localized plasma channel will result and the emitted radiation from the plasma dipole oscillation (PDO) will not be affected by surrounding absorption, resulting in effective radiation. We will depict the injection of laser pulses accounting for parameters such as field intensity, profile and phase difference defining the coordinated pulses to assess the potential of enhancing the efficiency and spectral properties of the transverse emitted radiation due to the counter-propagating pulses interaction in plasma.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLO18
About •	paper received ※ 27 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019
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WEPLE04	Recent Developments and Applications of Parallel Multi-Physics Accelerator Modeling Suite ACE3P	simulation, cavity, cryomodule, GUI	888
	Z. Li, L. Ge, C.-K. Ng, L. Xiao SLAC, Menlo Park, California, USA
	Funding: This work was supported by DOE Contract No. DE-AC02-76SF00515. SLAC’s ACE3P code suite is developed to harness the power of massively parallel computers to tackle large complex problems with increased memory and solve them at greater speed. ACE3P parallel multi-physics codes are based on higher-order finite elements for superior geometry fidelity and better solution accuracy. ACE3P consists of an integrated set of electromagnetic, thermal and mechanical solvers for accelerator modeling and virtual prototyping. The use of ACE3P has contributed to the design and optimization of existing and future accelerator projects around the world. Multi-physics analysis on high performance computing (HPC) platform enables thermal-mechanical simulations of largescale systems such as the LCLS-II cryomodule. Recently, new capabilities have been added to ACE3P including a nonlinear eigenvalue solver for calculating mode damping, a moving window for pulse propagation in the time domain to reduce computational cost, thin layer coating representation using a surface impedance model, and improved boundary conditions using perfectly matched layers (PML) to terminate wave propagation. These new developments are presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLE04
About •	paper received ※ 27 August 2019 paper accepted ※ 05 September 2019 issue date ※ 08 October 2019
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WEPLE07	Transfer Matrix Classification with Artificial Neural Network	network, quadrupole, 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
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Paper

Title

Other Keywords

Page

MOPLO14

From Start to Finish: Using 3D Printing Techniques to Build CBETA

permanent-magnet, experiment, collider, lattice

263

G.J. Mahler, S.J. Brooks, S.M. Trabocchi
BNL, Upton, New York, USA

Funding: NYSERDA contract with BNL
The extensive use of a simple 3D printer allowed for fast prototyping and development of many components used to build CBETA.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLO14

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paper received ※ 14 August 2019 paper accepted ※ 31 August 2019 issue date ※ 08 October 2019

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MOPLO20

Quench Performance and Field Quality of the 15 T Nb₃Sn Dipole Demonstrator MDPCT1 in the First Test Run

ion-effects, collider, magnet-design, hadron

282

A.V. Zlobin, E.Z. Barzi, J.R. Carmichael, G. Chlachidze, J. DiMarco, V.V. Kashikhin, S. Krave, I. Novitski, C.R. Orozco, S. Stoynev, T. Strauss, M.A. Tartaglia, D. Turrioni
Fermilab, Batavia, Illinois, USA

Funding: Work is supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy
U.S. Magnet Development Program (US-MDP) is developing high-field accelerator magnets for a post-LHC hadron collider. In June 2019 Fermilab has tested a new Nb₃Sn dipole model, which produced a world record field of 14.1 T at 4.5 K. The magnet design is based on 60 mm aperture 4-layer shell-type coils, graded between the inner and outer layers. The Rutherford cable in the two innermost layers consists of 28 strands 1.0 mm in diameter and the cable in the two outermost layers 40 strands 0.7 mm in diameter. Both cables were fabricated at Fermilab using RRP Nb₃Sn composite wires produced by Bruker-OST. An innovative mechanical structure based on aluminum clamps and a thick stainless-steel skin was developed to preload brittle Nb₃Sn coils and support large Lorentz forces. The maximum field for this design is limited by 15 T due to mechanical considerations. The first magnet assembly was done with lower coil pre-load to achieve 14 T and minimize the risk of coil damage during assembly. The 15 T dipole demonstrator design and the first results of magnet cold tests including quench performance and magnetic measurements are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOPLO20

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paper received ※ 27 August 2019 paper accepted ※ 03 September 2019 issue date ※ 08 October 2019

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TUZBB2

Reaching Low Emittance in Synchrotron Light Sources by Using Complex Bends

lattice, emittance, quadrupole, 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]

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

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

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TUZBB3

Precise Beam Velocity Matching for the Experimental Demonstration of Ion Cooling With a Bunched Electron Beam

electron, factory, beam-cooling, acceleration

356

S. Seletskiy, M. Blaskiewicz, K.A. Drees, A.V. Fedotov, W. Fischer, D.M. Gassner, R.L. Hulsart, D. Kayran, J. Kewisch, K. Mernick, R.J. Michnoff, T.A. Miller, G. Robert-Demolaize, V. Schoefer, H. Song, P. Thieberger, P. Wanderer
BNL, Upton, New York, USA

The first ever electron cooling based on the RF acceleration of electron bunches was experimentally demonstrated on April 5, 2019 at the Low Energy RHIC Electron Cooler (LEReC) at BNL. The critical step in obtaining successful cooling of the Au ion bunches in the RHIC cooling sections was the accurate matching of average longitudinal velocities of electron and ion beams corresponding to a relative error of less than 5·10^-4 in the e-beam momentum. Since the electron beam kinetic energy is just 1.6 MeV, measuring the absolute e-beam energy with sufficient accuracy and eventually achieving the electron-ion velocity matching was a nontrivial task. In this paper we describe our experience with measuring and setting the e-beam energy at LEReC.

Slides TUZBB3 [1.340 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUZBB3

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

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TUPLM09

A Fast Method to Evaluate Transverse Coupled-Bunch Stability at Non-Zero Chromaticity

synchrotron, wakefield, betatron, simulation

387

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.

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reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM09

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paper received ※ 25 August 2019 paper accepted ※ 01 September 2019 issue date ※ 08 October 2019

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TUPLM22

Off Axis Dependence of Current Dependent Coherent Tune Shifts in the UMER Ring

experiment, space-charge, electron, storage-ring

422

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.

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reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLM22

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paper received ※ 29 August 2019 paper accepted ※ 04 September 2019 issue date ※ 08 October 2019

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TUPLH03

Double-Bend Achromat Beamline for Injection Into a High-Power Superconducting Electron Linac

solenoid, electron, gun, cavity

494

C.H. Boulware, T.L. Grimm, R. Hipple
Niowave, Inc., Lansing, Michigan, USA
S.M. Lund
FRIB, East Lansing, Michigan, USA
V.S. Morozov
JLab, Newport News, Virginia, USA

To take advantage of the high duty cycle operation of superconducting electron linacs, commercial systems use thermionic cathode electron guns that fill every RF bucket with an electron bunch. In continuous operation, the exit energy is limited when compared to pulsed systems. Bunch length and energy spread at the exit of the gun are incompatible with low losses in the superconducting cavity. A solenoid double-bend achromatic beamline is in operation at Niowave which allows energy and bunch length filtering of the beam leaving the gun before injection into the superconducting cavity. This system uses two solenoids and two dipoles to produce a round beam, using the edge angles of the dipoles to balance the focusing effects in the two transverse planes. The design allows beam filtering on the symmetry plane where the dispersion is maximum. Additionally, the bend angle moves the electron gun off the high-energy beam axis, allowing multiple-pass operation of the superconducting booster. This contribution will discuss the beam optics design of the double-bend achromat along with the design of the magnets and beam chambers and the operational experience with the system.

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reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLH03

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paper received ※ 28 August 2019 paper accepted ※ 02 September 2019 issue date ※ 08 October 2019

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WEPLM02

Finding Beam Loss Locations in a Linac with Oscillating Dipole Correctors

linac, DTL, betatron, radiation

663

A.V. Shemyakin, K. Seiya
Fermilab, Batavia, Illinois, USA
R. Prakash
RRCAT, Indore, India

Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics
The paper proposes a method of finding the beam loss locations in a linac. If the beam is scraped at an aperture limitation, moving its centroid with two dipole correctors located upstream and oscillating in sync produces a line at the corresponding frequency in spectra of current-sensitive devices downstream of the loss point. The phase of this signal contains information about the location of the beam loss. Similar lines appear also in the position signals of Beam Position Monitors (BPMs). The phases of the BPM position lines change monotonically (within each 2π) along the linac and can be used a reference system. The phase of the loss signal compared with this reference system pinpoints the beam loss location, assuming that longitudinal coordinates of the BPMs are known. If the correctors deflection amplitudes and the phase offset between their waveforms are chosen optimally and well calibrated, the same measurement provides values of the β-function and the betatron phase advance at the BPM locations. Optics measurements of this type can be made parasitically, with negligible effect on the emittance, if a long measurement time is acceptable.

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reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM02

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paper received ※ 27 August 2019 paper accepted ※ 19 November 2019 issue date ※ 08 October 2019

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WEPLM73

Bunker Testing of FRIB Cryomodules

cavity, cryomodule, solenoid, SRF

765

W. Chang, S. Caton, A. Ganshyn, W. Hartung, S.H. Kim, B. Laumer, H. Maniar, J.T. Popielarski, K. Saito, M. Xu, T. Xu, C. Zhang, S. Zhao
FRIB, East Lansing, Michigan, USA

The FRIB superconducting driver Linac requires 10⁴ quarter-wave resonators (QWRs, β = 0.041, 0.085), 220 half-wave resonators (HWRs, β = 0.29, 0.53), and 74 superconducting solenoid packages. Resonators and solenoids are assembled into cryomodules; 4 accelerating and 2 matching cryomodule types are required. Each cryomodule undergoes cryogenic and RF testing in a bunker prior to installation in the tunnel. The cryomodule test verifies operation of the cavities, couplers, tuners, solenoid packages, magnetic shield, and thermal shield at 4.3 K and 2 K. All of the required cryomodules for β = 0.041, 0.085, and 0.29 have been tested and certified. As of May 2019, five of the β = 0.53 cryomodules have been certified; the remaining modules are being assembled or are in the queue for testing. Cryomodule test results will be presented, including cavity performance (accelerating gradient, field emission X-rays, multipacting conditioning); solenoid package operation (current, current-lead cooling flow rate); and cryomodule heat load (static and dynamic).

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reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM73

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paper received ※ 06 September 2019 paper accepted ※ 16 November 2020 issue date ※ 08 October 2019

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WEPLO18

Numerical Study of Coherent Radiation from Induced Plasma Dipole Oscillation by Detuned Laser Pulses

plasma, laser, radiation, simulation

874

P.C. Castillo, S.D. Rodriguez, D.A. Wan
SUNY Farmingdale State College, State University of New York, Farmingdale, New York, USA
B. Gross
City College of The City University of New York, New York, USA
M.S. Hur, S. Kylychbekov, H.S. Song
UNIST, Ulsan, Republic of Korea
D.G. Lee
SBU, Stony Brook, New York, USA
K. Yu
BNL, Upton, New York, USA

The study of intense laser-plasma interactions is a growing field of both theoretical and applied research. This research focuses on simulating the cross/self-interactions between high-intense short laser pulses and an initial target for preliminary ionization. Unlike our previous studies of laser-matter interaction over preformed plasma, we will explore the injection of laser pulses to induce background plasma driven by the self-guided laser wakefield mechanism, which is used to perturb the plasma for induced dipole oscillations followed by radiation. Inducing a cylindrical spatial plasma column within the laser beam radius regime, it is expected that a stable spatially localized plasma channel will result and the emitted radiation from the plasma dipole oscillation (PDO) will not be affected by surrounding absorption, resulting in effective radiation. We will depict the injection of laser pulses accounting for parameters such as field intensity, profile and phase difference defining the coordinated pulses to assess the potential of enhancing the efficiency and spectral properties of the transverse emitted radiation due to the counter-propagating pulses interaction in plasma.

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reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLO18

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

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WEPLE04

Recent Developments and Applications of Parallel Multi-Physics Accelerator Modeling Suite ACE3P

simulation, cavity, cryomodule, GUI

888

Z. Li, L. Ge, C.-K. Ng, L. Xiao
SLAC, Menlo Park, California, USA

Funding: This work was supported by DOE Contract No. DE-AC02-76SF00515.
SLAC’s ACE3P code suite is developed to harness the power of massively parallel computers to tackle large complex problems with increased memory and solve them at greater speed. ACE3P parallel multi-physics codes are based on higher-order finite elements for superior geometry fidelity and better solution accuracy. ACE3P consists of an integrated set of electromagnetic, thermal and mechanical solvers for accelerator modeling and virtual prototyping. The use of ACE3P has contributed to the design and optimization of existing and future accelerator projects around the world. Multi-physics analysis on high performance computing (HPC) platform enables thermal-mechanical simulations of largescale systems such as the LCLS-II cryomodule. Recently, new capabilities have been added to ACE3P including a nonlinear eigenvalue solver for calculating mode damping, a moving window for pulse propagation in the time domain to reduce computational cost, thin layer coating representation using a surface impedance model, and improved boundary conditions using perfectly matched layers (PML) to terminate wave propagation. These new developments are presented in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLE04

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

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WEPLE07

Transfer Matrix Classification with Artificial Neural Network

network, quadrupole, 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.

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

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

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