NAPAC2019 - List of Keywords (acceleration)

Paper	Title	Other Keywords	Page
MOZBB2	Experiments with Metamaterial-Based Metallic Accelerating Structures	experiment, wakefield, radiation, GUI	78
	X. Lu SLAC, Menlo Park, California, USA M.E. Conde, D.S. Doran, G. Ha, J.G. Power, J.H. Shao, E.E. Wisniewski ANL, Lemont, Illinois, USA C.-J. Jing Euclid TechLabs, LLC, Solon, Ohio, USA X. Lu, I. Mastovsky, J.F. Picard, M.A. Shapiro, R.J. Temkin MIT/PSFC, Cambridge, Massachusetts, USA M.M. Peng AAI/ANL, Lemont, Illinois, USA J. Seok UNIST, Ulsan, Republic of Korea
	Funding: U.S. Department of Energy, Office of Science, Office of High Energy Physics under Award No. DE-SC0015566 at MIT and No. DE-AC02-06CH11357 at ANL We present experimental studies of metamaterial (MTM) structures for wakefield acceleration. The MTM structure is an all-metal periodic structure with its period much smaller than the wavelength at X-band. The fundamental TM mode has a negative group velocity, so an electron beam traveling through the structure radiates by reversed Cherenkov radiation. Two experiments have been completed at the Argonne Wakefield Accelerator (AWA), namely the Stage-I and Stage-II experiments. Differences between the two experiments include: (1) Structure length (Stage-I 8 cm, Stage-II 20 cm); (2) Bunch number used to excite the structure (Stage-I up to 2 bunches, Stage-II up to 8 bunches). In the Stage-I experiment, two bunches with a total charge of 85 nC generated 80 MW of RF power in a 2 ns long pulse. In the Stage-II experiment, the highest peak power reached 380 MW in a 10 ns long pulse from a train of 8 bunches with a total charge of 224 nC. Acceleration of a witness bunch has not been demonstrated yet, but the extracted power can be transferred to a separate accelerator for two-beam acceleration or directly applied to a trailing witness bunch in the same structure for collinear acceleration.
	Slides MOZBB2 [8.172 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOZBB2
About •	paper received ※ 27 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	laser, extraction, quadrupole, 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)

TUZBB3	Precise Beam Velocity Matching for the Experimental Demonstration of Ion Cooling With a Bunched Electron Beam	electron, factory, beam-cooling, dipole	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
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPLH07	High-Gradient Short Pulse Accelerating Structures	electron, experiment, wakefield, impedance	500
	S.V. Kuzikov, S.P. Antipov, E. Gomez Euclid TechLabs, LLC, Solon, Ohio, USA A.A. Vikharev IAP/RAS, Nizhny Novgorod, Russia
	High gradients are necessary for lots of applications of electron accelerators. As the maximum gradient is limited by effects of RF breakdown, we present a development of an electron accelerating structure operating with a short multi-megawatt RF pulse. The structure exploits an idea to decrease the breakdown probability due to RF pulse length reduction. This concept requires to distribute RF power so that all accelerating cells are fed independently each other. This implies waveguide net system which allows to delay and to distribute properly RF radiation along the structure keeping synchronism of particles and waves. We have designed an X-band pi-mode structure including the RF design, optimization, and engineering. The structure will be tested as an RF power extractor at the Argonne Wakefield Accelerator Facility for two-beam acceleration experiments. In this regime we anticipate to obtain 10 ns, gigawatt power level RF pulses generated by train consisted of eight 25-50 nC relativistic bunches.
	Poster TUPLH07 [0.999 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLH07
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)

TUPLE16	RFA Measurement of E-Cloud Generation Process at Fermilab Main Injector	electron, simulation, ECR, proton	595
	Y. Ji IIT, Chicago, Illinois, USA L.K. Spentzouris Illinois Institute of Technology, Chicago, Illinois, USA R.M. Zwaska Fermilab, Batavia, Illinois, USA
	Fermilab aims to provide greater beam power for the neutrino physics program. As the beam power increases, the unwanted production of secondary electrons in the beam pipe, known as ‘electron cloud’ or ‘E-cloud’ may become disruptive to high intensity operation. Instrumentation has been deployed in the Fermilab Main Injector (MI) to study E-cloud. One of these is a Retard Field Analyzer (RFA) that can be used to directly measure E-cloud generation at the location of the instrument. Studies of the dependence of E-cloud on beam intensity and bunch length have been carried out. The experimental results are compared to POSINST simulations. These simulations are guided by measurements from a Secondary Electron Yield (SEY) test stand installed in the MI to measure the SEY of materials such as the beam pipe stainless steel. The SEY has a strong influence on the E-cloud density. Results of these comprehensive studies comparing the RFA data with realistic MI simulations will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLE16
About •	paper received ※ 28 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)

WEYBA3	Tolerances for Plasma Wakefield Acceleration Drivers	plasma, FEL, luminosity, emittance	614
	G.R. White, T.O. Raubenheimer SLAC, Menlo Park, California, USA
	Transverse jitter tolerances are considered for beam-driven plasma accelerators. A simple model for jitter transfer from the drive to witness beam was developed and con-crete examples were studied for: high-brightness witness bunch injectors; high-energy boosters for FEL’s; and future Linear Colliders. For the LC application, we con-sider a superconducting Linac designed to minimize the jitter conditions of the drive beam. We use a start-to-end tracking model to simulate expected jitter performance. The tolerances on each subsystem of the driver Linac are found to be very tight, especially for magnet vibration which must be controlled at the sub-nm level. Work supported by the Department of Energy under Contract Number: DE-AC02-76SF00515.
	Slides WEYBA3 [6.178 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEYBA3
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)

WEPLM50	Beam Driven Bimodal Cavity Structure for High Gradient Acceleration	cavity, simulation, bunching, site	707
	X. Chang, Y. Jiang, S.V. Shchelkunov Yale University, Beam Physics Laboratory, New Haven, Connecticut, USA J.L. Hirshfield Omega-P, Inc., New Haven, Connecticut, USA
	Funding: Supported by USA National Science Foundation, Award #1632588 Abstract: Research aiming to increase the RF breakdown threshold in electron/positron accelerators is being conducted at the Yale University Beam Physics Laboratory. Our two-beam accelerator approach employs a beam driven bimodal cavity structure. This cavity includes (i) two modes excited by the drive beam, with the higher mode frequency three times that of the fundamental TM010 mode; (ii) a low-current accelerated beam and high-current drive beam traversing the same cavity structure. This approach has the potential advantages of (a) operating at higher acceleration gradient with lower breakdown and pulsed heating rates than that of a single-mode cavity structure at the same acceleration gradient, due to the spatiotemporal field distribution properties in the bimodal cavities; and (b) obtaining high accelerating gradient with a low energy drive beam. Recent progress in simulations and work towards an experimental test stand is presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM50
About •	paper received ※ 23 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)

WEPLM67	Optimization of a Single-Cell Accelerating Structure for Rf Breakdown Test With Short Rf Pulses	accelerating-gradient, experiment, collider, linear-collider	747
	M.M. Peng, J. Shi TUB, Beijing, People’s Republic of China M.E. Conde, G. Ha, C.-J. Jing, W. Liu, J.G. Power, J. Seok, J.H. Shao, E.E. Wisniewski ANL, Lemont, Illinois, USA C.-J. Jing Euclid TechLabs, LLC, Solon, Ohio, USA
	RF breakdown is one of the major limitations to achieve high gradient acceleration for future structure-based normal conducting linear colliders. Previous statistic research shows that the breakdown rate is proportional to E_a³⁰ * t_p⁵, which indicates that the accelerating gradient E_a could be improved by using shorter RF pulses (t_p). An X-band 11.7~GHz metallic single-cell structure has been designed for RF breakdown study up to 273~MV/m using short pulses (~3ns) generated by a 400~MW power extractor at Argonne Wakefield Accelerator (AWA) facility. The structure has also been scaled to 11.424~GHz for the long pulse (100-1500~ns) breakdown study driven by a klystron and a pulse compressor at Tsinghua X-band High Power Test-stand (TPoT-X), with the gradient up to 246~MV/m with 200~MW input power.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM67
About •	paper received ※ 05 September 2019 paper accepted ※ 26 November 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPLM68	Design of a Dielectric-Loaded Accelerator for Short Pulse High Gradient Research	wakefield, simulation, accelerating-gradient, experiment	751
	M.M. Peng, J. Shi TUB, Beijing, People’s Republic of China M.E. Conde, G. Ha, C.-J. Jing, W. Liu, J.G. Power, J. Seok, J.H. Shao, E.E. Wisniewski ANL, Lemont, Illinois, USA C.-J. Jing Euclid TechLabs, LLC, Solon, Ohio, USA
	The short-pulse two-beam acceleration approach is a promising candidate to meet the cost and luminosity requirements for future linear colliders. Dielectric-loaded structure has been intensely investigated for this approach because of its low fabrication cost, low RF loss, and potential to withstand GV/m gradient. An X-band 11.7~GHz dielectric-loaded accelerator (DLA) has been designed for high power test with short RF pulses (3~ns) generated from a power extractor driven by high charge bunches at Argonne Wakefield Accelerator (AWA) facility. The gradient is expected to be over 100~MV/m with the maximum input power of 400~MW.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM68
About •	paper received ※ 05 September 2019 paper accepted ※ 27 November 2019 issue date ※ 08 October 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WEPLO11	Single Cycle THz Acceleration Structures	GUI, electron, laser, focusing	862
	S.V. Kuzikov, A.A. Vikharev IAP/RAS, Nizhny Novgorod, Russia S.P. Antipov, E. Gomez Euclid TechLabs, LLC, Solon, Ohio, USA
	Funding: This work was supported by the Russian Science Foundation under grant 19-42-04133 in the part of CST simulations for THz structures. Recently, gradients on the order of 1 GV/m level have been obtained in a form of single cycle (~1 ps) THz pulses produced by conversion of a high peak power laser radiation in nonlinear crystals (~1 mJ, 1 ps, up to 3% conversion efficiency). These pulses however are broadband (0.1-5 THz) and therefore a new accelerating structure type is required. For electron beam acceleration with such pulses we propose arrays of parabolic focusing micro-mirrors with common central. These novel structures could be produced by a femtosecond laser ablation system developed at Euclid Techlabs. This technology had already been tested for production of several millimeters long, multi-cell structure which has been testing with electron beam. We also propose using of structures where necessary GV/m E-fields are excited by a drive bunch travelling in the corrugated waveguide. The radiated by drive bunch sequence of short range delayed wakes are guided in this case by metallic disks and reflected back being focused exactly at time when the witness bunch arrives.
	Poster WEPLO11 [2.124 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLO11
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)

Paper

Title

Other Keywords

Page

MOZBB2

Experiments with Metamaterial-Based Metallic Accelerating Structures

experiment, wakefield, radiation, GUI

78

X. Lu
SLAC, Menlo Park, California, USA
M.E. Conde, D.S. Doran, G. Ha, J.G. Power, J.H. Shao, E.E. Wisniewski
ANL, Lemont, Illinois, USA
C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA
X. Lu, I. Mastovsky, J.F. Picard, M.A. Shapiro, R.J. Temkin
MIT/PSFC, Cambridge, Massachusetts, USA
M.M. Peng
AAI/ANL, Lemont, Illinois, USA
J. Seok
UNIST, Ulsan, Republic of Korea

Funding: U.S. Department of Energy, Office of Science, Office of High Energy Physics under Award No. DE-SC0015566 at MIT and No. DE-AC02-06CH11357 at ANL
We present experimental studies of metamaterial (MTM) structures for wakefield acceleration. The MTM structure is an all-metal periodic structure with its period much smaller than the wavelength at X-band. The fundamental TM mode has a negative group velocity, so an electron beam traveling through the structure radiates by reversed Cherenkov radiation. Two experiments have been completed at the Argonne Wakefield Accelerator (AWA), namely the Stage-I and Stage-II experiments. Differences between the two experiments include: (1) Structure length (Stage-I 8 cm, Stage-II 20 cm); (2) Bunch number used to excite the structure (Stage-I up to 2 bunches, Stage-II up to 8 bunches). In the Stage-I experiment, two bunches with a total charge of 85 nC generated 80 MW of RF power in a 2 ns long pulse. In the Stage-II experiment, the highest peak power reached 380 MW in a 10 ns long pulse from a train of 8 bunches with a total charge of 224 nC. Acceleration of a witness bunch has not been demonstrated yet, but the extracted power can be transferred to a separate accelerator for two-beam acceleration or directly applied to a trailing witness bunch in the same structure for collinear acceleration.

Slides MOZBB2 [8.172 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-MOZBB2

About •

paper received ※ 27 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

laser, extraction, quadrupole, 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)

TUZBB3

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

electron, factory, beam-cooling, dipole

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

Export •

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

TUPLH07

High-Gradient Short Pulse Accelerating Structures

electron, experiment, wakefield, impedance

500

S.V. Kuzikov, S.P. Antipov, E. Gomez
Euclid TechLabs, LLC, Solon, Ohio, USA
A.A. Vikharev
IAP/RAS, Nizhny Novgorod, Russia

High gradients are necessary for lots of applications of electron accelerators. As the maximum gradient is limited by effects of RF breakdown, we present a development of an electron accelerating structure operating with a short multi-megawatt RF pulse. The structure exploits an idea to decrease the breakdown probability due to RF pulse length reduction. This concept requires to distribute RF power so that all accelerating cells are fed independently each other. This implies waveguide net system which allows to delay and to distribute properly RF radiation along the structure keeping synchronism of particles and waves. We have designed an X-band pi-mode structure including the RF design, optimization, and engineering. The structure will be tested as an RF power extractor at the Argonne Wakefield Accelerator Facility for two-beam acceleration experiments. In this regime we anticipate to obtain 10 ns, gigawatt power level RF pulses generated by train consisted of eight 25-50 nC relativistic bunches.

Poster TUPLH07 [0.999 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLH07

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)

TUPLE16

RFA Measurement of E-Cloud Generation Process at Fermilab Main Injector

electron, simulation, ECR, proton

595

Y. Ji
IIT, Chicago, Illinois, USA
L.K. Spentzouris
Illinois Institute of Technology, Chicago, Illinois, USA
R.M. Zwaska
Fermilab, Batavia, Illinois, USA

Fermilab aims to provide greater beam power for the neutrino physics program. As the beam power increases, the unwanted production of secondary electrons in the beam pipe, known as ‘electron cloud’ or ‘E-cloud’ may become disruptive to high intensity operation. Instrumentation has been deployed in the Fermilab Main Injector (MI) to study E-cloud. One of these is a Retard Field Analyzer (RFA) that can be used to directly measure E-cloud generation at the location of the instrument. Studies of the dependence of E-cloud on beam intensity and bunch length have been carried out. The experimental results are compared to POSINST simulations. These simulations are guided by measurements from a Secondary Electron Yield (SEY) test stand installed in the MI to measure the SEY of materials such as the beam pipe stainless steel. The SEY has a strong influence on the E-cloud density. Results of these comprehensive studies comparing the RFA data with realistic MI simulations will be presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-TUPLE16

About •

paper received ※ 28 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)

WEYBA3

Tolerances for Plasma Wakefield Acceleration Drivers

plasma, FEL, luminosity, emittance

614

G.R. White, T.O. Raubenheimer
SLAC, Menlo Park, California, USA

Transverse jitter tolerances are considered for beam-driven plasma accelerators. A simple model for jitter transfer from the drive to witness beam was developed and con-crete examples were studied for: high-brightness witness bunch injectors; high-energy boosters for FEL’s; and future Linear Colliders. For the LC application, we con-sider a superconducting Linac designed to minimize the jitter conditions of the drive beam. We use a start-to-end tracking model to simulate expected jitter performance. The tolerances on each subsystem of the driver Linac are found to be very tight, especially for magnet vibration which must be controlled at the sub-nm level.
Work supported by the Department of Energy under Contract Number: DE-AC02-76SF00515.

Slides WEYBA3 [6.178 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEYBA3

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)

WEPLM50

Beam Driven Bimodal Cavity Structure for High Gradient Acceleration

cavity, simulation, bunching, site

707

X. Chang, Y. Jiang, S.V. Shchelkunov
Yale University, Beam Physics Laboratory, New Haven, Connecticut, USA
J.L. Hirshfield
Omega-P, Inc., New Haven, Connecticut, USA

Funding: Supported by USA National Science Foundation, Award #1632588
Abstract: Research aiming to increase the RF breakdown threshold in electron/positron accelerators is being conducted at the Yale University Beam Physics Laboratory. Our two-beam accelerator approach employs a beam driven bimodal cavity structure. This cavity includes (i) two modes excited by the drive beam, with the higher mode frequency three times that of the fundamental TM010 mode; (ii) a low-current accelerated beam and high-current drive beam traversing the same cavity structure. This approach has the potential advantages of (a) operating at higher acceleration gradient with lower breakdown and pulsed heating rates than that of a single-mode cavity structure at the same acceleration gradient, due to the spatiotemporal field distribution properties in the bimodal cavities; and (b) obtaining high accelerating gradient with a low energy drive beam. Recent progress in simulations and work towards an experimental test stand is presented.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM50

About •

paper received ※ 23 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)

WEPLM67

Optimization of a Single-Cell Accelerating Structure for Rf Breakdown Test With Short Rf Pulses

accelerating-gradient, experiment, collider, linear-collider

747

M.M. Peng, J. Shi
TUB, Beijing, People’s Republic of China
M.E. Conde, G. Ha, C.-J. Jing, W. Liu, J.G. Power, J. Seok, J.H. Shao, E.E. Wisniewski
ANL, Lemont, Illinois, USA
C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA

RF breakdown is one of the major limitations to achieve high gradient acceleration for future structure-based normal conducting linear colliders. Previous statistic research shows that the breakdown rate is proportional to E_a³⁰ * t_p⁵, which indicates that the accelerating gradient E_a could be improved by using shorter RF pulses (t_p). An X-band 11.7~GHz metallic single-cell structure has been designed for RF breakdown study up to 273~MV/m using short pulses (~3ns) generated by a 400~MW power extractor at Argonne Wakefield Accelerator (AWA) facility. The structure has also been scaled to 11.424~GHz for the long pulse (100-1500~ns) breakdown study driven by a klystron and a pulse compressor at Tsinghua X-band High Power Test-stand (TPoT-X), with the gradient up to 246~MV/m with 200~MW input power.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM67

About •

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

Export •

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

WEPLM68

Design of a Dielectric-Loaded Accelerator for Short Pulse High Gradient Research

wakefield, simulation, accelerating-gradient, experiment

751

M.M. Peng, J. Shi
TUB, Beijing, People’s Republic of China
M.E. Conde, G. Ha, C.-J. Jing, W. Liu, J.G. Power, J. Seok, J.H. Shao, E.E. Wisniewski
ANL, Lemont, Illinois, USA
C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA

The short-pulse two-beam acceleration approach is a promising candidate to meet the cost and luminosity requirements for future linear colliders. Dielectric-loaded structure has been intensely investigated for this approach because of its low fabrication cost, low RF loss, and potential to withstand GV/m gradient. An X-band 11.7~GHz dielectric-loaded accelerator (DLA) has been designed for high power test with short RF pulses (3~ns) generated from a power extractor driven by high charge bunches at Argonne Wakefield Accelerator (AWA) facility. The gradient is expected to be over 100~MV/m with the maximum input power of 400~MW.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLM68

About •

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

Export •

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

WEPLO11

Single Cycle THz Acceleration Structures

GUI, electron, laser, focusing

862

S.V. Kuzikov, A.A. Vikharev
IAP/RAS, Nizhny Novgorod, Russia
S.P. Antipov, E. Gomez
Euclid TechLabs, LLC, Solon, Ohio, USA

Funding: This work was supported by the Russian Science Foundation under grant 19-42-04133 in the part of CST simulations for THz structures.
Recently, gradients on the order of 1 GV/m level have been obtained in a form of single cycle (~1 ps) THz pulses produced by conversion of a high peak power laser radiation in nonlinear crystals (~1 mJ, 1 ps, up to 3% conversion efficiency). These pulses however are broadband (0.1-5 THz) and therefore a new accelerating structure type is required. For electron beam acceleration with such pulses we propose arrays of parabolic focusing micro-mirrors with common central. These novel structures could be produced by a femtosecond laser ablation system developed at Euclid Techlabs. This technology had already been tested for production of several millimeters long, multi-cell structure which has been testing with electron beam. We also propose using of structures where necessary GV/m E-fields are excited by a drive bunch travelling in the corrugated waveguide. The radiated by drive bunch sequence of short range delayed wakes are guided in this case by metallic disks and reflected back being focused exactly at time when the witness bunch arrives.

Poster WEPLO11 [2.124 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-NAPAC2019-WEPLO11

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)