IPAC2022 - Classification: MC3: Novel Particle Sources and Acceleration Techniques / A15: New Acceleration Techniques

Paper	Title	Page
MOPOMS001	Progress on Development of AXSIS: A Femtosecond THz-Driven MeV Accelerator and keV X-Ray Source	621
	N.H. Matlis, M. Fakhari, F.X. Kärtner, T. Kroh, M. Pergament, T. Rohwer, M. Vahdani, D. Zhang CFEL, Hamburg, Germany R. Bazrafshan, F.X. Kärtner, T. Rohwer Deutsches Elektronen Synchrotron (DESY) and Center for Free Electron Science (CFEL), Hamburg, Germany R. Bazrafshan, M. Vahdani University of Hamburg, Hamburg, Germany M. Fakhari, D. Zhang DESY, Hamburg, Germany F.X. Kärtner, T. Kroh The Hamburg Center for Ultrafast Imaging, University of Hamburg, Hamburg, Germany
	Funding: This work was supported by KA908-12/1 of the Deutsche Forschungsgemeinschaft and by the ERC under the European Union’s Seventh Framework Program (FP7/2007-2013) through Synergy Grant AXSIS (609920). We report on the design and progress in implementing a THz-driven relativistic electron accelerator and associated X-ray source, the AXSIS Facility at DESY. We have developed a full layout of the machine based on a THz gun followed by a multi-cycle dielectric loaded metal waveguide THz linear accelerator to generate 20 MeV level, 10 fs electron bunches. The required THz pulse energies are on the mJ-level for the gun and multi-10-mJ-level for the THz linac. Customized laser technologies have been developed allowing for the generation of these pulses up to 1 kHz repetition rate. The generated electron bunches are then focused into a counter propagating optical pulse ’optical undulator’ to generate X-rays in the 6-7 keV range. We will discuss the overall layout of the machine, status of its implementation and technical challenges in the different components as well as diagnostics of this new type of accelerator and X-ray source.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS001
About •	Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 21 June 2022
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPOMS003	Single-Sided Pumped Compact Terahertz Driven Booster Accelerator	625
SUSPMF026	use link to see paper's listing under its alternate paper code
	T. Kroh, R. Bazrafshan, F.X. Kärtner, N.H. Matlis Deutsches Elektronen Synchrotron (DESY) and Center for Free Electron Science (CFEL), Hamburg, Germany M. Fakhari, M. Pergament, T. Rohwer, M. Vahdani, D. Zhang CFEL, Hamburg, Germany F.X. Kärtner The Hamburg Center for Ultrafast Imaging, University of Hamburg, Hamburg, Germany K. Kawase JAEA, Kizugawa, Japan
	Funding: European Research Council under the European Union’s Seventh Framework Programme (FP7/2007-2013) through the Synergy Grant ’Frontiers in Attosecond X-ray Science: Imaging and Spectroscopy’ (609920). Scaling the RF-accelerator concept to terahertz (THz) frequencies brings several compelling advantages, including compactness, intrinsic timing between the photoemission and driving field sources, and high field gradients associated with the short THz wavelength and high breakdown threshold. Recent demonstrations of such THz powered accelerators relied on two counter-propagating single-cycle THz pulses. However, to achieve high energy gains in the acceleration process high energy THz pulses are needed which in turn require complex optical setups. Here, we present on the development of a matchbox sized multi-layered accelerator designed to boost the 50 keV output of a DC electron gun to energies of ~400 keV that only requires a single THz pulse to be powered. An integrated tunable mirror inside the structure interferes the front of the driving THz pulse with its rear part such that the field in the interaction region is optimized for efficient acceleration. This reduces the complexity of the required optical setup. Such a compact booster accelerator is very promising as electron source in ultrafast electron diffraction experiments and as booster stage prior to THz based LINACs.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS003
About •	Received ※ 08 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 20 June 2022
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MOPOMS005	Start-to-End Simulations of a THz-Driven ICS Source	631
	M. Fakhari, Y.-K. Kan DESY, Hamburg, Germany F.X. Kärtner The Hamburg Center for Ultrafast Imaging, University of Hamburg, Hamburg, Germany F.X. Kärtner Deutsches Elektronen Synchrotron (DESY) and Center for Free Electron Science (CFEL), Hamburg, Germany N.H. Matlis, M. Vahdani CFEL, Hamburg, Germany M. Vahdani University of Hamburg, Hamburg, Germany
	We present start-to-end simulations for a fully THz-driven table-top X-ray source. A dielectric-loaded metallic cavity operating at its Higher Order Mode accelerates 1 PC photo emitted electron bunch up to 430 keV kinetic energy. The output beam of the gun is injected into a dielectric-loaded waveguide where phase velocity of the traveling wave is adjusted in such a way that electrons see an accelerating field all the way along the tube resulting to an 18.5-MeV output beam which is then transported to an inverse Compton scattering (ICS) stage. The injection phase of the electrons can be tuned to introduce a negative energy chirp to the electron bunch leading to a ballistic bunch compression after the linac. In addition, a set of permanent magnet quadrupoles is designed to focus the beam at the ICS interaction point where the electron beam scatters off a 250-mJ, 0.5ps, 1-µm laser beam and generates an X-ray beam with 2.6x10⁷ photons per shot containing photon energies 2keV< Eph <8keV in a beam with 50 mrad half opening angle. The required terahertz waves to power the gun and linac are 550-ps pulses at 300 GHz containing 5 mJ and 23 mJ energies respectively with 1 kHz repetition rate.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS005
About •	Received ※ 08 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 25 June 2022
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MOPOMS007	Optimized Dielectric Loaded Waveguide Terahertz LINACs	634
SUSPMF028	use link to see paper's listing under its alternate paper code
	M. Vahdani University of Hamburg, Hamburg, Germany M. Fakhari DESY, Hamburg, Germany F.X. Kärtner The Hamburg Center for Ultrafast Imaging, University of Hamburg, Hamburg, Germany F.X. Kärtner Deutsches Elektronen Synchrotron (DESY) and Center for Free Electron Science (CFEL), Hamburg, Germany M. Vahdani CFEL, Hamburg, Germany
	Dielectric loaded waveguides (DLW) powered by multicycle terahertz (THz) pulses have shown promising performance as compact linear accelerators due to higher breakdown fields at THz frequencies compared to conventional RF components. By changing the dielectric dimensions one can control phase and group velocities of the THz pulse inside the DLW. Since optimum waveguide dimensions are dependent on initial electron energy, THz pulse energy, and etc., it is worthwhile to determine optimum values for different conditions to maximize final kinetic energy. In this work, we present a combined analytical/numerical guide to determine the optimum DLW parameters for single on-axis electron acceleration. We also introduce normalized graphic representations to visualize optimum designs for different initial electron and THz pulse energies.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS007
About •	Received ※ 09 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 21 June 2022
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MOPOMS008	Diagnosis of Transverse Emittance in Laser-Driven Ion Beam	637
SUSPMF029	use link to see paper's listing under its alternate paper code
	T. Miyatake, I. Takemoto, Y. Watanabe Kyushu University, Interdisciplinary Graduate School of Engineering Sciences, Kasuga-Shi, Japan T.-H. Dinh, M. Kando, S. Kojima, K. Kondo, K. Kondo, M. Nishikino, M. Nishiuchi, H. Sakaki National Institutes for Quantum Science and Technology, Kyoto, Japan
	Funding: This work was supported by JST-MIRAI R&D Program No. JPMJMI17A1. This work was supported by JSPS KAKENHI Grant Number JP21J22132. Ion beam produced in laser-driven ion acceleration by ultra-intense lasers has characteristics of high peak cur-rent and low emittance. These characteristics become an advantage to operate the request for the beam applica-tion. Therefore, we study how to control the parameters with the laser-plasma interaction. Here, we used 2D Particle-in-Cell code to simulate the laser-driven ion acceleration and investigated the results in terms of transverse emittance, beam current, and brightness. The laser spot size and target thickness were changed in the simulation. And, these qualitative results show that interaction target thickness is a major factor in controlling beam characteristics.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS008
About •	Received ※ 07 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 18 June 2022
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MOPOMS010	Beam Dynamics and Drive Beam Losses Within a Planar Dielectric Wakefield Accelerator	641
SUSPMF030	use link to see paper's listing under its alternate paper code
	T.J. Overton, Y.M. Saveliev Cockcroft Institute, Warrington, Cheshire, United Kingdom T.H. Pacey, Y.M. Saveliev STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom G.X. Xia UMAN, Manchester, United Kingdom
	Funding: Science and Technology Funding Council (STFC) Student Grant Beam-driven dielectric wakefield accelerators (DWA) have the potential to provide accelerating gradients in the GV/m range. The transverse dynamics in such devices need to be understood to avoid instabilities over long transport distances and facilitate beam matching to specific applications (e.g. FELs). This presentation details simulation studies of the magnitude of beam-breakup instability (BBU) in planar dielectric lined waveguides (DLWs). These are for DWA drive beams, with high charge and momentum that can be produced at current facilities. Using a series of perpendicular DLW segments has been proposed to control instabilities over larger distances. Using self-developed software, the beam dynamics of a drive beam within a DLW are simulated and the magnitude of beam losses along a DLW of varying lengths calculated and beam quality preservation investigated. Methods to reduce transverse instabilities have been explored, and the impact of these on the length of a possible DWA acceleration stage are investigated. An acceleration stage with m-scale length, consisting of multiple alternating planar DLWs, is suggested and preservation of beam quality along this distance is shown.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS010
About •	Received ※ 07 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 17 June 2022
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MOPOMS012	Simulation Studies of Drive Beam Instability in a Dielectric Wakefield Accelerator	645
	W.H. Tan, P. Piot Northern Illinois University, DeKalb, Illinois, USA A. Huebl, R. Jambunathan, R. Lehé, A. Myers, T. Rheaume, J.-L. Vay, W. Zhang LBNL, Berkeley, USA P. Piot ANL, Lemont, Illinois, USA
	Funding: This work is supported by the US DOE award DE-SC0018656 with NIU and DE-AC02-06CH11357 with ANL. This work used resources from NERSC, supported by DOE contract DE-AC02-05CH11231. This research used WarpX, which is supported by the US DOE Exascale Computing Project. Primary WarpX contributors are with LBNL, LLNL, CEA-LIDYL, SLAC, DESY, CERN, and Modern Electron. Beam-driven collinear wakefield acceleration using structure wakefield accelerators promises a high gradient acceleration within a smaller physical footprint. Sustainable extraction of energy from the drive beam relies on precise understanding of its long term dynamics and the possible onset or mitigation of the beam instability. The advance of computational power and tools makes it possible to model the full physics of beam-driven wakefield acceleration. Here we report on the long-term beam dynamics studies of a drive beam considering the example of a dielectric waveguide using high fidelity particle-in-cell simulations performed with WarpX.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS012
About •	Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 16 June 2022
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MOPOMS015	Temporal and Spatial Characterization of Ultrafast Terahertz Near-Fields for Particle Acceleration	656
SUSPMF031	use link to see paper's listing under its alternate paper code
	A.E. Gabriel, M.C. Hoffmann, E.A. Nanni, M.A.K. Othman SLAC, Menlo Park, California, USA
	Funding: This work was supported by Department of Energy contract DE-AC02-76SF00515. We have measured the THz near-field in order to inform the design of improved THz-frequency accelerating structures. THz-frequency accelerating structures could provide the accelerating gradients needed for next generation particle accelerators with compact, GV/m-scale devices. One of the most promising THz generation techniques for accelerator applications is optical rectification in lithium niobate using the tilted pulse front method. However, accelerator applications are limited by significant losses during transport of THz radiation from the generating nonlinear crystal to the acceleration structure. In addition, the spectral properties of high-field THz sources make it difficult to couple THz radiation into accelerating structures. A better understanding of the THz near-field source properties is necessary for the optimization of THz transport and coupling. We have developed a technique for detailed measurement of the THz near-fields and used it to reconstruct the full temporal 3D THz near-field close to the LN emission face. Analysis of the results from this measurement will inform designs of novel structures for use in THz particle acceleration.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS015
About •	Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 03 July 2022
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WEIXSP1	Towards High-Repetition Rate Petawatt Laser Experiments with Cryogenic Jets Using a Mechanical Chopper System	1594
	M. Rehwald, S. Assenbaum, C. Bernert, U. Schramm, K. Zeil HZDR, Dresden, Germany C.B. Curry, M. Gauthier, S.H. Glenzer, C. Schoenwaelder, F. Treffert SLAC, Menlo Park, California, USA S. Göde EuXFEL, Schenefeld, Germany
	Laser-plasma based ion accelerators require suitable high-repetition rate target systems that enable systematic studies at controlled plasma conditions and application-relevant particle flux. Self-refreshing, micrometer-sized cryogenic jets have proven to be an ideal target platform. Yet, operation of such systems in the harsh environmental conditions of high power laser induced plasma experiments have turned out to be challenging. Here we report on recent experiments deploying a cryogenic hydrogen jet as a source of pure proton beams generated with the PW-class ultrashort pulse laser DRACO. Damage to the jet target system during application of full energy laser shots was prevented by implementation of a mechanical chopper system interrupting the direct line of sight between the laser plasma interaction zone and the jet source.
	Slides WEIXSP1 [4.896 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEIXSP1
About •	Received ※ 16 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 15 June 2022
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WEOXSP3	mm-Wave Structure Development for High Gradient Acceleration	1606
	E.J.C. Snively, A.E. Gabriel, E.A. Nanni, M.A.K. Othman, A.V. Sy SLAC, Menlo Park, California, USA A.E. Gabriel UCSC, Santa Cruz, California, USA
	Funding: This work is supported by U.S. Department of Energy Contract No. DE-AC02-76SF00515, SLAC LDRD project 21-014 and Internal Agency Agreement 21-0007-IA (MIPR HR0011150657). We report on the design of mm-wave accelerator structures operating near 100 GHz. Simulations of the cavity geometry and RF coupling are performed in ANSYS-HFSS and using SLAC’s parallel electromagnetic code suite ACE3P. We present experimental results for structures fabricated from copper, niobium, and copper plated with NbTiNi. We report on techniques for tuning these high frequency structures, as well as preliminary brazing results. A mm-wave accelerator cavity enables not only a high achievable gradient due to higher breakdown thresholds, but also reduced fill times which decrease pulsed heating and allow for higher repetition rates. We discuss the potential advantages and challenges for applications requiring ultra-compact structures.
	Slides WEOXSP3 [1.800 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEOXSP3
About •	Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 16 June 2022
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Paper

Title

Page

Progress on Development of AXSIS: A Femtosecond THz-Driven MeV Accelerator and keV X-Ray Source

621

N.H. Matlis, M. Fakhari, F.X. Kärtner, T. Kroh, M. Pergament, T. Rohwer, M. Vahdani, D. Zhang
CFEL, Hamburg, Germany
R. Bazrafshan, F.X. Kärtner, T. Rohwer
Deutsches Elektronen Synchrotron (DESY) and Center for Free Electron Science (CFEL), Hamburg, Germany
R. Bazrafshan, M. Vahdani
University of Hamburg, Hamburg, Germany
M. Fakhari, D. Zhang
DESY, Hamburg, Germany
F.X. Kärtner, T. Kroh
The Hamburg Center for Ultrafast Imaging, University of Hamburg, Hamburg, Germany

Funding: This work was supported by KA908-12/1 of the Deutsche Forschungsgemeinschaft and by the ERC under the European Union’s Seventh Framework Program (FP7/2007-2013) through Synergy Grant AXSIS (609920).
We report on the design and progress in implementing a THz-driven relativistic electron accelerator and associated X-ray source, the AXSIS Facility at DESY. We have developed a full layout of the machine based on a THz gun followed by a multi-cycle dielectric loaded metal waveguide THz linear accelerator to generate 20 MeV level, 10 fs electron bunches. The required THz pulse energies are on the mJ-level for the gun and multi-10-mJ-level for the THz linac. Customized laser technologies have been developed allowing for the generation of these pulses up to 1 kHz repetition rate. The generated electron bunches are then focused into a counter propagating optical pulse ’optical undulator’ to generate X-rays in the 6-7 keV range. We will discuss the overall layout of the machine, status of its implementation and technical challenges in the different components as well as diagnostics of this new type of accelerator and X-ray source.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS001

About •

Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 21 June 2022

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

MOPOMS003

Single-Sided Pumped Compact Terahertz Driven Booster Accelerator

625

SUSPMF026

use link to see paper's listing under its alternate paper code

T. Kroh, R. Bazrafshan, F.X. Kärtner, N.H. Matlis
Deutsches Elektronen Synchrotron (DESY) and Center for Free Electron Science (CFEL), Hamburg, Germany
M. Fakhari, M. Pergament, T. Rohwer, M. Vahdani, D. Zhang
CFEL, Hamburg, Germany
F.X. Kärtner
The Hamburg Center for Ultrafast Imaging, University of Hamburg, Hamburg, Germany
K. Kawase
JAEA, Kizugawa, Japan

Funding: European Research Council under the European Union’s Seventh Framework Programme (FP7/2007-2013) through the Synergy Grant ’Frontiers in Attosecond X-ray Science: Imaging and Spectroscopy’ (609920).
Scaling the RF-accelerator concept to terahertz (THz) frequencies brings several compelling advantages, including compactness, intrinsic timing between the photoemission and driving field sources, and high field gradients associated with the short THz wavelength and high breakdown threshold. Recent demonstrations of such THz powered accelerators relied on two counter-propagating single-cycle THz pulses. However, to achieve high energy gains in the acceleration process high energy THz pulses are needed which in turn require complex optical setups. Here, we present on the development of a matchbox sized multi-layered accelerator designed to boost the 50 keV output of a DC electron gun to energies of ~400 keV that only requires a single THz pulse to be powered. An integrated tunable mirror inside the structure interferes the front of the driving THz pulse with its rear part such that the field in the interaction region is optimized for efficient acceleration. This reduces the complexity of the required optical setup. Such a compact booster accelerator is very promising as electron source in ultrafast electron diffraction experiments and as booster stage prior to THz based LINACs.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS003

About •

Received ※ 08 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 20 June 2022

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MOPOMS005

Start-to-End Simulations of a THz-Driven ICS Source

631

M. Fakhari, Y.-K. Kan
DESY, Hamburg, Germany
F.X. Kärtner
The Hamburg Center for Ultrafast Imaging, University of Hamburg, Hamburg, Germany
F.X. Kärtner
Deutsches Elektronen Synchrotron (DESY) and Center for Free Electron Science (CFEL), Hamburg, Germany
N.H. Matlis, M. Vahdani
CFEL, Hamburg, Germany
M. Vahdani
University of Hamburg, Hamburg, Germany

We present start-to-end simulations for a fully THz-driven table-top X-ray source. A dielectric-loaded metallic cavity operating at its Higher Order Mode accelerates 1 PC photo emitted electron bunch up to 430 keV kinetic energy. The output beam of the gun is injected into a dielectric-loaded waveguide where phase velocity of the traveling wave is adjusted in such a way that electrons see an accelerating field all the way along the tube resulting to an 18.5-MeV output beam which is then transported to an inverse Compton scattering (ICS) stage. The injection phase of the electrons can be tuned to introduce a negative energy chirp to the electron bunch leading to a ballistic bunch compression after the linac. In addition, a set of permanent magnet quadrupoles is designed to focus the beam at the ICS interaction point where the electron beam scatters off a 250-mJ, 0.5ps, 1-µm laser beam and generates an X-ray beam with 2.6x10⁷ photons per shot containing photon energies 2keV< Eph <8keV in a beam with 50 mrad half opening angle. The required terahertz waves to power the gun and linac are 550-ps pulses at 300 GHz containing 5 mJ and 23 mJ energies respectively with 1 kHz repetition rate.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS005

About •

Received ※ 08 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 25 June 2022

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MOPOMS007

Optimized Dielectric Loaded Waveguide Terahertz LINACs

634

SUSPMF028

use link to see paper's listing under its alternate paper code

M. Vahdani
University of Hamburg, Hamburg, Germany
M. Fakhari
DESY, Hamburg, Germany
F.X. Kärtner
The Hamburg Center for Ultrafast Imaging, University of Hamburg, Hamburg, Germany
F.X. Kärtner
Deutsches Elektronen Synchrotron (DESY) and Center for Free Electron Science (CFEL), Hamburg, Germany
M. Vahdani
CFEL, Hamburg, Germany

Dielectric loaded waveguides (DLW) powered by multicycle terahertz (THz) pulses have shown promising performance as compact linear accelerators due to higher breakdown fields at THz frequencies compared to conventional RF components. By changing the dielectric dimensions one can control phase and group velocities of the THz pulse inside the DLW. Since optimum waveguide dimensions are dependent on initial electron energy, THz pulse energy, and etc., it is worthwhile to determine optimum values for different conditions to maximize final kinetic energy. In this work, we present a combined analytical/numerical guide to determine the optimum DLW parameters for single on-axis electron acceleration. We also introduce normalized graphic representations to visualize optimum designs for different initial electron and THz pulse energies.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS007

About •

Received ※ 09 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 21 June 2022

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MOPOMS008

Diagnosis of Transverse Emittance in Laser-Driven Ion Beam

637

SUSPMF029

use link to see paper's listing under its alternate paper code

T. Miyatake, I. Takemoto, Y. Watanabe
Kyushu University, Interdisciplinary Graduate School of Engineering Sciences, Kasuga-Shi, Japan
T.-H. Dinh, M. Kando, S. Kojima, K. Kondo, K. Kondo, M. Nishikino, M. Nishiuchi, H. Sakaki
National Institutes for Quantum Science and Technology, Kyoto, Japan

Funding: This work was supported by JST-MIRAI R&D Program No. JPMJMI17A1. This work was supported by JSPS KAKENHI Grant Number JP21J22132.
Ion beam produced in laser-driven ion acceleration by ultra-intense lasers has characteristics of high peak cur-rent and low emittance. These characteristics become an advantage to operate the request for the beam applica-tion. Therefore, we study how to control the parameters with the laser-plasma interaction. Here, we used 2D Particle-in-Cell code to simulate the laser-driven ion acceleration and investigated the results in terms of transverse emittance, beam current, and brightness. The laser spot size and target thickness were changed in the simulation. And, these qualitative results show that interaction target thickness is a major factor in controlling beam characteristics.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS008

About •

Received ※ 07 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 18 June 2022

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

MOPOMS010

Beam Dynamics and Drive Beam Losses Within a Planar Dielectric Wakefield Accelerator

641

SUSPMF030

use link to see paper's listing under its alternate paper code

T.J. Overton, Y.M. Saveliev
Cockcroft Institute, Warrington, Cheshire, United Kingdom
T.H. Pacey, Y.M. Saveliev
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
G.X. Xia
UMAN, Manchester, United Kingdom

Funding: Science and Technology Funding Council (STFC) Student Grant
Beam-driven dielectric wakefield accelerators (DWA) have the potential to provide accelerating gradients in the GV/m range. The transverse dynamics in such devices need to be understood to avoid instabilities over long transport distances and facilitate beam matching to specific applications (e.g. FELs). This presentation details simulation studies of the magnitude of beam-breakup instability (BBU) in planar dielectric lined waveguides (DLWs). These are for DWA drive beams, with high charge and momentum that can be produced at current facilities. Using a series of perpendicular DLW segments has been proposed to control instabilities over larger distances. Using self-developed software, the beam dynamics of a drive beam within a DLW are simulated and the magnitude of beam losses along a DLW of varying lengths calculated and beam quality preservation investigated. Methods to reduce transverse instabilities have been explored, and the impact of these on the length of a possible DWA acceleration stage are investigated. An acceleration stage with m-scale length, consisting of multiple alternating planar DLWs, is suggested and preservation of beam quality along this distance is shown.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS010

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Received ※ 07 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 17 June 2022

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MOPOMS012

Simulation Studies of Drive Beam Instability in a Dielectric Wakefield Accelerator

645

W.H. Tan, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
A. Huebl, R. Jambunathan, R. Lehé, A. Myers, T. Rheaume, J.-L. Vay, W. Zhang
LBNL, Berkeley, USA
P. Piot
ANL, Lemont, Illinois, USA

Funding: This work is supported by the US DOE award DE-SC0018656 with NIU and DE-AC02-06CH11357 with ANL. This work used resources from NERSC, supported by DOE contract DE-AC02-05CH11231. This research used WarpX, which is supported by the US DOE Exascale Computing Project. Primary WarpX contributors are with LBNL, LLNL, CEA-LIDYL, SLAC, DESY, CERN, and Modern Electron.
Beam-driven collinear wakefield acceleration using structure wakefield accelerators promises a high gradient acceleration within a smaller physical footprint. Sustainable extraction of energy from the drive beam relies on precise understanding of its long term dynamics and the possible onset or mitigation of the beam instability. The advance of computational power and tools makes it possible to model the full physics of beam-driven wakefield acceleration. Here we report on the long-term beam dynamics studies of a drive beam considering the example of a dielectric waveguide using high fidelity particle-in-cell simulations performed with WarpX.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS012

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Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 16 June 2022

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MOPOMS015

Temporal and Spatial Characterization of Ultrafast Terahertz Near-Fields for Particle Acceleration

656

SUSPMF031

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A.E. Gabriel, M.C. Hoffmann, E.A. Nanni, M.A.K. Othman
SLAC, Menlo Park, California, USA

Funding: This work was supported by Department of Energy contract DE-AC02-76SF00515.
We have measured the THz near-field in order to inform the design of improved THz-frequency accelerating structures. THz-frequency accelerating structures could provide the accelerating gradients needed for next generation particle accelerators with compact, GV/m-scale devices. One of the most promising THz generation techniques for accelerator applications is optical rectification in lithium niobate using the tilted pulse front method. However, accelerator applications are limited by significant losses during transport of THz radiation from the generating nonlinear crystal to the acceleration structure. In addition, the spectral properties of high-field THz sources make it difficult to couple THz radiation into accelerating structures. A better understanding of the THz near-field source properties is necessary for the optimization of THz transport and coupling. We have developed a technique for detailed measurement of the THz near-fields and used it to reconstruct the full temporal 3D THz near-field close to the LN emission face. Analysis of the results from this measurement will inform designs of novel structures for use in THz particle acceleration.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS015

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Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 03 July 2022

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WEIXSP1

Towards High-Repetition Rate Petawatt Laser Experiments with Cryogenic Jets Using a Mechanical Chopper System

1594

M. Rehwald, S. Assenbaum, C. Bernert, U. Schramm, K. Zeil
HZDR, Dresden, Germany
C.B. Curry, M. Gauthier, S.H. Glenzer, C. Schoenwaelder, F. Treffert
SLAC, Menlo Park, California, USA
S. Göde
EuXFEL, Schenefeld, Germany

Laser-plasma based ion accelerators require suitable high-repetition rate target systems that enable systematic studies at controlled plasma conditions and application-relevant particle flux. Self-refreshing, micrometer-sized cryogenic jets have proven to be an ideal target platform. Yet, operation of such systems in the harsh environmental conditions of high power laser induced plasma experiments have turned out to be challenging. Here we report on recent experiments deploying a cryogenic hydrogen jet as a source of pure proton beams generated with the PW-class ultrashort pulse laser DRACO. Damage to the jet target system during application of full energy laser shots was prevented by implementation of a mechanical chopper system interrupting the direct line of sight between the laser plasma interaction zone and the jet source.

Slides WEIXSP1 [4.896 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEIXSP1

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Received ※ 16 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 15 June 2022

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WEOXSP3

mm-Wave Structure Development for High Gradient Acceleration

1606

E.J.C. Snively, A.E. Gabriel, E.A. Nanni, M.A.K. Othman, A.V. Sy
SLAC, Menlo Park, California, USA
A.E. Gabriel
UCSC, Santa Cruz, California, USA

Funding: This work is supported by U.S. Department of Energy Contract No. DE-AC02-76SF00515, SLAC LDRD project 21-014 and Internal Agency Agreement 21-0007-IA (MIPR HR0011150657).
We report on the design of mm-wave accelerator structures operating near 100 GHz. Simulations of the cavity geometry and RF coupling are performed in ANSYS-HFSS and using SLAC’s parallel electromagnetic code suite ACE3P. We present experimental results for structures fabricated from copper, niobium, and copper plated with NbTiNi. We report on techniques for tuning these high frequency structures, as well as preliminary brazing results. A mm-wave accelerator cavity enables not only a high achievable gradient due to higher breakdown thresholds, but also reduced fill times which decrease pulsed heating and allow for higher repetition rates. We discuss the potential advantages and challenges for applications requiring ultra-compact structures.

Slides WEOXSP3 [1.800 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEOXSP3

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Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 16 June 2022

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