IPAC2015 - List of Authors (Piot, P.)

Paper	Title	Page
MOPWA009	Channeling Radiation Experiment at Fermilab ASTA	95
	D. Mihalcea, P. Piot Northern Illinois University, DeKalb, Illinois, USA D.R. Edstrom, P. Piot, T. Sen Fermilab, Batavia, Illinois, USA W.D. Rush KU, Lawrence, Kansas, USA
	Electron beams with moderate energy ranging from 4 to 50 MeV can be used to produce x-rays through the Channeling Radiation (CR) mechanism. Typically, the x-ray spectrum from these sources extends up to 140 keV and this range covers the demand for most practical applications. The parameters of the electron beam determine the spectral brilliance of the x-ray source. The electron beam produced at the Fermilab new facility Advanced Superconducting Test Accelerator (ASTA) meets the requirements to assemble an experimental high brilliance CR x-ray source. In the first stage of the experiment the energy of the beam is 20 MeV and due to the very low emittance (100 nm) at low bunch charge (20 pC) the expected average brilliance of the x-ray source is 0.8x10⁷ photons/[s-(mm-mrad)²-0.1%BW]. In the second stage of the experiment the beam energy will be increased to 50 MeV and consequently the average brilliance will be 4.8x10⁸ photons/[s-(mm-mrad)²-0.1%BW]. Also, the x-ray spectrum will be extended from about 30 keV to 140 keV.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA009
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MOPMA049	Development of a Single-pass Amplifier for an Optical Stochastic Cooling Proof-of-principle Experiment at Fermilab's IOTA facility	659
	M.B. Andorf, P. Piot Northern Illinois University, DeKalb, Illinois, USA V.A. Lebedev, P. Piot Fermilab, Batavia, Illinois, USA
	Optical stochastic cooling (OSC) is a method of beam cooling which is expected to provide cooling rates orders of magnitude larger than ordinary stochastic cooling. Light from an undulator (the pickup) is amplified and fed back onto the particle beam via another undulator (the kicker). Fermilab is currently exploring a possible proof-of-principle experiment of the OSC at the integrable-optics test accelerator (IOTA) ring. To implement effective OSC a good correction of phase distortions in the entire band of the optical amplifier is required. In this contribution we present progress in experimental characterization of phase distortions associated to a Titanium Sapphire crystal laser-gain medium (a possible candidate gain medium for the OSC experiment to be performed at IOTA). We also discuss a possible option for a mid-IR amplifier.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMA049
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TUPJE080	First Beam and High-Gradient Cryomodule Commissioning Results of the Advanced Superconducting Test Accelerator at Fermilab	1831
	D.J. Crawford, C.M. Baffes, D.R. Broemmelsiek, K. Carlson, B.E. Chase, E. Cullerton, J.S. Diamond, N. Eddy, D.R. Edstrom, E.R. Harms, A. Hocker, C.D. Joe, A.L. Klebaner, M.J. Kucera, J.R. Leibfritz, A.H. Lumpkin, J.N. Makara, S. Nagaitsev, O.A. Nezhevenko, D.J. Nicklaus, L.E. Nobrega, P. Piot, P.S. Prieto, J. Reid, J. Ruan, J.K. Santucci, W.M. Soyars, G. Stancari, D. Sun, R.M. Thurman-Keup, A. Valishev, A. Warner, S.J. Wesseln Fermilab, Batavia, Illinois, USA
	Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy. The advanced superconducting test accelerator at Fermilab has accelerated electrons to 20 MeV and, separately, the International Linear Collider (ILC) style 8-cavity cryomodule has achieved the ILC performance milestone of 31.5 MV/m per cavity. When fully completed, the accelerator will consist of a photoinjector, one ILC-type cryomodule, multiple accelerator R&D beamlines, and a downstream beamline to inject 300 MeV electrons into the Integrable Optics Test Accelerator (IOTA). We report on the results of first beam, the achievement of our cryomodule to ILC gradient specifications, and near-term future plans for the facility.
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TUPMA007	Numerical Investigation of a Cascaded Longitudinal Space-Charge Amplifier at the Fermilab's Advanced Superconducting Test Accelerator	1850
	A. Halavanau, P. Piot Northern Illinois University, DeKalb, Illinois, USA P. Piot Fermilab, Batavia, Illinois, USA
	In a cascaded longitudinal space-charge amplifier (LSCA), initial density noise in a relativistic e-beam is amplified via the interplay of longitudinal space charge forces and properly located dispersive sections. This type of amplification process was shown to potentially result in large final density modulations * compatible with the production of broadband electromagnetic radiation. The technique was recently demonstrated in the optical domain *. In this paper we investigate, via numerical simulations, the performances of a cascaded LSCA beamline at the Fermilab's Advanced Superconducting Test Accelerator (ASTA). We especially explore the properties of the produced broadband radiation. Our studies have been conducted with an effective three-dimensional space-charge algorithm. Dohlus, M. et al. Proc. SPIE 8779. doi:10.1117/12.2017369 ** Marinelli, A. et al. Phys. Rev. Lett. 110, 264802 (2013)
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPMA007
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TUPMA008	Numerical Study of Three Dimensional Effects in Longitudinal Space-Charge Impedance	1853
	A. Halavanau, P. Piot Northern Illinois University, DeKalb, Illinois, USA P. Piot Fermilab, Batavia, Illinois, USA
	Longitudinal space-charge (LSC) effects are generally considered as detrimental in free-electron lasers as they can seed instabilities. Such "microbunching instabilities" were recently shown to be potentially useful to support the generation of broadband coherent radiation pulses. Therefore there has been an increasing interest in devising accelerator beamlines capable of sustaining this LSC instability as a mechanism to produce a coherent light source. To date most of these studies have been carried out with a one-dimensional impedance model for the LSC. In this paper we use a N-body "Barnes-Hut" algorithm * to simulate the 3D space charge force in the beam combined with Elegant ** and explore the limitation of the 1D model often used. * Barnes, J. & Hut, P., Nature 324, 446-449, 1986. ** Borland, M., Advanced Photon Source LS-287, 2000.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPMA008
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WEAD2	Experimental Results of Carbon NanoTube Cathodes inside RF Environment	2475
	L. Faillace, S. Boucher, J.J. Hartzell, A.Y. Murokh RadiaBeam, Santa Monica, California, USA D. Mihalcea, P. Piot, J.C.T. Thangaraj Fermilab, Batavia, Illinois, USA H. Panuganti Northern Illinois University, DeKalb, Illinois, USA
	Funding: Work supported by US DOE SBIR grant # DE-SC0004459 Carbon Nano Tubes (CNT’s) as field-emitters have been investigated for more than two decades and can produce relatively low emittance electron beams for a given cathode size. Unlike thermionic cathodes, CNT cathodes are able to produce electrons at room temperature and relatively low electric field (a few MV/m). In collaboration with FermiLab, we have recently tested CNT cathodes both with DC and RF fields. We observed a beam current close to 1A with a ~1cm² CNT cathode inside an L-band RF gun. Steady operation was obtained up to 650 mA and the measured current vs. surface field plot showed perfect agreement with the Fowler-Nordheim distribution.
	Slides WEAD2 [10.445 MB]
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WEPWA035	Initial EEX-based Bunch Shaping Experiment Results at the Argonne Wakefield Accelerator Facility	2575
	G. Ha, M.-H. Cho, W. Namkung POSTECH, Pohang, Kyungbuk, Republic of Korea M.E. Conde, D.S. Doran, W. Gai, G. Ha, C.-J. Jing, K.-J. Kim, W. Liu, J.G. Power, Y.-E. Sun, C. Whiteford, E.E. Wisniewski, A. Zholents ANL, Argonne, Illinois, USA C.-J. Jing Euclid TechLabs, LLC, Solon, Ohio, USA P. Piot Fermilab, Batavia, Illinois, USA
	Funding: This work is partly supported by POSTECH BK²¹⁺ and Argonne National Laboratory A program is under development at Argonne National Laboratory to use an emittance exchange (EEX) beamline to perform longitudinal bunch shaping (LBS). The double dog-leg EEX beamline was recently installed at the Argonne Wakefield Accelerator (AWA) and the goals of the proof-of-principle experiment are to demonstrate LBS and characterize its deformations from the ideal shape due to higher-order and collective effects. The LBS beamline at the AWA consists of insert-able transverse masks mounted on an actuator and four quadrupoles (to manipulate the transverse phase space) before the EEX beamline, which consists of two identical dog-legs and a deflecting cavity. The mask and input beam parameters are varied during the experiment to explore the shaping capability and clarify the deformation sources and their mitigation. Progress on the commissioning of the LBS beamline, initial experimental data and benchmarks to GPT simulations will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWA035
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WEPWA070	Considerations for an Efficient Terahertz-driven Electron Gun	2664
	F. Lemery, P. Piot Northern Illinois University, DeKalb, Illinois, USA P. Piot Fermilab, Batavia, Illinois, USA
	We investigate a dispersion-controlled-acceleration scheme of low-energy electrons to mitigate phase slipping using a tapered dielectric lined waveguide (DLW). Our approach matches the velocity of an electron being accelerated in a slab-symmetric structure in a constant electric field. We also present first experimental results of a THz pulse propagating in a slab-symmetric DLW.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWA070
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WEPWA071	A Compact X-Ray Source Based on a Low-Energy Beam-Driven Wakefield Accelerator	2667
	F. Lemery, D. Mihalcea, P. Piot Northern Illinois University, DeKalb, Illinois, USA K. Chouffani IAC, Pocatello, Idaho, USA P. Piot Fermilab, Batavia, Illinois, USA
	Accelerator-based X-ray sources have led to many scientific breakthroughs. Yet, their limited availability in large national laboratory settings due to the required infrastructure is a major limitation to their disseminations to a larger user community. In this contribution we explore the use of a low-energy electron beam produced out of a photoinjector coupled to a dielectric structure to produce a higher energy (~10-20 MeV) beam via a beam-driven acceleration scheme. The accelerated beam can then be used to produce X-ray via inverse Compton scattering. This paper discusses the concept and presents start-to-end simulations of the proposed setup.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWA071
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WEPJE019	Simulations of Field-Emission Electron Beams from CNT Cathodes in RF Photoinjectors	2711
	D. Mihalcea, H. Panuganti, P. Piot Northern Illinois University, DeKalb, Illinois, USA L. Faillace RadiaBeam, Santa Monica, California, USA P. Piot, J.C.T. Thangaraj Fermilab, Batavia, Illinois, USA
	Average field emission currents of up to 700 mA were produced by Carbon Nano Tube (CNT) cathodes in a 1.3 GHz RF gun at Fermilab High Brightness Electron Source Lab. (HBESL). The CNT cathodes were manufactured at Xintek and tested under DC conditions at RadiaBeam. The electron beam intensity as well as the other beam properties are directly related to the time-dependent electric field at the cathode and the geometry of the RF gun. This report focuses on simulations of the electron beam generated through field-emission and the results are compared with experimental measurements. These simulations were performed with the time-dependent Particle In Cell (PIC) code WARP.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPJE019
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MOPMA051	Generation of Modulated Bunch Using a Masked Chicane for Beam-Driven Acceleration Experiments at ASTA	666
	Y.-M. Shin, P. Piot Northern Illinois University, DeKalb, Illinois, USA D.R. Broemmelsiek, D.J. Crawford, A.H. Lumpkin Fermilab, Batavia, Illinois, USA A.T. Green Northern Illinois Univerity, Dekalb, Illinois, USA
	Funding: This work was supported by the DOE contract No. DEAC02-07CH11359 to the Fermi Research Alliance LLC. Longitudinal density modulations on electron beams can improve machine performance of beam-driven accelerators and FELs with resonance beam-wave coupling . The sub-ps beam modulation has been studied with a masked chicane * *** by the analytic model and simulations with the beam parameters of the Advanced Superconducting Test Accelerator (ASTA) in Fermilab. With the nominal 50 MeV chicane parameters and 3 ps bunch length, the analytic model showed that a slit-mask with slit period 900 um and aperture width 300 μm generates about 100-um modulation periodicity with 2.4% correlated energy spread. With the designed slit mask and a 3 ps bunch, particle-in-cell simulations (CST-PS), including nonlinear energy distributions, space charge force, and coherent synchrotron radiation (CSR) effect, also result in ~ 100 um of longitudinal modulation. The beam modulation has been extensively examined with three different beam conditions, 0.25, 1 , and 3.2 nC, by extended 3D tracking simulations (Elegant). The modulated bunch generation will be tested by a slit-mask installed at the chicane of the ASTA 50-MeV-injector beamline for beam-driven acceleration experiments. * E. Kallos, Southern California 2008 D. C. Nguyen, B. E. Carlston, NIMA 375, 597 (1996) * P. Muggli, V. Yakimenko, M. Babzien, E. Kallos, and K. P. Kusche, PRL 101, 054801 (2008)
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Paper

Title

Page

Channeling Radiation Experiment at Fermilab ASTA

95

D. Mihalcea, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
D.R. Edstrom, P. Piot, T. Sen
Fermilab, Batavia, Illinois, USA
W.D. Rush
KU, Lawrence, Kansas, USA

Electron beams with moderate energy ranging from 4 to 50 MeV can be used to produce x-rays through the Channeling Radiation (CR) mechanism. Typically, the x-ray spectrum from these sources extends up to 140 keV and this range covers the demand for most practical applications. The parameters of the electron beam determine the spectral brilliance of the x-ray source. The electron beam produced at the Fermilab new facility Advanced Superconducting Test Accelerator (ASTA) meets the requirements to assemble an experimental high brilliance CR x-ray source. In the first stage of the experiment the energy of the beam is 20 MeV and due to the very low emittance (100 nm) at low bunch charge (20 pC) the expected average brilliance of the x-ray source is 0.8x10⁷ photons/[s-(mm-mrad)²-0.1%BW]. In the second stage of the experiment the beam energy will be increased to 50 MeV and consequently the average brilliance will be 4.8x10⁸ photons/[s-(mm-mrad)²-0.1%BW]. Also, the x-ray spectrum will be extended from about 30 keV to 140 keV.

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MOPMA049

Development of a Single-pass Amplifier for an Optical Stochastic Cooling Proof-of-principle Experiment at Fermilab's IOTA facility

659

M.B. Andorf, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
V.A. Lebedev, P. Piot
Fermilab, Batavia, Illinois, USA

Optical stochastic cooling (OSC) is a method of beam cooling which is expected to provide cooling rates orders of magnitude larger than ordinary stochastic cooling. Light from an undulator (the pickup) is amplified and fed back onto the particle beam via another undulator (the kicker). Fermilab is currently exploring a possible proof-of-principle experiment of the OSC at the integrable-optics test accelerator (IOTA) ring. To implement effective OSC a good correction of phase distortions in the entire band of the optical amplifier is required. In this contribution we present progress in experimental characterization of phase distortions associated to a Titanium Sapphire crystal laser-gain medium (a possible candidate gain medium for the OSC experiment to be performed at IOTA). We also discuss a possible option for a mid-IR amplifier.

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TUPJE080

First Beam and High-Gradient Cryomodule Commissioning Results of the Advanced Superconducting Test Accelerator at Fermilab

1831

D.J. Crawford, C.M. Baffes, D.R. Broemmelsiek, K. Carlson, B.E. Chase, E. Cullerton, J.S. Diamond, N. Eddy, D.R. Edstrom, E.R. Harms, A. Hocker, C.D. Joe, A.L. Klebaner, M.J. Kucera, J.R. Leibfritz, A.H. Lumpkin, J.N. Makara, S. Nagaitsev, O.A. Nezhevenko, D.J. Nicklaus, L.E. Nobrega, P. Piot, P.S. Prieto, J. Reid, J. Ruan, J.K. Santucci, W.M. Soyars, G. Stancari, D. Sun, R.M. Thurman-Keup, A. Valishev, A. Warner, S.J. Wesseln
Fermilab, Batavia, Illinois, USA

Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
The advanced superconducting test accelerator at Fermilab has accelerated electrons to 20 MeV and, separately, the International Linear Collider (ILC) style 8-cavity cryomodule has achieved the ILC performance milestone of 31.5 MV/m per cavity. When fully completed, the accelerator will consist of a photoinjector, one ILC-type cryomodule, multiple accelerator R&D beamlines, and a downstream beamline to inject 300 MeV electrons into the Integrable Optics Test Accelerator (IOTA). We report on the results of first beam, the achievement of our cryomodule to ILC gradient specifications, and near-term future plans for the facility.

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TUPMA007

Numerical Investigation of a Cascaded Longitudinal Space-Charge Amplifier at the Fermilab's Advanced Superconducting Test Accelerator

1850

A. Halavanau, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
P. Piot
Fermilab, Batavia, Illinois, USA

In a cascaded longitudinal space-charge amplifier (LSCA), initial density noise in a relativistic e-beam is amplified via the interplay of longitudinal space charge forces and properly located dispersive sections. This type of amplification process was shown to potentially result in large final density modulations * compatible with the production of broadband electromagnetic radiation. The technique was recently demonstrated in the optical domain **. In this paper we investigate, via numerical simulations, the performances of a cascaded LSCA beamline at the Fermilab's Advanced Superconducting Test Accelerator (ASTA). We especially explore the properties of the produced broadband radiation. Our studies have been conducted with an effective three-dimensional space-charge algorithm.
* Dohlus, M. et al. Proc. SPIE 8779. doi:10.1117/12.2017369
** Marinelli, A. et al. Phys. Rev. Lett. 110, 264802 (2013)

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TUPMA008

Numerical Study of Three Dimensional Effects in Longitudinal Space-Charge Impedance

1853

A. Halavanau, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
P. Piot
Fermilab, Batavia, Illinois, USA

Longitudinal space-charge (LSC) effects are generally considered as detrimental in free-electron lasers as they can seed instabilities. Such "microbunching instabilities" were recently shown to be potentially useful to support the generation of broadband coherent radiation pulses. Therefore there has been an increasing interest in devising accelerator beamlines capable of sustaining this LSC instability as a mechanism to produce a coherent light source. To date most of these studies have been carried out with a one-dimensional impedance model for the LSC. In this paper we use a N-body "Barnes-Hut" algorithm * to simulate the 3D space charge force in the beam combined with Elegant ** and explore the limitation of the 1D model often used.
* Barnes, J. & Hut, P., Nature 324, 446-449, 1986.
** Borland, M., Advanced Photon Source LS-287, 2000.

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WEAD2

Experimental Results of Carbon NanoTube Cathodes inside RF Environment

2475

L. Faillace, S. Boucher, J.J. Hartzell, A.Y. Murokh
RadiaBeam, Santa Monica, California, USA
D. Mihalcea, P. Piot, J.C.T. Thangaraj
Fermilab, Batavia, Illinois, USA
H. Panuganti
Northern Illinois University, DeKalb, Illinois, USA

Funding: Work supported by US DOE SBIR grant # DE-SC0004459
Carbon Nano Tubes (CNT’s) as field-emitters have been investigated for more than two decades and can produce relatively low emittance electron beams for a given cathode size. Unlike thermionic cathodes, CNT cathodes are able to produce electrons at room temperature and relatively low electric field (a few MV/m). In collaboration with FermiLab, we have recently tested CNT cathodes both with DC and RF fields. We observed a beam current close to 1A with a ~1cm² CNT cathode inside an L-band RF gun. Steady operation was obtained up to 650 mA and the measured current vs. surface field plot showed perfect agreement with the Fowler-Nordheim distribution.

Slides WEAD2 [10.445 MB]

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WEPWA035

Initial EEX-based Bunch Shaping Experiment Results at the Argonne Wakefield Accelerator Facility

2575

G. Ha, M.-H. Cho, W. Namkung
POSTECH, Pohang, Kyungbuk, Republic of Korea
M.E. Conde, D.S. Doran, W. Gai, G. Ha, C.-J. Jing, K.-J. Kim, W. Liu, J.G. Power, Y.-E. Sun, C. Whiteford, E.E. Wisniewski, A. Zholents
ANL, Argonne, Illinois, USA
C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA
P. Piot
Fermilab, Batavia, Illinois, USA

Funding: This work is partly supported by POSTECH BK²¹⁺ and Argonne National Laboratory
A program is under development at Argonne National Laboratory to use an emittance exchange (EEX) beamline to perform longitudinal bunch shaping (LBS). The double dog-leg EEX beamline was recently installed at the Argonne Wakefield Accelerator (AWA) and the goals of the proof-of-principle experiment are to demonstrate LBS and characterize its deformations from the ideal shape due to higher-order and collective effects. The LBS beamline at the AWA consists of insert-able transverse masks mounted on an actuator and four quadrupoles (to manipulate the transverse phase space) before the EEX beamline, which consists of two identical dog-legs and a deflecting cavity. The mask and input beam parameters are varied during the experiment to explore the shaping capability and clarify the deformation sources and their mitigation. Progress on the commissioning of the LBS beamline, initial experimental data and benchmarks to GPT simulations will be presented.

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WEPWA070

Considerations for an Efficient Terahertz-driven Electron Gun

2664

F. Lemery, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
P. Piot
Fermilab, Batavia, Illinois, USA

We investigate a dispersion-controlled-acceleration scheme of low-energy electrons to mitigate phase slipping using a tapered dielectric lined waveguide (DLW). Our approach matches the velocity of an electron being accelerated in a slab-symmetric structure in a constant electric field. We also present first experimental results of a THz pulse propagating in a slab-symmetric DLW.

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WEPWA071

A Compact X-Ray Source Based on a Low-Energy Beam-Driven Wakefield Accelerator

2667

F. Lemery, D. Mihalcea, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
K. Chouffani
IAC, Pocatello, Idaho, USA
P. Piot
Fermilab, Batavia, Illinois, USA

Accelerator-based X-ray sources have led to many scientific breakthroughs. Yet, their limited availability in large national laboratory settings due to the required infrastructure is a major limitation to their disseminations to a larger user community. In this contribution we explore the use of a low-energy electron beam produced out of a photoinjector coupled to a dielectric structure to produce a higher energy (~10-20 MeV) beam via a beam-driven acceleration scheme. The accelerated beam can then be used to produce X-ray via inverse Compton scattering. This paper discusses the concept and presents start-to-end simulations of the proposed setup.

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WEPJE019

Simulations of Field-Emission Electron Beams from CNT Cathodes in RF Photoinjectors

2711

D. Mihalcea, H. Panuganti, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
L. Faillace
RadiaBeam, Santa Monica, California, USA
P. Piot, J.C.T. Thangaraj
Fermilab, Batavia, Illinois, USA

Average field emission currents of up to 700 mA were produced by Carbon Nano Tube (CNT) cathodes in a 1.3 GHz RF gun at Fermilab High Brightness Electron Source Lab. (HBESL). The CNT cathodes were manufactured at Xintek and tested under DC conditions at RadiaBeam. The electron beam intensity as well as the other beam properties are directly related to the time-dependent electric field at the cathode and the geometry of the RF gun. This report focuses on simulations of the electron beam generated through field-emission and the results are compared with experimental measurements. These simulations were performed with the time-dependent Particle In Cell (PIC) code WARP.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPJE019

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MOPMA051

Generation of Modulated Bunch Using a Masked Chicane for Beam-Driven Acceleration Experiments at ASTA

666

Y.-M. Shin, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
D.R. Broemmelsiek, D.J. Crawford, A.H. Lumpkin
Fermilab, Batavia, Illinois, USA
A.T. Green
Northern Illinois Univerity, Dekalb, Illinois, USA

Funding: This work was supported by the DOE contract No. DEAC02-07CH11359 to the Fermi Research Alliance LLC.
Longitudinal density modulations on electron beams can improve machine performance of beam-driven accelerators and FELs with resonance beam-wave coupling *. The sub-ps beam modulation has been studied with a masked chicane ** *** by the analytic model and simulations with the beam parameters of the Advanced Superconducting Test Accelerator (ASTA) in Fermilab. With the nominal 50 MeV chicane parameters and 3 ps bunch length, the analytic model showed that a slit-mask with slit period 900 um and aperture width 300 μm generates about 100-um modulation periodicity with 2.4% correlated energy spread. With the designed slit mask and a 3 ps bunch, particle-in-cell simulations (CST-PS), including nonlinear energy distributions, space charge force, and coherent synchrotron radiation (CSR) effect, also result in ~ 100 um of longitudinal modulation. The beam modulation has been extensively examined with three different beam conditions, 0.25, 1 , and 3.2 nC, by extended 3D tracking simulations (Elegant). The modulated bunch generation will be tested by a slit-mask installed at the chicane of the ASTA 50-MeV-injector beamline for beam-driven acceleration experiments.
* E. Kallos, Southern California 2008
** D. C. Nguyen, B. E. Carlston, NIMA 375, 597 (1996)
*** P. Muggli, V. Yakimenko, M. Babzien, E. Kallos, and K. P. Kusche, PRL 101, 054801 (2008)

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMA051

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