IPAC2015 - List of Authors (Zholents, A.)

Paper	Title	Page
TUPMA042	THz Radiation Generation in a Multimode Wakefield Structure	1929
	S.P. Antipov, S.V. Baryshev, C.-J. Jing, A. Kanareykin Euclid TechLabs, LLC, Solon, Ohio, USA M.G. Fedurin BNL, Upton, Long Island, New York, USA W. Gai, D. Wang, A. Zholents ANL, Argonne, Ilinois, USA
	Funding: Work supported by the Department of Energy SBIR program under Contract #DE-SC0009571 A number of methods for producing sub-picosecond beam microbunching have been developed in recent years. A train of these bunches is capable of generating THz radiation via multiple mechanisms like transition, Cherenkov and undulator radiation. We utilize a bunch train with tunable spacing to selectively excite high order TM0n - like modes in a multimode structure. In this paper we present experimental results obtained at the Accelerator Test Facility of Brookhaven National Laboratory.
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TUPMA043	Experimental Test of Semiconductor Dechirper	1932
	S.P. Antipov, S.V. Baryshev, C.-J. Jing, A. Kanareykin Euclid TechLabs, LLC, Solon, Ohio, USA S. Baturin LETI, Saint-Petersburg, Russia M.G. Fedurin, K. Kusche, C. Swinson BNL, Upton, Long Island, New York, USA W. Gai, S. Stoupin, A. Zholents ANL, Argonne, Illinois, USA
	Funding: Work supported by the Department of Energy SBIR program under Contract #DE-SC0006299 We report the observation of de-chirping of a linearly chirped (in energy) electron bunch by its passage through a 4 inch long rectangular waveguide loaded with two silicon bars 0.25 inch thick and 0.5 inch wide. Silicon being a semiconductor has a conductivity that allows it to drain the charge fast in case if some electrons get intercepted by the dechirper. At the same time the conductivity is low enough for the skin depth to be large (on the order of 1 cm) making the silicon loaded waveguide a slow wave structure supporting wakefields that dechirp the beam.
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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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WEPWA052	RF Conditioning of the Photo-Cathode RF Gun at the Advanced Photon Source - NWA RF Measurements	2621
	T.L. Smith, N.P. DiMonte, A. Nassiri, Y.-E. Sun, A. Zholents ANL, Argonne, Ilinois, USA
	Funding: Work supported by U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357 A new S-band photo-cathode (PC) gun was recently installed and RF conditioned at the Advanced Photon Source (APS) Injector Test-stand (ITS) at Argonne National Lab (ANL). The APS PC gun is a LCLS type gun fabricated at SLAC [1]. The PC gun was delivered to the APS in October 2013 and installed in the APS ITS in December 2013. At ANL, we developed a new method of fast detection and mitigation of the gun’s internal arcs during the RF conditioning process to protect the gun from arc damage and to RF condition more efficiently. Here, we report the results of RF measurements for the PC gun and an Auto-Restart method for high power RF conditioning.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWA052
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WEPJE007	Simulation Studies of BBU Suppression Methods and Acceptable Tolerances in Dielectric Wakefield Accelerators	2685
	D.Y. Shchegolkov, E.I. Simakov LANL, Los Alamos, New Mexico, USA A. Zholents ANL, Argonne, Illinois, USA
	Funding: This work is supported by the U.S. Department of Energy through the Laboratory Directed Research and Development (LDRD) program at Los Alamos National Laboratory. The advantage of dielectric wakefield accelerators (DWAs) is the ability to achieve accelerating gradients well above the limits of conventional accelerators. However DWAs will also produce high transverse wakefields if the beam propagates off-center, which grow even faster than the accelerating gradient when the width of the beam channel is decreased.* It is highly important to suppress single beam breakup (BBU) instability in order for the beam to propagate long enough so that a reasonable amount of energy (e.g., 80%) from the drive bunch is extracted. In addition bending of the dielectric channel has a similar effect to off-center steering of the beam with the required tolerances on the channel straightness typically in a few micron range. For both rectangular and circular dielectric lined waveguides we use a FODO lattice with a tapered strength for suppression of BBU. We impose initial energy chirp on the drive beam to make use of the BNS damping. We change rectangular waveguide orientation by 90 degrees with a small step to make use of the quadrupole wakefield focusing. These and other techniques and tolerance requirements are discussed and simulation results are presented in this presentation. * C. Li, W. Gai, C. Jing, J.G. Power, C.X. Tang, and A. Zholents, High gradient limits due to single bunch beam breakup in a collinear dielectric wakefield accelerator, PRSTAB 17, 091302 (2014).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPJE007
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WEPTY018	Analysis of a Quasi-waveguide Multicell Resonator for SPX	3299
	M.H. Awida, I.V. Gonin, T.N. Khabiboulline, A. Lunin, V.P. Yakovlev Fermilab, Batavia, Illinois, USA A. Zholents ANL, Argonne, Ilinois, USA
	A compact deflecting cavity is needed for the Short Pulse X-rays (SPX) at the Advanced Photon Source (APS) of Argonne national laboratory. The deflecting cavity has to quite efficient providing a 2 MV kick voltage and satisfying stringent requirements on aperture size and total cavity length. Meanwhile, the cavity should allow operation up to 100 mT peak surface magnetic field before quenching. In this paper, we report on the latest analysis carried out on the cavity structure to investigate frequency sensitivity to pressure fluctuations, frequency sensitivity to tuning forces, modal frequency, and wakefield losses.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY018
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Paper

Title

Page

THz Radiation Generation in a Multimode Wakefield Structure

1929

S.P. Antipov, S.V. Baryshev, C.-J. Jing, A. Kanareykin
Euclid TechLabs, LLC, Solon, Ohio, USA
M.G. Fedurin
BNL, Upton, Long Island, New York, USA
W. Gai, D. Wang, A. Zholents
ANL, Argonne, Ilinois, USA

Funding: Work supported by the Department of Energy SBIR program under Contract #DE-SC0009571
A number of methods for producing sub-picosecond beam microbunching have been developed in recent years. A train of these bunches is capable of generating THz radiation via multiple mechanisms like transition, Cherenkov and undulator radiation. We utilize a bunch train with tunable spacing to selectively excite high order TM0n - like modes in a multimode structure. In this paper we present experimental results obtained at the Accelerator Test Facility of Brookhaven National Laboratory.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPMA042

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

TUPMA043

Experimental Test of Semiconductor Dechirper

1932

S.P. Antipov, S.V. Baryshev, C.-J. Jing, A. Kanareykin
Euclid TechLabs, LLC, Solon, Ohio, USA
S. Baturin
LETI, Saint-Petersburg, Russia
M.G. Fedurin, K. Kusche, C. Swinson
BNL, Upton, Long Island, New York, USA
W. Gai, S. Stoupin, A. Zholents
ANL, Argonne, Illinois, USA

Funding: Work supported by the Department of Energy SBIR program under Contract #DE-SC0006299
We report the observation of de-chirping of a linearly chirped (in energy) electron bunch by its passage through a 4 inch long rectangular waveguide loaded with two silicon bars 0.25 inch thick and 0.5 inch wide. Silicon being a semiconductor has a conductivity that allows it to drain the charge fast in case if some electrons get intercepted by the dechirper. At the same time the conductivity is low enough for the skin depth to be large (on the order of 1 cm) making the silicon loaded waveguide a slow wave structure supporting wakefields that dechirp the beam.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPMA043

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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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WEPWA052

RF Conditioning of the Photo-Cathode RF Gun at the Advanced Photon Source - NWA RF Measurements

2621

T.L. Smith, N.P. DiMonte, A. Nassiri, Y.-E. Sun, A. Zholents
ANL, Argonne, Ilinois, USA

Funding: Work supported by U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-06CH11357
A new S-band photo-cathode (PC) gun was recently installed and RF conditioned at the Advanced Photon Source (APS) Injector Test-stand (ITS) at Argonne National Lab (ANL). The APS PC gun is a LCLS type gun fabricated at SLAC [1]. The PC gun was delivered to the APS in October 2013 and installed in the APS ITS in December 2013. At ANL, we developed a new method of fast detection and mitigation of the gun’s internal arcs during the RF conditioning process to protect the gun from arc damage and to RF condition more efficiently. Here, we report the results of RF measurements for the PC gun and an Auto-Restart method for high power RF conditioning.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWA052

Export •

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

WEPJE007

Simulation Studies of BBU Suppression Methods and Acceptable Tolerances in Dielectric Wakefield Accelerators

2685

D.Y. Shchegolkov, E.I. Simakov
LANL, Los Alamos, New Mexico, USA
A. Zholents
ANL, Argonne, Illinois, USA

Funding: This work is supported by the U.S. Department of Energy through the Laboratory Directed Research and Development (LDRD) program at Los Alamos National Laboratory.
The advantage of dielectric wakefield accelerators (DWAs) is the ability to achieve accelerating gradients well above the limits of conventional accelerators. However DWAs will also produce high transverse wakefields if the beam propagates off-center, which grow even faster than the accelerating gradient when the width of the beam channel is decreased.* It is highly important to suppress single beam breakup (BBU) instability in order for the beam to propagate long enough so that a reasonable amount of energy (e.g., 80%) from the drive bunch is extracted. In addition bending of the dielectric channel has a similar effect to off-center steering of the beam with the required tolerances on the channel straightness typically in a few micron range. For both rectangular and circular dielectric lined waveguides we use a FODO lattice with a tapered strength for suppression of BBU. We impose initial energy chirp on the drive beam to make use of the BNS damping. We change rectangular waveguide orientation by 90 degrees with a small step to make use of the quadrupole wakefield focusing. These and other techniques and tolerance requirements are discussed and simulation results are presented in this presentation.
* C. Li, W. Gai, C. Jing, J.G. Power, C.X. Tang, and A. Zholents, High gradient limits due to single bunch beam breakup in a collinear dielectric wakefield accelerator, PRSTAB 17, 091302 (2014).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPJE007

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WEPTY018

Analysis of a Quasi-waveguide Multicell Resonator for SPX

3299

M.H. Awida, I.V. Gonin, T.N. Khabiboulline, A. Lunin, V.P. Yakovlev
Fermilab, Batavia, Illinois, USA
A. Zholents
ANL, Argonne, Ilinois, USA

A compact deflecting cavity is needed for the Short Pulse X-rays (SPX) at the Advanced Photon Source (APS) of Argonne national laboratory. The deflecting cavity has to quite efficient providing a 2 MV kick voltage and satisfying stringent requirements on aperture size and total cavity length. Meanwhile, the cavity should allow operation up to 100 mT peak surface magnetic field before quenching. In this paper, we report on the latest analysis carried out on the cavity structure to investigate frequency sensitivity to pressure fluctuations, frequency sensitivity to tuning forces, modal frequency, and wakefield losses.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPTY018

Export •

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