IPAC2016 - List of Authors (Zhang, Z.)

Paper	Title	Page
MOPOW044	Commissioning of the RadiaBeam / SLAC Dechirper	809
	M.W. Guetg, K.L.F. Bane, A. Brachmann, A.S. Fisher, Z. Huang, R.H. Iverson, P. Krejcik, A.A. Lutman, T.J. Maxwell, A. Novokhatski, G. Stupakov, J. Zemella, Z. Zhang SLAC, Menlo Park, California, USA M.A. Harrison, M. Ruelas RadiaBeam Systems, Santa Monica, California, USA J. Zemella DESY, Hamburg, Germany Z. Zhang TUB, Beijing, People's Republic of China
	We present results on the commissioning of the two-module RadiaBeam / SLAC dechirper system at LCLS. This is the first installation and measurement of a corrugated dechirper at high energy (4.4 - 13.3 GeV), short pulses (< 200 fs) and while observing its effect on an operational FEL. Both the transverse and longitudinal wakefields allow more flexible electron beam tailoring. We verify that, for a single module at a given gap, the strength of the longitudinal wake on axis and the dipole near the axis agree well with the theoretical values. Using direct longitudinal phase space mapping and X-ray FEL spectrum measurements we demonstrate the energy chirp control capabilities.
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MOPOW022	Model-based Algorithm to Tune the LCLS Optics	763
	Z. Zhang TUB, Beijing, People's Republic of China Y. Ding, X. Huang SLAC, Menlo Park, California, USA
	Transverse phase space matching of electron beam to the undulator optics is important for achieving good performance in free-electron lasers. Usually there are dedicated matching quadrupoles distributed in the beamline, by measuring the beam phase space the matching quadrupoles are calculated and adjusted to match to the designed Twiss parameters. Further adjustment of the quadrupoles to overcome collective effects or realistic beamline errors is typically required for performance improvement. In this paper, we studied a method to decompose the Twiss parameters for an independent control of the phase space. Mathematical analysis and numerical simulations are both presented to show that through combining the quadrupoles into some multi-knobs, we can control the Twiss parameters independently. We also show some experimental results at the LCLS.
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TUPOW017	Twin Bunches at the FACET-II	1778
	Z. Zhang TUB, Beijing, People's Republic of China M.J. Hogan, Z. Huang, A. Marinelli SLAC, Menlo Park, California, USA
	Twin electron bunches, generated, accelerated and compressed in the same acceleration bucket, have attracted a lot of interest in the free-electron lasers and wakefield acceleration. The recent successful experiment at the LCLS used twin bunches to generate two-color two x-ray pulses with tunable time delay and energy separation. In this note, we apply the twin bunches to the plasma wakefield acceleration. Numerical simulations show that based on the beamline of the FACET-II, we can generate high-intensity two electron bunches with time delay from ∼ 100 fs to picoseconds, which will benefit the control of high-gradient witness bunch acceleration in a plasma.
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TUPOW018	Tunable High-Intensity Electron Bunch Train Production Based on Nonlinear Longitudinal Space Charge Oscillation	1782
SUPSS016	use link to see paper's listing under its alternate paper code
	Z. Zhang, H.B. Chen, Y.-C. Du, W.-H. Huang, J. Shi, X.L. Su, C.-X. Tang, Q.L. Tian, D. Wang, W. Wang, L.X. Yan, L.M. Zheng, Z. Zhou TUB, Beijing, People's Republic of China W. Gai ANL, Argonne, Illinois, USA
	High peak current electron bunch trains with tunable terahertz (THz) spacing are produced and measured experimentally. An initial picosecond periodic modulation in the temporal profile of a relativistic electron beam is magnified by the longitudinal space charge forces. As opposed to trying to reduce its smearing effect for large beam current, we take advantages of the nonlinear space charge oscillation through controlling the plasma phase advance. The spacing of the bunch train can be varied continuously either by tuning the velocity bunching of a radio-frequency gun or by tuning the compression of a downstream magnetic chicane. The narrow-band μJ-level THz radiation from the bunch train are also measured with tunable central frequency of the spectral from ~0.5 THz to 1.6 THz. The bunch train measurements are consistent with the particle tracking simulations.
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WEPMY013	A Spatially Separated Two Frequency RF Gun Design for Beam Brightness Improvement	2572
	Z. Zhang, C.-X. Tang, Z. Zhang TUB, Beijing, People's Republic of China H.J. Qian LBNL, Berkeley, California, USA
	Recent theoretical and experimental studies shows that transverse beam brightness of photoinjector can be improved by cigar beam photoemission, and beam peak current are then increased with a RF buncher following the gun. We apply this concept to a S-band photoinjector by adding a harmonic RF buncher closely to a S-band RF gun, forming a compact spatially separated two frequency RF gun, targeting a 200 pC beam with emittance < 0.2 mm·mrad and 30 A peak current. Both S/X-band and S/C-band combinations are considered, and an optimized solution with 30 A peak current and 0.1 mm·mrad slice emittance are presented.
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THPOW042	Start-to-End Simulation on Terahertz Superradiation of Ultrashort Electron Bunch in an Undulator	4041
	X.L. Su, Y.-C. Du, W.-H. Huang, C.-X. Tang, D. Wang, L.X. Yan, Z. Zhang TUB, Beijing, People's Republic of China
	The narrowband, intense and frequency-tunable THz radiation can be generated by letting an ultrashort electron bunch pass through an undulator. Start-to-end simulation of terahertz radiation from electron bunch in an undulator is studied in this paper. GPT code is used to track particle distribution from the photocathode RF gun to the entrance of the undulator and Genesis 1.3 is applied to simulate the radiation. The simulation results agree well with theoretical predictions.
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Paper

Title

Page

Commissioning of the RadiaBeam / SLAC Dechirper

809

M.W. Guetg, K.L.F. Bane, A. Brachmann, A.S. Fisher, Z. Huang, R.H. Iverson, P. Krejcik, A.A. Lutman, T.J. Maxwell, A. Novokhatski, G. Stupakov, J. Zemella, Z. Zhang
SLAC, Menlo Park, California, USA
M.A. Harrison, M. Ruelas
RadiaBeam Systems, Santa Monica, California, USA
J. Zemella
DESY, Hamburg, Germany
Z. Zhang
TUB, Beijing, People's Republic of China

We present results on the commissioning of the two-module RadiaBeam / SLAC dechirper system at LCLS. This is the first installation and measurement of a corrugated dechirper at high energy (4.4 - 13.3 GeV), short pulses (< 200 fs) and while observing its effect on an operational FEL. Both the transverse and longitudinal wakefields allow more flexible electron beam tailoring. We verify that, for a single module at a given gap, the strength of the longitudinal wake on axis and the dipole near the axis agree well with the theoretical values. Using direct longitudinal phase space mapping and X-ray FEL spectrum measurements we demonstrate the energy chirp control capabilities.

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

MOPOW022

Model-based Algorithm to Tune the LCLS Optics

763

Z. Zhang
TUB, Beijing, People's Republic of China
Y. Ding, X. Huang
SLAC, Menlo Park, California, USA

Transverse phase space matching of electron beam to the undulator optics is important for achieving good performance in free-electron lasers. Usually there are dedicated matching quadrupoles distributed in the beamline, by measuring the beam phase space the matching quadrupoles are calculated and adjusted to match to the designed Twiss parameters. Further adjustment of the quadrupoles to overcome collective effects or realistic beamline errors is typically required for performance improvement. In this paper, we studied a method to decompose the Twiss parameters for an independent control of the phase space. Mathematical analysis and numerical simulations are both presented to show that through combining the quadrupoles into some multi-knobs, we can control the Twiss parameters independently. We also show some experimental results at the LCLS.

Export •

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

TUPOW017

Twin Bunches at the FACET-II

1778

Z. Zhang
TUB, Beijing, People's Republic of China
M.J. Hogan, Z. Huang, A. Marinelli
SLAC, Menlo Park, California, USA

Twin electron bunches, generated, accelerated and compressed in the same acceleration bucket, have attracted a lot of interest in the free-electron lasers and wakefield acceleration. The recent successful experiment at the LCLS used twin bunches to generate two-color two x-ray pulses with tunable time delay and energy separation. In this note, we apply the twin bunches to the plasma wakefield acceleration. Numerical simulations show that based on the beamline of the FACET-II, we can generate high-intensity two electron bunches with time delay from ∼ 100 fs to picoseconds, which will benefit the control of high-gradient witness bunch acceleration in a plasma.

Export •

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

TUPOW018

Tunable High-Intensity Electron Bunch Train Production Based on Nonlinear Longitudinal Space Charge Oscillation

1782

SUPSS016

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

Z. Zhang, H.B. Chen, Y.-C. Du, W.-H. Huang, J. Shi, X.L. Su, C.-X. Tang, Q.L. Tian, D. Wang, W. Wang, L.X. Yan, L.M. Zheng, Z. Zhou
TUB, Beijing, People's Republic of China
W. Gai
ANL, Argonne, Illinois, USA

High peak current electron bunch trains with tunable terahertz (THz) spacing are produced and measured experimentally. An initial picosecond periodic modulation in the temporal profile of a relativistic electron beam is magnified by the longitudinal space charge forces. As opposed to trying to reduce its smearing effect for large beam current, we take advantages of the nonlinear space charge oscillation through controlling the plasma phase advance. The spacing of the bunch train can be varied continuously either by tuning the velocity bunching of a radio-frequency gun or by tuning the compression of a downstream magnetic chicane. The narrow-band μJ-level THz radiation from the bunch train are also measured with tunable central frequency of the spectral from ~0.5 THz to 1.6 THz. The bunch train measurements are consistent with the particle tracking simulations.

Export •

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

WEPMY013

A Spatially Separated Two Frequency RF Gun Design for Beam Brightness Improvement

2572

Z. Zhang, C.-X. Tang, Z. Zhang
TUB, Beijing, People's Republic of China
H.J. Qian
LBNL, Berkeley, California, USA

Recent theoretical and experimental studies shows that transverse beam brightness of photoinjector can be improved by cigar beam photoemission, and beam peak current are then increased with a RF buncher following the gun. We apply this concept to a S-band photoinjector by adding a harmonic RF buncher closely to a S-band RF gun, forming a compact spatially separated two frequency RF gun, targeting a 200 pC beam with emittance < 0.2 mm·mrad and 30 A peak current. Both S/X-band and S/C-band combinations are considered, and an optimized solution with 30 A peak current and 0.1 mm·mrad slice emittance are presented.

Export •

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

THPOW042

Start-to-End Simulation on Terahertz Superradiation of Ultrashort Electron Bunch in an Undulator

4041

X.L. Su, Y.-C. Du, W.-H. Huang, C.-X. Tang, D. Wang, L.X. Yan, Z. Zhang
TUB, Beijing, People's Republic of China

The narrowband, intense and frequency-tunable THz radiation can be generated by letting an ultrashort electron bunch pass through an undulator. Start-to-end simulation of terahertz radiation from electron bunch in an undulator is studied in this paper. GPT code is used to track particle distribution from the photocathode RF gun to the entrance of the undulator and Genesis 1.3 is applied to simulate the radiation. The simulation results agree well with theoretical predictions.

Export •

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