IPAC2016 - List of Authors (Huang, Z.)

Paper	Title	Page
MOPOW039	An Oscillator Configuration for Full Realization of Hard X-ray Free Electron Laser	801
	K.-J. Kim, T. Kolodziej, R.R. Lindberg, D. Shu, Yu. Shvyd'ko, S. Stoupin ANL, Argonne, Ilinois, USA V.D. Blank, S. Terentiev TISNCM, Troitsk, Russia Y. Ding, W.M. Fawley, J.B. Hastings, Z. Huang, J. Krzywinski, G. Marcus, T.J. Maxwell SLAC, Menlo Park, California, USA N.A. Medvedev CFEL, Hamburg, Germany W. Qin PKU, Beijing, People's Republic of China J. Zemella DESY, Hamburg, Germany
	Funding: Work at ANL supported under US Department of Energy contract DE-AC02-76SF00515 and at SLAC by the U.S. Department of Energy, Office of Science, under Contract No. DE-ACO2-O6CH11357 An X-ray free electron laser can be built in an oscillator (XFELO) configuration by employing an X-ray cavity with Bragg mirrors such as diamond. An XFELO at the 5th harmonic frequency may be implemented at the LCLS II using its 4 GeV superconducting linac. The XFELO will provide stable, coherent, high-spectral-purity hard x-rays. In addition, portions of its output may be enhanced by the LCLS amplifier for stable pulses of ultrashort duration determined by the electron bunch length. Much progress has been made recently on the feasibility of an XFELO: Analytical and numerical methods have been developed to compute the performance of a harmonic XFELO. The energy spread requirement over a sufficient length of the bunch can be met by temporal shaping of the photo-cathode drive laser. Experiments at the APS have shown that Be-compound refractive lenses are suitable for a low-loss focusing and that the synthetic diamond crystals can withstand the intense x-ray exposure, in accord with estimates based on molecular dynamics considerations. A strain-free mounting of thin diamond crystal (< 100 microns) can be realized by shaping a thick diamond into a blind alley*. R. R. Lindberg et al., PRSTAB 1010701 (2011) W. Qin et al., this conference * N. Medvedev et al., Phys. Rev. B 88, 224304 (2013) **** S. Terentyev, private communication
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW039
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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.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW044
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MOPOW045	Measurement of Advanced Dispersion-based Beam-tilt Correction	813
	M.W. Guetg, F.-J. Decker, Y. Ding, P. Emma, Z. Huang, T.J. Maxwell SLAC, Menlo Park, California, USA
	Funding: DOE contract \#DE-AC02-76SF00515 Free electron lasers in the X-ray regime require a good slice alignment along the electron bunch to achieve their best performance. A transverse beam slice shift reduces this alignment and spoils projected emittance and optics matching. Coherent synchrotron radiation, specifically for over-compression going through full compression, and transverse wakefields are major contributors to this. In the case of the large-bandwidth operation, with a strong energy chirp on the bunch, this misalignments furthermore reduce the spectral bandwidth of the FEL pulse. Well-defined manipulation of dispersion allows to compensate for this slice centroid shifts, therefore enhancing lasing power and in case of the large bandwidth mode, spectral bandwidth. This work shows the first application of this correction on an X-ray FEL resulting in increase in beam-power and bandwidth.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW045
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MOPOW046	RadiaBeam/SLAC Dechirper as a Passive Deflector	817
	A. Novokhatski, A. Brachmann, M. Dal Forno, V.A. Dolgashev, A.S. Fisher, M.W. Guetg, Z. Huang, R.H. Iverson, P. Krejcik, A.A. Lutman, T.J. Maxwell SLAC, Menlo Park, California, USA J. Zemella DESY, Hamburg, Germany
	Funding: This work was supported by Department of Energy Contract No. DE-AC02-76SF00515. We discuss the possibility of using the RadiBeam/SLAC dechirper recently installed at LCLS for measuring the bunch length of very short bunches, less than 1 fs perhaps as short as 100 atto second. When a bunch travels close to one of the jaws the particles of the bunch get a transverse kick depends upon the position of a particle in a bunch. The tail particles get more kick. The transverse force also gets a nonlinear dependence on the transverse position. The stretched bunch can be measured at the YAG screen that is 100 m downstream the dechirper. The most important aspect of this measurement is that that no synchronization is needed. The Green's function for the transverse kick was evaluated based on the precise wake field calculations of the dechirper corrugated structure. Using this function we can restore the longitudinal shape of the bunch. This may also help to see if a bunch has any micro-bunch structure. A. Noovokhatski "Wakefield potentials of corrugated structures",Phys. Rev. ST Accel. Beams 18, 104402 (2015)
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW046
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TUZA02	Twin-bunch Two-colour FEL at LCLS	1032
	A. Marinelli, R.N. Coffee, F.-J. Decker, Y. Ding, R.C. Field, S. Gilevich, Z. Huang, D. Kharakh, H. Loos, A.A. Lutman, T.J. Maxwell, J.L. Turner, S. Vetter SLAC, Menlo Park, California, USA
	Twin electron bunches have been the subject of much investigation at the Linac Coherent Light Source, due to their many applications to X-ray free-electron lasers (X-FEL). Twin bunches are trains of two electron bunches that are accelerated and compressed within the same accelerating RF period. At LCLS, these bunches are used in the downstream FEL undulator to generate two X-ray pulses of different energies for pump/probe applications or de novo phase determination of protein crystals. The spectral and temporal shaping of the two bunches requires exquisite control of the compression system to vary the main parameters of the system in a controlled way (peak current, temporal delay and energy separation). I will discuss recent experimental and theoretical results on this subject. In particular I will focus on the demonstration of mJ-level two-color X-ray pulses using twin bunches, as well as the temporal and spectral control of this new mode of operation. Finally, I will discuss our experience with user experiments as well as our future directions of investigation.
	Slides TUZA02 [5.738 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUZA02
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TUOCA01	LCLS Bunch Compressor Configuration Study for Soft X-ray Operation	1037
	S. Li, Y. Ding, Z. Huang, A. Marinelli, T.J. Maxwell, D.F. Ratner, F. Zhou SLAC, Menlo Park, California, USA C. Behrens DESY, Hamburg, Germany
	The microbunching instability (MBI) is a well-known problem for high brightness electron beams and has been observed at accelerator facilities around the world. Free-electron lasers (FELs) are particularly susceptible to MBI, which can distort the longitudinal phase space and increase the beam's slice energy spread (SES). Past studies of MBI at the Linac Coherent Light Source (LCLS) relied on optical transition radiation to infer the existence of microbunching. With the development of the x-band transverse deflecting cavity (XTCAV), we can for the first time directly image the longitudinal phase space at the end of the accelerator and complete a comprehensive study of MBI, revealing both detailed MBI behavior as well as insights into mitigation schemes [1]. The fine time resolution of the XTCAV also provides the first LCLS measurements of the final SES, a critical parameter for many advanced FEL schemes. Detailed MBI and SES measurements can aid in understanding MBI mechanisms, benchmarking simulation codes, and designing future high-brightness accelerators.
	Slides TUOCA01 [4.436 MB]
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUOCA01
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TUPOR018	Design Optimization of Compensation Chicanes in the LCLS-II Transport Lines	1695
	J. Qiang, C.E. Mitchell, M. Venturini LBNL, Berkeley, California, USA Y. Ding, P. Emma, Z. Huang, G. Marcus, Y. Nosochkov, T.O. Raubenheimer, L. Wang, M. Woodley SLAC, Menlo Park, California, USA
	LCLS-II is a 4th-generation high-repetition rate Free Electron Laser (FEL) based x-ray light source to be built at the SLAC National Accelerator Laboratory. To mitigate the microbunching instability, the transport lines from the exit of the Linac to the undulators will include a number of weak compensation chicanes with the purpose of cancelling the momentum compaction generated by the main bend magnets of the transport lines. In this paper, we will report on our design optimization study of these compensation chicanes in the presence of both longitudinal and transverse space-charge effects.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOR018
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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.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW017
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WEPOY019	Beam Optimization Study for an X-ray FEL Oscillator at the LCLS-II	3020
	W. Qin, S. Huang, K.X. Liu PKU, Beijing, People's Republic of China K.L.F. Bane, Y. Ding, Z. Huang, T.J. Maxwell SLAC, Menlo Park, California, USA K.-J. Kim, R.R. Lindberg ANL, Argonne, Ilinois, USA
	The 4 GeV LCLS-II superconducting linac with high repetition beam rate enables the possibility to drive an X-Ray FEL oscillator at harmonic frequencies . Compared to the regular LCLS-II machine setup, the oscillator mode requires a much longer bunch length with a relatively lower current. Also a flat longitudinal phase space distribution is critical to maintain the FEL gain since the X-ray cavity has extremely narrow bandwidth. In this paper, we study the longitudinal phase space optimization including shaping the initial beam from the injector and optimizing the bunch compressor and dechirper parameters. We obtain a bunch with a flat energy chirp over 400 fs in the core part with current above 100 A. The optimization was based on LiTrack and Elegant simulations using LCLS-II beam parameters. T. J. Maxwell et al., Feasibility study for an X-ray FEL oscillator at the LCLS-II, IPAC15, TUPMA028.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOY019
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THPMB027	Beam Transport Line of the LPA-FEL Facility Based on Transverse Gradient Undulator	3287
	T. Liu, B. Liu, D. Wang, T. Zhang SINAP, Shanghai, People's Republic of China Z. Huang SLAC, Menlo Park, California, USA J.S. Liu Shanghai Institute of Optics and Fine Mechanics, Shanghai, People's Republic of China
	Free electron lasers (FELs) based on Laser Plasma Accelerators (LPAs) present a main research direction for achieving next generation compact advanced light sources. There are several major challenges of the LPA beam to generate high-brilliance FEL radiation including the large initial angular divergence and the large energy spread. Based on the LPA facility in SIOM that has successfully obtained quasi-monochromatic beam with the central energy of hundreds of MeV, a specific design of a beam transport line is proposed to realize FEL gain using Transverse Gradient Undulator to compensate the relatively large beam energy spread. This beamline uses a single dipole, several strong focusing quadrupoles and correcting sextupoles to match proper beta functions and linear dispersion from the LPA beam to FEL radiation. The corresponding experimental facility of LPA-FEL in SIOM has been set up and will perform first tests to generate FEL radiation.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMB027
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Paper

Title

Page

An Oscillator Configuration for Full Realization of Hard X-ray Free Electron Laser

801

K.-J. Kim, T. Kolodziej, R.R. Lindberg, D. Shu, Yu. Shvyd'ko, S. Stoupin
ANL, Argonne, Ilinois, USA
V.D. Blank, S. Terentiev
TISNCM, Troitsk, Russia
Y. Ding, W.M. Fawley, J.B. Hastings, Z. Huang, J. Krzywinski, G. Marcus, T.J. Maxwell
SLAC, Menlo Park, California, USA
N.A. Medvedev
CFEL, Hamburg, Germany
W. Qin
PKU, Beijing, People's Republic of China
J. Zemella
DESY, Hamburg, Germany

Funding: Work at ANL supported under US Department of Energy contract DE-AC02-76SF00515 and at SLAC by the U.S. Department of Energy, Office of Science, under Contract No. DE-ACO2-O6CH11357
An X-ray free electron laser can be built in an oscillator (XFELO) configuration by employing an X-ray cavity with Bragg mirrors such as diamond*. An XFELO at the 5th harmonic frequency may be implemented at the LCLS II using its 4 GeV superconducting linac. The XFELO will provide stable, coherent, high-spectral-purity hard x-rays. In addition, portions of its output may be enhanced by the LCLS amplifier for stable pulses of ultrashort duration determined by the electron bunch length. Much progress has been made recently on the feasibility of an XFELO: Analytical and numerical methods have been developed to compute the performance of a harmonic XFELO. The energy spread requirement over a sufficient length of the bunch can be met by temporal shaping of the photo-cathode drive laser**. Experiments at the APS have shown that Be-compound refractive lenses are suitable for a low-loss focusing and that the synthetic diamond crystals can withstand the intense x-ray exposure, in accord with estimates based on molecular dynamics considerations***. A strain-free mounting of thin diamond crystal (< 100 microns) can be realized by shaping a thick diamond into a blind alley****.
* R. R. Lindberg et al., PRSTAB 1010701 (2011)
** W. Qin et al., this conference
*** N. Medvedev et al., Phys. Rev. B 88, 224304 (2013)
**** S. Terentyev, private communication

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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.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW044

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MOPOW045

Measurement of Advanced Dispersion-based Beam-tilt Correction

813

M.W. Guetg, F.-J. Decker, Y. Ding, P. Emma, Z. Huang, T.J. Maxwell
SLAC, Menlo Park, California, USA

Funding: DOE contract \#DE-AC02-76SF00515
Free electron lasers in the X-ray regime require a good slice alignment along the electron bunch to achieve their best performance. A transverse beam slice shift reduces this alignment and spoils projected emittance and optics matching. Coherent synchrotron radiation, specifically for over-compression going through full compression, and transverse wakefields are major contributors to this. In the case of the large-bandwidth operation, with a strong energy chirp on the bunch, this misalignments furthermore reduce the spectral bandwidth of the FEL pulse. Well-defined manipulation of dispersion allows to compensate for this slice centroid shifts, therefore enhancing lasing power and in case of the large bandwidth mode, spectral bandwidth. This work shows the first application of this correction on an X-ray FEL resulting in increase in beam-power and bandwidth.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOW045

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MOPOW046

RadiaBeam/SLAC Dechirper as a Passive Deflector

817

A. Novokhatski, A. Brachmann, M. Dal Forno, V.A. Dolgashev, A.S. Fisher, M.W. Guetg, Z. Huang, R.H. Iverson, P. Krejcik, A.A. Lutman, T.J. Maxwell
SLAC, Menlo Park, California, USA
J. Zemella
DESY, Hamburg, Germany

Funding: This work was supported by Department of Energy Contract No. DE-AC02-76SF00515.
We discuss the possibility of using the RadiBeam/SLAC dechirper recently installed at LCLS for measuring the bunch length of very short bunches, less than 1 fs perhaps as short as 100 atto second. When a bunch travels close to one of the jaws the particles of the bunch get a transverse kick depends upon the position of a particle in a bunch. The tail particles get more kick. The transverse force also gets a nonlinear dependence on the transverse position. The stretched bunch can be measured at the YAG screen that is 100 m downstream the dechirper. The most important aspect of this measurement is that that no synchronization is needed. The Green's function for the transverse kick was evaluated based on the precise wake field calculations of the dechirper corrugated structure*. Using this function we can restore the longitudinal shape of the bunch. This may also help to see if a bunch has any micro-bunch structure.
* A. Noovokhatski "Wakefield potentials of corrugated structures",Phys. Rev. ST Accel. Beams 18, 104402 (2015)

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TUZA02

Twin-bunch Two-colour FEL at LCLS

1032

A. Marinelli, R.N. Coffee, F.-J. Decker, Y. Ding, R.C. Field, S. Gilevich, Z. Huang, D. Kharakh, H. Loos, A.A. Lutman, T.J. Maxwell, J.L. Turner, S. Vetter
SLAC, Menlo Park, California, USA

Twin electron bunches have been the subject of much investigation at the Linac Coherent Light Source, due to their many applications to X-ray free-electron lasers (X-FEL). Twin bunches are trains of two electron bunches that are accelerated and compressed within the same accelerating RF period. At LCLS, these bunches are used in the downstream FEL undulator to generate two X-ray pulses of different energies for pump/probe applications or de novo phase determination of protein crystals. The spectral and temporal shaping of the two bunches requires exquisite control of the compression system to vary the main parameters of the system in a controlled way (peak current, temporal delay and energy separation). I will discuss recent experimental and theoretical results on this subject. In particular I will focus on the demonstration of mJ-level two-color X-ray pulses using twin bunches, as well as the temporal and spectral control of this new mode of operation. Finally, I will discuss our experience with user experiments as well as our future directions of investigation.

Slides TUZA02 [5.738 MB]

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TUOCA01

LCLS Bunch Compressor Configuration Study for Soft X-ray Operation

1037

S. Li, Y. Ding, Z. Huang, A. Marinelli, T.J. Maxwell, D.F. Ratner, F. Zhou
SLAC, Menlo Park, California, USA
C. Behrens
DESY, Hamburg, Germany

The microbunching instability (MBI) is a well-known problem for high brightness electron beams and has been observed at accelerator facilities around the world. Free-electron lasers (FELs) are particularly susceptible to MBI, which can distort the longitudinal phase space and increase the beam's slice energy spread (SES). Past studies of MBI at the Linac Coherent Light Source (LCLS) relied on optical transition radiation to infer the existence of microbunching. With the development of the x-band transverse deflecting cavity (XTCAV), we can for the first time directly image the longitudinal phase space at the end of the accelerator and complete a comprehensive study of MBI, revealing both detailed MBI behavior as well as insights into mitigation schemes [1]. The fine time resolution of the XTCAV also provides the first LCLS measurements of the final SES, a critical parameter for many advanced FEL schemes. Detailed MBI and SES measurements can aid in understanding MBI mechanisms, benchmarking simulation codes, and designing future high-brightness accelerators.

Slides TUOCA01 [4.436 MB]

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TUPOR018

Design Optimization of Compensation Chicanes in the LCLS-II Transport Lines

1695

J. Qiang, C.E. Mitchell, M. Venturini
LBNL, Berkeley, California, USA
Y. Ding, P. Emma, Z. Huang, G. Marcus, Y. Nosochkov, T.O. Raubenheimer, L. Wang, M. Woodley
SLAC, Menlo Park, California, USA

LCLS-II is a 4th-generation high-repetition rate Free Electron Laser (FEL) based x-ray light source to be built at the SLAC National Accelerator Laboratory. To mitigate the microbunching instability, the transport lines from the exit of the Linac to the undulators will include a number of weak compensation chicanes with the purpose of cancelling the momentum compaction generated by the main bend magnets of the transport lines. In this paper, we will report on our design optimization study of these compensation chicanes in the presence of both longitudinal and transverse space-charge effects.

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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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WEPOY019

Beam Optimization Study for an X-ray FEL Oscillator at the LCLS-II

3020

W. Qin, S. Huang, K.X. Liu
PKU, Beijing, People's Republic of China
K.L.F. Bane, Y. Ding, Z. Huang, T.J. Maxwell
SLAC, Menlo Park, California, USA
K.-J. Kim, R.R. Lindberg
ANL, Argonne, Ilinois, USA

The 4 GeV LCLS-II superconducting linac with high repetition beam rate enables the possibility to drive an X-Ray FEL oscillator at harmonic frequencies *. Compared to the regular LCLS-II machine setup, the oscillator mode requires a much longer bunch length with a relatively lower current. Also a flat longitudinal phase space distribution is critical to maintain the FEL gain since the X-ray cavity has extremely narrow bandwidth. In this paper, we study the longitudinal phase space optimization including shaping the initial beam from the injector and optimizing the bunch compressor and dechirper parameters. We obtain a bunch with a flat energy chirp over 400 fs in the core part with current above 100 A. The optimization was based on LiTrack and Elegant simulations using LCLS-II beam parameters.
* T. J. Maxwell et al., Feasibility study for an X-ray FEL oscillator at the LCLS-II, IPAC15, TUPMA028.

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THPMB027

Beam Transport Line of the LPA-FEL Facility Based on Transverse Gradient Undulator

3287

T. Liu, B. Liu, D. Wang, T. Zhang
SINAP, Shanghai, People's Republic of China
Z. Huang
SLAC, Menlo Park, California, USA
J.S. Liu
Shanghai Institute of Optics and Fine Mechanics, Shanghai, People's Republic of China

Free electron lasers (FELs) based on Laser Plasma Accelerators (LPAs) present a main research direction for achieving next generation compact advanced light sources. There are several major challenges of the LPA beam to generate high-brilliance FEL radiation including the large initial angular divergence and the large energy spread. Based on the LPA facility in SIOM that has successfully obtained quasi-monochromatic beam with the central energy of hundreds of MeV, a specific design of a beam transport line is proposed to realize FEL gain using Transverse Gradient Undulator to compensate the relatively large beam energy spread. This beamline uses a single dipole, several strong focusing quadrupoles and correcting sextupoles to match proper beta functions and linear dispersion from the LPA beam to FEL radiation. The corresponding experimental facility of LPA-FEL in SIOM has been set up and will perform first tests to generate FEL radiation.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMB027

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