FEL2015 - List of Keywords (space-charge)

Paper	Title	Other Keywords	Page
MOP060	RFTweak 5 - An Efficient Longitudinal Beam Dynamics Code	GUI, controls, diagnostics, radiation	176
	B. Beutner, H. Dinter, M. Dohlus DESY, Hamburg, Germany
	The shaping of the longitudinal phase space in bunch compression systems is essential for efficient FEL operation. RF systems and self-field interactions contribute to the overall phase space structure. The design of the various facilities relies on extensive beam dynamics simulations to define the longitudinal dynamics. However, in everyday control room applications such techniques are often not fast enough for efficient operation, e.g. for SASE tuning. Therefore efficient longitudinal beam dynamics codes are required while still maintaining reasonable accuracy. Our approach is to pre-calculate most of the required data for self-field interactions and store them on disc to reduce required online calculation time to a minimum. In this paper we present the fast longitudinal tracking code RFTweak 5, which includes wakes, space charge, and CSR interactions. With this code the full European XFEL with a 1M particles bunch is calculated on the order of minutes on a standard laptop. Neglecting CSR effects this time reduces to seconds.
	Poster MOP060 [0.799 MB]
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MOP063	Transverse Emittance Measurement of KAERI Linac with Thick Lens Quadrupole Scan	emittance, quadrupole, electron, experiment	185
	S. Setiniyaz, I.H. Baek, M.S. Chae, B.A. Gudkov, B. Han, K.H. Jang, Y.U. Jeong, H.W. Kim, S.V. Miginsky, J.H. Nam, S. Park, N. Vinokurov KAERI, Daejon, Republic of Korea S.V. Miginsky, N. Vinokurov BINP SB RAS, Novosibirsk, Russia
	The UED (Ultrafast Electron Diffraction) beamline of KAERI (Korea Atomic Energy Research Institute) WCI (World Class Institute) Center has been completed and successfully commissioned. Transverse emittance of the electron beam was measured at the entrance of the UED chamber with the quadrupole scan technique. In this technique, larger drift distance between the quad and screen is preferred because it gives better thin lens approximation. A space charge dominated beam however, will undergo emittance growth in the long drift caused by the space charge force. We suggest mitigating this growth by introducing quadrupole scan with short drift and without thin lens approximation. We shall discuss the measurement process and results.
	Poster MOP063 [1.287 MB]
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MOP066	Electron Bunch Length Measurement using an RF Deflecting Cavity	cavity, electron, simulation, resonance	188
	S. Park, E.-S. Kim Kyungpook National University, Daegu, Republic of Korea S. Bae, K.H. Jang, Y.U. Jeong, H.W. Kim, J. Mun, N. Vinokurov KAERI, Daejon, Republic of Korea
	Recently, the RF photogun based-ultrafast electron diffraction (UED) system has been developed in KAERI. In the system, the emitted electron bunches are experimentally confirmed to be accelerated up to 3 MeV at 5MW of RF power. And the time duration of the each bunch is initially designed to be less than 50 fs at the sample position. To analyses the performance of the system and to measure exactly the length of the electron bunches, we developed a rectangular type of S-band deflecting cavity working on TM120 mode. The principle of electron deflecting in the cavity, design & mechanical fabrication process and test results will be present in the conference.
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TUP008	High-Gain FEL in the Space-Charge Dominated Raman Limit	FEL, undulator, electron, simulation	347
	I.I. Gadjev, C. Emma, A. Nause, J.B. Rosenzweig UCLA, Los Angeles, USA
	While FEL technology has reached the EUV and X-ray regime at existing machines such as LCLS and SACLA, the scale of these projects is often impractical for research and industrial applications. Sub-millimeter period undulators can reduce the size of a high-gain EUV FEL, but will impose stringent conditions on the electron beam. In particular, a high-gain EUV FEL based on undulators with a sub-millimeter period will require electron beam currents upwards of 1 kA at energies below 100 MeV. Coupled with the small gap of such undulators and their low undulator strengths, K < 0.1, these beam parameters bring longitudinal space-charge effects to the foreground of the FEL process. When the wavelength of plasma oscillations in the electron beam becomes comparable to the gain-length, the 1D theoretical FEL model transitions from the Compton to the Raman limit. In this work, we investigate the behavior of the FEL's gain-length and efficiency in these two limits. The starting point for the analysis was the one-dimensional FEL theory including space-charge forces. The derived results were compared to numerical results of Genesis 1.3 simulations. This theoretical model predicts that in the Raman limit, the gain-length scales as the beam current to the -1/4th power while the efficiency plateaus to a constant.
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TUP066	Benchmark of ELEGANT and IMPACT	wakefield, linac, optics, undulator	505
	L. Wang, P. Emma, T.O. Raubenheimer SLAC, Menlo Park, California, USA J. Qiang LBNL, Berkeley, California, USA
	The beam dynamics codes ELEGANT and IMAPCT have many users. We use these two codes for the design of LCLSII. Both codes use a 1D model for the coherent synchrotron radiation (CSR) in bend magnets. In addition, IMPACT has a 3D space-charge model, while ELEGANT uses a 1D model. To compare the two codes, especially the space-charge effects, we systematically benchmark the two codes with different physics aspects: wakefields, CSR and space-charge forces.
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TUP071	A FAST Particle Tracking Code	wakefield, linac, collective-effects, bunching	530
	L. Wang SLAC, Menlo Park, California, USA
	This paper presents a fast particle tracking (FPT) code for linac beam dynamics. It includes wake fields, coherent synchrotron radiation (CSR) and longitudinal space charge. We systematically benchmark the FPT with ELEGANT with different physics aspects: pure optics, wakefields, CSR and space-charge forces
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WEP045	Study on Beam Modulation Technique using a Masked Chicane at FAST (Fermilab Accelerator Science and Technology) Facility	simulation, bunching, dipole, linac	665
	Y.-M. Shin, 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 chicane design parameters (bending angle of 18 degree, bending radius of 0.95 m and R56 ~ - 0.19 m) and a nominal beam of 3-ps bunch length, the analytic model showed that a slit-mask with slit period 900 microns and aperture width 300 microns generates about 100 microns 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 microns of longitudinal modulation. The beam modulation has been extensively examined with three different beam conditions, 2.25 ps (0.25 nC), 3.25 ps (1 nC), and 4.75 ps (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.
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WEP067	Simulation of Cascaded Longitudinal-Space-Charge Amplifier at the Fermilab Accelerator Science & Technology (Fast) Facility	bunching, simulation, radiation, impedance	707
	A. Halavanau, P. Piot Northern Illinois University, DeKalb, Illinois, USA P. Piot Fermilab, Batavia, Illinois, USA
	Funding: This work was supported by the US Department of Energy under contract DE-SC0011831 with Northern Illinois University. Cascaded longitudinal space-charge amplifier (LSCA) have been proposed as a mechanism to generate density modulation over broadband.[1] The scheme was recently demonstrated in the optical regime and confirmed the production of broadband optical radiation.[2] In this paper we investigate, via numerical simulations, the performances of a cascaded LSCA beamline at the Fermilab's Advanced Superconducting Test Accelerator (ASTA) to produce broadband ultraviolet radiation. Our studies are carried using a three-dimensional space charge algorithm coupled with ELEGANT [3] and based on a tree-based space-charge algorithm (see details in Ref. [4]) [1] M. Dohlus, PRSTAB, 14 090702 (2011). [2] A. Marinelli, PRL, 110 264802 (2013). [3] M. Borland, Advanced Photon Source, LS-287, 2000. [4] A. Halavanau, Proc. IPAC15, TUPMA007 (2015).
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Paper

Title

Other Keywords

Page

MOP060

RFTweak 5 - An Efficient Longitudinal Beam Dynamics Code

GUI, controls, diagnostics, radiation

176

B. Beutner, H. Dinter, M. Dohlus
DESY, Hamburg, Germany

The shaping of the longitudinal phase space in bunch compression systems is essential for efficient FEL operation. RF systems and self-field interactions contribute to the overall phase space structure. The design of the various facilities relies on extensive beam dynamics simulations to define the longitudinal dynamics. However, in everyday control room applications such techniques are often not fast enough for efficient operation, e.g. for SASE tuning. Therefore efficient longitudinal beam dynamics codes are required while still maintaining reasonable accuracy. Our approach is to pre-calculate most of the required data for self-field interactions and store them on disc to reduce required online calculation time to a minimum. In this paper we present the fast longitudinal tracking code RFTweak 5, which includes wakes, space charge, and CSR interactions. With this code the full European XFEL with a 1M particles bunch is calculated on the order of minutes on a standard laptop. Neglecting CSR effects this time reduces to seconds.

Poster MOP060 [0.799 MB]

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reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

MOP063

Transverse Emittance Measurement of KAERI Linac with Thick Lens Quadrupole Scan

emittance, quadrupole, electron, experiment

185

S. Setiniyaz, I.H. Baek, M.S. Chae, B.A. Gudkov, B. Han, K.H. Jang, Y.U. Jeong, H.W. Kim, S.V. Miginsky, J.H. Nam, S. Park, N. Vinokurov
KAERI, Daejon, Republic of Korea
S.V. Miginsky, N. Vinokurov
BINP SB RAS, Novosibirsk, Russia

The UED (Ultrafast Electron Diffraction) beamline of KAERI (Korea Atomic Energy Research Institute) WCI (World Class Institute) Center has been completed and successfully commissioned. Transverse emittance of the electron beam was measured at the entrance of the UED chamber with the quadrupole scan technique. In this technique, larger drift distance between the quad and screen is preferred because it gives better thin lens approximation. A space charge dominated beam however, will undergo emittance growth in the long drift caused by the space charge force. We suggest mitigating this growth by introducing quadrupole scan with short drift and without thin lens approximation. We shall discuss the measurement process and results.

Poster MOP063 [1.287 MB]

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MOP066

Electron Bunch Length Measurement using an RF Deflecting Cavity

cavity, electron, simulation, resonance

188

S. Park, E.-S. Kim
Kyungpook National University, Daegu, Republic of Korea
S. Bae, K.H. Jang, Y.U. Jeong, H.W. Kim, J. Mun, N. Vinokurov
KAERI, Daejon, Republic of Korea

Recently, the RF photogun based-ultrafast electron diffraction (UED) system has been developed in KAERI. In the system, the emitted electron bunches are experimentally confirmed to be accelerated up to 3 MeV at 5MW of RF power. And the time duration of the each bunch is initially designed to be less than 50 fs at the sample position. To analyses the performance of the system and to measure exactly the length of the electron bunches, we developed a rectangular type of S-band deflecting cavity working on TM120 mode. The principle of electron deflecting in the cavity, design & mechanical fabrication process and test results will be present in the conference.

Export •

reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

TUP008

High-Gain FEL in the Space-Charge Dominated Raman Limit

FEL, undulator, electron, simulation

347

I.I. Gadjev, C. Emma, A. Nause, J.B. Rosenzweig
UCLA, Los Angeles, USA

While FEL technology has reached the EUV and X-ray regime at existing machines such as LCLS and SACLA, the scale of these projects is often impractical for research and industrial applications. Sub-millimeter period undulators can reduce the size of a high-gain EUV FEL, but will impose stringent conditions on the electron beam. In particular, a high-gain EUV FEL based on undulators with a sub-millimeter period will require electron beam currents upwards of 1 kA at energies below 100 MeV. Coupled with the small gap of such undulators and their low undulator strengths, K < 0.1, these beam parameters bring longitudinal space-charge effects to the foreground of the FEL process. When the wavelength of plasma oscillations in the electron beam becomes comparable to the gain-length, the 1D theoretical FEL model transitions from the Compton to the Raman limit. In this work, we investigate the behavior of the FEL's gain-length and efficiency in these two limits. The starting point for the analysis was the one-dimensional FEL theory including space-charge forces. The derived results were compared to numerical results of Genesis 1.3 simulations. This theoretical model predicts that in the Raman limit, the gain-length scales as the beam current to the -1/4th power while the efficiency plateaus to a constant.

Export •

reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

TUP066

Benchmark of ELEGANT and IMPACT

wakefield, linac, optics, undulator

505

L. Wang, P. Emma, T.O. Raubenheimer
SLAC, Menlo Park, California, USA
J. Qiang
LBNL, Berkeley, California, USA

The beam dynamics codes ELEGANT and IMAPCT have many users. We use these two codes for the design of LCLSII. Both codes use a 1D model for the coherent synchrotron radiation (CSR) in bend magnets. In addition, IMPACT has a 3D space-charge model, while ELEGANT uses a 1D model. To compare the two codes, especially the space-charge effects, we systematically benchmark the two codes with different physics aspects: wakefields, CSR and space-charge forces.

Export •

reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

TUP071

A FAST Particle Tracking Code

wakefield, linac, collective-effects, bunching

530

L. Wang
SLAC, Menlo Park, California, USA

This paper presents a fast particle tracking (FPT) code for linac beam dynamics. It includes wake fields, coherent synchrotron radiation (CSR) and longitudinal space charge. We systematically benchmark the FPT with ELEGANT with different physics aspects: pure optics, wakefields, CSR and space-charge forces

Export •

reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

WEP045

Study on Beam Modulation Technique using a Masked Chicane at FAST (Fermilab Accelerator Science and Technology) Facility

simulation, bunching, dipole, linac

665

Y.-M. Shin, 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 chicane design parameters (bending angle of 18 degree, bending radius of 0.95 m and R56 ~ - 0.19 m) and a nominal beam of 3-ps bunch length, the analytic model showed that a slit-mask with slit period 900 microns and aperture width 300 microns generates about 100 microns 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 microns of longitudinal modulation. The beam modulation has been extensively examined with three different beam conditions, 2.25 ps (0.25 nC), 3.25 ps (1 nC), and 4.75 ps (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.

Export •

reference for this paper to ※ LaTeX, ※ Text, ※ IS/RefMan, ※ EndNote (xml)

WEP067

Simulation of Cascaded Longitudinal-Space-Charge Amplifier at the Fermilab Accelerator Science & Technology (Fast) Facility

bunching, simulation, radiation, impedance

707

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

Funding: This work was supported by the US Department of Energy under contract DE-SC0011831 with Northern Illinois University.
Cascaded longitudinal space-charge amplifier (LSCA) have been proposed as a mechanism to generate density modulation over broadband.[1] The scheme was recently demonstrated in the optical regime and confirmed the production of broadband optical radiation.[2] In this paper we investigate, via numerical simulations, the performances of a cascaded LSCA beamline at the Fermilab's Advanced Superconducting Test Accelerator (ASTA) to produce broadband ultraviolet radiation. Our studies are carried using a three-dimensional space charge algorithm coupled with ELEGANT [3] and based on a tree-based space-charge algorithm (see details in Ref. [4])
[1] M. Dohlus, PRSTAB, 14 090702 (2011).
[2] A. Marinelli, PRL, 110 264802 (2013).
[3] M. Borland, Advanced Photon Source, LS-287, 2000.
[4] A. Halavanau, Proc. IPAC15, TUPMA007 (2015).

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