FEL2015 - List of Keywords (dipole)

Paper	Title	Other Keywords	Page
MOP016	Status of the Fabrication of PAL-XFEL Magnet Power Supplies	power-supply, quadrupole, controls, operation	66
	S.-H. Jeong, Y.-G. Jung, H.-S. Kang, D.E. Kim, I.S. Ko, H.-G. Lee, S.B. Lee, B.G. Oh, K.-H. Park, H.S. Suh PAL, Pohang, Kyungbuk, Republic of Korea
	PAL-XFEL has been constructing including a 10 GeV linac, hard X-ray and soft X-ray branches. PAL-XFEL required for about six hundreds of magnet power supply (MPS). The eight different prototypes of MPS are developing to confirm the performance, functions, size, heat load and so on. This paper describes the test results of the prototype MPS in major specifications. All MPSs have to be installed the end of September in 2015. The installation progress of the MPS was also described.
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MOP049	Design, Development and Test of the Magnets for PAL-XFEL	quadrupole, multipole, undulator, status	139
	H.S. Suh, M.-H. Cho, S.-H. Jeong, Y.-G. Jung, H.-S. Kang, D.E. Kim, I.S. Ko, H.-G. Lee, S.B. Lee, B.G. Oh, K.-H. Park PAL, Pohang, Kyungbuk, Republic of Korea
	PAL-XFEL is now being constructed with the goal of 0.1 nm hard X-ray in Pohang, Korea. As the first phase we will construct 10 GeV linac, one hard X-ray and one soft X-ray beamlines which require 6 different families of 55 dipole magnets, 11 families of 209 quadrupole magnets, and 3 families of 48 corrector magnets. We have designed these magnets with considering the efficient production and the proper power supplies. This paper describes an outline of the design and test results of the magnets until now.
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MOP052	Linear Vlasov Solver For Microbunching Gain Estimation with Inclusion of CSR, LSC, And Linac Geometric Impedances	linac, impedance, simulation, electron	147
	C.-Y. Tsai Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA D. Douglas, R. Li, C. Tennant JLab, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. As is known, microbunching instability (MBI) has been one of the most challenging issues in designs of magnetic chicanes for short-wavelength free-electron lasers or linear colliders, as well as those of transport lines for recirculating or energy recovery linac machines. To more accurately quantify MBI in a single-pass system, we further extend and continue to increase the capabilities of our previously developed linear Vlasov solver [1] to incorporate more relevant impedance models into the code, including transient and steady-state free-space and/or shielding CSR impedances, the LSC and linac geometric impedances with extension of the existing formulation to include beam acceleration [2]. Then, we directly solve the linearized Vlasov equation numerically for microbunching gain amplification factor. In this study we apply this code to a beamline lattice of transport arc [3] following an upstream linac section. The resultant gain functions and spectra are presented here, and some results are compared with particle tracking simulation by ELEGANT [4]. We also discuss some underlying physics with inclusion of these collective effects and the limitation of the existing formulation. It is anticipated that this more thorough analysis can further improve the understanding of MBI mechanisms and shed light on how to suppress or compensate MBI effects in lattice designs. [1] C. -Y. Tsai et al., FEL'14 (THP022), IPAC'15 (MOPMA028) and ERL2015 (TUICLH2034) [2] M. Venturini, Phys. Rev. ST Accel. Beams 10, 104401 (2007) [3] D. Douglas et al., arXiv: 1403.2318v1 [physics.acc-ph] [4] M. Borland, APS Light Source Note LS-287 (2000)
	Poster MOP052 [4.934 MB]
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MOP067	Transverse Emittance-Preserving Transfer Line and Arc Compressor for High Brightness Electron Sources	emittance, optics, electron, FEL	191
	S. Di Mitri, M. Cornacchia, S. Spampinati Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy S. Spampinati Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Minimizing transverse emittance is essential in single- or few-passes accelerators designed to deliver high brightness electron beams. Emission of coherent synchrotron radiation (CSR) is an important factor of emittance degradation. We have demonstrated, with analytical and experimental results, that this perturbation may be cancelled by imposing certain conditions on the electron optics when the bunch length is constant along the line. This scheme of CSR suppression is then enlarged, analytically and numerically, to cover the case of varying bunch length in a periodic arc compressor. The proposed solution hold the promise of cost-saving of compact transfer lines with large bending angles, and new schemes for beam longitudinal gymnastics both in recirculating and in single-pass accelerators driving free electron lasers. S. Di Mitri, M. Cornacchia, S. Spampinati, Phys. Rev. Letters, 110, 014801 (2013) ** S. Di Mitri, M. Cornacchia, Europhys. Letters, 109, 62002 (2015)
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MOP087	Multistage CSR Microbunching Gain Development in Transport or Recirculation Arcs	lattice, damping, optics, bunching	263
	C.-Y. Tsai Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA D. Douglas, R. Li, C. Tennant JLab, Newport News, Virginia, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. Coherent synchrotron radiation (CSR) induced microbunching instability has been one of the most challenging issues in the design of modern accelerators. A linear Vlasov solver has been developed [1] and applied to investigate the physical processes of microbunching gain amplification for several example lattices [2]. In this paper, by further extending the concept of stage gain as proposed by Huang and Kim [3], we develop a method to characterize the microbunching development in terms of stage orders that allow the quantitative comparison of optics impacts on microbunching gain for different lattices. We find that the microbunching instability in our demonstrated arcs has a distinguishing feature of multistage amplification (e.g, up to 6th stage amplification for our example transport arcs, in contrast to two-stage amplification for a typical 4-dipole bunch compressor chicane). We also try to connect lattice optics pattern with the obtained stage gain functions by a physical interpretation. This Vlasov analysis is validated by ELEGANT [4] tracking results with excellent agreement. [1] C. -Y. Tsai et al., MOP052, these proceedings [2] See, for example, C. -Y. Tsai et al., ERL2015 (TUICLH2034) [3] Z. Huang and K. -J. Kim, Phys. Rev. ST Accel. Beams 5, 074401 (2002) [4] M. Borland, APS Light Source Note LS-287 (2000)
	Poster MOP087 [1.962 MB]
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TUP043	PAL-XFEL Cavity BPM Prototype Beam Test at ITF	cavity, pick-up, electron, simulation	468
	S.J. Lee, J.H. Han, H.-S. Kang, C. Kim, S.H. Kim, I.S. Ko, Y.J. Park, D.C. Shin PAL, Pohang, Kyungbuk, Republic of Korea
	To achieve sub-micrometer resolution, PAL-XFEL undulator section will use X-band Cavity beam position monitor (BPM) systems. The prototype cavity BPM pick-up was designed and fabricated to test the performance of the cavity BPM system. The fabricated prototype cavity BPM pick-up was installed at Pohang Accelerator Laboratory injector test facility (PAL ITF) for the beam test. Under 200 pC beam charge condition, the signal properties of the cavity BPM pick-up were measured. Also, the dynamic range of the cavity BPM pick-up was measured by using the corrector magnet. In this paper, the design and beam test results of the prototype cavity BPM pick-up will be discussed.
	Poster TUP043 [0.695 MB]
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TUP055	Technical Overview of Bunch Compressor System for PAL XFEL	quadrupole, vacuum, electron, diagnostics	490
	H.-G. Lee, Y.-G. Jung, H.-S. Kang, D.E. Kim, K.W. Kim, S.B. Lee, D.H. Na, B.G. Oh, K.-H. Park, H.S. Suh, Y.J. Suh PAL, Pohang, Kyungbuk, Republic of Korea
	Pohang Accelerator Laboratory(PAL) is developing a SASE X-ray Free Electron Laser based on 10 GeV linear accelerator. Bunch compressor (BC) systems are developed to be used for the linear accelerator tunnel. It consists of three(BC1, BC2, BC3_H) hard X-ray line and one(BC3_S) soft X-ray line. BC systems are composed of four dipole magnets, three quadrupole magnet, BPM and collimator. The support system is based on an asymmetric four-dipole magnet chicane in which asymmetry and variable R56. can be optimized. This flexibility is achieved by allowing the middle two dipole magnets to move transversely. In this paper, we describe the design of the stages used for precise movement of the bunch compressor magnets and associated diagnostics components.
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WEP045	Study on Beam Modulation Technique using a Masked Chicane at FAST (Fermilab Accelerator Science and Technology) Facility	simulation, bunching, space-charge, 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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WEP069	Minimization of the Emittance Growth Induced by Coherent Synchrotron Radiation in Arc Compressor	emittance, synchrotron-radiation, simulation, synchrotron	711
	X.Y. Huang, X. Cui, Y. Jiao, G. Xu IHEP, Beijing, People's Republic of China
	Funding: Supported by National Natural Science Foundation of China (11475202, 11405187). Coherent synchrotron radiation (CSR) is a critical issue when electron bunches with short bunch length and high peak current transporting through a bending system in high-brightness light sources and linear colliders. For example, a high peak current of electron beam can be achieved by using magnetic bunch compressor, however, CSR induced transverse emittance growth will limit the performance of bunch compressor. In this paper, based on our 'two-dimensional point-kick analysis', an arc compressor with high compression factor is studied. Through analytical and numerical research, an easy optics design technique is introduced that could minimize the emittance dilution within this compressor. It is demonstrated that the strong compression of bunch length and the transverse emittance preservation can be achieved at the same time.
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Paper

Title

Other Keywords

Page

MOP016

Status of the Fabrication of PAL-XFEL Magnet Power Supplies

power-supply, quadrupole, controls, operation

66

S.-H. Jeong, Y.-G. Jung, H.-S. Kang, D.E. Kim, I.S. Ko, H.-G. Lee, S.B. Lee, B.G. Oh, K.-H. Park, H.S. Suh
PAL, Pohang, Kyungbuk, Republic of Korea

PAL-XFEL has been constructing including a 10 GeV linac, hard X-ray and soft X-ray branches. PAL-XFEL required for about six hundreds of magnet power supply (MPS). The eight different prototypes of MPS are developing to confirm the performance, functions, size, heat load and so on. This paper describes the test results of the prototype MPS in major specifications. All MPSs have to be installed the end of September in 2015. The installation progress of the MPS was also described.

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MOP049

Design, Development and Test of the Magnets for PAL-XFEL

quadrupole, multipole, undulator, status

139

H.S. Suh, M.-H. Cho, S.-H. Jeong, Y.-G. Jung, H.-S. Kang, D.E. Kim, I.S. Ko, H.-G. Lee, S.B. Lee, B.G. Oh, K.-H. Park
PAL, Pohang, Kyungbuk, Republic of Korea

PAL-XFEL is now being constructed with the goal of 0.1 nm hard X-ray in Pohang, Korea. As the first phase we will construct 10 GeV linac, one hard X-ray and one soft X-ray beamlines which require 6 different families of 55 dipole magnets, 11 families of 209 quadrupole magnets, and 3 families of 48 corrector magnets. We have designed these magnets with considering the efficient production and the proper power supplies. This paper describes an outline of the design and test results of the magnets until now.

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MOP052

Linear Vlasov Solver For Microbunching Gain Estimation with Inclusion of CSR, LSC, And Linac Geometric Impedances

linac, impedance, simulation, electron

147

C.-Y. Tsai
Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
D. Douglas, R. Li, C. Tennant
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
As is known, microbunching instability (MBI) has been one of the most challenging issues in designs of magnetic chicanes for short-wavelength free-electron lasers or linear colliders, as well as those of transport lines for recirculating or energy recovery linac machines. To more accurately quantify MBI in a single-pass system, we further extend and continue to increase the capabilities of our previously developed linear Vlasov solver [1] to incorporate more relevant impedance models into the code, including transient and steady-state free-space and/or shielding CSR impedances, the LSC and linac geometric impedances with extension of the existing formulation to include beam acceleration [2]. Then, we directly solve the linearized Vlasov equation numerically for microbunching gain amplification factor. In this study we apply this code to a beamline lattice of transport arc [3] following an upstream linac section. The resultant gain functions and spectra are presented here, and some results are compared with particle tracking simulation by ELEGANT [4]. We also discuss some underlying physics with inclusion of these collective effects and the limitation of the existing formulation. It is anticipated that this more thorough analysis can further improve the understanding of MBI mechanisms and shed light on how to suppress or compensate MBI effects in lattice designs.
[1] C. -Y. Tsai et al., FEL'14 (THP022), IPAC'15 (MOPMA028) and ERL2015 (TUICLH2034)
[2] M. Venturini, Phys. Rev. ST Accel. Beams 10, 104401 (2007)
[3] D. Douglas et al., arXiv: 1403.2318v1 [physics.acc-ph]
[4] M. Borland, APS Light Source Note LS-287 (2000)

Poster MOP052 [4.934 MB]

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MOP067

Transverse Emittance-Preserving Transfer Line and Arc Compressor for High Brightness Electron Sources

emittance, optics, electron, FEL

191

S. Di Mitri, M. Cornacchia, S. Spampinati
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
S. Spampinati
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Minimizing transverse emittance is essential in single- or few-passes accelerators designed to deliver high brightness electron beams. Emission of coherent synchrotron radiation (CSR) is an important factor of emittance degradation. We have demonstrated, with analytical and experimental results, that this perturbation may be cancelled by imposing certain conditions on the electron optics when the bunch length is constant along the line*. This scheme of CSR suppression is then enlarged, analytically and numerically, to cover the case of varying bunch length in a periodic arc compressor**. The proposed solution hold the promise of cost-saving of compact transfer lines with large bending angles, and new schemes for beam longitudinal gymnastics both in recirculating and in single-pass accelerators driving free electron lasers.
* S. Di Mitri, M. Cornacchia, S. Spampinati, Phys. Rev. Letters, 110, 014801 (2013)
** S. Di Mitri, M. Cornacchia, Europhys. Letters, 109, 62002 (2015)

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MOP087

Multistage CSR Microbunching Gain Development in Transport or Recirculation Arcs

lattice, damping, optics, bunching

263

C.-Y. Tsai
Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
D. Douglas, R. Li, C. Tennant
JLab, Newport News, Virginia, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177.
Coherent synchrotron radiation (CSR) induced microbunching instability has been one of the most challenging issues in the design of modern accelerators. A linear Vlasov solver has been developed [1] and applied to investigate the physical processes of microbunching gain amplification for several example lattices [2]. In this paper, by further extending the concept of stage gain as proposed by Huang and Kim [3], we develop a method to characterize the microbunching development in terms of stage orders that allow the quantitative comparison of optics impacts on microbunching gain for different lattices. We find that the microbunching instability in our demonstrated arcs has a distinguishing feature of multistage amplification (e.g, up to 6th stage amplification for our example transport arcs, in contrast to two-stage amplification for a typical 4-dipole bunch compressor chicane). We also try to connect lattice optics pattern with the obtained stage gain functions by a physical interpretation. This Vlasov analysis is validated by ELEGANT [4] tracking results with excellent agreement.
[1] C. -Y. Tsai et al., MOP052, these proceedings
[2] See, for example, C. -Y. Tsai et al., ERL2015 (TUICLH2034)
[3] Z. Huang and K. -J. Kim, Phys. Rev. ST Accel. Beams 5, 074401 (2002)
[4] M. Borland, APS Light Source Note LS-287 (2000)

Poster MOP087 [1.962 MB]

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TUP043

PAL-XFEL Cavity BPM Prototype Beam Test at ITF

cavity, pick-up, electron, simulation

468

S.J. Lee, J.H. Han, H.-S. Kang, C. Kim, S.H. Kim, I.S. Ko, Y.J. Park, D.C. Shin
PAL, Pohang, Kyungbuk, Republic of Korea

To achieve sub-micrometer resolution, PAL-XFEL undulator section will use X-band Cavity beam position monitor (BPM) systems. The prototype cavity BPM pick-up was designed and fabricated to test the performance of the cavity BPM system. The fabricated prototype cavity BPM pick-up was installed at Pohang Accelerator Laboratory injector test facility (PAL ITF) for the beam test. Under 200 pC beam charge condition, the signal properties of the cavity BPM pick-up were measured. Also, the dynamic range of the cavity BPM pick-up was measured by using the corrector magnet. In this paper, the design and beam test results of the prototype cavity BPM pick-up will be discussed.

Poster TUP043 [0.695 MB]

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TUP055

Technical Overview of Bunch Compressor System for PAL XFEL

quadrupole, vacuum, electron, diagnostics

490

H.-G. Lee, Y.-G. Jung, H.-S. Kang, D.E. Kim, K.W. Kim, S.B. Lee, D.H. Na, B.G. Oh, K.-H. Park, H.S. Suh, Y.J. Suh
PAL, Pohang, Kyungbuk, Republic of Korea

Pohang Accelerator Laboratory(PAL) is developing a SASE X-ray Free Electron Laser based on 10 GeV linear accelerator. Bunch compressor (BC) systems are developed to be used for the linear accelerator tunnel. It consists of three(BC1, BC2, BC3_H) hard X-ray line and one(BC3_S) soft X-ray line. BC systems are composed of four dipole magnets, three quadrupole magnet, BPM and collimator. The support system is based on an asymmetric four-dipole magnet chicane in which asymmetry and variable R56. can be optimized. This flexibility is achieved by allowing the middle two dipole magnets to move transversely. In this paper, we describe the design of the stages used for precise movement of the bunch compressor magnets and associated diagnostics components.

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WEP045

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

simulation, bunching, space-charge, 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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WEP069

Minimization of the Emittance Growth Induced by Coherent Synchrotron Radiation in Arc Compressor

emittance, synchrotron-radiation, simulation, synchrotron

711

X.Y. Huang, X. Cui, Y. Jiao, G. Xu
IHEP, Beijing, People's Republic of China

Funding: Supported by National Natural Science Foundation of China (11475202, 11405187).
Coherent synchrotron radiation (CSR) is a critical issue when electron bunches with short bunch length and high peak current transporting through a bending system in high-brightness light sources and linear colliders. For example, a high peak current of electron beam can be achieved by using magnetic bunch compressor, however, CSR induced transverse emittance growth will limit the performance of bunch compressor. In this paper, based on our 'two-dimensional point-kick analysis', an arc compressor with high compression factor is studied. Through analytical and numerical research, an easy optics design technique is introduced that could minimize the emittance dilution within this compressor. It is demonstrated that the strong compression of bunch length and the transverse emittance preservation can be achieved at the same time.

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