IPAC2016 - List of Keywords (bunching)

Paper	Title	Other Keywords	Page
MOPMB016	Single-Shot Spectral Analysis of Synchrotron Radiation in THz Regime at ANKA	detector, radiation, synchrotron, synchrotron-radiation	115
	A. Schmid, M. Brosi, E. Bründermann, K.S. Ilin, B. Kehrer, K. Kuzmin, A.-S. Müller, J. Raasch, M. Schuh, P. Schönfeldt, M. Siegel, J.L. Steinmann, S. Wuensch KIT, Karlsruhe, Germany S.A. Kuznetsov NSU, Novosibirsk, Russia
	Funding: This work was supported by BMBF contract number 05K13VK4 and the Ministry of Education and Sci- ence of the Russian Federation (State Assignment Contract No. 3002). Micro-bunching instabilities limit the longitudinal compression of bunches in an electron storage ring. They create substructures on the bunch profile of some hundred micrometer size leading to coherently emitted synchrotron radiation in the THz range. To detect the changing THz spectrum, single-shot bunch-by-bunch and turn-by-turn measurements are necessary. We present recent experiments at ANKA where the spectral information is extracted by simultaneous detection with several narrowband THz detectors, each of them sensitive in a different frequency range.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB016
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MOPMY014	Design Study of RF Section and Cavities for Cepc 650 MHz Klystron	klystron, cavity, simulation, electron	543
	O. Xiao Institute of High Energy Physics (IHEP), People's Republic of China D.D. Dong, S. Fukuda, Z.J. Lu, G. Pei, S.C. Wang, .. Zaib-un-Nisa, Z.S. Zhou IHEP, Beijing, People's Republic of China S. Fukuda KEK, Ibaraki, Japan
	An 800 kW CW klystron operating at 650 MHz is de-veloped for CEPC at Institute of High Energy Physics in China. The conceptual design has been finished and the main parameters are presented in this paper. A 1D large signal disk model code, AJDISK, has been used to design and optimize klystron RF section parameters. In addition, the RF cavities have been designed using SUPERFISH, HFSS and CST.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMY014
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MOPOW008	Reverse Undulator Tapering for Polarization Control at XFELs	undulator, FEL, resonance, radiation	722
	E. Schneidmiller, M.V. Yurkov DESY, Hamburg, Germany
	Baseline design of a typical X-ray FEL undulator assumes a planar configuration which results in a linear polarization of the FEL radiation. However, many experiments at X-ray FEL user facilities would profit from using a circularly polarized radiation. As a cheap upgrade one can consider an installation of a short helical afterburner, but then one should have an efficient method to suppress powerful linearly polarized background from the main undulator. We describe a method for such a suppression: an application of the reverse taper in the main undulator. In a certain range of the taper strength, the density modulation (bunching) at saturation is practically the same as in the case of non-tapered undulator while the power of linearly polarized radiation is suppressed by orders of magnitude. Then strongly modulated electron beam radiates at full power in the afterburner. The scheme was successfully tested at LCLS* and is routinely used in user experiments. In this contribution we present the theoretical description of the method as well as the results of experiments with reverse taper at FLASH2. * E.A. Schneidmiller and M.V. Yurkov, Phys. Rev. ST-AB 16, 110702 (2013) ** H.-D. Nuhn et al., "Commissioning of the DELTA polarizing undulator at LCLS", Proc. of FEL2015 Conf., Daejeon, Korea
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MOPOY016	HSI RFQ Upgrade for the UNILAC Injection to FAIR	rfq, emittance, simulation, ion	877
	C. Zhang, L. Groening, O.K. Kester, S. Mickat, H. Vormann GSI, Darmstadt, Germany M. Baschke, H. Podlech, U. Ratzinger, R. Tiede IAP, Frankfurt am Main, Germany
	As an injector to the future FAIR facility, the UNILAC accelerator is required to deliver ion beams with high intensities as well as good beam quality. The electrodes of the current HSI RFQ are exhausted and the current RFQ itself is assigned to be one bottle-neck for improving the brilliance performance of the whole linac. Based on the so-called NFSP (New Four-Section Procedure) method, a new RFQ electrode design has been developed and optimized for 20 emA, U⁴⁺ beams at the RFQ entrance. Since only the electrodes will be replaced, the RFQ length has been kept unchanged. Even with a lowered inter-vane voltage, the new RFQ design has achieved better beam performance compared to the previous design. This paper will focus on the performed study with respect to beam dynamics.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPOY016
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TUOCA01	LCLS Bunch Compressor Configuration Study for Soft X-ray Operation	electron, laser, linac, 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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TUPOR005	A Parallelized Vlasov-Fokker-Planck-Solver for Desktop PCs	simulation, damping, synchrotron, collective-effects	1658
	P. Schönfeldt, M. Brosi, A.-S. Müller, J.L. Steinmann KIT, Karlsruhe, Germany
	In order simulate the dynamics of an electron bunch due to the self-interaction with its own coherent synchrotron radiation it is a well established method to numerically solve the Vlasov-Fokker-Planck equation. In this paper we present a new, modularly extensible program that uses OpenCL to massively parallelize the computation, allowing a standard desktop PC to work with appropriate accuracy and yield reliable results within minutes. We provide numerical stability studies of over a huge parameter range and comparisons of our numerical results to other techniques.
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TUPOW009	Generation of Coherent Undulator Radiation using Extremely Short Electron Bunch at t-ACTS, Tohoku University	radiation, undulator, electron, injection	1760
	S. Kashiwagi, T. Abe, H. Hama, F. Hinode, T. Muto, I. Nagasawa, K. Nanbu, H. Saito, Y. Shibasaki, K. Takahashi, C. Tokoku Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
	An accelerator test facility, t-ACTS, was established at Research Center for Electron Photon Science, Tohoku University, in which an intense coherent terahertz (THz) radiation is generated from an extremely short electron bunch. Velocity bunching scheme in a traveling-wave accelerating structure is employed to produce the short electron bunch, and a production of sub-picosecond electron bunch was demonstrated. A long-period linear undulator, which has 25 periods with a period length of 10 cm and a peak magnetic field of 0.41 T, has been developed to produce intense coherent THz radiation. Properties of the radiation from the THz undulator such as radiation fields, spectrum and angular distribution were numerically investigated based on the parameters of short electron bunch and THz undulator. By optimization of bunch compression, it is possible to extract a coherent radiation of fundamental mode excluding higher-order mode. The detail of the numerical studies for the coherent undulator radiation will be reported in the conference.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW009
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TUPOW010	Production of Ultra-short Electron Pulse and Observation of Coherent Transition Radiation at t-ACTS, Tohoku University	radiation, electron, detector, injection	1763
	T. Abe, H. Hama, F. Hinode, S. Kashiwagi, T. Muto, I. Nagasawa, K. Nanbu, H. Saito, Y. Shibasaki, K. Takahashi, C. Tokoku Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
	A test-Accelerator as Coherent Terahertz Source (t-ACTS) project has been under development at Research Center for Electron Photon Science, Tohoku University. In order to generate a coherent radiation in terahertz (THz) region, it is necessary to produce sub-picosecond electron pulses. Velocity bunching scheme is employed for the short electron pulse production in t-ACTS. We experimentally confirmed the production of short electron pulse under 500 fs by measuring the bunch length using a streak camera. Coherent transition radiation in THz region was produced by which the short electron pulses pass through a vacuum-metal interface. Several radiation properties including　spatial distribution, polarization and spectrum were measured and compared with theoretical calculations. The details of the beam experiment at t-ACTS are described.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW010
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TUPOW016	Development of a C-Band 4/8 Mev Dual-Energy Accelerator for Cargo Inspection System	gun, cathode, controls, linac	1775
	J.H. Shao, H.B. Chen, W.-H. Huang, Q.X. Jin, Y.H. Liu, J. Shi, C.-X. Tang, X.W. Wu TUB, Beijing, People's Republic of China
	Modern cargo inspection system applies dual-energy X-ray for material discrimination. Based on the com-pact C-band 6 MeV standing-wave accelerating struc-tures developed at Tsinghua University, a compact C-band 4/8 MeV dual-energy accelerator has been pro-posed, fabricated and tested. Compared with that of the conventional S-band 3/6 MeV dual-energy accelera-tor at Tsinghua University, the volume and the weight of the C-band one has been reduced by ~40% and ~30%, respectively. Detailed review of this C-band dual-energy accelerator is present in the paper.
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TUPOW021	Beam Dynamics Optimization and Future Plans for LUE-200 Linac Upgrade	simulation, beam-loading, klystron, linac	1788
	S.M. Polozov, T.V. Bondarenko MEPhI, Moscow, Russia A.V. Butenko, V. Kobets, A.P. Sumbaev JINR, Dubna, Moscow Region, Russia
	The IREN facility (Intense Resonance Neutron Source) is now been tested and upgraded in JINR. The linear electron accelerator LUE-200 is used to generate intense fluxes of resonant photo-neutrons. Linac should deliver up to 200 MeV electron beam with 1 A or more current in 100 - 200 ns pulses. It consists of electron source, LEBT including buncher and two main accelerating sections (only one is installed up to now). Test operations shows that beam loading sufficiently influences the output beam parameters and beam energy after first section decreases from planned 55-60 MeV to 35 MeV. The buncher doesn't provide an efficient beam bunching also and beam recapturing by main section due to this is very low. Dynamics of the electron beam for traveling wave S-band linac LUE-200 was studied by numerical simulations. In report results of beam dynamics simulation and optimization taking into account beam loading discuss, parameters for new more effective buncher presents and first results of such buncher development shows.
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TUPOW023	New 10 MeV High-power Electron Linac for Industrial Application	linac, coupling, simulation, electron	1794
	S.M. Polozov, D.S. Bazyl, T.V. Bondarenko, M. Gusarova, Yu.D. Kliuchevskaia, M.V. Lalayan, V.I. Rashchikov, E.A. Savin MEPhI, Moscow, Russia M.I. Demsky, A.A. Eliseev, V.V. Krotov, D.E. Trifonov CORAD Ltd., St. Petersburg, Russia B.S. Han, W.G. Kang, H.G. Park EB TECH Co. Ltd., Daejeon, Republic of Korea
	Joint team of CORAD and MEPhI developed a new industrial accelerating structure for average beam power up to 20 kW and energy range from 7.5 to 10 MeV. The use of modern methods and codes for beam dynamics simulation, raised coupling coefficient and group velocity of SW biperiodic accelerating structure allowed to reach high pulse power utilization and obtain high efficiency. Gentle buncher provides high capturing coefficient and narrow energy spectrum. The first linear accelerator with this structure was constructed and tested in collaboration with the company EB Tech.
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WEPOW014	Spectral Studies of Ultrashort and Coherent Radiation Pulses at the DELTA Storage Ring	laser, radiation, electron, undulator	2851
	S. Khan, F.H. Bahnsen, M. Bolsinger, F. Götz, S. Hilbrich, M.A. Jebramcik, N.M. Lockmann, C. Mai, A. Meyer auf der Heide, R. Niemczyk, G. Shayeganrad, P. Ungelenk, D. Zimmermann DELTA, Dortmund, Germany
	Funding: Work supported by the BMBF (05K13PEC, 05K13PE3), the DFG (INST 212/236-1 FUGG), the Stiftung Mercator (Pr-2014-0047) and the state of NRW. At the 1.5-GeV synchrotron light source DELTA operated by the TU Dortmund University, ultrashort and coherent radiation pulses in the VUV and THz regime are routinely generated by the interaction of electron bunches with 45-fs laser pulses. A laser-induced modulation of the electron energy is converted into a density modulation (microbunching) by a magnetic chicane, giving rise to coherent emission at harmonics of the initial laser wavelength (coherent harmonic generation, CHG). As a first step towards active control of the shape and spectrum of CHG pulses, spectral studies were performed under variation of the chicane strength and the laser properties. The spectral phase of the laser pulses was controlled by tuning the compressor of the laser amplifier and was monitored using FROG (frequency-resolved optical gating). In this paper, monochromator scans as well as single-shot spectrograms of the CHG radiation are presented and compared to simulations of the laser-electron interaction and microbunching process. In addition, other results from the short-pulse facility as well as a future upgrade employing the echo-enabled harmonic generation (EEHG) scheme will be outlined.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOW014
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WEPOY028	Laser Heater System Test at PAL-XFEL ITF	laser, electron, undulator, FEL	3048
	J. H. Lee POSTECH, Pohang, Kyungbuk, Republic of Korea J.H. Han, J.H. Hong, C.H. Kim, I.S. Ko, S.J. Lee PAL, Pohang, Kyungbuk, Republic of Korea
	Coherent x-ray photons are generated by a free electron laser (FEL). In PAL-XFEL, a photon beam with a 0.1 nm wavelength is generated from an electron bunch based on self-amplified spontaneous emission (SASE). An electron bunch with an uncorrelated energy spread in a level of 3 keV, which is generated from the photocathode RF gun, may be sensitive to longitudinal micro-bunching instability. The energy spread of an electron bunch can be increased to suppress the instability by Landau damping. In order to control the uncorrelated energy spread, a laser heater system, which has a chicane with four dipoles chicane and a 0.5 m long undulator, was installed in the injector test facility (ITF) of PAL. In this paper, we introduce the parameters of the laser heater and heating effect on the electron bunch.
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Paper

Title

Other Keywords

Page

MOPMB016

Single-Shot Spectral Analysis of Synchrotron Radiation in THz Regime at ANKA

detector, radiation, synchrotron, synchrotron-radiation

115

A. Schmid, M. Brosi, E. Bründermann, K.S. Ilin, B. Kehrer, K. Kuzmin, A.-S. Müller, J. Raasch, M. Schuh, P. Schönfeldt, M. Siegel, J.L. Steinmann, S. Wuensch
KIT, Karlsruhe, Germany
S.A. Kuznetsov
NSU, Novosibirsk, Russia

Funding: This work was supported by BMBF contract number 05K13VK4 and the Ministry of Education and Sci- ence of the Russian Federation (State Assignment Contract No. 3002).
Micro-bunching instabilities limit the longitudinal compression of bunches in an electron storage ring. They create substructures on the bunch profile of some hundred micrometer size leading to coherently emitted synchrotron radiation in the THz range. To detect the changing THz spectrum, single-shot bunch-by-bunch and turn-by-turn measurements are necessary. We present recent experiments at ANKA where the spectral information is extracted by simultaneous detection with several narrowband THz detectors, each of them sensitive in a different frequency range.

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MOPMY014

Design Study of RF Section and Cavities for Cepc 650 MHz Klystron

klystron, cavity, simulation, electron

543

O. Xiao
Institute of High Energy Physics (IHEP), People's Republic of China
D.D. Dong, S. Fukuda, Z.J. Lu, G. Pei, S.C. Wang, .. Zaib-un-Nisa, Z.S. Zhou
IHEP, Beijing, People's Republic of China
S. Fukuda
KEK, Ibaraki, Japan

An 800 kW CW klystron operating at 650 MHz is de-veloped for CEPC at Institute of High Energy Physics in China. The conceptual design has been finished and the main parameters are presented in this paper. A 1D large signal disk model code, AJDISK, has been used to design and optimize klystron RF section parameters. In addition, the RF cavities have been designed using SUPERFISH, HFSS and CST.

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MOPOW008

Reverse Undulator Tapering for Polarization Control at XFELs

undulator, FEL, resonance, radiation

722

E. Schneidmiller, M.V. Yurkov
DESY, Hamburg, Germany

Baseline design of a typical X-ray FEL undulator assumes a planar configuration which results in a linear polarization of the FEL radiation. However, many experiments at X-ray FEL user facilities would profit from using a circularly polarized radiation. As a cheap upgrade one can consider an installation of a short helical afterburner, but then one should have an efficient method to suppress powerful linearly polarized background from the main undulator. We describe a method for such a suppression: an application of the reverse taper in the main undulator*. In a certain range of the taper strength, the density modulation (bunching) at saturation is practically the same as in the case of non-tapered undulator while the power of linearly polarized radiation is suppressed by orders of magnitude. Then strongly modulated electron beam radiates at full power in the afterburner. The scheme was successfully tested at LCLS** and is routinely used in user experiments. In this contribution we present the theoretical description of the method as well as the results of experiments with reverse taper at FLASH2.
* E.A. Schneidmiller and M.V. Yurkov, Phys. Rev. ST-AB 16, 110702 (2013)
** H.-D. Nuhn et al., "Commissioning of the DELTA polarizing undulator at LCLS", Proc. of FEL2015 Conf., Daejeon, Korea

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MOPOY016

HSI RFQ Upgrade for the UNILAC Injection to FAIR

rfq, emittance, simulation, ion

877

C. Zhang, L. Groening, O.K. Kester, S. Mickat, H. Vormann
GSI, Darmstadt, Germany
M. Baschke, H. Podlech, U. Ratzinger, R. Tiede
IAP, Frankfurt am Main, Germany

As an injector to the future FAIR facility, the UNILAC accelerator is required to deliver ion beams with high intensities as well as good beam quality. The electrodes of the current HSI RFQ are exhausted and the current RFQ itself is assigned to be one bottle-neck for improving the brilliance performance of the whole linac. Based on the so-called NFSP (New Four-Section Procedure) method, a new RFQ electrode design has been developed and optimized for 20 emA, U⁴⁺ beams at the RFQ entrance. Since only the electrodes will be replaced, the RFQ length has been kept unchanged. Even with a lowered inter-vane voltage, the new RFQ design has achieved better beam performance compared to the previous design. This paper will focus on the performed study with respect to beam dynamics.

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TUOCA01

LCLS Bunch Compressor Configuration Study for Soft X-ray Operation

electron, laser, linac, 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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TUPOR005

A Parallelized Vlasov-Fokker-Planck-Solver for Desktop PCs

simulation, damping, synchrotron, collective-effects

1658

P. Schönfeldt, M. Brosi, A.-S. Müller, J.L. Steinmann
KIT, Karlsruhe, Germany

In order simulate the dynamics of an electron bunch due to the self-interaction with its own coherent synchrotron radiation it is a well established method to numerically solve the Vlasov-Fokker-Planck equation. In this paper we present a new, modularly extensible program that uses OpenCL to massively parallelize the computation, allowing a standard desktop PC to work with appropriate accuracy and yield reliable results within minutes. We provide numerical stability studies of over a huge parameter range and comparisons of our numerical results to other techniques.

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TUPOW009

Generation of Coherent Undulator Radiation using Extremely Short Electron Bunch at t-ACTS, Tohoku University

radiation, undulator, electron, injection

1760

S. Kashiwagi, T. Abe, H. Hama, F. Hinode, T. Muto, I. Nagasawa, K. Nanbu, H. Saito, Y. Shibasaki, K. Takahashi, C. Tokoku
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan

An accelerator test facility, t-ACTS, was established at Research Center for Electron Photon Science, Tohoku University, in which an intense coherent terahertz (THz) radiation is generated from an extremely short electron bunch. Velocity bunching scheme in a traveling-wave accelerating structure is employed to produce the short electron bunch, and a production of sub-picosecond electron bunch was demonstrated. A long-period linear undulator, which has 25 periods with a period length of 10 cm and a peak magnetic field of 0.41 T, has been developed to produce intense coherent THz radiation. Properties of the radiation from the THz undulator such as radiation fields, spectrum and angular distribution were numerically investigated based on the parameters of short electron bunch and THz undulator. By optimization of bunch compression, it is possible to extract a coherent radiation of fundamental mode excluding higher-order mode. The detail of the numerical studies for the coherent undulator radiation will be reported in the conference.

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TUPOW010

Production of Ultra-short Electron Pulse and Observation of Coherent Transition Radiation at t-ACTS, Tohoku University

radiation, electron, detector, injection

1763

T. Abe, H. Hama, F. Hinode, S. Kashiwagi, T. Muto, I. Nagasawa, K. Nanbu, H. Saito, Y. Shibasaki, K. Takahashi, C. Tokoku
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan

A test-Accelerator as Coherent Terahertz Source (t-ACTS) project has been under development at Research Center for Electron Photon Science, Tohoku University. In order to generate a coherent radiation in terahertz (THz) region, it is necessary to produce sub-picosecond electron pulses. Velocity bunching scheme is employed for the short electron pulse production in t-ACTS. We experimentally confirmed the production of short electron pulse under 500 fs by measuring the bunch length using a streak camera. Coherent transition radiation in THz region was produced by which the short electron pulses pass through a vacuum-metal interface. Several radiation properties including　spatial distribution, polarization and spectrum were measured and compared with theoretical calculations. The details of the beam experiment at t-ACTS are described.

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TUPOW016

Development of a C-Band 4/8 Mev Dual-Energy Accelerator for Cargo Inspection System

gun, cathode, controls, linac

1775

J.H. Shao, H.B. Chen, W.-H. Huang, Q.X. Jin, Y.H. Liu, J. Shi, C.-X. Tang, X.W. Wu
TUB, Beijing, People's Republic of China

Modern cargo inspection system applies dual-energy X-ray for material discrimination. Based on the com-pact C-band 6 MeV standing-wave accelerating struc-tures developed at Tsinghua University, a compact C-band 4/8 MeV dual-energy accelerator has been pro-posed, fabricated and tested. Compared with that of the conventional S-band 3/6 MeV dual-energy accelera-tor at Tsinghua University, the volume and the weight of the C-band one has been reduced by ~40% and ~30%, respectively. Detailed review of this C-band dual-energy accelerator is present in the paper.

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TUPOW021

Beam Dynamics Optimization and Future Plans for LUE-200 Linac Upgrade

simulation, beam-loading, klystron, linac

1788

S.M. Polozov, T.V. Bondarenko
MEPhI, Moscow, Russia
A.V. Butenko, V. Kobets, A.P. Sumbaev
JINR, Dubna, Moscow Region, Russia

The IREN facility (Intense Resonance Neutron Source) is now been tested and upgraded in JINR. The linear electron accelerator LUE-200 is used to generate intense fluxes of resonant photo-neutrons. Linac should deliver up to 200 MeV electron beam with 1 A or more current in 100 - 200 ns pulses. It consists of electron source, LEBT including buncher and two main accelerating sections (only one is installed up to now). Test operations shows that beam loading sufficiently influences the output beam parameters and beam energy after first section decreases from planned 55-60 MeV to 35 MeV. The buncher doesn't provide an efficient beam bunching also and beam recapturing by main section due to this is very low. Dynamics of the electron beam for traveling wave S-band linac LUE-200 was studied by numerical simulations. In report results of beam dynamics simulation and optimization taking into account beam loading discuss, parameters for new more effective buncher presents and first results of such buncher development shows.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW021

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TUPOW023

New 10 MeV High-power Electron Linac for Industrial Application

linac, coupling, simulation, electron

1794

S.M. Polozov, D.S. Bazyl, T.V. Bondarenko, M. Gusarova, Yu.D. Kliuchevskaia, M.V. Lalayan, V.I. Rashchikov, E.A. Savin
MEPhI, Moscow, Russia
M.I. Demsky, A.A. Eliseev, V.V. Krotov, D.E. Trifonov
CORAD Ltd., St. Petersburg, Russia
B.S. Han, W.G. Kang, H.G. Park
EB TECH Co. Ltd., Daejeon, Republic of Korea

Joint team of CORAD and MEPhI developed a new industrial accelerating structure for average beam power up to 20 kW and energy range from 7.5 to 10 MeV. The use of modern methods and codes for beam dynamics simulation, raised coupling coefficient and group velocity of SW biperiodic accelerating structure allowed to reach high pulse power utilization and obtain high efficiency. Gentle buncher provides high capturing coefficient and narrow energy spectrum. The first linear accelerator with this structure was constructed and tested in collaboration with the company EB Tech.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW023

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WEPOW014

Spectral Studies of Ultrashort and Coherent Radiation Pulses at the DELTA Storage Ring

laser, radiation, electron, undulator

2851

S. Khan, F.H. Bahnsen, M. Bolsinger, F. Götz, S. Hilbrich, M.A. Jebramcik, N.M. Lockmann, C. Mai, A. Meyer auf der Heide, R. Niemczyk, G. Shayeganrad, P. Ungelenk, D. Zimmermann
DELTA, Dortmund, Germany

Funding: Work supported by the BMBF (05K13PEC, 05K13PE3), the DFG (INST 212/236-1 FUGG), the Stiftung Mercator (Pr-2014-0047) and the state of NRW.
At the 1.5-GeV synchrotron light source DELTA operated by the TU Dortmund University, ultrashort and coherent radiation pulses in the VUV and THz regime are routinely generated by the interaction of electron bunches with 45-fs laser pulses. A laser-induced modulation of the electron energy is converted into a density modulation (microbunching) by a magnetic chicane, giving rise to coherent emission at harmonics of the initial laser wavelength (coherent harmonic generation, CHG). As a first step towards active control of the shape and spectrum of CHG pulses, spectral studies were performed under variation of the chicane strength and the laser properties. The spectral phase of the laser pulses was controlled by tuning the compressor of the laser amplifier and was monitored using FROG (frequency-resolved optical gating). In this paper, monochromator scans as well as single-shot spectrograms of the CHG radiation are presented and compared to simulations of the laser-electron interaction and microbunching process. In addition, other results from the short-pulse facility as well as a future upgrade employing the echo-enabled harmonic generation (EEHG) scheme will be outlined.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOW014

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WEPOY028

Laser Heater System Test at PAL-XFEL ITF

laser, electron, undulator, FEL

3048

J. H. Lee
POSTECH, Pohang, Kyungbuk, Republic of Korea
J.H. Han, J.H. Hong, C.H. Kim, I.S. Ko, S.J. Lee
PAL, Pohang, Kyungbuk, Republic of Korea

Coherent x-ray photons are generated by a free electron laser (FEL). In PAL-XFEL, a photon beam with a 0.1 nm wavelength is generated from an electron bunch based on self-amplified spontaneous emission (SASE). An electron bunch with an uncorrelated energy spread in a level of 3 keV, which is generated from the photocathode RF gun, may be sensitive to longitudinal micro-bunching instability. The energy spread of an electron bunch can be increased to suppress the instability by Landau damping. In order to control the uncorrelated energy spread, a laser heater system, which has a chicane with four dipoles chicane and a 0.5 m long undulator, was installed in the injector test facility (ITF) of PAL. In this paper, we introduce the parameters of the laser heater and heating effect on the electron bunch.

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reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOY028

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