IPAC2017 - Classification: 05 Beam Dynamics and Electromagnetic Fields / D09 Emittance Manipulation, Bunch Compression and Cooling

Paper	Title	Page
MOZA2	Beams by Design and FEL Seeding
	E. Hemsing SLAC, Menlo Park, California, USA
	In a modern light source, the ability to carefully manipulate the electron beam longitudinal phase space enables detailed control of the resulting radiation pulse. This talk will describe techniques to tailor the electron beam distribution for seeding of an FEL including experimental demonstrations at NLCTA, FLASH, Shanghai, and FERMI. Recent results include measurements of the Echo (EEHG) technique to generate the 75th harmonic.
	Slides MOZA2 [8.739 MB]
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THPAB012	Beam Transport Optimization for Applying an SRF Gun at the ELBE Center	3712
	P.N. Lu, A. Arnold, P. Murcek, J. Teichert, H. Vennekate, R. Xiang HZDR, Dresden, Germany
	An SRF gun at the ELBE center has been operated with a magnesium cathode. Electron beams were produced with a maximum bunch charge of 200 pC and an emit-tance of 7.7 μm. Simulations have been conducted with ASTRA and Elegant for applying the SRF gun to ELBE user experiments, including neutron beam generation, positron beam generation, THz radiation and Compton backscattering experiment. Beam transport has been optimized to solve the best beam performance for these user stations at the bunch charge of 200 pC. Simulation results indicate that the SRF gun is potential to benefit the high bunch charge applications at ELBE.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB012
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THPAB024	Emittance Growth at Charge-Exchanging Multi-Turn Injection in KURRI FFAG	3747
	T. Uesugi, Y. Ishi, Y. Kuriyama, Y. Mori Kyoto University, Research Reactor Institute, Osaka, Japan
	In the fixed field alternating gradient (FFAG) synchrotron in Kyoto university research reactor institute (KURRI), rapid beam loss of factor 100 is observed right after the injection. In the synchrotron, charge-exchanging multi-turn injection is adopted with a stripping foil located on the closed orbit of the injection energy. No bump orbit system is used and the injected beams escape from the foil according to the closed-orbit shift by acceleration. The particles hit the foil many times and that is why the emittance grows up during the injection. In this paper, simulation studies are done to estimate the emittance growth and beam losses. The scattering effect at the foil is modeled by GEANT4.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB024
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THPAB034	Generation of Short Intense Heavy-Ion Pulses in HIAF	3774
	D.Y. Yin, H. Du, L.J. Mao, G.D. Shen, J.W. Xia, J.C. Yang IMP/CAS, Lanzhou, People's Republic of China
	The HIAF is a new accelerator complex under design at IMP to provide intense primary and radioactive ion beams for nuclear physics, atomic physics, high energy density physics and other applications. As a key part of HIAF, the Booster Ring (BRing) is designed to accumulate and accelerate heavy ion beams provided by iLinac up to high intensity and energy. The high quality, well focused, strongly bunched intense Uranium beam (U³⁴⁺) with high energy and high intensity of 10¹¹ will open a new area for the HED physics research in laboratory. Based on the beam parameters of 238U³⁴⁺ proposed by the BRing, the two critical issues of producing short bunch with high beam intensity are studied. One is efficiency of adiabatic capture which can be a necessary prerequisite to ensure the beam intensity, and the other one is bunch compression in longitudinal which is an effective way of producing short pulse duration bunch. In this article, the analytical calculations and tracking simulations are described, the capture efficiency and possible bunch length under the action of planning RF system are presented
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB034
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THPAB036	An Experimental Study of Beam Dynamics in the ERL-Based Novosibirsk Free Electron Laser	3781
	V.M. Borin, L.M. Schegolev, O.A. Shevchenko, N.A. Vinokurov BINP SB RAS, Novosibirsk, Russia V.L. Dorokhov, O.I. Meshkov BINP, Novosibirsk, Russia
	Transverse and longitudinal dynamics of the electron beam of the Novosibirsk infrared Free Electron Laser is studied. The Novosibirsk FEL is based on the multi-turn energy recovery linac (ERL). The ERL operate in CW mode with an average current about 10 mA. Therefore non-destructive beam diagnostics is preferable. The beam energy at the last track of the ERL is 42 MeV. As a result, significant part of synchrotron radiation from bending magnets is in the visible range. The transverse beam dimensions were measured with the optical diagnostics before and after the undulator applied for generation of middle-infrared coherent radiation. The obtained data is used to calculate the beam energy spread and emittance. The longitudinal beam dynamics was studied with electro-optical dissector.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB036
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THPAB061	Limiting Effects in the Double EEX Beamline	3858
	G. Ha POSTECH, Pohang, Kyungbuk, Republic of Korea M.E. Conde, D.S. Doran, J.G. Power ANL, Argonne, Illinois, USA
	Funding: This work is supported by Department of Energy, Office of High Energy Physics, under Contract No. DE-AC02-06CH11357. The double emittance exchange (EEX) beamline is suggested to overcome the large horizontal emittance and transverse jitter issues associated with the single EEX beamline while preserving its powerful phase-space manipulation capability. However, the double EEX beamline also has potential limitations due to coherent synchrotron radiation (CSR) and transverse jitter. The former limitation arises because double EEX uses twice as many bending magnets as single EEX which means stronger CSR effects degrading the beam quality. The latter limitation arises because a longitudinal jitter in front of the first EEX beamline is converted into a transverse jitter in the middle section (between the EEX beamlines) which can cause beam loss or beam degradation. In this paper, we numerically explore the effects of these two limitations on the emittance and beam transport.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB061
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THPAB062	Preliminary Simulations on Chirpless Bunch Compression using Double-EEX Beamline	3862
	G. Ha POSTECH, Pohang, Kyungbuk, Republic of Korea M.E. Conde, D.S. Doran, W. Gai, J.G. Power ANL, Argonne, Illinois, USA
	Funding: This work is supported by Department of Energy, Office of High Energy Physics, under Contract No. DE-AC02-06CH11357. An emittance exchange (EEX) beamline can be used to compress an electron bunch via its transverse-to-longitudinal exchange mechanism. We are investigating this as an alternative to the normal magnetic chicane bunch compressor. The chicane method requires a longitudinal chirp before the chicane (since it relies on the path length difference of different energies) which results in an unwanted chirp after the compressor. Alternatively, the EEX method uses quadrupole magnets to compress the bunch. In this paper, we present preliminary simulations in preparation for a demonstration of chirp-less bunch compression using an EEX beamline at the Argonne Wakefield Accelerator facility.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB062
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THPAB073	Magnetized and Flat Beam Experiment at FAST	3876
	A. Halavanau, P. Piot Northern Illinois University, DeKalb, Illinois, USA J. Hyun Sokendai, Ibaraki, Japan D. Mihalcea, P. Piot, T. Sen, J.C.T. Thangaraj Fermilab, Batavia, Illinois, USA
	A photocathode, immersed in solenoidal magnetic field, can produce canonical-angular-momentum (CAM) dominated electron beams. Such beams have an application in electron cooling of hadron beams and can also be uncoupled to yield asymmetric-emittance (flat) beams. In the present paper we explore the possibilities of the flat beam generation at Fermilab's Accelerator Science and Technology (FAST) facility linear accelerator. We present optimization of the beam flatness and four-dimensional transverse emittance and investigate the mapping and its limitations of the produced eigen-emittances to conventional emittances using a skew-quadrupole channel. Possible application of flat beams at the FAST facility are also discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB073
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THPAB079	Terahertz Chirper for the Bunch Compression of Ultra-Low Emittance Beams	3899
	A.R. Vrielink, A. Marinelli, E.A. Nanni SLAC, Menlo Park, California, USA
	Recent efforts have demonstrated the possibility of achieving ultralow transverse emittance beams for high brightness light sources and free electron lasers. While these lower emittances should translate to improved lasing efficiency and higher peak brightness in FELs, these beams are commensurately more vulnerable to coherent synchrotron radiation (CSR) for the selfsame reasons. Conserving these ultralow emittances through the bunch compressors in an FEL given their increased propensity to emit CSR is particularly challenging. We investigate the possibility of imposing a large energy chirp at terahertz wavelengths to reduce the required magnetic fields in the compressor, counteracting the ultralow emittance in the generation of CSR. A second, higher frequency THz chirper would then be used to dechirp the beam after the chicane. Operation at THz as opposed to conventional radiofrequencies offers significantly larger chirp at similar input powers, yet still with wavelengths greater than typical FEL bunch lengths (several femtoseconds). Potential experimental schemes will be suggested in the context of LCLS and their feasibility evaluated. S. Bettoni, M. Pedrozzi and S. Reiche, Phys. Rev. ST Accel. Beams. 18, 123403 (December, 2015).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB079
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THPAB084	Integration of the Full-Acceptance Detector Into the JLEIC	3912
	G.H. Wei, F. Lin, V.S. Morozov, F.C. Pilat, Y. Zhang JLab, Newport News, Virginia, USA Y.M. Nosochkov SLAC, Menlo Park, California, USA M.-H. Wang Self Employment, Private address, USA
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contracts No. DE-AC05-06OR23177 and DE-AC02-06CH11357. Work supported also by the U.S. DOE Contract DE-AC02-76SF00515. For physics requirements, the JLEIC (Jefferson Lab Electron Ion Collider) has a full-acceptance detector, which brings many new challenges to the beam dynamics integration. For example, asymmetric lattice and beam envelopes at interaction region (IR), forward detection, and large crossing angle with crab dynamics. Also some common problems complicate the picture, like coupling and coherent orbit from detector solenoid, high chromaticity and high multipole sensitivity from low beta-star at interaction point (IP), collision mode with different energy and ion species. Meanwhile, to get a luminosity level of a few 10³³ cm^-2ses⁻¹, small beta-star are necessary at the IP, which also means large beta in the final focus area, chromaticity correction sections, etc. This sets a constraint on the field quality of magnets in large beta areas, in order to ensure a large enough dynamic aperture (DA). In this context, limiting multipole components of magnets are surveyed to get a standard line. And continuously, multipole magnets as dedicated correctors are studied to provide semi-local corrections of specific multipole components beyond the standard line.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB084
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THPAB087	Emittance Measurements and Simulations in 112 MHz Super-Conducting RF Electron Gun With CsK2Sb Photo-Cathode	3921
SUSPSIK063	use link to see paper's listing under its alternate paper code
	K. Mihara Stony Brook University, Stony Brook, USA D. Kayran, V. Litvinenko, T.A. Miller, I. Pinayev BNL, Upton, Long Island, New York, USA
	The commissioning of the coherent electron cooling (CeC) proof of principle experiment is under way at Relativistic Heavy Ion Collider (RHIC).. A 112 MHz superconducting radio frequency photo-emission gun is used to generate the electron beam for this experiment. In this paper we report selected results of experimental emittance measurements and compare them with our simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB087
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THPAB088	Comparison of Theory, Simulation, and Experiment for Dynamical Extinction of Relativistic Electron Beams Diffracted Through a Si Crystal Membrane	3924
SUSPSIK064	use link to see paper's listing under its alternate paper code
	L.E. Malin, W.S. Graves, J. Spence, C. Zhang Arizona State University, Tempe, USA R.K. Li, C. Limborg, E.A. Nanni, X. Shen, S.P. Weathersby SLAC, Menlo Park, California, USA
	Diffraction in the transmission geometry through a single-crystal silicon slab is exploited to control the intensity of a relativistic electron beam. The choice of crystal thickness and incidence angle can extinguish or maximize the transmitted beam intensity via coherent multiple Bragg scattering; thus, the crystal acts as a dynamical beam stop through the Pendel'sung effect, a well-known phenomenon in X-ray and electron diffraction. In an initial experiment, we have measured the ability of this method to transmit or extinguish the primary beam and diffract into a single Bragg peak. Using lithographic etching of patterns in the crystal we intend to use this method to nanopattern an electron beam for production of coherent x-rays. We compare the experimental results with simulations using the multislice method to model the diffraction pattern from a perfect silicon crystal of uniform thickness, considering multiple scattering, crystallographic orientation, temperature effects, and partial coherence from the momentum spread of the beam. The simulations are compared to data collected at the ASTA UED facility at SLAC for a 340 nm thick Si(100) wafer with a beam energy of 2.35 MeV.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB088
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THPIK093	Blow-Up Due to Intra Beam Scattering during Deceleration in ELENA	4303
	C. Carli, M. Martini CERN, Geneva, Switzerland
	Intra Beam Scattering (IBS) is expected to be the main performance limitation of the Extra Low Energy Antiproton ring (ELENA), a small synchrotron equipped with electron cooling under construction at CERN to decelerate antiprotons from 5.3 MeV to 100 keV. Thus, the duration of the ramps must not be too long to avoid excessive blow up due to IBS. On the other hand, the bending magnets are C-shaped and the vacuum chambers are without insulated junctions, which are difficult for fully baked machines; thus, the ramps must not be too short. The evolution of transverse and longitudinal emittances along the ramps have been estimated assuming that IBS is the main phenomenon leading to blow-up. The blow-up due to IBS found along the ramps have been found to be acceptable.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK093
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FRXAA1	Laser Cooling of Relativistic Heavy Ion Beams
	M.H. Bussmann, M. Löser HZDR, Dresden, Germany O. Boine-Frankenheim, L. Eidam TEMF, TU Darmstadt, Darmstadt, Germany O. Boine-Frankenheim, L. Eidam, T. Kühl, F. Nolden, R.M. Sanchez Alarcon, M. Steck, T. Stöhlker, D.F.A. Winters GSI, Darmstadt, Germany A. Buss, V. Hannen, D. Winzen Westfälische Wilhelms-Universität Münster, Institut für Kernphysik, Münster, Germany Z. Huang, X. Ma, H. Wang, W.Q. Wen IMP/CAS, Lanzhou, People's Republic of China D. Kiefer, S. Klammes, W. Nörtershäuser, J. Ullmann, T. Walther TU Darmstadt, Darmstadt, Germany U. Schramm TU Dresden, Dresden, Germany U. Schramm, M. Siebold Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiation Physics, Dresden, Germany T. Stöhlker IOQ, Jena, Germany T. Stöhlker HIJ, Jena, Germany C. Weinheimer Institut für Kernphysik, Westfälische Wilhelms-Universität Münster, Münster, Germany
	At high energies laser cooling is a very promising technique to reduce phase space of beams of high energy ions effciently and fast. With the advent of new facilities such as FAIR and HIAF research focuses on developing robust laser cooling setups. This requires an understanding of the underlying beam dynamics at high beam intensities, the development of reliable laser systems that can be used to cool a large variety of ion species and optical detection systems that complement standard accelerator beam diagnostics. Based on the lessons learned from ongoing experiments at the ESR at GSI, Darmstadt, and the CSRe at IMP, Lanzhou, the important design aspects of future laser cooling installations will be discussed. The talk will follow a how-to approach to discuss key design aspects of laser cooling setups and emphasize the important connection between advanced beam dynamics studies and optical control and diagnostics.
	Slides FRXAA1 [4.765 MB]
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Paper

Title

Page

MOZA2

Beams by Design and FEL Seeding

E. Hemsing
SLAC, Menlo Park, California, USA

In a modern light source, the ability to carefully manipulate the electron beam longitudinal phase space enables detailed control of the resulting radiation pulse. This talk will describe techniques to tailor the electron beam distribution for seeding of an FEL including experimental demonstrations at NLCTA, FLASH, Shanghai, and FERMI. Recent results include measurements of the Echo (EEHG) technique to generate the 75th harmonic.

Slides MOZA2 [8.739 MB]

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THPAB012

Beam Transport Optimization for Applying an SRF Gun at the ELBE Center

3712

P.N. Lu, A. Arnold, P. Murcek, J. Teichert, H. Vennekate, R. Xiang
HZDR, Dresden, Germany

An SRF gun at the ELBE center has been operated with a magnesium cathode. Electron beams were produced with a maximum bunch charge of 200 pC and an emit-tance of 7.7 μm. Simulations have been conducted with ASTRA and Elegant for applying the SRF gun to ELBE user experiments, including neutron beam generation, positron beam generation, THz radiation and Compton backscattering experiment. Beam transport has been optimized to solve the best beam performance for these user stations at the bunch charge of 200 pC. Simulation results indicate that the SRF gun is potential to benefit the high bunch charge applications at ELBE.

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THPAB024

Emittance Growth at Charge-Exchanging Multi-Turn Injection in KURRI FFAG

3747

T. Uesugi, Y. Ishi, Y. Kuriyama, Y. Mori
Kyoto University, Research Reactor Institute, Osaka, Japan

In the fixed field alternating gradient (FFAG) synchrotron in Kyoto university research reactor institute (KURRI), rapid beam loss of factor 100 is observed right after the injection. In the synchrotron, charge-exchanging multi-turn injection is adopted with a stripping foil located on the closed orbit of the injection energy. No bump orbit system is used and the injected beams escape from the foil according to the closed-orbit shift by acceleration. The particles hit the foil many times and that is why the emittance grows up during the injection. In this paper, simulation studies are done to estimate the emittance growth and beam losses. The scattering effect at the foil is modeled by GEANT4.

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THPAB034

Generation of Short Intense Heavy-Ion Pulses in HIAF

3774

D.Y. Yin, H. Du, L.J. Mao, G.D. Shen, J.W. Xia, J.C. Yang
IMP/CAS, Lanzhou, People's Republic of China

The HIAF is a new accelerator complex under design at IMP to provide intense primary and radioactive ion beams for nuclear physics, atomic physics, high energy density physics and other applications. As a key part of HIAF, the Booster Ring (BRing) is designed to accumulate and accelerate heavy ion beams provided by iLinac up to high intensity and energy. The high quality, well focused, strongly bunched intense Uranium beam (U³⁴⁺) with high energy and high intensity of 10¹¹ will open a new area for the HED physics research in laboratory. Based on the beam parameters of 238U³⁴⁺ proposed by the BRing, the two critical issues of producing short bunch with high beam intensity are studied. One is efficiency of adiabatic capture which can be a necessary prerequisite to ensure the beam intensity, and the other one is bunch compression in longitudinal which is an effective way of producing short pulse duration bunch. In this article, the analytical calculations and tracking simulations are described, the capture efficiency and possible bunch length under the action of planning RF system are presented

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THPAB036

An Experimental Study of Beam Dynamics in the ERL-Based Novosibirsk Free Electron Laser

3781

V.M. Borin, L.M. Schegolev, O.A. Shevchenko, N.A. Vinokurov
BINP SB RAS, Novosibirsk, Russia
V.L. Dorokhov, O.I. Meshkov
BINP, Novosibirsk, Russia

Transverse and longitudinal dynamics of the electron beam of the Novosibirsk infrared Free Electron Laser is studied. The Novosibirsk FEL is based on the multi-turn energy recovery linac (ERL). The ERL operate in CW mode with an average current about 10 mA. Therefore non-destructive beam diagnostics is preferable. The beam energy at the last track of the ERL is 42 MeV. As a result, significant part of synchrotron radiation from bending magnets is in the visible range. The transverse beam dimensions were measured with the optical diagnostics before and after the undulator applied for generation of middle-infrared coherent radiation. The obtained data is used to calculate the beam energy spread and emittance. The longitudinal beam dynamics was studied with electro-optical dissector.

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THPAB061

Limiting Effects in the Double EEX Beamline

3858

G. Ha
POSTECH, Pohang, Kyungbuk, Republic of Korea
M.E. Conde, D.S. Doran, J.G. Power
ANL, Argonne, Illinois, USA

Funding: This work is supported by Department of Energy, Office of High Energy Physics, under Contract No. DE-AC02-06CH11357.
The double emittance exchange (EEX) beamline is suggested to overcome the large horizontal emittance and transverse jitter issues associated with the single EEX beamline while preserving its powerful phase-space manipulation capability. However, the double EEX beamline also has potential limitations due to coherent synchrotron radiation (CSR) and transverse jitter. The former limitation arises because double EEX uses twice as many bending magnets as single EEX which means stronger CSR effects degrading the beam quality. The latter limitation arises because a longitudinal jitter in front of the first EEX beamline is converted into a transverse jitter in the middle section (between the EEX beamlines) which can cause beam loss or beam degradation. In this paper, we numerically explore the effects of these two limitations on the emittance and beam transport.

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THPAB062

Preliminary Simulations on Chirpless Bunch Compression using Double-EEX Beamline

3862

G. Ha
POSTECH, Pohang, Kyungbuk, Republic of Korea
M.E. Conde, D.S. Doran, W. Gai, J.G. Power
ANL, Argonne, Illinois, USA

Funding: This work is supported by Department of Energy, Office of High Energy Physics, under Contract No. DE-AC02-06CH11357.
An emittance exchange (EEX) beamline can be used to compress an electron bunch via its transverse-to-longitudinal exchange mechanism. We are investigating this as an alternative to the normal magnetic chicane bunch compressor. The chicane method requires a longitudinal chirp before the chicane (since it relies on the path length difference of different energies) which results in an unwanted chirp after the compressor. Alternatively, the EEX method uses quadrupole magnets to compress the bunch. In this paper, we present preliminary simulations in preparation for a demonstration of chirp-less bunch compression using an EEX beamline at the Argonne Wakefield Accelerator facility.

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THPAB073

Magnetized and Flat Beam Experiment at FAST

3876

A. Halavanau, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
J. Hyun
Sokendai, Ibaraki, Japan
D. Mihalcea, P. Piot, T. Sen, J.C.T. Thangaraj
Fermilab, Batavia, Illinois, USA

A photocathode, immersed in solenoidal magnetic field, can produce canonical-angular-momentum (CAM) dominated electron beams. Such beams have an application in electron cooling of hadron beams and can also be uncoupled to yield asymmetric-emittance (flat) beams. In the present paper we explore the possibilities of the flat beam generation at Fermilab's Accelerator Science and Technology (FAST) facility linear accelerator. We present optimization of the beam flatness and four-dimensional transverse emittance and investigate the mapping and its limitations of the produced eigen-emittances to conventional emittances using a skew-quadrupole channel. Possible application of flat beams at the FAST facility are also discussed.

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THPAB079

Terahertz Chirper for the Bunch Compression of Ultra-Low Emittance Beams

3899

A.R. Vrielink, A. Marinelli, E.A. Nanni
SLAC, Menlo Park, California, USA

Recent efforts have demonstrated the possibility of achieving ultralow transverse emittance beams for high brightness light sources and free electron lasers*. While these lower emittances should translate to improved lasing efficiency and higher peak brightness in FELs, these beams are commensurately more vulnerable to coherent synchrotron radiation (CSR) for the selfsame reasons. Conserving these ultralow emittances through the bunch compressors in an FEL given their increased propensity to emit CSR is particularly challenging. We investigate the possibility of imposing a large energy chirp at terahertz wavelengths to reduce the required magnetic fields in the compressor, counteracting the ultralow emittance in the generation of CSR. A second, higher frequency THz chirper would then be used to dechirp the beam after the chicane. Operation at THz as opposed to conventional radiofrequencies offers significantly larger chirp at similar input powers, yet still with wavelengths greater than typical FEL bunch lengths (several femtoseconds). Potential experimental schemes will be suggested in the context of LCLS and their feasibility evaluated.
* S. Bettoni, M. Pedrozzi and S. Reiche, Phys. Rev. ST Accel. Beams. 18, 123403 (December, 2015).

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THPAB084

Integration of the Full-Acceptance Detector Into the JLEIC

3912

G.H. Wei, F. Lin, V.S. Morozov, F.C. Pilat, Y. Zhang
JLab, Newport News, Virginia, USA
Y.M. Nosochkov
SLAC, Menlo Park, California, USA
M.-H. Wang
Self Employment, Private address, USA

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contracts No. DE-AC05-06OR23177 and DE-AC02-06CH11357. Work supported also by the U.S. DOE Contract DE-AC02-76SF00515.
For physics requirements, the JLEIC (Jefferson Lab Electron Ion Collider) has a full-acceptance detector, which brings many new challenges to the beam dynamics integration. For example, asymmetric lattice and beam envelopes at interaction region (IR), forward detection, and large crossing angle with crab dynamics. Also some common problems complicate the picture, like coupling and coherent orbit from detector solenoid, high chromaticity and high multipole sensitivity from low beta-star at interaction point (IP), collision mode with different energy and ion species. Meanwhile, to get a luminosity level of a few 10³³ cm^-2ses⁻¹, small beta-star are necessary at the IP, which also means large beta in the final focus area, chromaticity correction sections, etc. This sets a constraint on the field quality of magnets in large beta areas, in order to ensure a large enough dynamic aperture (DA). In this context, limiting multipole components of magnets are surveyed to get a standard line. And continuously, multipole magnets as dedicated correctors are studied to provide semi-local corrections of specific multipole components beyond the standard line.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB084

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THPAB087

Emittance Measurements and Simulations in 112 MHz Super-Conducting RF Electron Gun With CsK2Sb Photo-Cathode

3921

SUSPSIK063

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K. Mihara
Stony Brook University, Stony Brook, USA
D. Kayran, V. Litvinenko, T.A. Miller, I. Pinayev
BNL, Upton, Long Island, New York, USA

The commissioning of the coherent electron cooling (CeC) proof of principle experiment is under way at Relativistic Heavy Ion Collider (RHIC).. A 112 MHz superconducting radio frequency photo-emission gun is used to generate the electron beam for this experiment. In this paper we report selected results of experimental emittance measurements and compare them with our simulations.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB087

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THPAB088

Comparison of Theory, Simulation, and Experiment for Dynamical Extinction of Relativistic Electron Beams Diffracted Through a Si Crystal Membrane

3924

SUSPSIK064

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L.E. Malin, W.S. Graves, J. Spence, C. Zhang
Arizona State University, Tempe, USA
R.K. Li, C. Limborg, E.A. Nanni, X. Shen, S.P. Weathersby
SLAC, Menlo Park, California, USA

Diffraction in the transmission geometry through a single-crystal silicon slab is exploited to control the intensity of a relativistic electron beam. The choice of crystal thickness and incidence angle can extinguish or maximize the transmitted beam intensity via coherent multiple Bragg scattering; thus, the crystal acts as a dynamical beam stop through the Pendel'sung effect, a well-known phenomenon in X-ray and electron diffraction. In an initial experiment, we have measured the ability of this method to transmit or extinguish the primary beam and diffract into a single Bragg peak. Using lithographic etching of patterns in the crystal we intend to use this method to nanopattern an electron beam for production of coherent x-rays. We compare the experimental results with simulations using the multislice method to model the diffraction pattern from a perfect silicon crystal of uniform thickness, considering multiple scattering, crystallographic orientation, temperature effects, and partial coherence from the momentum spread of the beam. The simulations are compared to data collected at the ASTA UED facility at SLAC for a 340 nm thick Si(100) wafer with a beam energy of 2.35 MeV.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPAB088

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THPIK093

Blow-Up Due to Intra Beam Scattering during Deceleration in ELENA

4303

C. Carli, M. Martini
CERN, Geneva, Switzerland

Intra Beam Scattering (IBS) is expected to be the main performance limitation of the Extra Low Energy Antiproton ring (ELENA), a small synchrotron equipped with electron cooling under construction at CERN to decelerate antiprotons from 5.3 MeV to 100 keV. Thus, the duration of the ramps must not be too long to avoid excessive blow up due to IBS. On the other hand, the bending magnets are C-shaped and the vacuum chambers are without insulated junctions, which are difficult for fully baked machines; thus, the ramps must not be too short. The evolution of transverse and longitudinal emittances along the ramps have been estimated assuming that IBS is the main phenomenon leading to blow-up. The blow-up due to IBS found along the ramps have been found to be acceptable.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2017-THPIK093

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FRXAA1

Laser Cooling of Relativistic Heavy Ion Beams

M.H. Bussmann, M. Löser
HZDR, Dresden, Germany
O. Boine-Frankenheim, L. Eidam
TEMF, TU Darmstadt, Darmstadt, Germany
O. Boine-Frankenheim, L. Eidam, T. Kühl, F. Nolden, R.M. Sanchez Alarcon, M. Steck, T. Stöhlker, D.F.A. Winters
GSI, Darmstadt, Germany
A. Buss, V. Hannen, D. Winzen
Westfälische Wilhelms-Universität Münster, Institut für Kernphysik, Münster, Germany
Z. Huang, X. Ma, H. Wang, W.Q. Wen
IMP/CAS, Lanzhou, People's Republic of China
D. Kiefer, S. Klammes, W. Nörtershäuser, J. Ullmann, T. Walther
TU Darmstadt, Darmstadt, Germany
U. Schramm
TU Dresden, Dresden, Germany
U. Schramm, M. Siebold
Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Radiation Physics, Dresden, Germany
T. Stöhlker
IOQ, Jena, Germany
T. Stöhlker
HIJ, Jena, Germany
C. Weinheimer
Institut für Kernphysik, Westfälische Wilhelms-Universität Münster, Münster, Germany

At high energies laser cooling is a very promising technique to reduce phase space of beams of high energy ions effciently and fast. With the advent of new facilities such as FAIR and HIAF research focuses on developing robust laser cooling setups. This requires an understanding of the underlying beam dynamics at high beam intensities, the development of reliable laser systems that can be used to cool a large variety of ion species and optical detection systems that complement standard accelerator beam diagnostics. Based on the lessons learned from ongoing experiments at the ESR at GSI, Darmstadt, and the CSRe at IMP, Lanzhou, the important design aspects of future laser cooling installations will be discussed. The talk will follow a how-to approach to discuss key design aspects of laser cooling setups and emphasize the important connection between advanced beam dynamics studies and optical control and diagnostics.

Slides FRXAA1 [4.765 MB]

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