FLS2023 - List of Keywords (emittance)

Paper	Title	Other Keywords	Page
MO3B2	Beam Dynamics Using Superconducting Passive Harmonic Cavities with High Current per Bunch	cavity, dipole, synchrotron, impedance	14
	A. Gamelin, V. Gubaidulin, A. Loulergue, P. Marchand, L.S. Nadolski, R. Nagaoka SOLEIL, Gif-sur-Yvette, France N. Yamamoto KEK, Ibaraki, Japan
	In 4th generation synchrotron light sources, harmonic cavities (HCs) are critical components needed to achieve the required performance. They provide longer bunches, which helps to reduce statistical effects (intra-beam scattering and Touschek effect). In "timing" modes, where the bunch spacing is larger than in conventional modes and the number of particles per bunch is higher, this need is even greater. In this article, we present the beam dynamics in the high current per bunch regime and how it interacts with the single bunch collective effects. In particular, a dipole-quadrupole instability is observed above the microwave threshold and a coupling between the dipole and cavity modes is shown to limit bunch lengthening at low current. The effective gain from the use of HCs in terms of lifetime, emittance, and energy spread is also discussed.
	Slides MO3B2 [1.529 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-MO3B2
About •	Received ※ 13 August 2023 — Revised ※ 15 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MO4C2	Development of a Compact Light Source using a Two-beam-acceleration Technique	electron, cathode, brightness, linac	42
	P. Piot, E.A. Frame, X. Lu Northern Illinois University, DeKalb, Illinois, USA G. Chen, C.-J. Jing, X. Lu, J.G. Power ANL, Lemont, Illinois, USA C.-J. Jing, S.V. Kuzikov Euclid Beamlabs, Bolingbrook, USA
	Funding: This work is supported by the U.S. DOE, under award No. DE-AC02-06CH11357 with ANL. This work is partially supported by Laboratory Directed Research and Development (LDRD) funding at ANL. The recent demonstration of sub-GV/m accelerating fields at X-band frequencies* offers an alternative pathway to designing a compact light source. The high fields were enabled by powering the accelerating structures using short (<10 ns) X-band RF pulses produced via a two-beam-accelerator (TBA) scheme. In this contribution, we present a conceptual design to scale the concept to a ~0.5 GeV accelerator. We present the optimization of the photoinjector and preliminary beam-dynamics modeling of the accelerator. Finally, we will discuss ongoing and planned experiments toward developing an integrated proof-of-principle experiment at Argonne National Laboratory combining the 0.5 GeV linac with a free-electron laser. * W.H. Tan, et al. DOI: 10.1103/PhysRevAccelBeams.25.083402 (2022).
	Slides MO4C2 [2.690 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-MO4C2
About •	Received ※ 31 August 2023 — Revised ※ 31 August 2023 — Accepted ※ 01 September 2023 — Issued ※ 02 December 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TU1B1	A Highly Competitive Non-Standard Lattice for a 4th Generation Light Source With Metrology and Timing Capabilities	lattice, sextupole, operation, HOM	58
	P. Goslawski, M. Abo-Bakr, J. Bengtsson, K. Holldack, Z. Hüsges, A. Jankowiak, K. Kiefer, B.C. Kuske, A. Meseck, R. Müller, M.K. Sauerborn, O. Schwarzkopf, J. Viefhaus, J. Völker HZB, Berlin, Germany
	The PTB, Germany’s national institute for standards and metrology, has relied on synchrotron radiation for metrology purposes for over 40 years and the most prominent customers are lithography systems from ASML/ZEIS. HZB is now working on a concept for a BESSY II successor, based on a 4th generation light source with an emittance of 100 pmrad @ 2.5 GeV. It is essential, that this new facility continues to serve the PTB for metrology purposes. This sets clear boundary conditions for the lattice design, in particular, the need for homogeneous bends as metrological radiation sources. Different Higher-Order-Multi-Bend-Achromat lattices have been developed, based on combined function gradient bends and homogeneous bends in a systematic lattice design approach. All lattices are linearly equivalent with the same emittance and maximum field strength. However, they differ significantly in their non-linear behavior. Based on this analysis, the choice of the BESSY III lattice type is motivated. A special focus is set also on TRIBs (Transverse Resonance Island Buckets) to operate with two orbits as a bunch separation scheme in MBAs, for different repetition rates or for the separation of short and long bunches.
	Slides TU1B1 [7.584 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU1B1
About •	Received ※ 23 August 2023 — Revised ※ 28 August 2023 — Accepted ※ 30 August 2023 — Issued ※ 02 December 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TU4P05	Design of the Test Platform for High Current VHF Electron Gun	electron, vacuum, gun, cathode	80
	Z.P. Liu, X.D. Li SINAP, Shanghai, People’s Republic of China H.X. Deng, Z.G. Jiang SARI-CAS, Pudong, Shanghai, People’s Republic of China H.J. Qian DESY Zeuthen, Zeuthen, Germany G. Shu IHEP, Beijing, People’s Republic of China
	A high-average-current VHF electron gun operating in the CW mode is under construction at Shanghai Advanced Research Institute, which is the key component of a kW-power-order free electron laser facility. The average current and the frequency of this electron gun is 1-10 mA and 217 MHz, respectively. To validate the performance of this instrument, a test platform has been designed. The R&D of its vacuum and diagnostics are presented in this work.
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU4P05
About •	Received ※ 23 August 2023 — Revised ※ 28 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TU4P08	Design and Commissioning of the Beam Switchyard for the SXFEL-UF	FEL, linac, MMI, undulator	91
	S. Chen, K.Q. Zhang SSRF, Shanghai, People’s Republic of China H.X. Deng, C. Feng, B. Liu, T. Liu, Z. Qi, Z.T. Zhao SARI-CAS, Pudong, Shanghai, People’s Republic of China
	As an important measure of improving the efficiency and usability of X-ray free electron laser facilities, parallel operation of multiple undulator lines realized by a beam switchyard has become a standard configuration in the recent built XFEL facilities. SXFEL-UF, the first soft X-ray free electron laser user facility in China, has finished construction and commissioning recently. The electron beams from the linac are separated and delivered alternately to the two parallel undulator beam lines through a beam switchyard. A stable and fast kicker magnet is used to achieve bunch-by-bunch separation. Optics measures are applied to mitigate the impact of various collective effects, such as coherent synchrotron radiation and micro-bunching instability, on the beam quality after passing through the deflection line of the beam switchyard. In this study, the comprehensive physical design of the beam switchyard is described and the latest results of its commissioning process are presented.
	Poster TU4P08 [4.643 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU4P08
About •	Received ※ 23 August 2023 — Revised ※ 30 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TU4P12	Injection Into XFELs, a Review of Trends and Challenges	FEL, gun, electron, linac	99
	C. Davut UMAN, Manchester, United Kingdom Ö. Apsimon Cockcroft Institute, Warrington, Cheshire, United Kingdom B.L. Militsyn, S.S. Percival STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	Funding: Science and Technology Facilities Council, STFC In this contribution, we review the low-energy electron injectors for existing X-ray Free-Electron Laser (XFEL) facilities focusing on the buncher and booster sections. The technology choices are parallel to the increasing demand for stricter six-dimensional phase space quality. The current capability for beam parameters and future requirements are laid out alongside a discussion on challenges and technological bottlenecks. In light of this review, preliminary results for a high capability injector providing high repetition rate, and continuous wave emission is presented as an option for the UK XFEL.
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU4P12
About •	Received ※ 23 August 2023 — Revised ※ 24 August 2023 — Accepted ※ 30 August 2023 — Issued ※ 02 December 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TU4P17	Non-destructive Vertical Halo-monitors on the ESRF Electron Beam	electron, vacuum, SRF, diagnostics	112
	K.B. Scheidt ESRF, Grenoble, France
	The ESRF EBS storage ring has since spring 2022 among its electron beam diagnostics two independent units of vertical Halo-monitors. The principle and the components of this unique diagnostic will be explained in details. It uses the available X-rays in a non-used Front-End, emitted from a 0.57 T standard dipole magnet in the EBS lattice. This instrument measures the so-called "far-away" Halo level, i.e. in a zone of roughly 1-3 mm away from the beam centre, which represents 200-600 times the electron’s vertical beam-size, supposedly Gaussian, of 5 um. It is measured, and expressed quantitively in picoAmp beam current, at 1 Hz rate. Both units are yielding very satisfying and well-correlated results that will be presented in details, and in relation with studies on the electron beam and the accelerator components like variation of current, filling-patterns, vertical emittance, quality of the vacuum, settings of the undulator gaps, collimators, scrapers etc. and also in direct correlation with measurements of our 128 beamloss detectors and beam lifetime.
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU4P17
About •	Received ※ 21 August 2023 — Revised ※ 28 August 2023 — Accepted ※ 30 August 2023 — Issued ※ 02 December 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TU4P19	Evolution of Equilibrium Parameters Ramp Including Collective Effects in the Diamond-II Booster	impedance, booster, simulation, extraction	120
	R. Husain, R.T. Fielder, I.P.S. Martin DLS, Oxfordshire, United Kingdom P. Burrows Oxford University, Physics Department, Oxford, Oxon, United Kingdom
	Efficient top-up injection into the Diamond-II storage ring will require upgrading the booster lattice for a beam emittance of <20 nm rad and a bunch length of <40 ps, including when operating with high single-bunch charge. The small vacuum chamber dimensions will drive the resistive wall instability and may adversely affect equilibrium parameters along the beam energy ramp. In addition, various diagnostic and vacuum chamber components will generate geometric impedances which may further disrupt the equilibrium parameters. Based on the detailed engineering designs, impedance models of the major components have been simulated using CST Studio and included in ELEGANT tracking simulations of the booster. In addition, the effects of synchrotron radiation emission and intra-beam scattering on the equilibrium parameters during the ramp are studied.
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU4P19
About •	Received ※ 22 August 2023 — Revised ※ 28 August 2023 — Accepted ※ 30 August 2023 — Issued ※ 02 December 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TU4P26	Special Operational Modes for SLS 2.0	brightness, lattice, photon, quadrupole	127
	J. Kallestrup, M. Aiba PSI, Villigen PSI, Switzerland
	The SLS 2.0 storage ring will achieve low emittance and high brightness while maintaining large dynamic aperture and lifetime comparable to the present SLS. Special operational modes are investigated to further explore the potential of the lattice. In this contribution, the first considerations on such modes for the SLS 2.0 are outlined. A promising high-brightness mode, increasing brightness by up to 25% at insertion devices with minor deterioration to dynamic and momentum aperture is presented. The use of round-beams and its impact on beam dynamics and the beamlines in the SLS 2.0 portfolio is discussed.
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU4P26
About •	Received ※ 27 July 2023 — Revised ※ 24 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WE4P13	Physics Design and Beam Dynamics Optimization of the SHINE Accelerator	linac, electron, FEL, cryomodule	174
	D. Gu, Z. Wang, M. Zhang SARI-CAS, Pudong, Shanghai, People’s Republic of China
	Shanghai HIgh Repetition Rate X-ray Free Electron Laser and Extreme Light Facility (SHINE) is a hard X-ray FEL facility which is driven by a 1.3 km supercon-ducting Linac, aims to provide high repetition rate pulses up to 1 MHz . In this study, we present the physics design of the SHINE accelerator and considerations of beam dynamics optimizations. Start-to-end simulation results show that, a high brightness electron beam with over 1500 A quasi-flat-top current can be attained which fully meet the requirements of FEL lines. Furthermore, design of the bypass line is also discussed.
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P13
About •	Received ※ 23 August 2023 — Revised ※ 30 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WE4P18	Preliminary Design of Higher-order Achromat Lattice for the Upgrade of the Taiwan Photon Source	lattice, dipole, storage-ring, radiation	184
	N.Y. Huang, M.-S. Chiu, P.J. Chou, G.-H. Luo, H.W. Luo, H.-J. Tsai, F.H. Tseng NSRRC, Hsinchu, Taiwan
	We study the upgrade of Taiwan Photon Source (TPS) with energy saving as the prime objective. The upgrade design is dubbed TPS-II. To accommodate the constraints imposed by the existing TPS tunnel, we choose the higher-order achromat (HOA) lattice configuration which is composed of the 5BA and 4BA cells. This HOA lattice produces a natural beam emittance about 131 pm-rad for a 3 GeV, 518.4 m storage ring. The on-momentum dynamic aperture is about 8 mm and the estimated Touschek life time reaches around 5.7 hours at total beam current of 500 mA. As a result of the ultralow beam emittance, the brightness and coherence fraction (CF) of the photon beam are improved with a factor of several tens especially in the photon wavelength around 0.1 nm. The challenges and preliminary results of this HOA lattice design will be presented.
	Poster WE4P18 [5.398 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P18
About •	Received ※ 21 August 2023 — Revised ※ 28 August 2023 — Accepted ※ 30 August 2023 — Issued ※ 02 December 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WE4P24	Optics for an Electron Cooler for the EIC Based on an Electron Storage Ring	electron, wiggler, sextupole, scattering	200
	J. Kewisch, A.V. Fedotov, X. Gu, Y.C. Jing, D. Kayran, I. Pinayev, S. Seletskiy BNL, Upton, New York, USA
	Funding: Supported by the US Department of Energy, Contract DE-SC0012704 An electron cooler based on a storage ring is one of the options to improve the luminosity in the Electron-Ion Collider (EIC). The transverse emittance of the electrons in the cooler is driven by the quantum excitation in dipoles and wigglers, as well as by both beam-beam scattering with the ions and intra-beam scattering of the electrons in the regions with a non-zero dispersion. The resulting demand to minimize a dispersion conflicts with the need of a sufficient dispersion in sextupoles for chromaticity correction. In this report we discuss our studies of several approaches to electron ring lattice, including those typically used in light sources, and present resulting compromise between various requirements.
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P24
About •	Received ※ 23 August 2023 — Revised ※ 29 August 2023 — Accepted ※ 30 August 2023 — Issued ※ 02 December 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WE4P31	Deterministic Approach to the Lattice Design of BESSY III	lattice, sextupole, quadrupole, dynamic-aperture	203
	B.C. Kuske, P. Goslawski HZB, Berlin, Germany
	Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association Since 2021 HZB pursues the design of a 2.5 GeV storage ring as a successor of BESSY II in Berlin. The user’s demand for diffraction-limited radiation at 1 keV corresponds to an emittance of 100 pm, making an MBA lattice indispensable. The envisaged location limits the circumference to ~350 m. MBA lattices are composed of smaller substructures that can be analyzed and optimized separately, before combining them into one super period. The prerequisite for this approach is a clear idea of the goal parameters and their prioritization, as the design process is dominated by permanent decisions between different options. The resulting generic baseline lattice for BESSY III is a simple structure with few non-linear elements, already fulfilling all goal parameters and showing a very compatible nonlinear behavior. This is our starting point for further optimizations including swarm or MOGA approaches.
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P31
About •	Received ※ 30 August 2023 — Revised ※ 30 August 2023 — Accepted ※ 01 September 2023 — Issued ※ 02 December 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

MO3B2

Beam Dynamics Using Superconducting Passive Harmonic Cavities with High Current per Bunch

cavity, dipole, synchrotron, impedance

14

A. Gamelin, V. Gubaidulin, A. Loulergue, P. Marchand, L.S. Nadolski, R. Nagaoka
SOLEIL, Gif-sur-Yvette, France
N. Yamamoto
KEK, Ibaraki, Japan

In 4th generation synchrotron light sources, harmonic cavities (HCs) are critical components needed to achieve the required performance. They provide longer bunches, which helps to reduce statistical effects (intra-beam scattering and Touschek effect). In "timing" modes, where the bunch spacing is larger than in conventional modes and the number of particles per bunch is higher, this need is even greater. In this article, we present the beam dynamics in the high current per bunch regime and how it interacts with the single bunch collective effects. In particular, a dipole-quadrupole instability is observed above the microwave threshold and a coupling between the dipole and cavity modes is shown to limit bunch lengthening at low current. The effective gain from the use of HCs in terms of lifetime, emittance, and energy spread is also discussed.

Slides MO3B2 [1.529 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-MO3B2

About •

Received ※ 13 August 2023 — Revised ※ 15 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MO4C2

Development of a Compact Light Source using a Two-beam-acceleration Technique

electron, cathode, brightness, linac

42

P. Piot, E.A. Frame, X. Lu
Northern Illinois University, DeKalb, Illinois, USA
G. Chen, C.-J. Jing, X. Lu, J.G. Power
ANL, Lemont, Illinois, USA
C.-J. Jing, S.V. Kuzikov
Euclid Beamlabs, Bolingbrook, USA

Funding: This work is supported by the U.S. DOE, under award No. DE-AC02-06CH11357 with ANL. This work is partially supported by Laboratory Directed Research and Development (LDRD) funding at ANL.
The recent demonstration of sub-GV/m accelerating fields at X-band frequencies* offers an alternative pathway to designing a compact light source. The high fields were enabled by powering the accelerating structures using short (<10 ns) X-band RF pulses produced via a two-beam-accelerator (TBA) scheme. In this contribution, we present a conceptual design to scale the concept to a ~0.5 GeV accelerator. We present the optimization of the photoinjector and preliminary beam-dynamics modeling of the accelerator. Finally, we will discuss ongoing and planned experiments toward developing an integrated proof-of-principle experiment at Argonne National Laboratory combining the 0.5 GeV linac with a free-electron laser.
* W.H. Tan, et al. DOI: 10.1103/PhysRevAccelBeams.25.083402 (2022).

Slides MO4C2 [2.690 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-MO4C2

About •

Received ※ 31 August 2023 — Revised ※ 31 August 2023 — Accepted ※ 01 September 2023 — Issued ※ 02 December 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TU1B1

A Highly Competitive Non-Standard Lattice for a 4th Generation Light Source With Metrology and Timing Capabilities

lattice, sextupole, operation, HOM

58

P. Goslawski, M. Abo-Bakr, J. Bengtsson, K. Holldack, Z. Hüsges, A. Jankowiak, K. Kiefer, B.C. Kuske, A. Meseck, R. Müller, M.K. Sauerborn, O. Schwarzkopf, J. Viefhaus, J. Völker
HZB, Berlin, Germany

The PTB, Germany’s national institute for standards and metrology, has relied on synchrotron radiation for metrology purposes for over 40 years and the most prominent customers are lithography systems from ASML/ZEIS. HZB is now working on a concept for a BESSY II successor, based on a 4th generation light source with an emittance of 100 pmrad @ 2.5 GeV. It is essential, that this new facility continues to serve the PTB for metrology purposes. This sets clear boundary conditions for the lattice design, in particular, the need for homogeneous bends as metrological radiation sources. Different Higher-Order-Multi-Bend-Achromat lattices have been developed, based on combined function gradient bends and homogeneous bends in a systematic lattice design approach. All lattices are linearly equivalent with the same emittance and maximum field strength. However, they differ significantly in their non-linear behavior. Based on this analysis, the choice of the BESSY III lattice type is motivated. A special focus is set also on TRIBs (Transverse Resonance Island Buckets) to operate with two orbits as a bunch separation scheme in MBAs, for different repetition rates or for the separation of short and long bunches.

Slides TU1B1 [7.584 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU1B1

About •

Received ※ 23 August 2023 — Revised ※ 28 August 2023 — Accepted ※ 30 August 2023 — Issued ※ 02 December 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TU4P05

Design of the Test Platform for High Current VHF Electron Gun

electron, vacuum, gun, cathode

80

Z.P. Liu, X.D. Li
SINAP, Shanghai, People’s Republic of China
H.X. Deng, Z.G. Jiang
SARI-CAS, Pudong, Shanghai, People’s Republic of China
H.J. Qian
DESY Zeuthen, Zeuthen, Germany
G. Shu
IHEP, Beijing, People’s Republic of China

A high-average-current VHF electron gun operating in the CW mode is under construction at Shanghai Advanced Research Institute, which is the key component of a kW-power-order free electron laser facility. The average current and the frequency of this electron gun is 1-10 mA and 217 MHz, respectively. To validate the performance of this instrument, a test platform has been designed. The R&D of its vacuum and diagnostics are presented in this work.

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU4P05

About •

Received ※ 23 August 2023 — Revised ※ 28 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TU4P08

Design and Commissioning of the Beam Switchyard for the SXFEL-UF

FEL, linac, MMI, undulator

91

S. Chen, K.Q. Zhang
SSRF, Shanghai, People’s Republic of China
H.X. Deng, C. Feng, B. Liu, T. Liu, Z. Qi, Z.T. Zhao
SARI-CAS, Pudong, Shanghai, People’s Republic of China

As an important measure of improving the efficiency and usability of X-ray free electron laser facilities, parallel operation of multiple undulator lines realized by a beam switchyard has become a standard configuration in the recent built XFEL facilities. SXFEL-UF, the first soft X-ray free electron laser user facility in China, has finished construction and commissioning recently. The electron beams from the linac are separated and delivered alternately to the two parallel undulator beam lines through a beam switchyard. A stable and fast kicker magnet is used to achieve bunch-by-bunch separation. Optics measures are applied to mitigate the impact of various collective effects, such as coherent synchrotron radiation and micro-bunching instability, on the beam quality after passing through the deflection line of the beam switchyard. In this study, the comprehensive physical design of the beam switchyard is described and the latest results of its commissioning process are presented.

Poster TU4P08 [4.643 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU4P08

About •

Received ※ 23 August 2023 — Revised ※ 30 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TU4P12

Injection Into XFELs, a Review of Trends and Challenges

FEL, gun, electron, linac

99

C. Davut
UMAN, Manchester, United Kingdom
Ö. Apsimon
Cockcroft Institute, Warrington, Cheshire, United Kingdom
B.L. Militsyn, S.S. Percival
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Funding: Science and Technology Facilities Council, STFC
In this contribution, we review the low-energy electron injectors for existing X-ray Free-Electron Laser (XFEL) facilities focusing on the buncher and booster sections. The technology choices are parallel to the increasing demand for stricter six-dimensional phase space quality. The current capability for beam parameters and future requirements are laid out alongside a discussion on challenges and technological bottlenecks. In light of this review, preliminary results for a high capability injector providing high repetition rate, and continuous wave emission is presented as an option for the UK XFEL.

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU4P12

About •

Received ※ 23 August 2023 — Revised ※ 24 August 2023 — Accepted ※ 30 August 2023 — Issued ※ 02 December 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TU4P17

Non-destructive Vertical Halo-monitors on the ESRF Electron Beam

electron, vacuum, SRF, diagnostics

112

K.B. Scheidt
ESRF, Grenoble, France

The ESRF EBS storage ring has since spring 2022 among its electron beam diagnostics two independent units of vertical Halo-monitors. The principle and the components of this unique diagnostic will be explained in details. It uses the available X-rays in a non-used Front-End, emitted from a 0.57 T standard dipole magnet in the EBS lattice. This instrument measures the so-called "far-away" Halo level, i.e. in a zone of roughly 1-3 mm away from the beam centre, which represents 200-600 times the electron’s vertical beam-size, supposedly Gaussian, of 5 um. It is measured, and expressed quantitively in picoAmp beam current, at 1 Hz rate. Both units are yielding very satisfying and well-correlated results that will be presented in details, and in relation with studies on the electron beam and the accelerator components like variation of current, filling-patterns, vertical emittance, quality of the vacuum, settings of the undulator gaps, collimators, scrapers etc. and also in direct correlation with measurements of our 128 beamloss detectors and beam lifetime.

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU4P17

About •

Received ※ 21 August 2023 — Revised ※ 28 August 2023 — Accepted ※ 30 August 2023 — Issued ※ 02 December 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TU4P19

Evolution of Equilibrium Parameters Ramp Including Collective Effects in the Diamond-II Booster

impedance, booster, simulation, extraction

120

R. Husain, R.T. Fielder, I.P.S. Martin
DLS, Oxfordshire, United Kingdom
P. Burrows
Oxford University, Physics Department, Oxford, Oxon, United Kingdom

Efficient top-up injection into the Diamond-II storage ring will require upgrading the booster lattice for a beam emittance of <20 nm rad and a bunch length of <40 ps, including when operating with high single-bunch charge. The small vacuum chamber dimensions will drive the resistive wall instability and may adversely affect equilibrium parameters along the beam energy ramp. In addition, various diagnostic and vacuum chamber components will generate geometric impedances which may further disrupt the equilibrium parameters. Based on the detailed engineering designs, impedance models of the major components have been simulated using CST Studio and included in ELEGANT tracking simulations of the booster. In addition, the effects of synchrotron radiation emission and intra-beam scattering on the equilibrium parameters during the ramp are studied.

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU4P19

About •

Received ※ 22 August 2023 — Revised ※ 28 August 2023 — Accepted ※ 30 August 2023 — Issued ※ 02 December 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TU4P26

Special Operational Modes for SLS 2.0

brightness, lattice, photon, quadrupole

127

J. Kallestrup, M. Aiba
PSI, Villigen PSI, Switzerland

The SLS 2.0 storage ring will achieve low emittance and high brightness while maintaining large dynamic aperture and lifetime comparable to the present SLS. Special operational modes are investigated to further explore the potential of the lattice. In this contribution, the first considerations on such modes for the SLS 2.0 are outlined. A promising high-brightness mode, increasing brightness by up to 25% at insertion devices with minor deterioration to dynamic and momentum aperture is presented. The use of round-beams and its impact on beam dynamics and the beamlines in the SLS 2.0 portfolio is discussed.

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU4P26

About •

Received ※ 27 July 2023 — Revised ※ 24 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WE4P13

Physics Design and Beam Dynamics Optimization of the SHINE Accelerator

linac, electron, FEL, cryomodule

174

D. Gu, Z. Wang, M. Zhang
SARI-CAS, Pudong, Shanghai, People’s Republic of China

Shanghai HIgh Repetition Rate X-ray Free Electron Laser and Extreme Light Facility (SHINE) is a hard X-ray FEL facility which is driven by a 1.3 km supercon-ducting Linac, aims to provide high repetition rate pulses up to 1 MHz . In this study, we present the physics design of the SHINE accelerator and considerations of beam dynamics optimizations. Start-to-end simulation results show that, a high brightness electron beam with over 1500 A quasi-flat-top current can be attained which fully meet the requirements of FEL lines. Furthermore, design of the bypass line is also discussed.

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P13

About •

Received ※ 23 August 2023 — Revised ※ 30 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WE4P18

Preliminary Design of Higher-order Achromat Lattice for the Upgrade of the Taiwan Photon Source

lattice, dipole, storage-ring, radiation

184

N.Y. Huang, M.-S. Chiu, P.J. Chou, G.-H. Luo, H.W. Luo, H.-J. Tsai, F.H. Tseng
NSRRC, Hsinchu, Taiwan

We study the upgrade of Taiwan Photon Source (TPS) with energy saving as the prime objective. The upgrade design is dubbed TPS-II. To accommodate the constraints imposed by the existing TPS tunnel, we choose the higher-order achromat (HOA) lattice configuration which is composed of the 5BA and 4BA cells. This HOA lattice produces a natural beam emittance about 131 pm-rad for a 3 GeV, 518.4 m storage ring. The on-momentum dynamic aperture is about 8 mm and the estimated Touschek life time reaches around 5.7 hours at total beam current of 500 mA. As a result of the ultralow beam emittance, the brightness and coherence fraction (CF) of the photon beam are improved with a factor of several tens especially in the photon wavelength around 0.1 nm. The challenges and preliminary results of this HOA lattice design will be presented.

Poster WE4P18 [5.398 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P18

About •

Received ※ 21 August 2023 — Revised ※ 28 August 2023 — Accepted ※ 30 August 2023 — Issued ※ 02 December 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WE4P24

Optics for an Electron Cooler for the EIC Based on an Electron Storage Ring

electron, wiggler, sextupole, scattering

200

J. Kewisch, A.V. Fedotov, X. Gu, Y.C. Jing, D. Kayran, I. Pinayev, S. Seletskiy
BNL, Upton, New York, USA

Funding: Supported by the US Department of Energy, Contract DE-SC0012704
An electron cooler based on a storage ring is one of the options to improve the luminosity in the Electron-Ion Collider (EIC). The transverse emittance of the electrons in the cooler is driven by the quantum excitation in dipoles and wigglers, as well as by both beam-beam scattering with the ions and intra-beam scattering of the electrons in the regions with a non-zero dispersion. The resulting demand to minimize a dispersion conflicts with the need of a sufficient dispersion in sextupoles for chromaticity correction. In this report we discuss our studies of several approaches to electron ring lattice, including those typically used in light sources, and present resulting compromise between various requirements.

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P24

About •

Received ※ 23 August 2023 — Revised ※ 29 August 2023 — Accepted ※ 30 August 2023 — Issued ※ 02 December 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WE4P31

Deterministic Approach to the Lattice Design of BESSY III

lattice, sextupole, quadrupole, dynamic-aperture

203

B.C. Kuske, P. Goslawski
HZB, Berlin, Germany

Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association
Since 2021 HZB pursues the design of a 2.5 GeV storage ring as a successor of BESSY II in Berlin. The user’s demand for diffraction-limited radiation at 1 keV corresponds to an emittance of 100 pm, making an MBA lattice indispensable. The envisaged location limits the circumference to ~350 m. MBA lattices are composed of smaller substructures that can be analyzed and optimized separately, before combining them into one super period. The prerequisite for this approach is a clear idea of the goal parameters and their prioritization, as the design process is dominated by permanent decisions between different options. The resulting generic baseline lattice for BESSY III is a simple structure with few non-linear elements, already fulfilling all goal parameters and showing a very compatible nonlinear behavior. This is our starting point for further optimizations including swarm or MOGA approaches.

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P31

About •

Received ※ 30 August 2023 — Revised ※ 30 August 2023 — Accepted ※ 01 September 2023 — Issued ※ 02 December 2023

Cite •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)