FLS2023 - List of Keywords (undulator)

Paper	Title	Other Keywords	Page
MO3A2	Status and Perspectives for the Swiss Free-Electron Laser (SwissFEL)	FEL, electron, laser, operation	26
	T. Schietinger PSI, Villigen PSI, Switzerland
	We summarize the status of SwissFEL, the X-ray free-electron laser at the Paul Scherrer Institute. Apart from some key operational performance figures the presentation covers the state of the experimental stations and their capabilities, gives a few scientific highlights and an overview of the use of special modes beyond SASE at our facility. Furthermore we report on progress of our seeding upgrade program on the soft X-ray line. Lastly we mention our long-term upgrade plans for a third undulator beamline in the tender and hard X-ray regime.
	Slides MO3A2 [8.398 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-MO3A2
About •	Received ※ 29 August 2023 — Revised ※ 30 August 2023 — Accepted ※ 30 August 2023 — Issued ※ 02 December 2023
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MO3A5	FLASH: Status and Upgrade	laser, FEL, electron, operation	32
	M. Vogt, S. Schreiber, J. Zemella DESY, Hamburg, Germany
	FLASH, the Soft X-Ray and Extreme-UV Free Electron Laser at DESY, is undergoing a substantial upgrade and refurbishment project, called FLASH2020+. The project will finally enable external seeded and SASE FEL operation for a wavelength range down to 4 nm with the EEHG method. This is achieved in two long shutdowns from November 2021 to August 2022 and from June 2024 to August 2025. Key ingredient of the upgrade were installation of a laser heater, replacing two early TTF-type L-band SRF accelerating modules by modern, high-gradient XFEL-type modules, redesign of the 2nd bunch compressor, and complete redesign of the FLASH1 beam line for HGHG/EEHG seeding. This talk will report on the project and the status of FLASH after the first shutdown with emphasis on beam dynamics aspects.
	Slides MO3A5 [1.108 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-MO3A5
About •	Received ※ 25 August 2023 — Revised ※ 26 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023
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TU2A2	Single Longitudinal Mode Generation in Slippage-dominated, Tapered-undulator SASE Soft X-ray FEL	FEL, electron, simulation, photon	70
	D.C. Nguyen, M. Dunham, W. Lou, C.E. Mayes, G. Stupakov xLight, Palo Alto, USA
	SASE FELs operating in the soft X-ray region exhibit multiple temporal and spectral spikes with an overall spectral bandwidth of about 1.5 times the FEL rho parameter. While many ideas have been proposed to achieve fully coherent X-ray FELs, only monochromatic seeding, either harmonic seeding* or SASE self-seeding*, has been experimentally demonstrated to narrow the output spectra of soft X-ray FELs. In this paper, we study a different method that relies on the Slippage-dominated Tapered Undulator (STU) SASE concept to produce a single longitudinal mode in a soft X-ray FEL driven by ~10-fs, 16-pC electron bunches. We pre-sent numerical simulation results that demonstrate single-mode generation and narrow-lined spectra without seeding in a STU-SASE FEL at 6.67 nm. E. Alaria et al., Nat Photon 7 (2013) 913-918 ** D. Ratner et al., PRL 114 (2015) 050801
	Slides TU2A2 [1.125 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU2A2
About •	Received ※ 22 August 2023 — Revised ※ 23 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023
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TU4P06	The Experimental Progress for the Strong Field Terahertz Radiation at Shanghai Soft X-ray Free-electron Laser Facility	radiation, laser, electron, FEL	83
	K.Q. Zhang, C. Feng SSRF, Shanghai, People’s Republic of China Y. Kang SINAP, Shanghai, People’s Republic of China
	Strong field Terahertz (THz) light source has been in-creasingly important for many scientific frontiers, while it is still a challenge to obtain THz radiation with high pulse energy at wide-tunable frequency. In this paper, we introduce an accelerator-based strong filed THz light source to obtain coherent THz radiation with high pulse energy and tunable frequency and X-ray pulse at the same time, which adopts a frequency beating laser pulse modulated electron beam. Here, we present the experi-mental progress for the strong filed THz radiation at shanghai soft X-ray free-electron laser (SXFEL) facility and show its simulated radiation performance.
	Poster TU4P06 [1.310 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU4P06
About •	Received ※ 21 August 2023 — Revised ※ 28 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023
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TU4P07	Design of the Beam Distribution System of SHINE	kicker, linac, electron, FEL	87
	S. Chen SSRF, Shanghai, People’s Republic of China H.X. Deng, X. Fu, B. Liu SARI-CAS, Pudong, Shanghai, People’s Republic of China B.Y. Yan SINAP, Shanghai, People’s Republic of China
	The Shanghai high-repetition-rate XFEL and extreme light facility (SHINE), as the first hard X-ray free electron laser facility in China, is now under construction. CW electron beam with up to 1 MHz bunch repetition rate from a superconducting RF linac is used to feed at least three individual undulator lines that covers a wide photon energy range (0.4 keV ~ 25 keV). In order to maximize the efficiency of the facility, a beam switchyard between the linac and undulator lines is used to enable the simultaneously operation of the three undulator lines. In this work, the schematic design of the beam switchyard for bunch-by-bunch beam separation of CW beam is described, and the current lattice design of the linac-to-undulator deflection branches and the start-to-end tracking simulation results are presented.
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU4P07
About •	Received ※ 22 August 2023 — Revised ※ 28 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023
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TU4P08	Design and Commissioning of the Beam Switchyard for the SXFEL-UF	FEL, emittance, linac, MMI	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
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TU4P28	Useful Formulas and Example Parameters Set for the Design of SSMB Storage Rings	radiation, laser, bunching, storage-ring	135
	X.J. Deng, A. Chao, W.-H. Huang, Z.Z. Li, Z. Pan, C.-X. Tang TUB, Beijing, People’s Republic of China
	A promising accelerator light source mechanism called steady-state microbunching (SSMB) has been actively studied in recent years. Here we summarize some important formulas for the design of SSMB storage rings. Generally we group our formulas into two categories, i.e., a longitudinal weak focusing storage ring for a desired radiation wavelength larger than 100 nm, and a transverse-longitudinal coupling, or a generalized longitudinal strong focusing, storage ring for a desired radiation wavelength between 1 nm and 100 nm. In each category, we have presented an example parameters set for the corresponding SSMB storage ring, to generate kW-level infrared, EUV and soft X-ray radiation, respectively.
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU4P28
About •	Received ※ 15 August 2023 — Revised ※ 24 August 2023 — Accepted ※ 30 August 2023 — Issued ※ 02 December 2023
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TU4P29	Why is the Coherent Radiation from Laser-induced Microbunches Narrowbanded and Collimated	radiation, electron, laser, bunching	139
	X.J. Deng, A. Chao TUB, Beijing, People’s Republic of China
	There are two reasons: one is the long coherence length of radiation from micobunches imprinted by the modulation laser, the second is the finite transverse electron beam size. In other words, one is due to the longitudinal form factor, and the other the transverse form factor of the electron beam. Here we study the role of these form factors in shaping the energy spectrum and spatial distribution of microbunching radiation. The investigations are of value for cases like steady-state microbunching (SSMB), coherent harmonic generation (CHG) and free-electron laser (FEL).
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU4P29
About •	Received ※ 14 August 2023 — Revised ※ 24 August 2023 — Accepted ※ 30 August 2023 — Issued ※ 02 December 2023
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TU4P30	Optical Stochastic Cooling in a General Coupled Lattice	damping, pick-up, radiation, storage-ring	143
	X.J. Deng TUB, Beijing, People’s Republic of China
	Here we present a formalism of optical stochastic cooling in a 3D general coupled lattice. The formalism is general, and can treat a variety of damping and diffusion mechanisms within a single framework. We expect the work to be of value for the development of future light source.
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU4P30
About •	Received ※ 15 August 2023 — Revised ※ 24 August 2023 — Accepted ※ 30 August 2023 — Issued ※ 02 December 2023
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WE3A3	Multi-FELOs Driven by a Common Electron Beam	electron, FEL, radiation, laser	164
	C.-Y. Tsai HUST, Wuhan, People’s Republic of China Y. Zhang JLab, Newport News, Virginia, USA
	Generating an FEL requires a high-brightness electron beam. To produce multiple FELs, the linac beam must be shared to enable one beam driving an undulator. This leads to a reduced average current and compromised FEL performance. Recently, a concept of multiple FELs driven by one electron beam was proposed, which enables reduction of equipment and improvement of productivity. We present here a simulation study based on an extended 1D FEL oscillator model to demonstrate this concept. The system consists of two FEL oscillators arranged side-by-side and one electron beam passing through them. As such, the second, downstream oscillator is driven by bunches already been used once, while the first oscillator always receives fresh bunches from the linac. The study shows lasing could be achieved for both oscillators, their radiation intensities at saturation are comparable, thus meet needs of users. The concept also enables a potential application using a circulator ring such that an oscillator can be driven alternately by fresh linac bunches from and used bunches in the circulator ring. Extending the concept to cases of more than two FEL oscillators driven by one beam is also explored.
	Slides WE3A3 [0.540 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE3A3
About •	Received ※ 23 August 2023 — Revised ※ 23 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023
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WE4P14	Layout of the Undulator-to-dump line at the SHINE	electron, FEL, radiation, linac	177
	T. Liu, S. Chen, H.X. Deng, B. Liu, Z. Qi SARI-CAS, Pudong, Shanghai, People’s Republic of China Z.F. Gao SSRF, Shanghai, People’s Republic of China N. Huang Zhangjiang Lab, Shanghai, People’s Republic of China
	The Shanghai HIgh repetitioN rate XFEL and Extreme light Facility as the first hard X-ray free-electron laser (FEL) facility in China, is currently under construction in the Zhangjiang area, Shanghai. It aims to deliver X-ray covering photon energy range from 0.4 to 25 keV, with electron beam power up to 800 kW. Downstream of the undulator line, the beam transport design of the undulator-to-dump line is critical which is mainly used for realization of FEL diagnostics based on transverse deflecting structure and beam absorption in the dump. In this manuscript we describe the current layout of this system.
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P14
About •	Received ※ 20 August 2023 — Revised ※ 22 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023
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WE4P36	The Cryogenic Undulator Upgrade Programme at Diamond Light Source	vacuum, MMI, cryogenics, insertion-device	211
	Z. Patel, W. Cheng, A. George, S.H. Hale, R. Mercado, A. Ramezani Moghaddam, M. Reeves, G. Sharma, S. Tripathi DLS, Oxfordshire, United Kingdom M.V. Marziani University of Cape Town, Cape Town, South Africa
	Diamond Light Source has installed four 2 m long, 17.6 mm period Cryogenic Permanent Magnet Undulators (CPMUs) as upgrades for crystallography beamlines since 2020, with two more planned within the next year. The CPMUs provide 2 - 3 times more brightness and 2 - 4 times more flux than the pure permanent magnet (PPM) devices they are replacing. They have been designed, built, and measured in-house. All four have a 4 mm minimum operating gap and are almost identical in their construction: the main difference being an increase in the number of in-vacuum magnet beam support points from four to five, between CPMU-1 and CPMUs 2 - 4, to better facilitate shimming, particularly at cold temperatures. The ability to shim at cryogenic temperatures necessitated the development of an in-vacuum measurement system. The details of the measurement system will be presented alongside the mechanical and cryogenic design of the undulators; including issues with the magnet foils, and the shimming procedures and tools used to reach the tight magnetic specifications at room temperature and at 77 K.
	Poster WE4P36 [1.656 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P36
About •	Received ※ 23 August 2023 — Revised ※ 29 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023
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WE4P37	Laser Interferometer for Hall Probe Alignment and Measurement of Undulator	laser, alignment, controls, software	215
	S.M. Khan, G. Mishra Devi Ahilya University, Indore, India M. Gehlot DESY, Hamburg, Germany S. Mishra Devi Ahilya Vishwa Vidyalaya, Institute of Engineering & Technology, Indore, India
	In the Hall probe Magnetic measurement method the field mapping is done along the length of the undulator. The field integral and phase error computed from the field mapping works as the figure of merit of the undulator. In this paper, we discuss the working of a laser interferometer for precise Hall probe alignment. A new user friendly software based on MATLAB has been developed. The phase error and magnetic field integrals are calculated for both taper and untaper U50 undulator of the Laser and Insertion Device Application (LIDA) Laboratory.
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P37
About •	Received ※ 22 August 2023 — Revised ※ 22 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023
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WE4P38	Pulsed Wire Measurement of 20 mm Period Hybrid Undulator and Effects of Dispersion	experiment, laser, vacuum, insertion-device	218
	S.M. Khan, G. Mishra Devi Ahilya University, Indore, India M. Gehlot DESY, Hamburg, Germany
	In the pulsed wire method, a thin wire is stretched along the undulator axis with a sensor located near the undulator end. When a current flows through the wire, the Lorentz force on the wire sets up a travelling wave that is picked up by a sensor. Sensor output v. time gives the field integral v. position along the undulator length. We investigate pulsed wire measurements of field integrals and phase error of a 20 mm-period, 500 mm-long undulator and discuss variation in performance with Hall probe data, without any dispersion correction algorithm. Dispersion in the wire introduces dispersion corrected pulse lengths for the field integral measurements. Two field integrals of the undulator were measured with an accuracy close to 2 Gcm and 2 Gcm² with the Hall probe result. The contributions of dispersion to the phase error of the undulator are analyzed. The dispersion assisted phase advance in the undulator in the pulsed wire is measured with a higher slope in comparison to the Hall probe data. Dispersion limited optical phase growth along the undulator length causes period length fluctuations and yields a discrepancy in the phase error computation in comparison to Hall probe data.
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P38
About •	Received ※ 22 August 2023 — Revised ※ 22 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023
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WE4P39	Larmor Radius Effect on IFEL Accelerator With Staggered Undulator	electron, laser, FEL, radiation	221
	R. Khullar, S.M. Khan, G. Mishra Devi Ahilya University, Indore, India
	In this paper, the theory of inverse free electron (IFEL) accelerator using staggered undulator has been discussed. The important contribution of staggered undulator parameter and the finite larmour radius effect on energy saturation, saturation length and accelerating gradient of the IFEL accelerator are included in the analysis. Considering the synchrotron radiation losses, the IFEL accelerator equations are derived. Key words- undulator, inverse free electron laser accelerator, accelerator
	Poster WE4P39 [0.786 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P39
About •	Received ※ 23 August 2023 — Revised ※ 30 August 2023 — Accepted ※ 01 September 2023 — Issued ※ 02 December 2023
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TH1D2	A Bulk Superconductor and its Application to Insertion Devices	solenoid, controls, permanent-magnet, experiment	224
	T. Kii Kyoto University, Kyoto, Japan
	Funding: This work was supported by KAKENHI JP17H01127 and JP22H03870 High-field short-period undulator will be one of the key technologies for the future light sources. Various approaches have been continued under the limitation of materials for permanent/superconducting magnets. A use of bulk superconductor is attractive for its high current density under existence of high magnetic field. The critical current density for rare-earth barium copper oxide (REBCO) bulk superconductor exceeds 10 kA/mm2 even at 10 K in a field range below about 3 T and exceeds 20 kA/mm2 at 4.2 K. In order to utilize the quite high current density in the bulk REBCO and to generate periodic magnetic field we proposed bulk superconductor staggered array undulator in 2006. Recently we have developed the third undulaor prototype which consists of 6T solenoid and 6 period of bulk REBCO array, and successfully demonstrated periodic field amplitude of 2.22 T for period length of 10 mm and undulator gap of 4.0 mm at 7 K. In the presentation, we will summarize properties and performances of bulk REBCO superconductors and discuss on the performance of bulk superconductor staggered array undulator and potential as an insertion device for the future light sources. T. Kii et al.: Proc. FEL2006 (2006) p. 653.
	Slides TH1D2 [2.682 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-TH1D2
About •	Received ※ 22 August 2023 — Revised ※ 23 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023
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TH1D4	Bi-periodic Undulator: Innovative Insertion Device for SOLEIL II	synchrotron, electron, radiation, storage-ring	228
	A. Potet, F. Blache, P. Brunelle, M.-E. Couprie, O. Marcouillé, A. Mary, T. Mutin, A. Nadji, K. Tavakoli, C. de Oliveira SOLEIL, Gif-sur-Yvette, France
	SOLEIL II project will lead to optimize the production of photons by a modification of the present facility. The storage ring will be redesigned to reduce electron beam emittance, increase photon beam flux and brightness, and improve beamline resolution. The number of magnetic elements will be increased and the space reserved for insertion devices will be decreased by 30%. SOLEIL magnetic group searches for solutions to generate different magnetic periods in a smaller space to maintain the full spectral domain. Bi-Periodic undulator is an innovative and compact device allowing the use of two selectable magnetic periodicities by superimposition of magnets. The magnetic period can be switched from one value to its triple value by mechanical shift of magnetic arrays. A magnetic design has been performed and the construction of a prototype, including magnetic measurements and corrections, is under progress. The prototype will be installed in the storage ring with the goal to verify the feasibility of the model and to characterize the system. The magnetic fields, the radiation produced and the electron beam dynamics will be considered to have a complete knowledge on this undulator.
	Slides TH1D4 [2.442 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-TH1D4
About •	Received ※ 23 August 2023 — Revised ※ 26 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023
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TH2C1	The COXINEL Seeded Free Electron Laser Driven by the Laser Plasma Accelerator at HZDR	laser, electron, plasma, FEL	232
	M.-E. Couprie, T. André, A. Berlioux, P. Berteaud, F. Blache, F. Bouvet, F. Briquez, Y. Dietrich, J.P. Duval, M. El Ajjouri, C. Herbeaux, N. Hubert, C.A. Kitégi, M. Labat, S. Lê, B. Leluan, A. Loulergue, F. Marteau, M.-H. Nguyen, D. Oumbarek Espinos, D. Pereira, J.P. Ricaud, P. Rommeluère, M. Sebdaoui, K. Tavakoli, M. Valléau, M.V. Vandenberghe, J. Vétéran, C. de Oliveira SOLEIL, Gif-sur-Yvette, France I.A. Andriyash, J. Gautier, J.-P. Goddet, O.S. Kononenko, G. Lambert, J.P. Rousseau, A. Tafzi, C. Thaury LOA, Palaiseau, France S. Bock, Y.Y. Chang, A.D. Debus, C. Eisenmann, R. Gebhardt, A. Ghaith, S. Grams, U. Helbig, A. Irman, M. Kuntzsch, R.G. Pausch, T. Püschel, S. Schöbel, U. Schramm, K. Steiniger, P. Ufer HZDR, Dresden, Germany M. LaBerge The University of Texas at Austin, Austin, Texas, USA V. Malka Weizmann Institute of Science, Physics, Rehovot, Israel E. Roussel PhLAM/CERLA, Villeneuve d’Ascq, France
	Laser Plasma Accelerators know a tremendous development these recent years. Being able to reach up to ~100 GV/m, they open new perspectives for compact accelerators. Their performance can be qualified by a Free Electron Laser Application. We report here on the COXINEL seeded Free Electron Laser in the UV using the using high-quality electron beam generated by the 150 TW DRACO laser. The COXINEL line developed at Synchrotron SOLEIL (France) is first introduced. First electron beam transport and undulator radiation observation using electrons from the Laser Plasma Accelerator developed at Laboratoire d’Optique Appliquée (France) are described. Then, we present the first COXINEL results driven by the DRACO laser high performance plasma accelerator after its move to Helmholtz-Zentrum Dresden-Rossendorf (HZDR) (Germany): proper electron beam transport, undulator seed and undulator radiation temporal, spectral and spatial overlaps, allowing the seeded Free Electron Laser to be observed in the UV. Good agreement is found between measurements and simulations.
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-TH2C1
About •	Received ※ 22 August 2023 — Revised ※ 29 August 2023 — Accepted ※ 30 August 2023 — Issued ※ 02 December 2023
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TH2C2	Development of Laser-Driven Plasma Accelerator Undulator Radiation Source at ELI-Beamlines	electron, laser, plasma, photon	237
	A.Y. Molodozhentsev Czech Republic Academy of Sciences, Institute of Physics, Prague, Czech Republic J.T. Green, P. Zimmermann ELI-BEAMS, Prague, Czech Republic A. Jancarek, S.M. Maity, A. Mondal, S.N. Niekrasz, E. Vishnyakov ELI ERIC, Dolni Brezany, Czech Republic
	Over the last decade, the mechanism of the laser-plasma acceleration of electrons was studied intensively by many experimental teams aiming to achieve high-energy, high-quality electron beams required to generate high-brilliance incoherent and, as the next step, coherent undulator photon radiation for wide-range applications. The laser-driven plasma accelerator based compact undulator radiation source is currently under commissioning at ELI-Beamlines (Institute of Physics CAS, Czech Republic) in the frame of the LUIS project, which aims to deliver stable and reliable incoherent photon beam with a wavelength around 5 nm to an user-station. As the result of this project, the electron beam parameters should be improved to generate the coherent photon radiation reaching the saturation of the photon pulse energy in a single-unit dedicated undulator (LPA-based FEL). An overview of the current status of the LUIS project will be presented, including the high-power high-repetition rate laser, acceleration of the electron beam in the plasma channel, the electron and photon beam-lines with relevant diagnostics. Challenges and future development beyond the LUIS project also being discussed.
	Slides TH2C2 [3.474 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-TH2C2
About •	Received ※ 23 August 2023 — Revised ※ 29 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023
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TH3B2	Novel X-ray Beam Position Monitor for Coherent Soft X-ray Beamlines	detector, operation, photon, vacuum	241
	B. Podobedov, D.M. Bacescu, C. Eng, S. Hulbert, C. Mazzoli, C.S. Nelson BNL, Upton, New York, USA D. Donetski, K. Kucharczyk, J. Liu, R. Lutchman, J. Zhao Stony Brook University, Stony Brook, New York, USA
	A novel soft X-ray BPM (sXBPM) for high-power white beams of synchrotron undulator radiation is being developed through a joint effort of BNL/NSLS-II and Stony Brook University. In our approach, custom-made multi-pixel GaAs detector arrays are placed into the outer portions of the X-ray beam, and the beam position is inferred from the pixel photocurrents. Our goal is to achieve micron-scale positional and ~50 nrad angular resolution without interfering with user experiments, especially the most sensitive ones exploiting coherent properties of the beam. To this end, an elaborate mechanical system has been designed, fabricated, and installed in the 23-ID canted undulator beamline first optical enclosure, which allows positioning of the detectors with micron-scale accuracy, and provisions for possible intercepts of kW-level beam in abnormal conditions. Separately, GaAs detectors with specially tailored spectral response have been designed, fabricated, and tested in the soft and hard X-ray regions at two NSLS-II beamlines. In this talk we plan to give an overview of the sXBPM system and present the first results from the high-power white X-ray beam.
	Slides TH3B2 [5.100 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-TH3B2
About •	Received ※ 15 September 2023 — Revised ※ 15 September 2023 — Accepted ※ 17 September 2023 — Issued ※ 02 December 2023
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TH3D2	Radiation Protection Issues in Undulator Upgrades for the European XFEL	radiation, photon, simulation, FEL	245
	A.T. Potter, A. Wolski The University of Liverpool, Liverpool, United Kingdom S. Casalbuoni, S. Karabekyan, H. Sinn, F. Wolff-Fabris EuXFEL, Schenefeld, Germany W. Decking, A. Leuschner, S. Liu DESY, Hamburg, Germany F. Jackson STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
	European XFEL is the first free electron laser operating at MHz repetition rate with electron beam energy up to 17.5 GeV. The high repetition rate together with the high electron beam energy provides unique opportunities for users in different domains. To further extend the operation schemes, some upgrades have already been implemented and several more are planned. The advanced operation schemes may require devices inserted into the beam like slotted foil or narrow vacuum chambers such as for the corrugated structure, the Apple-X undulator, and the superconducting undulator. Due to the high beam power generated by the superconducting linac, there are concerns about increased radiation loads. Therefore, simulations and measurements have been carried out to study the radiation dose rates that may be generated. We give an overview of the simulations and measurements for the above mentioned schemes.
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-TH3D2
About •	Received ※ 30 August 2023 — Revised ※ 31 August 2023 — Accepted ※ 01 September 2023 — Issued ※ 02 December 2023
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TH4A4	A Proposal for Generating Fully Coherent X-ray FEL with Femtosecond Pulse Based on Fresh-Slice	polarization, FEL, radiation, electron	261
	Z.F. Gao SSRF, Shanghai, People’s Republic of China J.W. Yan EuXFEL, Schenefeld, Germany
	This study aims to propose a new principle for generating fully coherent femtosecond X-ray pulse on the Shanghai soft X-ray Free Electron Laser User Facility (SXFEL-UF), which was based on fresh-slice technique. The electron beam was kicked transversely to get a time-related transverse tilt. The sub-10-femtosecond bunch was achieved first because of the spatiotemporal synchronization effect of the seed laser modulation. Then the FEL pulse duration was even shorter because of harmonic lasing. In the cascaded HGHG mode, the laser generated by the beam tail modulated the beam head in the second stage to reach higher harmonics, while in the EEHG mode, the same part of the electron beam was modulated twice. The influence of emittance and energy chirp of the electron beam on the scheme was analyzed, and the instability caused by transverse position jitter and energy jitter of the chirped beam was evaluated. The relationship between the pulse duration and the transverse deflection of the beam is verified. The scheme is also explored to generate linearly polarized femtosecond pulse at 6 nm and circularly polarized femtosecond pulse at 3 nm simultaneously.
	Slides TH4A4 [3.281 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-TH4A4
About •	Received ※ 21 August 2023 — Revised ※ 24 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023
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Paper

Title

Other Keywords

Page

MO3A2

Status and Perspectives for the Swiss Free-Electron Laser (SwissFEL)

FEL, electron, laser, operation

26

T. Schietinger
PSI, Villigen PSI, Switzerland

We summarize the status of SwissFEL, the X-ray free-electron laser at the Paul Scherrer Institute. Apart from some key operational performance figures the presentation covers the state of the experimental stations and their capabilities, gives a few scientific highlights and an overview of the use of special modes beyond SASE at our facility. Furthermore we report on progress of our seeding upgrade program on the soft X-ray line. Lastly we mention our long-term upgrade plans for a third undulator beamline in the tender and hard X-ray regime.

Slides MO3A2 [8.398 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-MO3A2

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

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MO3A5

FLASH: Status and Upgrade

laser, FEL, electron, operation

32

M. Vogt, S. Schreiber, J. Zemella
DESY, Hamburg, Germany

FLASH, the Soft X-Ray and Extreme-UV Free Electron Laser at DESY, is undergoing a substantial upgrade and refurbishment project, called FLASH2020+. The project will finally enable external seeded and SASE FEL operation for a wavelength range down to 4 nm with the EEHG method. This is achieved in two long shutdowns from November 2021 to August 2022 and from June 2024 to August 2025. Key ingredient of the upgrade were installation of a laser heater, replacing two early TTF-type L-band SRF accelerating modules by modern, high-gradient XFEL-type modules, redesign of the 2nd bunch compressor, and complete redesign of the FLASH1 beam line for HGHG/EEHG seeding. This talk will report on the project and the status of FLASH after the first shutdown with emphasis on beam dynamics aspects.

Slides MO3A5 [1.108 MB]

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reference for this paper ※ doi:10.18429/JACoW-FLS2023-MO3A5

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Received ※ 25 August 2023 — Revised ※ 26 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023

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TU2A2

Single Longitudinal Mode Generation in Slippage-dominated, Tapered-undulator SASE Soft X-ray FEL

FEL, electron, simulation, photon

70

D.C. Nguyen, M. Dunham, W. Lou, C.E. Mayes, G. Stupakov
xLight, Palo Alto, USA

SASE FELs operating in the soft X-ray region exhibit multiple temporal and spectral spikes with an overall spectral bandwidth of about 1.5 times the FEL rho parameter. While many ideas have been proposed to achieve fully coherent X-ray FELs, only monochromatic seeding, either harmonic seeding* or SASE self-seeding**, has been experimentally demonstrated to narrow the output spectra of soft X-ray FELs. In this paper, we study a different method that relies on the Slippage-dominated Tapered Undulator (STU) SASE concept to produce a single longitudinal mode in a soft X-ray FEL driven by ~10-fs, 16-pC electron bunches. We pre-sent numerical simulation results that demonstrate single-mode generation and narrow-lined spectra without seeding in a STU-SASE FEL at 6.67 nm.
* E. Alaria et al., Nat Photon 7 (2013) 913-918
** D. Ratner et al., PRL 114 (2015) 050801

Slides TU2A2 [1.125 MB]

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reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU2A2

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Received ※ 22 August 2023 — Revised ※ 23 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023

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TU4P06

The Experimental Progress for the Strong Field Terahertz Radiation at Shanghai Soft X-ray Free-electron Laser Facility

radiation, laser, electron, FEL

83

K.Q. Zhang, C. Feng
SSRF, Shanghai, People’s Republic of China
Y. Kang
SINAP, Shanghai, People’s Republic of China

Strong field Terahertz (THz) light source has been in-creasingly important for many scientific frontiers, while it is still a challenge to obtain THz radiation with high pulse energy at wide-tunable frequency. In this paper, we introduce an accelerator-based strong filed THz light source to obtain coherent THz radiation with high pulse energy and tunable frequency and X-ray pulse at the same time, which adopts a frequency beating laser pulse modulated electron beam. Here, we present the experi-mental progress for the strong filed THz radiation at shanghai soft X-ray free-electron laser (SXFEL) facility and show its simulated radiation performance.

Poster TU4P06 [1.310 MB]

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reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU4P06

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Received ※ 21 August 2023 — Revised ※ 28 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023

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TU4P07

Design of the Beam Distribution System of SHINE

kicker, linac, electron, FEL

87

S. Chen
SSRF, Shanghai, People’s Republic of China
H.X. Deng, X. Fu, B. Liu
SARI-CAS, Pudong, Shanghai, People’s Republic of China
B.Y. Yan
SINAP, Shanghai, People’s Republic of China

The Shanghai high-repetition-rate XFEL and extreme light facility (SHINE), as the first hard X-ray free electron laser facility in China, is now under construction. CW electron beam with up to 1 MHz bunch repetition rate from a superconducting RF linac is used to feed at least three individual undulator lines that covers a wide photon energy range (0.4 keV ~ 25 keV). In order to maximize the efficiency of the facility, a beam switchyard between the linac and undulator lines is used to enable the simultaneously operation of the three undulator lines. In this work, the schematic design of the beam switchyard for bunch-by-bunch beam separation of CW beam is described, and the current lattice design of the linac-to-undulator deflection branches and the start-to-end tracking simulation results are presented.

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reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU4P07

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Received ※ 22 August 2023 — Revised ※ 28 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023

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TU4P08

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

FEL, emittance, linac, MMI

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]

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

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

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TU4P28

Useful Formulas and Example Parameters Set for the Design of SSMB Storage Rings

radiation, laser, bunching, storage-ring

135

X.J. Deng, A. Chao, W.-H. Huang, Z.Z. Li, Z. Pan, C.-X. Tang
TUB, Beijing, People’s Republic of China

A promising accelerator light source mechanism called steady-state microbunching (SSMB) has been actively studied in recent years. Here we summarize some important formulas for the design of SSMB storage rings. Generally we group our formulas into two categories, i.e., a longitudinal weak focusing storage ring for a desired radiation wavelength larger than 100 nm, and a transverse-longitudinal coupling, or a generalized longitudinal strong focusing, storage ring for a desired radiation wavelength between 1 nm and 100 nm. In each category, we have presented an example parameters set for the corresponding SSMB storage ring, to generate kW-level infrared, EUV and soft X-ray radiation, respectively.

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU4P28

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Received ※ 15 August 2023 — Revised ※ 24 August 2023 — Accepted ※ 30 August 2023 — Issued ※ 02 December 2023

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TU4P29

Why is the Coherent Radiation from Laser-induced Microbunches Narrowbanded and Collimated

radiation, electron, laser, bunching

139

X.J. Deng, A. Chao
TUB, Beijing, People’s Republic of China

There are two reasons: one is the long coherence length of radiation from micobunches imprinted by the modulation laser, the second is the finite transverse electron beam size. In other words, one is due to the longitudinal form factor, and the other the transverse form factor of the electron beam. Here we study the role of these form factors in shaping the energy spectrum and spatial distribution of microbunching radiation. The investigations are of value for cases like steady-state microbunching (SSMB), coherent harmonic generation (CHG) and free-electron laser (FEL).

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU4P29

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Received ※ 14 August 2023 — Revised ※ 24 August 2023 — Accepted ※ 30 August 2023 — Issued ※ 02 December 2023

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TU4P30

Optical Stochastic Cooling in a General Coupled Lattice

damping, pick-up, radiation, storage-ring

143

X.J. Deng
TUB, Beijing, People’s Republic of China

Here we present a formalism of optical stochastic cooling in a 3D general coupled lattice. The formalism is general, and can treat a variety of damping and diffusion mechanisms within a single framework. We expect the work to be of value for the development of future light source.

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU4P30

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Received ※ 15 August 2023 — Revised ※ 24 August 2023 — Accepted ※ 30 August 2023 — Issued ※ 02 December 2023

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WE3A3

Multi-FELOs Driven by a Common Electron Beam

electron, FEL, radiation, laser

164

C.-Y. Tsai
HUST, Wuhan, People’s Republic of China
Y. Zhang
JLab, Newport News, Virginia, USA

Generating an FEL requires a high-brightness electron beam. To produce multiple FELs, the linac beam must be shared to enable one beam driving an undulator. This leads to a reduced average current and compromised FEL performance. Recently, a concept of multiple FELs driven by one electron beam was proposed, which enables reduction of equipment and improvement of productivity. We present here a simulation study based on an extended 1D FEL oscillator model to demonstrate this concept. The system consists of two FEL oscillators arranged side-by-side and one electron beam passing through them. As such, the second, downstream oscillator is driven by bunches already been used once, while the first oscillator always receives fresh bunches from the linac. The study shows lasing could be achieved for both oscillators, their radiation intensities at saturation are comparable, thus meet needs of users. The concept also enables a potential application using a circulator ring such that an oscillator can be driven alternately by fresh linac bunches from and used bunches in the circulator ring. Extending the concept to cases of more than two FEL oscillators driven by one beam is also explored.

Slides WE3A3 [0.540 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE3A3

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

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WE4P14

Layout of the Undulator-to-dump line at the SHINE

electron, FEL, radiation, linac

177

T. Liu, S. Chen, H.X. Deng, B. Liu, Z. Qi
SARI-CAS, Pudong, Shanghai, People’s Republic of China
Z.F. Gao
SSRF, Shanghai, People’s Republic of China
N. Huang
Zhangjiang Lab, Shanghai, People’s Republic of China

The Shanghai HIgh repetitioN rate XFEL and Extreme light Facility as the first hard X-ray free-electron laser (FEL) facility in China, is currently under construction in the Zhangjiang area, Shanghai. It aims to deliver X-ray covering photon energy range from 0.4 to 25 keV, with electron beam power up to 800 kW. Downstream of the undulator line, the beam transport design of the undulator-to-dump line is critical which is mainly used for realization of FEL diagnostics based on transverse deflecting structure and beam absorption in the dump. In this manuscript we describe the current layout of this system.

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reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P14

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Received ※ 20 August 2023 — Revised ※ 22 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023

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WE4P36

The Cryogenic Undulator Upgrade Programme at Diamond Light Source

vacuum, MMI, cryogenics, insertion-device

211

Z. Patel, W. Cheng, A. George, S.H. Hale, R. Mercado, A. Ramezani Moghaddam, M. Reeves, G. Sharma, S. Tripathi
DLS, Oxfordshire, United Kingdom
M.V. Marziani
University of Cape Town, Cape Town, South Africa

Diamond Light Source has installed four 2 m long, 17.6 mm period Cryogenic Permanent Magnet Undulators (CPMUs) as upgrades for crystallography beamlines since 2020, with two more planned within the next year. The CPMUs provide 2 - 3 times more brightness and 2 - 4 times more flux than the pure permanent magnet (PPM) devices they are replacing. They have been designed, built, and measured in-house. All four have a 4 mm minimum operating gap and are almost identical in their construction: the main difference being an increase in the number of in-vacuum magnet beam support points from four to five, between CPMU-1 and CPMUs 2 - 4, to better facilitate shimming, particularly at cold temperatures. The ability to shim at cryogenic temperatures necessitated the development of an in-vacuum measurement system. The details of the measurement system will be presented alongside the mechanical and cryogenic design of the undulators; including issues with the magnet foils, and the shimming procedures and tools used to reach the tight magnetic specifications at room temperature and at 77 K.

Poster WE4P36 [1.656 MB]

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reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P36

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Received ※ 23 August 2023 — Revised ※ 29 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023

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WE4P37

Laser Interferometer for Hall Probe Alignment and Measurement of Undulator

laser, alignment, controls, software

215

S.M. Khan, G. Mishra
Devi Ahilya University, Indore, India
M. Gehlot
DESY, Hamburg, Germany
S. Mishra
Devi Ahilya Vishwa Vidyalaya, Institute of Engineering & Technology, Indore, India

In the Hall probe Magnetic measurement method the field mapping is done along the length of the undulator. The field integral and phase error computed from the field mapping works as the figure of merit of the undulator. In this paper, we discuss the working of a laser interferometer for precise Hall probe alignment. A new user friendly software based on MATLAB has been developed. The phase error and magnetic field integrals are calculated for both taper and untaper U50 undulator of the Laser and Insertion Device Application (LIDA) Laboratory.

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reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P37

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Received ※ 22 August 2023 — Revised ※ 22 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023

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WE4P38

Pulsed Wire Measurement of 20 mm Period Hybrid Undulator and Effects of Dispersion

experiment, laser, vacuum, insertion-device

218

S.M. Khan, G. Mishra
Devi Ahilya University, Indore, India
M. Gehlot
DESY, Hamburg, Germany

In the pulsed wire method, a thin wire is stretched along the undulator axis with a sensor located near the undulator end. When a current flows through the wire, the Lorentz force on the wire sets up a travelling wave that is picked up by a sensor. Sensor output v. time gives the field integral v. position along the undulator length. We investigate pulsed wire measurements of field integrals and phase error of a 20 mm-period, 500 mm-long undulator and discuss variation in performance with Hall probe data, without any dispersion correction algorithm. Dispersion in the wire introduces dispersion corrected pulse lengths for the field integral measurements. Two field integrals of the undulator were measured with an accuracy close to 2 Gcm and 2 Gcm² with the Hall probe result. The contributions of dispersion to the phase error of the undulator are analyzed. The dispersion assisted phase advance in the undulator in the pulsed wire is measured with a higher slope in comparison to the Hall probe data. Dispersion limited optical phase growth along the undulator length causes period length fluctuations and yields a discrepancy in the phase error computation in comparison to Hall probe data.

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reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P38

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Received ※ 22 August 2023 — Revised ※ 22 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023

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WE4P39

Larmor Radius Effect on IFEL Accelerator With Staggered Undulator

electron, laser, FEL, radiation

221

R. Khullar, S.M. Khan, G. Mishra
Devi Ahilya University, Indore, India

In this paper, the theory of inverse free electron (IFEL) accelerator using staggered undulator has been discussed. The important contribution of staggered undulator parameter and the finite larmour radius effect on energy saturation, saturation length and accelerating gradient of the IFEL accelerator are included in the analysis. Considering the synchrotron radiation losses, the IFEL accelerator equations are derived.
Key words- undulator, inverse free electron laser accelerator, accelerator

Poster WE4P39 [0.786 MB]

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reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P39

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Received ※ 23 August 2023 — Revised ※ 30 August 2023 — Accepted ※ 01 September 2023 — Issued ※ 02 December 2023

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TH1D2

A Bulk Superconductor and its Application to Insertion Devices

solenoid, controls, permanent-magnet, experiment

224

T. Kii
Kyoto University, Kyoto, Japan

Funding: This work was supported by KAKENHI JP17H01127 and JP22H03870
High-field short-period undulator will be one of the key technologies for the future light sources. Various approaches have been continued under the limitation of materials for permanent/superconducting magnets. A use of bulk superconductor is attractive for its high current density under existence of high magnetic field. The critical current density for rare-earth barium copper oxide (REBCO) bulk superconductor exceeds 10 kA/mm2 even at 10 K in a field range below about 3 T and exceeds 20 kA/mm2 at 4.2 K. In order to utilize the quite high current density in the bulk REBCO and to generate periodic magnetic field we proposed bulk superconductor staggered array undulator in 2006*. Recently we have developed the third undulaor prototype which consists of 6T solenoid and 6 period of bulk REBCO array, and successfully demonstrated periodic field amplitude of 2.22 T for period length of 10 mm and undulator gap of 4.0 mm at 7 K. In the presentation, we will summarize properties and performances of bulk REBCO superconductors and discuss on the performance of bulk superconductor staggered array undulator and potential as an insertion device for the future light sources.
* T. Kii et al.: Proc. FEL2006 (2006) p. 653.

Slides TH1D2 [2.682 MB]

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reference for this paper ※ doi:10.18429/JACoW-FLS2023-TH1D2

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Received ※ 22 August 2023 — Revised ※ 23 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023

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TH1D4

Bi-periodic Undulator: Innovative Insertion Device for SOLEIL II

synchrotron, electron, radiation, storage-ring

228

A. Potet, F. Blache, P. Brunelle, M.-E. Couprie, O. Marcouillé, A. Mary, T. Mutin, A. Nadji, K. Tavakoli, C. de Oliveira
SOLEIL, Gif-sur-Yvette, France

SOLEIL II project will lead to optimize the production of photons by a modification of the present facility. The storage ring will be redesigned to reduce electron beam emittance, increase photon beam flux and brightness, and improve beamline resolution. The number of magnetic elements will be increased and the space reserved for insertion devices will be decreased by 30%. SOLEIL magnetic group searches for solutions to generate different magnetic periods in a smaller space to maintain the full spectral domain. Bi-Periodic undulator is an innovative and compact device allowing the use of two selectable magnetic periodicities by superimposition of magnets. The magnetic period can be switched from one value to its triple value by mechanical shift of magnetic arrays. A magnetic design has been performed and the construction of a prototype, including magnetic measurements and corrections, is under progress. The prototype will be installed in the storage ring with the goal to verify the feasibility of the model and to characterize the system. The magnetic fields, the radiation produced and the electron beam dynamics will be considered to have a complete knowledge on this undulator.

Slides TH1D4 [2.442 MB]

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reference for this paper ※ doi:10.18429/JACoW-FLS2023-TH1D4

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Received ※ 23 August 2023 — Revised ※ 26 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023

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TH2C1

The COXINEL Seeded Free Electron Laser Driven by the Laser Plasma Accelerator at HZDR

laser, electron, plasma, FEL

232

M.-E. Couprie, T. André, A. Berlioux, P. Berteaud, F. Blache, F. Bouvet, F. Briquez, Y. Dietrich, J.P. Duval, M. El Ajjouri, C. Herbeaux, N. Hubert, C.A. Kitégi, M. Labat, S. Lê, B. Leluan, A. Loulergue, F. Marteau, M.-H. Nguyen, D. Oumbarek Espinos, D. Pereira, J.P. Ricaud, P. Rommeluère, M. Sebdaoui, K. Tavakoli, M. Valléau, M.V. Vandenberghe, J. Vétéran, C. de Oliveira
SOLEIL, Gif-sur-Yvette, France
I.A. Andriyash, J. Gautier, J.-P. Goddet, O.S. Kononenko, G. Lambert, J.P. Rousseau, A. Tafzi, C. Thaury
LOA, Palaiseau, France
S. Bock, Y.Y. Chang, A.D. Debus, C. Eisenmann, R. Gebhardt, A. Ghaith, S. Grams, U. Helbig, A. Irman, M. Kuntzsch, R.G. Pausch, T. Püschel, S. Schöbel, U. Schramm, K. Steiniger, P. Ufer
HZDR, Dresden, Germany
M. LaBerge
The University of Texas at Austin, Austin, Texas, USA
V. Malka
Weizmann Institute of Science, Physics, Rehovot, Israel
E. Roussel
PhLAM/CERLA, Villeneuve d’Ascq, France

Laser Plasma Accelerators know a tremendous development these recent years. Being able to reach up to ~100 GV/m, they open new perspectives for compact accelerators. Their performance can be qualified by a Free Electron Laser Application. We report here on the COXINEL seeded Free Electron Laser in the UV using the using high-quality electron beam generated by the 150 TW DRACO laser. The COXINEL line developed at Synchrotron SOLEIL (France) is first introduced. First electron beam transport and undulator radiation observation using electrons from the Laser Plasma Accelerator developed at Laboratoire d’Optique Appliquée (France) are described. Then, we present the first COXINEL results driven by the DRACO laser high performance plasma accelerator after its move to Helmholtz-Zentrum Dresden-Rossendorf (HZDR) (Germany): proper electron beam transport, undulator seed and undulator radiation temporal, spectral and spatial overlaps, allowing the seeded Free Electron Laser to be observed in the UV. Good agreement is found between measurements and simulations.

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reference for this paper ※ doi:10.18429/JACoW-FLS2023-TH2C1

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Received ※ 22 August 2023 — Revised ※ 29 August 2023 — Accepted ※ 30 August 2023 — Issued ※ 02 December 2023

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TH2C2

Development of Laser-Driven Plasma Accelerator Undulator Radiation Source at ELI-Beamlines

electron, laser, plasma, photon

237

A.Y. Molodozhentsev
Czech Republic Academy of Sciences, Institute of Physics, Prague, Czech Republic
J.T. Green, P. Zimmermann
ELI-BEAMS, Prague, Czech Republic
A. Jancarek, S.M. Maity, A. Mondal, S.N. Niekrasz, E. Vishnyakov
ELI ERIC, Dolni Brezany, Czech Republic

Over the last decade, the mechanism of the laser-plasma acceleration of electrons was studied intensively by many experimental teams aiming to achieve high-energy, high-quality electron beams required to generate high-brilliance incoherent and, as the next step, coherent undulator photon radiation for wide-range applications. The laser-driven plasma accelerator based compact undulator radiation source is currently under commissioning at ELI-Beamlines (Institute of Physics CAS, Czech Republic) in the frame of the LUIS project, which aims to deliver stable and reliable incoherent photon beam with a wavelength around 5 nm to an user-station. As the result of this project, the electron beam parameters should be improved to generate the coherent photon radiation reaching the saturation of the photon pulse energy in a single-unit dedicated undulator (LPA-based FEL). An overview of the current status of the LUIS project will be presented, including the high-power high-repetition rate laser, acceleration of the electron beam in the plasma channel, the electron and photon beam-lines with relevant diagnostics. Challenges and future development beyond the LUIS project also being discussed.

Slides TH2C2 [3.474 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-TH2C2

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Received ※ 23 August 2023 — Revised ※ 29 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023

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TH3B2

Novel X-ray Beam Position Monitor for Coherent Soft X-ray Beamlines

detector, operation, photon, vacuum

241

B. Podobedov, D.M. Bacescu, C. Eng, S. Hulbert, C. Mazzoli, C.S. Nelson
BNL, Upton, New York, USA
D. Donetski, K. Kucharczyk, J. Liu, R. Lutchman, J. Zhao
Stony Brook University, Stony Brook, New York, USA

A novel soft X-ray BPM (sXBPM) for high-power white beams of synchrotron undulator radiation is being developed through a joint effort of BNL/NSLS-II and Stony Brook University. In our approach, custom-made multi-pixel GaAs detector arrays are placed into the outer portions of the X-ray beam, and the beam position is inferred from the pixel photocurrents. Our goal is to achieve micron-scale positional and ~50 nrad angular resolution without interfering with user experiments, especially the most sensitive ones exploiting coherent properties of the beam. To this end, an elaborate mechanical system has been designed, fabricated, and installed in the 23-ID canted undulator beamline first optical enclosure, which allows positioning of the detectors with micron-scale accuracy, and provisions for possible intercepts of kW-level beam in abnormal conditions. Separately, GaAs detectors with specially tailored spectral response have been designed, fabricated, and tested in the soft and hard X-ray regions at two NSLS-II beamlines. In this talk we plan to give an overview of the sXBPM system and present the first results from the high-power white X-ray beam.

Slides TH3B2 [5.100 MB]

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reference for this paper ※ doi:10.18429/JACoW-FLS2023-TH3B2

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Received ※ 15 September 2023 — Revised ※ 15 September 2023 — Accepted ※ 17 September 2023 — Issued ※ 02 December 2023

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TH3D2

Radiation Protection Issues in Undulator Upgrades for the European XFEL

radiation, photon, simulation, FEL

245

A.T. Potter, A. Wolski
The University of Liverpool, Liverpool, United Kingdom
S. Casalbuoni, S. Karabekyan, H. Sinn, F. Wolff-Fabris
EuXFEL, Schenefeld, Germany
W. Decking, A. Leuschner, S. Liu
DESY, Hamburg, Germany
F. Jackson
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

European XFEL is the first free electron laser operating at MHz repetition rate with electron beam energy up to 17.5 GeV. The high repetition rate together with the high electron beam energy provides unique opportunities for users in different domains. To further extend the operation schemes, some upgrades have already been implemented and several more are planned. The advanced operation schemes may require devices inserted into the beam like slotted foil or narrow vacuum chambers such as for the corrugated structure, the Apple-X undulator, and the superconducting undulator. Due to the high beam power generated by the superconducting linac, there are concerns about increased radiation loads. Therefore, simulations and measurements have been carried out to study the radiation dose rates that may be generated. We give an overview of the simulations and measurements for the above mentioned schemes.

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reference for this paper ※ doi:10.18429/JACoW-FLS2023-TH3D2

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Received ※ 30 August 2023 — Revised ※ 31 August 2023 — Accepted ※ 01 September 2023 — Issued ※ 02 December 2023

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TH4A4

A Proposal for Generating Fully Coherent X-ray FEL with Femtosecond Pulse Based on Fresh-Slice

polarization, FEL, radiation, electron

261

Z.F. Gao
SSRF, Shanghai, People’s Republic of China
J.W. Yan
EuXFEL, Schenefeld, Germany

This study aims to propose a new principle for generating fully coherent femtosecond X-ray pulse on the Shanghai soft X-ray Free Electron Laser User Facility (SXFEL-UF), which was based on fresh-slice technique. The electron beam was kicked transversely to get a time-related transverse tilt. The sub-10-femtosecond bunch was achieved first because of the spatiotemporal synchronization effect of the seed laser modulation. Then the FEL pulse duration was even shorter because of harmonic lasing. In the cascaded HGHG mode, the laser generated by the beam tail modulated the beam head in the second stage to reach higher harmonics, while in the EEHG mode, the same part of the electron beam was modulated twice. The influence of emittance and energy chirp of the electron beam on the scheme was analyzed, and the instability caused by transverse position jitter and energy jitter of the chirped beam was evaluated. The relationship between the pulse duration and the transverse deflection of the beam is verified. The scheme is also explored to generate linearly polarized femtosecond pulse at 6 nm and circularly polarized femtosecond pulse at 3 nm simultaneously.

Slides TH4A4 [3.281 MB]

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reference for this paper ※ doi:10.18429/JACoW-FLS2023-TH4A4

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Received ※ 21 August 2023 — Revised ※ 24 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023

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