FLS2023 - Table of Session: WE4P (Poster Session)

Paper	Title	Page
WE4P09	Heat Load and Radiation Pulse of Corrugated Structure at SHINE Facility	168
	J.J. Guo Zhangjiang Lab, Shanghai, People’s Republic of China H.X. Deng, D. Gu, Q. Gu, M. Meng, Z. Wang SARI-CAS, Pudong, Shanghai, People’s Republic of China
	Corrugated structure modules are being proposed for installation after the end of the linac and before the undulator regions of SHINE facility, where it has been used for energy chirp control and as a fast kicker for two color operation of the FEL. When ultra-relativistic bunch of electrons passing through corrugated structure will generate strong wakefield, we find most of the wake power lost by the beam is radiated out to the sides of the corrugated structure in the form of THz waves, and the remaining part casue Joule heating load on the corrugated structure wall. In this paper, we estimate the radiation pulse power and Joule power loss of the corrugated structure in SHINE facility.
	Poster WE4P09 [0.787 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P09
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)

WE4P12	Upgrades of High Level Applications at Shanghai Soft X-Ray FEL Facility	171
	H. Luo, D. Gu, T. Liu, Z. Wang SARI-CAS, Pudong, Shanghai, People’s Republic of China K.Q. Zhang SSRF, Shanghai, People’s Republic of China
	The Shanghai soft X-ray free-electron laser(SXFEL) facility has made significant progress in recent years with the rapid, upgraded iterations of the high level software, including but not limited to energy matching, orbit feedback and load, beam optimization, etc. These tools are key components in operation and experiment of free electron laser facility. Some key applications are presented in this paper.
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P12
About •	Received ※ 21 August 2023 — Revised ※ 29 August 2023 — Accepted ※ 30 August 2023 — Issued ※ 02 December 2023
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WE4P13	Physics Design and Beam Dynamics Optimization of the SHINE Accelerator	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
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WE4P14	Layout of the Undulator-to-dump line at the SHINE	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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WE4P15	Multichromatic Free-electron Laser Generation Through Frequency-beating in a Chirped Electron Beam	181
	Z. Qi, C. Feng SARI-CAS, Pudong, Shanghai, People’s Republic of China
	We propose a simple method to generate mode-locked multichromatic free-electron laser (FEL) through a longitudinal phase space frequency-beating in a chirped electron beam. Utilizing the two stage modulator-chicane setups in Shanghai Soft X-ray FEL facility, together with a chirped electron beam, we are going to imprint a frequency-beating effect into the electron beam. Hence periodic bunching trains can be formed and can be used to generate mode-locked FEL radiation pulses. Theoretical analysis and numerical simulations are given out to demonstrate the performance of the method. The results indicate that mode-locked FEL in temporal and frequency domain can be formed at the 18th harmonic of the seed laser, with the central wavelength being about 14.58nm and the peak power over 2GW.
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P15
About •	Received ※ 01 September 2023 — Revised ※ 01 September 2023 — Accepted ※ 01 September 2023 — Issued ※ 02 December 2023
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WE4P18	Preliminary Design of Higher-order Achromat Lattice for the Upgrade of the Taiwan Photon Source	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
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WE4P19	Simulation Study of Orbit Correction by Neural Network in Taiwan Photon Source	188
	M.-S. Chiu, Y.-S. Cheng, G.-H. Luo, H.-J. Tsai, F.H. Tseng NSRRC, Hsinchu, Taiwan C.P. Felix MCL/ITRI, Hsinchu, Taiwan
	Machine learning has been applied in many fields in re-cent decades. Many research articles also presented re-markable achievements in either operation or designing of the particle accelerator. This paper focuses on the simulated orbit correction by neural networks, a subset of machine learning, in Taiwan Photon Source. The training data for the neural network is generated by accelerator toolbox (AT).
	Poster WE4P19 [0.843 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P19
About •	Received ※ 23 August 2023 — Revised ※ 29 August 2023 — Accepted ※ 30 August 2023 — Issued ※ 02 December 2023
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WE4P20	Alignment Results of Tandem EPUs at the Taiwan Photon Source	192
	Y.-C. Liu, C.M. Cheng, T.Y. Chung, Y.M. Hsiao, F.H. Tseng NSRRC, Hsinchu, Taiwan
	Taiwan Photon Source (TPS) has been open to user operation since 2016. We report the alignment results of tandem EPUs in one double mini-beta y long straight section. The goal is to increase the brilliance of the synchrotron lights produced by the tandem EPUs through well-alignment and using a phase shifter to achieve both spatial and temporal coherence. The calculated brilliance gain of the tandem EPUs is compared, and the difference between the measured and numerical results is analyzed.
	Poster WE4P20 [4.435 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P20
About •	Received ※ 16 August 2023 — Revised ※ 30 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023
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WE4P21	Some Beam Dynamic Issues in the HALF Storage Ring	196
	J.Y. Tang USTC, SNST, Anhui, People’s Republic of China Z.H. Bai, T.L. He, G. Liu, Y. Mo, A.X. Wang, P.H. Yang, Z. Zhao USTC/NSRL, Hefei, Anhui, People’s Republic of China
	HALF (Hefei Advanced Light Facility) is a fourth-generation synchrotron light source that just started construction in 2023. With 2.2 GeV in energy, 350 mA in beam current and 86 pm.rad in emittance, the HALF storage ring faces several beam dynamics challenges. This presentation gives the recent study on some of these issues, in particular the beam collimation and the influence and compensation of the insertion devices. For beam collimation, different beam loss mechanisms have been studied, and the Touschek scattering and beam dumping are considered the two major effects in designing the collimation system. Then two collimators with movable horizontal blades and fixed passive vertical blades are being designed, with the main focus on the collimation efficiency and impedance. For the influence of the insertion devices, it is found that some of the long-period undulators have a high impact on the beam dynamic aperture due to low beam energy and originally small dynamic aperture. The local compensation methods for both linear and non-linear effects have been studied. Instead of the traditional compensation method by electrical wires, the method of using two combined magnets with quadrupole and octupole fields at the two ID ends in restoring the dynamic aperture is also studied and compared.
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P21
About •	Received ※ 23 August 2023 — Revised ※ 30 August 2023 — Accepted ※ 01 September 2023 — Issued ※ 02 December 2023
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WE4P24	Optics for an Electron Cooler for the EIC Based on an Electron Storage Ring	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
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WE4P31	Deterministic Approach to the Lattice Design of BESSY III	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
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WE4P33	Design of a 166.6 MHz HOM Damped Copper Cavity for the Southern Advanced Photon Source	207
	J.Y. Zhu, X. Li, Z.J. Lu IHEP, Beijing, People’s Republic of China J.B. Yu IHEP CSNS, Guangdong Province, People’s Republic of China
	Funding: This work was supported by the National Natural Science Foundation of China (12205168). The Southern Advanced Photon Source (SAPS) aims to achieve ultra-low emittances and is expected to adopt low-frequency cavities (< 200 MHz) to accommodates on-axis injection. This paper focuses on the design of a 166.6 MHz HOM-damped normal conducting (NC) cavity for the SAPS. We propose a novel approach to achieve efficient HOM damping by optimizing the lowest frequency HOM and implementing a beam-line absorber in a coaxial resonant NC cavity. Notably, unlike beam-line absorbers for conventional NC cavities, the presence of a large beam tube in a coaxial resonant cavity does not affect the accelerating performance. This enables effective HOM damping while maintaining a high shunt impedance in a NC cavity. The numerical simulation results show that a compact copper cavity with effective HOM damping and excellent RF properties has been achieved.
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P33
About •	Received ※ 23 August 2023 — Revised ※ 30 August 2023 — Accepted ※ 01 September 2023 — Issued ※ 02 December 2023
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WE4P36	The Cryogenic Undulator Upgrade Programme at Diamond Light Source	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	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	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	221
	R. Khullar, S.M. Khanpresenter, 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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Paper

Title

Page

Heat Load and Radiation Pulse of Corrugated Structure at SHINE Facility

168

J.J. Guo
Zhangjiang Lab, Shanghai, People’s Republic of China
H.X. Deng, D. Gu, Q. Gu, M. Meng, Z. Wang
SARI-CAS, Pudong, Shanghai, People’s Republic of China

Corrugated structure modules are being proposed for installation after the end of the linac and before the undulator regions of SHINE facility, where it has been used for energy chirp control and as a fast kicker for two color operation of the FEL. When ultra-relativistic bunch of electrons passing through corrugated structure will generate strong wakefield, we find most of the wake power lost by the beam is radiated out to the sides of the corrugated structure in the form of THz waves, and the remaining part casue Joule heating load on the corrugated structure wall. In this paper, we estimate the radiation pulse power and Joule power loss of the corrugated structure in SHINE facility.

Poster WE4P09 [0.787 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P09

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)

WE4P12

Upgrades of High Level Applications at Shanghai Soft X-Ray FEL Facility

171

H. Luo, D. Gu, T. Liu, Z. Wang
SARI-CAS, Pudong, Shanghai, People’s Republic of China
K.Q. Zhang
SSRF, Shanghai, People’s Republic of China

The Shanghai soft X-ray free-electron laser(SXFEL) facility has made significant progress in recent years with the rapid, upgraded iterations of the high level software, including but not limited to energy matching, orbit feedback and load, beam optimization, etc. These tools are key components in operation and experiment of free electron laser facility. Some key applications are presented in this paper.

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P12

About •

Received ※ 21 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)

WE4P13

Physics Design and Beam Dynamics Optimization of the SHINE Accelerator

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)

WE4P14

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

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

Cite •

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

WE4P15

Multichromatic Free-electron Laser Generation Through Frequency-beating in a Chirped Electron Beam

181

Z. Qi, C. Feng
SARI-CAS, Pudong, Shanghai, People’s Republic of China

We propose a simple method to generate mode-locked multichromatic free-electron laser (FEL) through a longitudinal phase space frequency-beating in a chirped electron beam. Utilizing the two stage modulator-chicane setups in Shanghai Soft X-ray FEL facility, together with a chirped electron beam, we are going to imprint a frequency-beating effect into the electron beam. Hence periodic bunching trains can be formed and can be used to generate mode-locked FEL radiation pulses. Theoretical analysis and numerical simulations are given out to demonstrate the performance of the method. The results indicate that mode-locked FEL in temporal and frequency domain can be formed at the 18th harmonic of the seed laser, with the central wavelength being about 14.58nm and the peak power over 2GW.

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P15

About •

Received ※ 01 September 2023 — Revised ※ 01 September 2023 — Accepted ※ 01 September 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

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)

WE4P19

Simulation Study of Orbit Correction by Neural Network in Taiwan Photon Source

188

M.-S. Chiu, Y.-S. Cheng, G.-H. Luo, H.-J. Tsai, F.H. Tseng
NSRRC, Hsinchu, Taiwan
C.P. Felix
MCL/ITRI, Hsinchu, Taiwan

Machine learning has been applied in many fields in re-cent decades. Many research articles also presented re-markable achievements in either operation or designing of the particle accelerator. This paper focuses on the simulated orbit correction by neural networks, a subset of machine learning, in Taiwan Photon Source. The training data for the neural network is generated by accelerator toolbox (AT).

Poster WE4P19 [0.843 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P19

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

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WE4P20

Alignment Results of Tandem EPUs at the Taiwan Photon Source

192

Y.-C. Liu, C.M. Cheng, T.Y. Chung, Y.M. Hsiao, F.H. Tseng
NSRRC, Hsinchu, Taiwan

Taiwan Photon Source (TPS) has been open to user operation since 2016. We report the alignment results of tandem EPUs in one double mini-beta y long straight section. The goal is to increase the brilliance of the synchrotron lights produced by the tandem EPUs through well-alignment and using a phase shifter to achieve both spatial and temporal coherence. The calculated brilliance gain of the tandem EPUs is compared, and the difference between the measured and numerical results is analyzed.

Poster WE4P20 [4.435 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P20

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Received ※ 16 August 2023 — Revised ※ 30 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023

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WE4P21

Some Beam Dynamic Issues in the HALF Storage Ring

196

J.Y. Tang
USTC, SNST, Anhui, People’s Republic of China
Z.H. Bai, T.L. He, G. Liu, Y. Mo, A.X. Wang, P.H. Yang, Z. Zhao
USTC/NSRL, Hefei, Anhui, People’s Republic of China

HALF (Hefei Advanced Light Facility) is a fourth-generation synchrotron light source that just started construction in 2023. With 2.2 GeV in energy, 350 mA in beam current and 86 pm.rad in emittance, the HALF storage ring faces several beam dynamics challenges. This presentation gives the recent study on some of these issues, in particular the beam collimation and the influence and compensation of the insertion devices. For beam collimation, different beam loss mechanisms have been studied, and the Touschek scattering and beam dumping are considered the two major effects in designing the collimation system. Then two collimators with movable horizontal blades and fixed passive vertical blades are being designed, with the main focus on the collimation efficiency and impedance. For the influence of the insertion devices, it is found that some of the long-period undulators have a high impact on the beam dynamic aperture due to low beam energy and originally small dynamic aperture. The local compensation methods for both linear and non-linear effects have been studied. Instead of the traditional compensation method by electrical wires, the method of using two combined magnets with quadrupole and octupole fields at the two ID ends in restoring the dynamic aperture is also studied and compared.

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P21

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

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WE4P24

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

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

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

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WE4P31

Deterministic Approach to the Lattice Design of BESSY III

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

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

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WE4P33

Design of a 166.6 MHz HOM Damped Copper Cavity for the Southern Advanced Photon Source

207

J.Y. Zhu, X. Li, Z.J. Lu
IHEP, Beijing, People’s Republic of China
J.B. Yu
IHEP CSNS, Guangdong Province, People’s Republic of China

Funding: This work was supported by the National Natural Science Foundation of China (12205168).
The Southern Advanced Photon Source (SAPS) aims to achieve ultra-low emittances and is expected to adopt low-frequency cavities (< 200 MHz) to accommodates on-axis injection. This paper focuses on the design of a 166.6 MHz HOM-damped normal conducting (NC) cavity for the SAPS. We propose a novel approach to achieve efficient HOM damping by optimizing the lowest frequency HOM and implementing a beam-line absorber in a coaxial resonant NC cavity. Notably, unlike beam-line absorbers for conventional NC cavities, the presence of a large beam tube in a coaxial resonant cavity does not affect the accelerating performance. This enables effective HOM damping while maintaining a high shunt impedance in a NC cavity. The numerical simulation results show that a compact copper cavity with effective HOM damping and excellent RF properties has been achieved.

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-WE4P33

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

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WE4P36

The Cryogenic Undulator Upgrade Programme at Diamond Light Source

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

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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

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

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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

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

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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

221

R. Khullar, S.M. Khanpresenter, 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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