FLS2023 - List of Keywords (HOM)

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

TU3D4	Compact HOM-damped RF Cavity for a Next Generation Light Source	cavity, damping, impedance, operation	74
	H. Ego KEK, Ibaraki, Japan T. Asaka, N. Nishimori QST, Sendai, Miyagi, Japan T. Inagaki, H. Tanaka RIKEN SPring-8 Center, Hyogo, Japan T. Ohshima, T. Tomai, H. Yamaguchi JASRI, Hyogo, Japan
	A beam-accelerating RF cavity with a new HOM-damping structure was designed in order to suppress coupled-bunch instabilities in a next generation light source with an ultra-low emittance and supplying X-rays approaching their diffraction limits. The TM020 mode at 509 MHz is selected as a beam-accelerating mode because it has a high Q-value of 60,000 and a shunt impedance sufficient for beam acceleration and brings a compact HOM-damping structure to the cavity differently from massive types of cavities with waveguides or pipes extracting HOM power. Two shallow slots are cut on the cavity inner-wall and materials absorbing RF waves are directly fitted into them. They work as HOM dampers without affecting the RF properties of the beam-accelerating mode. A prototype cavity of OFHC copper was fabricated to demonstrate the HOM-damping and generating an accelerating voltage of 900 kV in the cavity. Since the cavity was successful in operation up to 135 kW, the feasibility of both the high-power operation and the damping structure was proved. Four actual cavities were produced and installed to the new 3-GeV synchrotron radiation facility, NanoTerasu in Japan.
	Slides TU3D4 [8.581 MB]
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU3D4
About •	Received ※ 22 August 2023 — Revised ※ 23 August 2023 — Accepted ※ 31 August 2023 — Issued ※ 02 December 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TU4P33	An Inverse-Compton Scattering Simulation Module for RF-Track	photon, scattering, simulation, laser	151
	A. Latina, V. Mușat CERN, Meyrin, Switzerland
	A simulation module implementing Inverse-Compton scattering (ICS) was added to the tracking code RF-Track. The module consists of a special beamline element that simulates the interaction between the tracked beam and a laser, making RF-Track capable of simulating a complete ICS source in one go, from the electron source to the photons. The description of the laser allows the user to thoroughly quality the laser in terms of wavelength, pulse energy, pulse length, incoming direction, M2 parameter, aspect ratio, polarisation and whether the laser profile should be Gaussian or uniform. Furthermore, as the code implements fully generic expressions, the scattering between photons and different particles than electrons can be simulated. A benchmark against CAIN showed excellent agreement and that RF-Track outperforms CAIN in terms of computational speed by orders of magnitude.
DOI •	reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU4P33
About •	Received ※ 22 August 2023 — Revised ※ 28 August 2023 — Accepted ※ 30 August 2023 — Issued ※ 02 December 2023
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

WE4P33	Design of a 166.6 MHz HOM Damped Copper Cavity for the Southern Advanced Photon Source	cavity, impedance, damping, photon	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
Cite •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Other Keywords

Page

TU1B1

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

lattice, emittance, sextupole, operation

58

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

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

Slides TU1B1 [7.584 MB]

DOI •

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

About •

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

Cite •

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

TU3D4

Compact HOM-damped RF Cavity for a Next Generation Light Source

cavity, damping, impedance, operation

74

H. Ego
KEK, Ibaraki, Japan
T. Asaka, N. Nishimori
QST, Sendai, Miyagi, Japan
T. Inagaki, H. Tanaka
RIKEN SPring-8 Center, Hyogo, Japan
T. Ohshima, T. Tomai, H. Yamaguchi
JASRI, Hyogo, Japan

A beam-accelerating RF cavity with a new HOM-damping structure was designed in order to suppress coupled-bunch instabilities in a next generation light source with an ultra-low emittance and supplying X-rays approaching their diffraction limits. The TM020 mode at 509 MHz is selected as a beam-accelerating mode because it has a high Q-value of 60,000 and a shunt impedance sufficient for beam acceleration and brings a compact HOM-damping structure to the cavity differently from massive types of cavities with waveguides or pipes extracting HOM power. Two shallow slots are cut on the cavity inner-wall and materials absorbing RF waves are directly fitted into them. They work as HOM dampers without affecting the RF properties of the beam-accelerating mode. A prototype cavity of OFHC copper was fabricated to demonstrate the HOM-damping and generating an accelerating voltage of 900 kV in the cavity. Since the cavity was successful in operation up to 135 kW, the feasibility of both the high-power operation and the damping structure was proved. Four actual cavities were produced and installed to the new 3-GeV synchrotron radiation facility, NanoTerasu in Japan.

Slides TU3D4 [8.581 MB]

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU3D4

About •

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

Cite •

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

TU4P33

An Inverse-Compton Scattering Simulation Module for RF-Track

photon, scattering, simulation, laser

151

A. Latina, V. Mușat
CERN, Meyrin, Switzerland

A simulation module implementing Inverse-Compton scattering (ICS) was added to the tracking code RF-Track. The module consists of a special beamline element that simulates the interaction between the tracked beam and a laser, making RF-Track capable of simulating a complete ICS source in one go, from the electron source to the photons. The description of the laser allows the user to thoroughly quality the laser in terms of wavelength, pulse energy, pulse length, incoming direction, M2 parameter, aspect ratio, polarisation and whether the laser profile should be Gaussian or uniform. Furthermore, as the code implements fully generic expressions, the scattering between photons and different particles than electrons can be simulated. A benchmark against CAIN showed excellent agreement and that RF-Track outperforms CAIN in terms of computational speed by orders of magnitude.

DOI •

reference for this paper ※ doi:10.18429/JACoW-FLS2023-TU4P33

About •

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

Cite •

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

WE4P33

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

cavity, impedance, damping, photon

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

Cite •

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