IPAC2018 - List of Authors (Tseng, F.H.)

Paper	Title	Page
WEPAL062	Bunch Length Measurements with a Streak Camera in Low Alpha Lattice Operation at the TPS	2316
	C.H. Chen, J.Y. Chen, M.-S. Chiu, P.J. Chou, K.T. Hsu, K.H. Hu, C.-C. Kuo, C.C. Liang, C.Y. Liao, Y.-C. Liu, G.-H. Luo, H.-J. Tsai, F.H. Tseng NSRRC, Hsinchu, Taiwan
	We developed and tested lattice with lower momentum compaction factor (low alpha) in TPS (Taiwan Photon Source) recently. Operating low alpha lattice can provide picosecond bunch length for time-resolved research and coherent IR/THz synchrotron light. The bunch length around 2.5 picosecond rms was measured by a streak camera* in low alpha mode while operating in the routine users mode** it was around 10 picosecond. This paper presents the related processes and measurements. * L.Y. Liao et al., "Preliminary beam test of synchrotron radiation monitoring system at Taiwan Photon Source", IPAC'15. ** C.C. Kuo et al., "Commissioning of Taiwan Photon Source", IPAC'15.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL062
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THPAK053	Side Effects of Local Bump in TPS Storage Ring	3340
	M.-S. Chiu, C.H. Chen, J.Y. Chen, P.J. Chou, F.H. Tseng NSRRC, Hsinchu, Taiwan
	The Taiwan Photon Source (TPS) is a low-emittance 3-GeV light source at National Synchrotron Radiation Research Center. Five in-vacuum undulator beamlines were delivered to users on Sep. 22, 2016. Another 2 EPU beamlines will be open to user in near future. In the beginning, the local bump was used to do ID spectrum optimization since 2016. After this procedure, the ID spectrum are consistent between theoretical simulation and measurement. Recently, we found the local bump will cause tune shift and orbit distortion. In this paper, we will present the effect of local bump in TPS.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK053
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THPAK054	Optics Calibration and Measurement for Low Alpha Lattices in TPS Storage Ring	3343
	F.H. Tseng, C.H. Chen, J.Y. Chen, P.C. Chiu, C.H. Huang, C.-C. Kuo, C.C. Liang, C.Y. Liao, Y.-C. Liu, H.-J. Tsai NSRRC, Hsinchu, Taiwan
	In order to provide short-pulse radiation for pump-probe experiments and coherent radiation for THz/IR measurements, we develop low alpha lattices to reduce the momentum compaction factor from nominal operation values 2.410^-4 to 2.610-5 or lower. The corresponding bunch length at 2.8 MV RF voltage and zero current are from 10.78 ps to 3.55 ps or less. In the low alpha operations, the bunch lengthening as a function of bunch current, the orbit drift and noise enhancements as well as rf stability effect are observed. In this report we will present our studies on the lattice design, optics correction, beam parameters measurements and alpha measurements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK054
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THPAK055	Suppression of Transverse Beam Instabilities by Stripline Kickers at TPS	3346
	P.J. Chou, C.K. Chan, C.-C. Chang, K.T. Hsu, K.H. Hu, C.K. Kuan, I.C. Sheng, F.H. Tseng NSRRC, Hsinchu, Taiwan
	Collective beam instabilities could limit the accelerator performance if proper countermeasures are not in place. Active beam feedback systems are commonly used to suppress beam instabilities. The resistive wall impedance including phase-II insertion devices at TPS are calculated with analytical formulas. The growth rate of transverse coupled bunch instabilities due to wall impedance is estimated by theory. The RF properties of existing stripline kickers in TPS are analyzed with a 3-D electromagnetic simulation code GdfidL. Based on the above analysis, the requirements for a beam feedback system are calculated and the results are reported.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK055
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THPMK013	A Wiggler Magnet Design for the TPS	4317
	J.C. Jan, Y.L. Chu, C.-S. Hwang, F.H. Tseng NSRRC, Hsinchu, Taiwan
	The Taiwan Photon Source (TPS) at the National Synchrotron Radiation Research Center (NSRRC) is an advanced photon source facility operating at an electron energy of 3 GeV. Ten insertion devices (IDs) have been installed in phase-I during 2015. Recently, plans and designs for several phase-II IDs including In-vacuum Undulators (IU), Cryogenic Undulators (CU), Elliptical Polarization Undulators (EPU) and Wiggler magnets are pursued at NSRRC. These IDs are expected to be installed before 2020. In particular, a room temperature wiggler magnet with 100 mm period length (W100), will be designed and installed for phase-II. The field strength of the W100 is 1.8 T and the number of main periods is four. It is designed to generate 5-50 keV photons for the microscopy beam line. The magnetic design and photon characteristics of the W100 together with its effects on the stored beam will be discussed in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK013
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THPMK015	Low Momentum Compaction Lattice Operation of the Taiwan Photon Source	4325
	C.-C. Kuo, C.H. Chen, J.Y. Chen, P.C. Chiu, K.T. Hsu, K.H. Hu, C.H. Huang, C.C. Liang, C.Y. Liao, Y.-C. Liu, Z.K. Liu, H.-J. Tsai, F.H. Tseng NSRRC, Hsinchu, Taiwan
	In order to provide short bunch length for picosecond time-resolved experiments and for coherent IR/THz radiation, low momentum compaction factor (alpha) lattices have been commissioned recently at the Taiwan Photon Source (TPS). The momentum compaction can be positive or negative and its value can be reduced by more than two orders of magnitude. In this paper, we discuss variable low alpha lattice optics, its beam dynamics issues, the measured momentum compaction and bunch lengths as well as beam orbit stability issues, etc.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK015
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THPMK020	Beam-Based Alignment Procedures for Small Gap in-Vacuum Undulators at the Taiwan Photon Source	4342
	Y.-C. Liu, J.C. Huang, F.H. Tseng NSRRC, Hsinchu, Taiwan
	We have developed a beam-based alignment procedure for small gap IVUs (In-vacuum undulators) at TPS, which allow us to measure the field center and mechanical canter of IVUs with 0.1 mm accuracy. The measurement method and results are presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK020
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Paper

Title

Page

Bunch Length Measurements with a Streak Camera in Low Alpha Lattice Operation at the TPS

2316

C.H. Chen, J.Y. Chen, M.-S. Chiu, P.J. Chou, K.T. Hsu, K.H. Hu, C.-C. Kuo, C.C. Liang, C.Y. Liao, Y.-C. Liu, G.-H. Luo, H.-J. Tsai, F.H. Tseng
NSRRC, Hsinchu, Taiwan

We developed and tested lattice with lower momentum compaction factor (low alpha) in TPS (Taiwan Photon Source) recently. Operating low alpha lattice can provide picosecond bunch length for time-resolved research and coherent IR/THz synchrotron light. The bunch length around 2.5 picosecond rms was measured by a streak camera* in low alpha mode while operating in the routine users mode** it was around 10 picosecond. This paper presents the related processes and measurements.
* L.Y. Liao et al., "Preliminary beam test of synchrotron radiation monitoring system at Taiwan Photon Source", IPAC'15.
** C.C. Kuo et al., "Commissioning of Taiwan Photon Source", IPAC'15.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-WEPAL062

Export •

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

THPAK053

Side Effects of Local Bump in TPS Storage Ring

3340

M.-S. Chiu, C.H. Chen, J.Y. Chen, P.J. Chou, F.H. Tseng
NSRRC, Hsinchu, Taiwan

The Taiwan Photon Source (TPS) is a low-emittance 3-GeV light source at National Synchrotron Radiation Research Center. Five in-vacuum undulator beamlines were delivered to users on Sep. 22, 2016. Another 2 EPU beamlines will be open to user in near future. In the beginning, the local bump was used to do ID spectrum optimization since 2016. After this procedure, the ID spectrum are consistent between theoretical simulation and measurement. Recently, we found the local bump will cause tune shift and orbit distortion. In this paper, we will present the effect of local bump in TPS.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK053

Export •

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

THPAK054

Optics Calibration and Measurement for Low Alpha Lattices in TPS Storage Ring

3343

F.H. Tseng, C.H. Chen, J.Y. Chen, P.C. Chiu, C.H. Huang, C.-C. Kuo, C.C. Liang, C.Y. Liao, Y.-C. Liu, H.-J. Tsai
NSRRC, Hsinchu, Taiwan

In order to provide short-pulse radiation for pump-probe experiments and coherent radiation for THz/IR measurements, we develop low alpha lattices to reduce the momentum compaction factor from nominal operation values 2.4*10^-4 to 2.6*10-5 or lower. The corresponding bunch length at 2.8 MV RF voltage and zero current are from 10.78 ps to 3.55 ps or less. In the low alpha operations, the bunch lengthening as a function of bunch current, the orbit drift and noise enhancements as well as rf stability effect are observed. In this report we will present our studies on the lattice design, optics correction, beam parameters measurements and alpha measurements.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK054

Export •

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

THPAK055

Suppression of Transverse Beam Instabilities by Stripline Kickers at TPS

3346

P.J. Chou, C.K. Chan, C.-C. Chang, K.T. Hsu, K.H. Hu, C.K. Kuan, I.C. Sheng, F.H. Tseng
NSRRC, Hsinchu, Taiwan

Collective beam instabilities could limit the accelerator performance if proper countermeasures are not in place. Active beam feedback systems are commonly used to suppress beam instabilities. The resistive wall impedance including phase-II insertion devices at TPS are calculated with analytical formulas. The growth rate of transverse coupled bunch instabilities due to wall impedance is estimated by theory. The RF properties of existing stripline kickers in TPS are analyzed with a 3-D electromagnetic simulation code GdfidL. Based on the above analysis, the requirements for a beam feedback system are calculated and the results are reported.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPAK055

Export •

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

THPMK013

A Wiggler Magnet Design for the TPS

4317

J.C. Jan, Y.L. Chu, C.-S. Hwang, F.H. Tseng
NSRRC, Hsinchu, Taiwan

The Taiwan Photon Source (TPS) at the National Synchrotron Radiation Research Center (NSRRC) is an advanced photon source facility operating at an electron energy of 3 GeV. Ten insertion devices (IDs) have been installed in phase-I during 2015. Recently, plans and designs for several phase-II IDs including In-vacuum Undulators (IU), Cryogenic Undulators (CU), Elliptical Polarization Undulators (EPU) and Wiggler magnets are pursued at NSRRC. These IDs are expected to be installed before 2020. In particular, a room temperature wiggler magnet with 100 mm period length (W100), will be designed and installed for phase-II. The field strength of the W100 is 1.8 T and the number of main periods is four. It is designed to generate 5-50 keV photons for the microscopy beam line. The magnetic design and photon characteristics of the W100 together with its effects on the stored beam will be discussed in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK013

Export •

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

THPMK015

Low Momentum Compaction Lattice Operation of the Taiwan Photon Source

4325

C.-C. Kuo, C.H. Chen, J.Y. Chen, P.C. Chiu, K.T. Hsu, K.H. Hu, C.H. Huang, C.C. Liang, C.Y. Liao, Y.-C. Liu, Z.K. Liu, H.-J. Tsai, F.H. Tseng
NSRRC, Hsinchu, Taiwan

In order to provide short bunch length for picosecond time-resolved experiments and for coherent IR/THz radiation, low momentum compaction factor (alpha) lattices have been commissioned recently at the Taiwan Photon Source (TPS). The momentum compaction can be positive or negative and its value can be reduced by more than two orders of magnitude. In this paper, we discuss variable low alpha lattice optics, its beam dynamics issues, the measured momentum compaction and bunch lengths as well as beam orbit stability issues, etc.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK015

Export •

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

THPMK020

Beam-Based Alignment Procedures for Small Gap in-Vacuum Undulators at the Taiwan Photon Source

4342

Y.-C. Liu, J.C. Huang, F.H. Tseng
NSRRC, Hsinchu, Taiwan

We have developed a beam-based alignment procedure for small gap IVUs (In-vacuum undulators) at TPS, which allow us to measure the field center and mechanical canter of IVUs with 0.1 mm accuracy. The measurement method and results are presented in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2018-THPMK020

Export •

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