IPAC2019 - List of Authors (Tian, K.)

Paper	Title	Page
TUPRB101	Damping Trapped Modes in an in-Vacuum Undulator at a Synchrotron Radiation Light Source	1895
TUPRB098	use link to see paper's listing under its alternate paper code
	K. Tian, Z. Li, A. Ringwall, J.J. Sebek SLAC, Menlo Park, California, USA
	Funding: Work supported by US Department of Energy Contract DE-AC03-76SF00515. In this paper, we report the efforts in solving the problem of coupled-bunch instabilities caused by an in-vacuum undulator in the SPEAR3 storage ring. After exploring several approaches to reduce the strength of the trapped modes, we found that ferrite dampers were the most effective and simplest way for mode damping in our SPEAR3 in-vacuum undulator. The results of the first RF cold measurement on an in-vacuum undulator equipped with these ferrite dampers agree well with numerical simulations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB101
About •	paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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TUPRB102	Numerical Study of the Delta II Polarizing Undulator for LCLS II	1899
	K. Tian, H.-D. Nuhn SLAC, Menlo Park, California, USA
	Funding: Work supported by US Department of Energy Contract DE-AC03-76SF00515. The Delta undulator has been operated successfully in LCLS with full control of the polarization mode and K value of the device. In LCLS II, a new Delta II undulator will be based on a similar design but with some differences. In this paper, we will present numerical simulation results that provide guidance to choose the geometric shape of the magnet poles and define the required tolerance for assembling the undulator magnets.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB102
About •	paper received ※ 10 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
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WEPMP051	Impedance Study of a New Septum Chamber of SPEAR3	2447
	K. Tian, J. Langton, J.J. Sebek SLAC, Menlo Park, California, USA
	Funding: Work supported by US Department of Energy Contract DE-AC03-76SF00515. A new Septum magnet and chamber has been designed for the storage ring as a part of the accelerator improvement plan for operating a lower emittance lattice in SPEAR3. Therefore it is necessary to analyze the impedance effects on the beam from the new Septum chamber. Due to the complex design at the downstream transition of the Septum chamber, the longitudinal impedance is particular of concern. In this paper, we will present numerical simulation results for this particular component as well as the general analysis for the impedance effects of the whole chamber.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP051
About •	paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPRB112	Commission of the Transverse Bunch-by-Bunch Feedback at SPEAR3	4081
	K. Tian, W.J. Corbett, X. Huang, N. Kurita, D.J. Martin, J.A. Safranek, J.J. Sebek SLAC, Menlo Park, California, USA D. Teytelman Dimtel, San Jose, USA
	Funding: Work supported by US Department of Energy Contract DE-AC03-76SF00515. Driven by the demand of suppressing transverse beam instabilities and developing novel short pulse operation modes in SPEAR3 storage ring, a wide-band transverse bunch-by-bunch feedback system has been recently commissioned for SPEAR3 storage ring. The system was demonstrated to be sufficient to suppress the transverse coupled bunch instabilities caused by trapped RF modes in one of the in vacuum insertion devices. A new function of beam instability interlock has been developed and is part of machine protection system for the in vacuum insertion device. In addition, the bunch-by-bunch feedback system serves as a indispensable diagnostic tool that enables us to measure machine parameters, beam impedance, and characteristics of the beam instability modes. In this paper, we describe the scheme and performance of the bunch-by-bunch feedback system at SPEAR3.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB112
About •	paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

TUPRB101

Damping Trapped Modes in an in-Vacuum Undulator at a Synchrotron Radiation Light Source

1895

TUPRB098

use link to see paper's listing under its alternate paper code

K. Tian, Z. Li, A. Ringwall, J.J. Sebek
SLAC, Menlo Park, California, USA

Funding: Work supported by US Department of Energy Contract DE-AC03-76SF00515.
In this paper, we report the efforts in solving the problem of coupled-bunch instabilities caused by an in-vacuum undulator in the SPEAR3 storage ring. After exploring several approaches to reduce the strength of the trapped modes, we found that ferrite dampers were the most effective and simplest way for mode damping in our SPEAR3 in-vacuum undulator. The results of the first RF cold measurement on an in-vacuum undulator equipped with these ferrite dampers agree well with numerical simulations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB101

About •

paper received ※ 13 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

Export •

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

TUPRB102

Numerical Study of the Delta II Polarizing Undulator for LCLS II

1899

K. Tian, H.-D. Nuhn
SLAC, Menlo Park, California, USA

Funding: Work supported by US Department of Energy Contract DE-AC03-76SF00515.
The Delta undulator has been operated successfully in LCLS with full control of the polarization mode and K value of the device. In LCLS II, a new Delta II undulator will be based on a similar design but with some differences. In this paper, we will present numerical simulation results that provide guidance to choose the geometric shape of the magnet poles and define the required tolerance for assembling the undulator magnets.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-TUPRB102

About •

paper received ※ 10 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

Export •

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

WEPMP051

Impedance Study of a New Septum Chamber of SPEAR3

2447

K. Tian, J. Langton, J.J. Sebek
SLAC, Menlo Park, California, USA

Funding: Work supported by US Department of Energy Contract DE-AC03-76SF00515.
A new Septum magnet and chamber has been designed for the storage ring as a part of the accelerator improvement plan for operating a lower emittance lattice in SPEAR3. Therefore it is necessary to analyze the impedance effects on the beam from the new Septum chamber. Due to the complex design at the downstream transition of the Septum chamber, the longitudinal impedance is particular of concern. In this paper, we will present numerical simulation results for this particular component as well as the general analysis for the impedance effects of the whole chamber.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-WEPMP051

About •

paper received ※ 14 May 2019 paper accepted ※ 20 May 2019 issue date ※ 21 June 2019

Export •

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

THPRB112

Commission of the Transverse Bunch-by-Bunch Feedback at SPEAR3

4081

K. Tian, W.J. Corbett, X. Huang, N. Kurita, D.J. Martin, J.A. Safranek, J.J. Sebek
SLAC, Menlo Park, California, USA
D. Teytelman
Dimtel, San Jose, USA

Funding: Work supported by US Department of Energy Contract DE-AC03-76SF00515.
Driven by the demand of suppressing transverse beam instabilities and developing novel short pulse operation modes in SPEAR3 storage ring, a wide-band transverse bunch-by-bunch feedback system has been recently commissioned for SPEAR3 storage ring. The system was demonstrated to be sufficient to suppress the transverse coupled bunch instabilities caused by trapped RF modes in one of the in vacuum insertion devices. A new function of beam instability interlock has been developed and is part of machine protection system for the in vacuum insertion device. In addition, the bunch-by-bunch feedback system serves as a indispensable diagnostic tool that enables us to measure machine parameters, beam impedance, and characteristics of the beam instability modes. In this paper, we describe the scheme and performance of the bunch-by-bunch feedback system at SPEAR3.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2019-THPRB112

About •

paper received ※ 14 May 2019 paper accepted ※ 23 May 2019 issue date ※ 21 June 2019

Export •

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