IPAC2015 - List of Authors (Tang, C.-X.)

Paper	Title	Page
MOPJE001	Effect on Beam Dynamics From Wakefields in Travelling Wave Structure Excited by Bunch Train	289
	D. Wang, C.-X. Tang TUB, Beijing, People's Republic of China W. Gai, C.-J. Jing, J.G. Power ANL, Argonne, Illinois, USA J.Q. Qiu Euclid TechLabs, LLC, Solon, Ohio, USA
	Electron bunch train technology is used to excited coherent high power RF radiation in travelling wave (TW) structures. This article concentrates on the analytical expression of wakefields excited by bunch train in TW structures and the effects of wakefields on beam dynamics. We focus on the first monopole mode and the first dipole mode wakefields. The long range wake function has a linear decrease which agrees well with the ABCi simulations. Taking example of the 11.7 GHz wakefields structure at the Argonne Wakefield Accelerator (AWA) facility, with 1.3 GHz interval drive electron bunch train, we have done the beam dynamics simulation with a point to point (P2P) code. Results shows the effects of wakefields on the energy distribution and the transverse instability for each sub-bunch.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE001
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TUPJE014	An X-Band Linac with Tunable Beam Energy	1644
	L. Zhang, H.B. Chen, Y.-C. Du, Q.X. Jin, J. Shi, C.-X. Tang, P. Wang, Z. Zhang TUB, Beijing, People's Republic of China
	The low-energy X-band linac has a wide application in medical imaging. In this paper, an X-band linac is designed to produce beam energy between 0.5MeV and 1.5MeV, and the output beam energy is continuously adjustable within this range. Two sections of linacs are combined and powered by a single microwave source. During the experiment, we can tune the RF phase and amplitude of the second section of the linac, the electron beam can see either acceleration or deceleration, which tunes the output energy. This paper presented the production of the whole linac system, as well as the measurement of the continuously-adjustable beam energy.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE014
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WEPWA028	Numerical Simulation on Emittance Growth Caused by Roughness of a Metallic Photocathode	2559
	Z. Zhang, C.-X. Tang TUB, Beijing, People's Republic of China
	The roughness of a photocathode could lead to an additional uncorrelated divergence of the emitted electrons and therefore to an increased thermal emittance. The randomness of the real-life photocathode surface makes it unrealistic to perform typical beam dynamics simulation to study the roughness emittance growth. We developed a numerical simulation code based on the point spread function (PSF) and an estimated form of electric field distribution on an arbitrary gently undulating surface to deal with the problem. The simulation result surprisingly shows that the emittance growth factor is much smaller than expected (1.5 ~ 2).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWA028
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WEPMN017	High Power RF Radiation at W-band Based on Wakefields Excited by Intense Electron Beam	2960
	D. Wang, C.-X. Tang TUB, Beijing, People's Republic of China S.P. Antipov, C.-J. Jing, J.Q. Qiu Euclid TechLabs, LLC, Solon, Ohio, USA M.E. Conde, D.S. Doran, W. Gai, G. Ha, W. Liu, J.G. Power, E.E. Wisniewski ANL, Argonne, Illinois, USA
	We report the experiment design and preliminary results on high power RF generation at W-band based on coherent wakefields from the metallic periodic structure of 91 GHz PETS (power extraction and transfer structure), excited by intense electron beam at the Argonne Wakefield Accelerator (AWA) facility. The recently output RF power is 0.7 MW, with 67 MeV, 1.4 nC single electron beam going through the structure. The RF pulse length is 3.4 ns. We measure the energy loss of electron beam as reference to the RF generation, which agrees well with the simulation results. Next run is to increase the output RF power with higher charge and to excite coherent wakefields with electron bunch train. The output RF peak power is expected to be ~100 MW and the electrical field gradient can reach up to 400 MV/m, with RF pulse duration adjustable from few ns to 30 ns when excited with 5~10 nC charge in a single bunch and up to 32 sub bunches in total.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN017
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Paper

Title

Page

Effect on Beam Dynamics From Wakefields in Travelling Wave Structure Excited by Bunch Train

289

D. Wang, C.-X. Tang
TUB, Beijing, People's Republic of China
W. Gai, C.-J. Jing, J.G. Power
ANL, Argonne, Illinois, USA
J.Q. Qiu
Euclid TechLabs, LLC, Solon, Ohio, USA

Electron bunch train technology is used to excited coherent high power RF radiation in travelling wave (TW) structures. This article concentrates on the analytical expression of wakefields excited by bunch train in TW structures and the effects of wakefields on beam dynamics. We focus on the first monopole mode and the first dipole mode wakefields. The long range wake function has a linear decrease which agrees well with the ABCi simulations. Taking example of the 11.7 GHz wakefields structure at the Argonne Wakefield Accelerator (AWA) facility, with 1.3 GHz interval drive electron bunch train, we have done the beam dynamics simulation with a point to point (P2P) code. Results shows the effects of wakefields on the energy distribution and the transverse instability for each sub-bunch.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPJE001

Export •

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

TUPJE014

An X-Band Linac with Tunable Beam Energy

1644

L. Zhang, H.B. Chen, Y.-C. Du, Q.X. Jin, J. Shi, C.-X. Tang, P. Wang, Z. Zhang
TUB, Beijing, People's Republic of China

The low-energy X-band linac has a wide application in medical imaging. In this paper, an X-band linac is designed to produce beam energy between 0.5MeV and 1.5MeV, and the output beam energy is continuously adjustable within this range. Two sections of linacs are combined and powered by a single microwave source. During the experiment, we can tune the RF phase and amplitude of the second section of the linac, the electron beam can see either acceleration or deceleration, which tunes the output energy. This paper presented the production of the whole linac system, as well as the measurement of the continuously-adjustable beam energy.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPJE014

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WEPWA028

Numerical Simulation on Emittance Growth Caused by Roughness of a Metallic Photocathode

2559

Z. Zhang, C.-X. Tang
TUB, Beijing, People's Republic of China

The roughness of a photocathode could lead to an additional uncorrelated divergence of the emitted electrons and therefore to an increased thermal emittance. The randomness of the real-life photocathode surface makes it unrealistic to perform typical beam dynamics simulation to study the roughness emittance growth. We developed a numerical simulation code based on the point spread function (PSF) and an estimated form of electric field distribution on an arbitrary gently undulating surface to deal with the problem. The simulation result surprisingly shows that the emittance growth factor is much smaller than expected (1.5 ~ 2).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWA028

Export •

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

WEPMN017

High Power RF Radiation at W-band Based on Wakefields Excited by Intense Electron Beam

2960

D. Wang, C.-X. Tang
TUB, Beijing, People's Republic of China
S.P. Antipov, C.-J. Jing, J.Q. Qiu
Euclid TechLabs, LLC, Solon, Ohio, USA
M.E. Conde, D.S. Doran, W. Gai, G. Ha, W. Liu, J.G. Power, E.E. Wisniewski
ANL, Argonne, Illinois, USA

We report the experiment design and preliminary results on high power RF generation at W-band based on coherent wakefields from the metallic periodic structure of 91 GHz PETS (power extraction and transfer structure), excited by intense electron beam at the Argonne Wakefield Accelerator (AWA) facility. The recently output RF power is 0.7 MW, with 67 MeV, 1.4 nC single electron beam going through the structure. The RF pulse length is 3.4 ns. We measure the energy loss of electron beam as reference to the RF generation, which agrees well with the simulation results. Next run is to increase the output RF power with higher charge and to excite coherent wakefields with electron bunch train. The output RF peak power is expected to be ~100 MW and the electrical field gradient can reach up to 400 MV/m, with RF pulse duration adjustable from few ns to 30 ns when excited with 5~10 nC charge in a single bunch and up to 32 sub bunches in total.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN017

Export •

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