IPAC2015 - List of Authors (Chen, H.B.)

Paper	Title	Page
MOPWA072	Emittance Exchange Beam Line Design In THU Accelerator Lab	285
	Q. Gao, H.B. Chen, Y.-C. Du, W.-H. Huang, J. Shi TUB, Beijing, People's Republic of China W. Gai ANL, Argonne, Illinois, USA
	Funding: National Natural Science Foundation of China Emittance exchange (EEX) provides a novel tool to enhance the phase space manipulation techniques. Based on Tsinghua Thomson scattering experimental platform, this study presented a beam line design for exchanging the transverse and longitudinal emittance of an electron bunch. This beam line consists of a 2.856 GHz half-one-half cell deflecting cavity with no axis offset and two doglegs. In this paper, by optimizing the beam envelope parameter for Tsinghua Thomson scattering source, we report the theoretical analysis and a good particle tracking simulation result about emittance exchange and longitudinal shaping.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA072
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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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WEPMN014	A C-band Deflecting Cavity Design for High-precision Bunch Length Measurement	2948
	J. Jiang, H.B. Chen, J. Shi, P. Wang TUB, Beijing, People's Republic of China
	Funding: NSFC 11375098 and 11327902 A standing wave RF deflecting structure has been designed as a tool for high-precision bunch length measurement. This 3-cell deflecting cavity is designed to operate at a frequency of 5.712GHz. In this paper, the RF design and thermal analysis of the deflecting cavity are introduced. We study the electromagnetic field distribution inside the cavity. The coupler design is also discussed. And the beam dynamics simulation is shown.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN014
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WEPMN015	Dark Current Imaging Experiment in an L-band RF Gun	2952
	J.H. Shao, H.B. Chen, J. Shi, D. Wang TUB, Beijing, People's Republic of China S.P. Antipov, S.V. Baryshev, C.-J. Jing, J.Q. Qiu Euclid TechLabs, LLC, Solon, Ohio, USA M.E. Conde, D.S. Doran, W. Gai, W. Liu, J.G. Power, C. Whiteford, E.E. Wisniewski ANL, Argonne, Illinois, USA F.Y. Wang, L. Xiao SLAC, Menlo Park, California, USA
	The localized high electric field enhancement or low work function is the trigger for strong field emission, which however has yet been well experimentally studied. Using an L-band photocathode gun test stand at Argonne Wakefield Accelerator Facility (AWA), we’ve constructed an imaging beam line to observe field emission current from predefined emitters on cathode. Preliminary experiment results are present. Future plan is discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN015
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WEPMN016	Observation of Dark Current Dependence on Stored Energy in an L-Band RF Gun	2956
	J.H. Shao, H.B. Chen, J. Shi, D. Wang TUB, Beijing, People's Republic of China S.P. Antipov, S.V. Baryshev, C.-J. Jing, J.Q. Qiu Euclid TechLabs, LLC, Solon, Ohio, USA M.E. Conde, D.S. Doran, W. Gai, W. Liu, J.G. Power, C. Whiteford, E.E. Wisniewski ANL, Argonne, Illinois, USA F.Y. Wang, L. Xiao SLAC, Menlo Park, California, USA
	A pin cathode has been installed into an L-band photocathode gun to study the influence of stored energy on field emission. The stored energy was varied by tuning the recess of the cathode in order to have the same E-field on the cathode tip. We have observed 5 times difference of dark current level at the same E-field, while by varying the stored energy by three fold. Dynamics study reveals the difference is not caused by transmission, but by emission process itself. We'll present experiment results and discuss possible mechanisms about the phenomena.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN016
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WEPMN018	Measurement of Cell-Cell Coupling Coefficient in Photocathode RF Gun	2963
	P. Wang, H.B. Chen, Q. Gao, J. Shi, L. Zhang TUB, Beijing, People's Republic of China
	A photocathode RF gun is under cold rest in Tsinghua University. We measured the single cavity frequency and the cell-cell coupling coefficient by the detuning method with high accuracy. We use a simplified model to illustrate the whole process of the measurement. The data obtained in the cold test seem to accord with that from the model very well.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN018
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WEPMN019	Calorimetric Power Measurements in X-band High Power RF	2967
	X.W. Wu, H.B. Chen, L. Zhang TUB, Beijing, People's Republic of China N. Catalán Lasheras, B.J. Woolley, W. Wuensch CERN, Geneva, Switzerland
	With the aim to test prototype accelerating structures for CLIC at high-gradient, new klystron-based, X-band high power test stands are being built at CERN. These tests stands are referred to as Xboxes with Xbox1 and Xbox2 being already operational. Stainless steel loads are placed in the end of the Xbox-1 system to absorb the remaining power which comes out of the accelerating structure. Power information is important and needs to be measured precisely. A new power measuring method based on calorimetry is proposed independent from RF measurements subject to frequent calibration. The principles of the method and simulations are presented and the results of actual experimentation are used to validate the method. The results show calorimetric measurement is feasible method and have a good precision at this power level.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN019
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Paper

Title

Page

Emittance Exchange Beam Line Design In THU Accelerator Lab

285

Q. Gao, H.B. Chen, Y.-C. Du, W.-H. Huang, J. Shi
TUB, Beijing, People's Republic of China
W. Gai
ANL, Argonne, Illinois, USA

Funding: National Natural Science Foundation of China
Emittance exchange (EEX) provides a novel tool to enhance the phase space manipulation techniques. Based on Tsinghua Thomson scattering experimental platform, this study presented a beam line design for exchanging the transverse and longitudinal emittance of an electron bunch. This beam line consists of a 2.856 GHz half-one-half cell deflecting cavity with no axis offset and two doglegs. In this paper, by optimizing the beam envelope parameter for Tsinghua Thomson scattering source, we report the theoretical analysis and a good particle tracking simulation result about emittance exchange and longitudinal shaping.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPWA072

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

Export •

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

WEPMN014

A C-band Deflecting Cavity Design for High-precision Bunch Length Measurement

2948

J. Jiang, H.B. Chen, J. Shi, P. Wang
TUB, Beijing, People's Republic of China

Funding: NSFC 11375098 and 11327902
A standing wave RF deflecting structure has been designed as a tool for high-precision bunch length measurement. This 3-cell deflecting cavity is designed to operate at a frequency of 5.712GHz. In this paper, the RF design and thermal analysis of the deflecting cavity are introduced. We study the electromagnetic field distribution inside the cavity. The coupler design is also discussed. And the beam dynamics simulation is shown.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN014

Export •

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

WEPMN015

Dark Current Imaging Experiment in an L-band RF Gun

2952

J.H. Shao, H.B. Chen, J. Shi, D. Wang
TUB, Beijing, People's Republic of China
S.P. Antipov, S.V. Baryshev, C.-J. Jing, J.Q. Qiu
Euclid TechLabs, LLC, Solon, Ohio, USA
M.E. Conde, D.S. Doran, W. Gai, W. Liu, J.G. Power, C. Whiteford, E.E. Wisniewski
ANL, Argonne, Illinois, USA
F.Y. Wang, L. Xiao
SLAC, Menlo Park, California, USA

The localized high electric field enhancement or low work function is the trigger for strong field emission, which however has yet been well experimentally studied. Using an L-band photocathode gun test stand at Argonne Wakefield Accelerator Facility (AWA), we’ve constructed an imaging beam line to observe field emission current from predefined emitters on cathode. Preliminary experiment results are present. Future plan is discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN015

Export •

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

WEPMN016

Observation of Dark Current Dependence on Stored Energy in an L-Band RF Gun

2956

J.H. Shao, H.B. Chen, J. Shi, D. Wang
TUB, Beijing, People's Republic of China
S.P. Antipov, S.V. Baryshev, C.-J. Jing, J.Q. Qiu
Euclid TechLabs, LLC, Solon, Ohio, USA
M.E. Conde, D.S. Doran, W. Gai, W. Liu, J.G. Power, C. Whiteford, E.E. Wisniewski
ANL, Argonne, Illinois, USA
F.Y. Wang, L. Xiao
SLAC, Menlo Park, California, USA

A pin cathode has been installed into an L-band photocathode gun to study the influence of stored energy on field emission. The stored energy was varied by tuning the recess of the cathode in order to have the same E-field on the cathode tip. We have observed 5 times difference of dark current level at the same E-field, while by varying the stored energy by three fold. Dynamics study reveals the difference is not caused by transmission, but by emission process itself. We'll present experiment results and discuss possible mechanisms about the phenomena.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN016

Export •

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

WEPMN018

Measurement of Cell-Cell Coupling Coefficient in Photocathode RF Gun

2963

P. Wang, H.B. Chen, Q. Gao, J. Shi, L. Zhang
TUB, Beijing, People's Republic of China

A photocathode RF gun is under cold rest in Tsinghua University. We measured the single cavity frequency and the cell-cell coupling coefficient by the detuning method with high accuracy. We use a simplified model to illustrate the whole process of the measurement. The data obtained in the cold test seem to accord with that from the model very well.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN018

Export •

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

WEPMN019

Calorimetric Power Measurements in X-band High Power RF

2967

X.W. Wu, H.B. Chen, L. Zhang
TUB, Beijing, People's Republic of China
N. Catalán Lasheras, B.J. Woolley, W. Wuensch
CERN, Geneva, Switzerland

With the aim to test prototype accelerating structures for CLIC at high-gradient, new klystron-based, X-band high power test stands are being built at CERN. These tests stands are referred to as Xboxes with Xbox1 and Xbox2 being already operational. Stainless steel loads are placed in the end of the Xbox-1 system to absorb the remaining power which comes out of the accelerating structure. Power information is important and needs to be measured precisely. A new power measuring method based on calorimetry is proposed independent from RF measurements subject to frequent calibration. The principles of the method and simulations are presented and the results of actual experimentation are used to validate the method. The results show calorimetric measurement is feasible method and have a good precision at this power level.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPMN019

Export •

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