IPAC2016 - List of Authors (Chen, H.B.)

Paper	Title	Page
MOPMB037	Beam Position Monitor Design for Dielectric Wakefield Accelerator In THz Range	171
	Q. Gao, H.B. Chen, J. Shi TUB, Beijing, People's Republic of China W. Gai ANL, Argonne, Illinois, USA C.-J. Jing Euclid TechLabs, LLC, Solon, Ohio, USA
	Dielectric based collinear wakefield accelerator have been broadly selected for the THz accelerator due to its simplicity. In order to move the THz accelerators from the current exploratory research into the practical phase, certain common accelerator components are indispensable. Beam Position Monitor (BPM) is one of them. However, most of conventional BPM techniques are hardly scaled down to THz regime. Here we propose a BPM design which uses the dominant dipole mode excited in the dielectric wakefield accelerators to extract information of the beam position.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB037
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMR059	Development of S-band High Power Load	383
	X.C. Meng, H.B. Chen, C. Cheng, Y.-C. Du, Q. Gao, J. Shi, P. Wang, Z.F. Xiong TUB, Beijing, People's Republic of China
	Several types of S-band high power loads have been designed, manufactured and tested successfully in Tsinghua University. The high power loads, which work at 2856 MHz for 10 MW~100 MW range, are made of all stainless steel. In this paper, we will present the design, fabrication and the high power test results.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR059
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

MOPMR060	C-Band Deflecting Cavity for Bunch Length Measurement of 2.5 MeV Electron Beam	386
	J. Jiang, H.B. Chen, J. Shi, P. Wang, L. Zhang, S.X. Zheng TUB, Beijing, People's Republic of China
	The C-band deflecting cavity designed last year is finished. In this paper, the RF measurement of the cavity is introduced. After tuning, it works well at 5.712GHz with a coupling factor degree around 1.05. And we measured the electromagnetic field with bead-pull method. The flatness of the magnetic field is around 0.9, which is not ideal but meet the requirements of the bunch length measurement. And we propose a method of tuning to make sure both frequency and field flatness.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR060
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW014	Simulation of High Resolution Field Emission Imaging in an rf Photocathode Gun	1769
	J.H. Shao, H.B. Chen, J. Shi, X.W. Wu TUB, Beijing, People's Republic of China S.P. Antipov, C.-J. Jing Euclid TechLabs, LLC, Solon, Ohio, USA W. Gai ANL, Argonne, Illinois, USA F.Y. Wang SLAC, Menlo Park, California, USA
	Precisely locating field emission (FE) emitters on a realistic surface in rf structures is technically chal-lenging in general due to the wide emitting phase and the broad energy spread. A method to achieve in situ high resolution FE imaging has been proposed by using solenoids and a collimator to select electrons emitted at certain phases. The phase selection criterion and imaging properties have been studied by the beam dynamics code ASTRA. Detailed results are presented in this paper.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW014
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW015	Experiment of High Resolution Field Emission Imaging in an rf Photocathode Gun	1772
	J.H. Shao, H.B. Chen, J. Shi, X.W. Wu TUB, Beijing, People's Republic of China S.P. Antipov, S.V. Baryshev, C.-J. Jing Euclid TechLabs, LLC, Solon, Ohio, USA M.E. Conde, W. Gai, G. Ha, E.E. Wisniewski ANL, Argonne, Illinois, USA F.Y. Wang SLAC, Menlo Park, California, USA
	The first in situ high resolution field emission (FE) imaging experiment has been carried out on an L-band photocathode gun test stand at Argonne Wakefield Accelerator facility (AWA). Separated strong emitters have been observed to dominate the field emission. Field enhancement factor, beta, of small regions on the cathode has been measured with the imaging system. It is shown that most strong emitters overlaps with the high beta regions. The post surface examinations reveal the origins of ~75% strong emitters overlap with the spots where rf breakdown have occurred. Detailed results are presented in this paper.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW015
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW016	Development of a C-Band 4/8 Mev Dual-Energy Accelerator for Cargo Inspection System	1775
	J.H. Shao, H.B. Chen, W.-H. Huang, Q.X. Jin, Y.H. Liu, J. Shi, C.-X. Tang, X.W. Wu TUB, Beijing, People's Republic of China
	Modern cargo inspection system applies dual-energy X-ray for material discrimination. Based on the com-pact C-band 6 MeV standing-wave accelerating struc-tures developed at Tsinghua University, a compact C-band 4/8 MeV dual-energy accelerator has been pro-posed, fabricated and tested. Compared with that of the conventional S-band 3/6 MeV dual-energy accelera-tor at Tsinghua University, the volume and the weight of the C-band one has been reduced by ~40% and ~30%, respectively. Detailed review of this C-band dual-energy accelerator is present in the paper.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW016
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

TUPOW018	Tunable High-Intensity Electron Bunch Train Production Based on Nonlinear Longitudinal Space Charge Oscillation	1782
SUPSS016	use link to see paper's listing under its alternate paper code
	Z. Zhang, H.B. Chen, Y.-C. Du, W.-H. Huang, J. Shi, X.L. Su, C.-X. Tang, Q.L. Tian, D. Wang, W. Wang, L.X. Yan, L.M. Zheng, Z. Zhou TUB, Beijing, People's Republic of China W. Gai ANL, Argonne, Illinois, USA
	High peak current electron bunch trains with tunable terahertz (THz) spacing are produced and measured experimentally. An initial picosecond periodic modulation in the temporal profile of a relativistic electron beam is magnified by the longitudinal space charge forces. As opposed to trying to reduce its smearing effect for large beam current, we take advantages of the nonlinear space charge oscillation through controlling the plasma phase advance. The spacing of the bunch train can be varied continuously either by tuning the velocity bunching of a radio-frequency gun or by tuning the compression of a downstream magnetic chicane. The narrow-band μJ-level THz radiation from the bunch train are also measured with tunable central frequency of the spectral from ~0.5 THz to 1.6 THz. The bunch train measurements are consistent with the particle tracking simulations.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW018
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPMW022	The RF Design of a Compact, High Power Pulse Compressor with a Flat Output Pulse	3591
SUPSS105	use link to see paper's listing under its alternate paper code
	P. Wang, H.B. Chen, J. Shi TUB, Beijing, People's Republic of China I. Syratchev, W. Wuensch, H. Zha CERN, Geneva, Switzerland
	An X-band, high-power pulse compressor, which can produce a flat pulse and a power gain of 4.3, has been designed. The device is compact, with the dimensions of within 1m, and is designed for CLIC first energy stage based on klystrons. We also discuss about a two stage pulse compressor with power gain of 9.18, which may be a candidate of the X-FEL using CLIC X-band linacs and klystrons with low peak power.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMW022
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOR041	High Gradient Properties of a CLIC Prototype Accelerating Structure made by Tsinghua University	3874
	X.W. Wu, H.B. Chen, J. Shi TUB, Beijing, People's Republic of China T. Higo, S. Matsumoto KEK, Ibaraki, Japan W. Wuensch CERN, Geneva, Switzerland
	A CLIC prototype structure, T24_THU_#1, was recently high-gradient tested at KEK X-band test stand, Nextef. The copper parts of this 24-cell TW structure were delivered from CERN, were bonded and brazed, bench-tested and tuned in Tsinghua University. The aim of this test was not only to verify the cavity high-gradient properties under 100 MV/m but also to study the breakdown phenomenon in high gradient. High power test results were presented and breakdown rate under 100 MV/m was compared to previously-tested CLIC prototype structures. The assembly capability of Tsinghua University for X-band high gradient structures was validated by the good high gradient performance of T24_THU_#1.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR041
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOR042	New Quantity Describing the Pulse Shape Dependence of the High Gradient Limit in Single Cell Standing-Wave Accelerating Structures	3878
	J. Shi, H.B. Chen, X.W. Wu TUB, Beijing, People's Republic of China V.A. Dolgashev SLAC, Menlo Park, California, USA A. Grudiev, W. Wuensch CERN, Geneva, Switzerland Y. Higashi KEK, Ibaraki, Japan B. Spataro INFN/LNF, Frascati (Roma), Italy
	A new quantity has been developed to study the relationship among the breakdown rate, the pulse width and the gradient. Difference pulse shapes can be treated by introducing a Green's function. This paper describes the quantity and the results while it is applied to the data of many high-power test runs of different single-cell standing wave accelerating structures. A remarkably similar relationship between the new quantity and breakdown rate is observed from all of the test results.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR042
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

THPOR043	High Power Test of X-band Single Cell HOM-free Choke-mode Damped Accelerating Structure made by Tsinghua University	3881
	X.W. Wu, H.B. Chen, J. Shi TUB, Beijing, People's Republic of China T. Abe, T. Higo KEK, Ibaraki, Japan W. Wuensch, H. Zha CERN, Geneva, Switzerland
	As an alternative design for CLIC main accelerating structures, X-band choke-mode damped structures had been studied for several years. However, the performance of choke-mode cavity under high power is still in lack of research. Two standing wave single cell choke-mode damped accelerating structures with different choke dimensions which are working at 11.424 GHz were designed, manufactured and bench tested by accelerator group in Tsinghua University. High power test was carried out on it to study the breakdown phenomenon in high gradient. A single cell structure without choke which almost has the same inner dimension as choke-mode cavity will also be tested to make a comparison and study how the choke affects high-gradient properties.
DOI •	reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR043
Export •	reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)

Paper

Title

Page

Beam Position Monitor Design for Dielectric Wakefield Accelerator In THz Range

171

Q. Gao, H.B. Chen, J. Shi
TUB, Beijing, People's Republic of China
W. Gai
ANL, Argonne, Illinois, USA
C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA

Dielectric based collinear wakefield accelerator have been broadly selected for the THz accelerator due to its simplicity. In order to move the THz accelerators from the current exploratory research into the practical phase, certain common accelerator components are indispensable. Beam Position Monitor (BPM) is one of them. However, most of conventional BPM techniques are hardly scaled down to THz regime. Here we propose a BPM design which uses the dominant dipole mode excited in the dielectric wakefield accelerators to extract information of the beam position.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMB037

Export •

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

MOPMR059

Development of S-band High Power Load

383

X.C. Meng, H.B. Chen, C. Cheng, Y.-C. Du, Q. Gao, J. Shi, P. Wang, Z.F. Xiong
TUB, Beijing, People's Republic of China

Several types of S-band high power loads have been designed, manufactured and tested successfully in Tsinghua University. The high power loads, which work at 2856 MHz for 10 MW~100 MW range, are made of all stainless steel. In this paper, we will present the design, fabrication and the high power test results.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR059

Export •

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

MOPMR060

C-Band Deflecting Cavity for Bunch Length Measurement of 2.5 MeV Electron Beam

386

J. Jiang, H.B. Chen, J. Shi, P. Wang, L. Zhang, S.X. Zheng
TUB, Beijing, People's Republic of China

The C-band deflecting cavity designed last year is finished. In this paper, the RF measurement of the cavity is introduced. After tuning, it works well at 5.712GHz with a coupling factor degree around 1.05. And we measured the electromagnetic field with bead-pull method. The flatness of the magnetic field is around 0.9, which is not ideal but meet the requirements of the bunch length measurement. And we propose a method of tuning to make sure both frequency and field flatness.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-MOPMR060

Export •

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

TUPOW014

Simulation of High Resolution Field Emission Imaging in an rf Photocathode Gun

1769

J.H. Shao, H.B. Chen, J. Shi, X.W. Wu
TUB, Beijing, People's Republic of China
S.P. Antipov, C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA
W. Gai
ANL, Argonne, Illinois, USA
F.Y. Wang
SLAC, Menlo Park, California, USA

Precisely locating field emission (FE) emitters on a realistic surface in rf structures is technically chal-lenging in general due to the wide emitting phase and the broad energy spread. A method to achieve in situ high resolution FE imaging has been proposed by using solenoids and a collimator to select electrons emitted at certain phases. The phase selection criterion and imaging properties have been studied by the beam dynamics code ASTRA. Detailed results are presented in this paper.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW014

Export •

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

TUPOW015

Experiment of High Resolution Field Emission Imaging in an rf Photocathode Gun

1772

J.H. Shao, H.B. Chen, J. Shi, X.W. Wu
TUB, Beijing, People's Republic of China
S.P. Antipov, S.V. Baryshev, C.-J. Jing
Euclid TechLabs, LLC, Solon, Ohio, USA
M.E. Conde, W. Gai, G. Ha, E.E. Wisniewski
ANL, Argonne, Illinois, USA
F.Y. Wang
SLAC, Menlo Park, California, USA

The first in situ high resolution field emission (FE) imaging experiment has been carried out on an L-band photocathode gun test stand at Argonne Wakefield Accelerator facility (AWA). Separated strong emitters have been observed to dominate the field emission. Field enhancement factor, beta, of small regions on the cathode has been measured with the imaging system. It is shown that most strong emitters overlaps with the high beta regions. The post surface examinations reveal the origins of ~75% strong emitters overlap with the spots where rf breakdown have occurred. Detailed results are presented in this paper.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW015

Export •

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

TUPOW016

Development of a C-Band 4/8 Mev Dual-Energy Accelerator for Cargo Inspection System

1775

J.H. Shao, H.B. Chen, W.-H. Huang, Q.X. Jin, Y.H. Liu, J. Shi, C.-X. Tang, X.W. Wu
TUB, Beijing, People's Republic of China

Modern cargo inspection system applies dual-energy X-ray for material discrimination. Based on the com-pact C-band 6 MeV standing-wave accelerating struc-tures developed at Tsinghua University, a compact C-band 4/8 MeV dual-energy accelerator has been pro-posed, fabricated and tested. Compared with that of the conventional S-band 3/6 MeV dual-energy accelera-tor at Tsinghua University, the volume and the weight of the C-band one has been reduced by ~40% and ~30%, respectively. Detailed review of this C-band dual-energy accelerator is present in the paper.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW016

Export •

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

TUPOW018

Tunable High-Intensity Electron Bunch Train Production Based on Nonlinear Longitudinal Space Charge Oscillation

1782

SUPSS016

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

Z. Zhang, H.B. Chen, Y.-C. Du, W.-H. Huang, J. Shi, X.L. Su, C.-X. Tang, Q.L. Tian, D. Wang, W. Wang, L.X. Yan, L.M. Zheng, Z. Zhou
TUB, Beijing, People's Republic of China
W. Gai
ANL, Argonne, Illinois, USA

High peak current electron bunch trains with tunable terahertz (THz) spacing are produced and measured experimentally. An initial picosecond periodic modulation in the temporal profile of a relativistic electron beam is magnified by the longitudinal space charge forces. As opposed to trying to reduce its smearing effect for large beam current, we take advantages of the nonlinear space charge oscillation through controlling the plasma phase advance. The spacing of the bunch train can be varied continuously either by tuning the velocity bunching of a radio-frequency gun or by tuning the compression of a downstream magnetic chicane. The narrow-band μJ-level THz radiation from the bunch train are also measured with tunable central frequency of the spectral from ~0.5 THz to 1.6 THz. The bunch train measurements are consistent with the particle tracking simulations.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPOW018

Export •

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

THPMW022

The RF Design of a Compact, High Power Pulse Compressor with a Flat Output Pulse

3591

SUPSS105

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

P. Wang, H.B. Chen, J. Shi
TUB, Beijing, People's Republic of China
I. Syratchev, W. Wuensch, H. Zha
CERN, Geneva, Switzerland

An X-band, high-power pulse compressor, which can produce a flat pulse and a power gain of 4.3, has been designed. The device is compact, with the dimensions of within 1m, and is designed for CLIC first energy stage based on klystrons. We also discuss about a two stage pulse compressor with power gain of 9.18, which may be a candidate of the X-FEL using CLIC X-band linacs and klystrons with low peak power.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMW022

Export •

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

THPOR041

High Gradient Properties of a CLIC Prototype Accelerating Structure made by Tsinghua University

3874

X.W. Wu, H.B. Chen, J. Shi
TUB, Beijing, People's Republic of China
T. Higo, S. Matsumoto
KEK, Ibaraki, Japan
W. Wuensch
CERN, Geneva, Switzerland

A CLIC prototype structure, T24_THU_#1, was recently high-gradient tested at KEK X-band test stand, Nextef. The copper parts of this 24-cell TW structure were delivered from CERN, were bonded and brazed, bench-tested and tuned in Tsinghua University. The aim of this test was not only to verify the cavity high-gradient properties under 100 MV/m but also to study the breakdown phenomenon in high gradient. High power test results were presented and breakdown rate under 100 MV/m was compared to previously-tested CLIC prototype structures. The assembly capability of Tsinghua University for X-band high gradient structures was validated by the good high gradient performance of T24_THU_#1.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR041

Export •

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

THPOR042

New Quantity Describing the Pulse Shape Dependence of the High Gradient Limit in Single Cell Standing-Wave Accelerating Structures

3878

J. Shi, H.B. Chen, X.W. Wu
TUB, Beijing, People's Republic of China
V.A. Dolgashev
SLAC, Menlo Park, California, USA
A. Grudiev, W. Wuensch
CERN, Geneva, Switzerland
Y. Higashi
KEK, Ibaraki, Japan
B. Spataro
INFN/LNF, Frascati (Roma), Italy

A new quantity has been developed to study the relationship among the breakdown rate, the pulse width and the gradient. Difference pulse shapes can be treated by introducing a Green's function. This paper describes the quantity and the results while it is applied to the data of many high-power test runs of different single-cell standing wave accelerating structures. A remarkably similar relationship between the new quantity and breakdown rate is observed from all of the test results.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR042

Export •

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

THPOR043

High Power Test of X-band Single Cell HOM-free Choke-mode Damped Accelerating Structure made by Tsinghua University

3881

X.W. Wu, H.B. Chen, J. Shi
TUB, Beijing, People's Republic of China
T. Abe, T. Higo
KEK, Ibaraki, Japan
W. Wuensch, H. Zha
CERN, Geneva, Switzerland

As an alternative design for CLIC main accelerating structures, X-band choke-mode damped structures had been studied for several years. However, the performance of choke-mode cavity under high power is still in lack of research. Two standing wave single cell choke-mode damped accelerating structures with different choke dimensions which are working at 11.424 GHz were designed, manufactured and bench tested by accelerator group in Tsinghua University. High power test was carried out on it to study the breakdown phenomenon in high gradient. A single cell structure without choke which almost has the same inner dimension as choke-mode cavity will also be tested to make a comparison and study how the choke affects high-gradient properties.

DOI •

reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPOR043

Export •

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