IPAC2013 - List of Authors (Chen, J.E.)

Paper

Title

Page

Coherent Wiggler Radiation of Picosecond CW Electron Beam Produced by DC-SRF Photoinjector

160

S. Huang, J.E. Chen, S. Chen, K.X. Liu, S.W. Quan, Zh.W. Wang, X.D. Wen, F. Zhu
PKU, Beijing, People's Republic of China

The DC-SRF photoinjector at Peking University is capable of providing CW electron beam with the energy of 3-5 MeV. The beam has high repetition rate, picosecond bunch length and high quality, which can be used to produce high repetition rate THz wave by wiggler radiation. Through off-crest acceleration, electron beam from the injector may be bunched, which will lead to coherent enhancement of the radiation power. With current setup of the DC-SRF injector and a 10-period wiggler, THz radiation power of 10s mW to a few watts can be achieved within the wavelength range of 200 μm to 500 μm. In this work, we will present the calculation results about THz radiation produced by the electron beam from DC-SRF photoinjector. The preparation for the experiments will be also described.

MOPEA039

Beam Commissioning and Neutron Radiography on a High Current Deuteron RFQ

163

Y.R. Lu, J. Chen, J.E. Chen, S.L. Gao, Z.Y. Guo, F.J. Jia, G. Liu, S.X. Peng, H.T. Ren, W.L. Xia, X.Q. Yan, K. Zhu
PKU, Beijing, People's Republic of China
S.Q. Liu, S. Wang, J. Zhao, B.Y. Zou
State Key Laboratory of Nuclear Physics and Technology, Beijing, Haidian District, People's Republic of China

Funding: Supported by NSFC 11079001 and Peking University
The high current deuteron RFQ has been developed and widely used in many projects, especially for accelerator based neutron source and its application. This paper reviews not only the recent developments in the world wide, also presents the beam dynamics, structure design ,RF full power test, beam commissioning of PKUNIFTY, which is consisted of a high current very compact ECR source, a 201.5MHz four-rod deuteron RFQ, thicker beryllium target and its moderating, collimation and neutron radiography system. RF and beam commissioning with duty cycle of 4% show the RFQ inter-vane voltage reaches 70kV at about 240kW, the delivered deuteron peak beam current is about 12mA at 290kW with the beam transmission of about 60%. The improvement of transmission is going on. The initial neutron radiography commissioning has been carried out. The results will promote the future development of small accelerator based neutron source.

MOPFI033

Commissioning Results and Progress of a Helium Injector for Coupled RFQ and SFRFQ Project at Peking University

357

J. Chen, J.E. Chen, S.L. Gao, Z.Y. Guo, Y.T. Luo, S.X. Peng, H.T. Ren, Z. Wang, Z.H. Wang, W.L. Xia, Y. Xu, A.L. Zhang, T. Zhang, J. Zhao
PKU, Beijing, People's Republic of China

At Peking University (PKU) a new helium injector for coupled radio frequency quadrupole(RFQ) and separated function radio frequency quadrupole(SFRFQ) within one cavity, so called as coupled RFQ & SFRFQ, was designed recently*. It will provide a 30keV 20mA He⁺ beam whose emittance is less than 0.15 π.mm.mrad for the accelerator. It is a combination of a 2.45GHz PKU PMECRIS (Permanent Magnet ECRIS) and a 1.16 m long LEBT. Within the 1.16 m LEBT, 2 solenoids, 2 steering magnets, a kicker, a space charge compensation section, a collimator, two vacuum valves, a Faraday cup and an ACCT are installed. The manufacture has been completed and the commissioning is on the way. In this paper we will address the commissioning results and its progress.
* Haitao Ren, et al., A Helium Injector for Coupled RFQ and SFRFQ Cavity Project at Peking University. Proc. LINAC’12, Paper TUPB034, Israel, 2012

MOPFI034

First Intense H⁻ Beam Generated by a Microwave-driven Pure Volume Source

360

S.X. Peng, J. Chen, J.E. Chen, Z.Y. Guo, H.T. Ren, Zh.W. Wang, Y. Xu, T. Zhang
PKU, Beijing, People's Republic of China
A.L. Zhang
Graduate University, Chinese Academy of Sciences, Beijing, People's Republic of China
J. Zhao
State Key Laboratory of Nuclear Physics and Technology, Beijing, Haidian District, People's Republic of China

The 2.45 GHz Electron cyclotron resonance (ECR) plasma generators have demonstrated their efficiency, reproducibility on producing H⁺, D⁺, O+, N+, He+, Ar+* and He2+ at Peking University(PKU). Recently, modifications on magnet field configuration, discharge chamber structure and extraction system have been done to set-up a microwave-driven pure volume H⁻ ion source. First experiment was done on PKU ion source test bench at the beginning of Nov, 2012. A 15 mA H⁻ ion beam has been produced at 40 keV by this prototype source. This paper describes the source principle and design in detail and reports on the current status of the development work.
* H. T. Ren, S. X. Peng*, P. N. Lu, S. Yan, Q. F. Zhou, J. Zhao, Z. X. Yuan, Z. Y. Guo and J. E. Chen, Rev. Sci. Instrum. 83, 02B905 (2012)

MOPFI035

Preliminary Results of H²⁺ Beam Generated by a 2.45 GHz Permanent Magnet ECR Ion Source at PKU

363

Y. Xu, J. Chen, J.E. Chen, Z.Y. Guo, Y.T. Luo, S.X. Peng, H.T. Ren, Z.H. Wang, T. Zhang, J. Zhao
PKU, Beijing, People's Republic of China
A.L. Zhang
Graduate University, Chinese Academy of Sciences, Beijing, People's Republic of China

Recently, the need to build an ion source generating high current hydrogen molecular ion H²⁺ beam has been growing rapidly. For example, H²⁺ ion can be used as a pilot beam of the intense deuteron beam during the commission phase of linear accelerators to minimize the activation of components. And it is an effective way to improve the output current of cyclotrons by accelerating H²⁺ and stripping it into H⁺ at the exit of accelerator, instead of accelerating H⁺ beam directly. To obtain high-yield H²⁺ ion beam, experimental and theoretical study was carried out on the 2.45 GHz Peking University permanent magnet electron cyclotron resonance ion source (PKU PMECR). With PMECR II*, studies on the size of discharge chamber and the operation pressure were carried out to increase H²⁺ ion fraction. Beam analysis results prove that the H²⁺ can reach 40.5% with suitable operation parameters. More details will be presented in this paper.
* Zhizhong Song, Shixiang Peng et al., Rev. Sci. Instrum. 77, 03A305 (2006)
** Author to whom correspondence should be addressed. Electronic mail:
sxpeng@pku.edu.cn.

MOPME035

Design of a Non-Intercepting Beam Diagnostic Device Using Neutral Beam Fluorescence Method

547

J. Zhao, J. Chen, J.E. Chen, Z.Y. Guo, S.X. Peng, H.T. Ren, Y. Xu, A.L. Zhang, T. Zhang
PKU, Beijing, People's Republic of China
H.W. Zhao
IMP, Lanzhou, People's Republic of China

The forward neutral beam from deflecting magntic field carries some characteristic properties of high intensity particle beams, such as profile, emittance etc. Therefore a reliable measurement of neutral beam fluorescence can be used to develop a fast and non-interceptive beam diagnostic tool. A non-intercepting beam emittance (profile) monitor using neutral beam fluorescence method has being constructed at Peking University. As a performance test, an emttiance of an extracted proton beam from a permanent magnetic electron cyclotron resonance (ECR) ion source was successfully measured. The details of design and results of measurement will be presented in this paper.

MOPWO014

Numerical Methods to the Space Charge Compensation (SCC) Effect of the LEBT Beam

915

S.X. Peng, J. Chen, J.E. Chen, Z.Y. Guo, P.N. Lu, Y.T. Luo, H.T. Ren, Z.H. Wang, Y. Xu, T. Zhang, J. Zhao
PKU, Beijing, People's Republic of China
A.L. Zhang
Graduate University, Chinese Academy of Sciences, Beijing, People's Republic of China

Numerical simulation as well as experimental researches on space charge compensation for high intensity, low energy ion beam has been done at Peking University (PKU). In this paper we will describe the simulation model proposed at PKU and use it on the PKU ECR single-charged ion source. It consists of a new concept of equivalent density and more consideration of physical process. A series of arithmetical equations is gained through theoretical derivation. Although no numerical solutions have been carried out from our computation, it is foreseeable that the final result will be achieved soon.

TUPEA018

Recent Progress of Laser Plasma Proton Accelerator at Peking University

1199

X.Q. Yan, J.E. Chen, H.Z. Fu, Y.X. Geng, Z.Y. Guo, C. Lin, Y.R. Lu, Y. Shang, Z.X. Yuan, S. Zhao, K. Zhu
PKU, Beijing, People's Republic of China

Funding: National Natural Science Foundation of China (Grant Nos.10935002, 10835003, 11025523)
Recent a project called Laser plasma Proton Accelerator (LAPA) is approved by MOST in China. A prototype of laser driven proton accelerator (1~15MeV) based on the PSA mechanism and plasma lens is going to be built at Peking University in the next five years. It can be used for the applications such as cancer therapy, plasma imaging and fast ignition for inertial confine fusion. The recent progress of LAPA is reported here.

TUPEA019

Proton Acceleration driven by High Energy Density Electrons

1202

S. Zhao, C. Chao, J.E. Chen, H.Z. Fu, Y.X. Geng, C. Lin, B. Liu, H. Wang, X.Q. Yan
PKU, Beijing, People's Republic of China

Resonance Electrons Driving Ion Acceleration S. Zhao, C. Lin, X. Q. Yan Institute of Heavy Ion Physics, Peking University Proton acceleration driven by resonance electrons is proposed. Energetic electron beam generated through direct laser acceleration in the near critical dense plasma is dense and directional. When interacting with a thin foil target, resonance electrons can transmit the target and drive periodical electrostatic field at the back surface, therefore protons are more efficiently accelerated in a much longer distance in propagation direction of resonance electrons, compared to the classical target normal sheath acceleration. For a Gaussian laser pulse with pulse duration of 80fs, peak intensity I=1.38*10⁸W/cm² , the cutoff energy of the output collimated proton beam is 14MeV, enhanced by a factor of 3 or 4. The scaling law predicts hundreds MeV Proton beam can be generated in laser intensity of 10²⁰W/cm².

TUPWA021

Multi-Pass, Multi-Bunch Beam Breakup of ERLs with 9-cell Tesla Cavities

1769

S. Chen, J.E. Chen, L.W. Feng, S. Huang, Y.M. Li, K.X. Liu, S.W. Quan, F. Zhu
PKU, Beijing, People's Republic of China

Funding: Supported by the Major State Basic Research Development Program of China under Grant No. 2011CB808303 and No. 2011CB808304
In this paper, multi-pass, multi-bunch beam break-up of some small-scale Energy Recovery Linac(ERL) configuration using 9-cell Tesla cavity is discussed. The threshold currents of different cases are investigated and some factors that influence the threshold currents are discussed.

TUPWA022

Beam Dynamics Design of a 325 MHz RFQ

1772

F.J. Jia, J.E. Chen, G. Liu, Y.R. Lu, X.Q. Yan
PKU, Beijing, People's Republic of China
B.Q. Cui, J.H. Li, G.H. Wei
CIAE, Beijing, People's Republic of China

The beam dynamic design of a 325 MHz Radio Frequency Quadrupole (RFQ) is presented in this paper. This 4-vane RFQ will accelerate pulsed proton beam from 30 keV to 3 MeV with repetition frequency of 1 MHz. A 1 MHz chopper and a 5 MHz buncher are arranged in the Low-Energy-Beam-Transport (LEBT) to produce the injected beam. The beam length at the RFQ entrance is about 3 ns, and the energy-spread is about 10%. The code of PARMTEQM is used to simulate RFQ structure. The design should realize high transmission for very high intensity beam meanwhile low emittance growth and relatively short length should be kept.

TUPWA023

Design of the Tuning System for the He⁺ Coupled RFQ-SFRFQ Cavity

1775

W.L. Xia, J.E. Chen, S.L. Gao, Z.Y. Guo, Y.R. Lu, S.X. Peng, Z. Wang, X.Q. Yan, J. Zhao, K. Zhu
PKU, Beijing, People's Republic of China

Funding: Supported by NSFC 10905003, 11079001, 91026012 Corresponding author: wangzhi@pku.edu.cn
The CRS (coupled RFQ-SFRFQ) cavity is a new type linac that couples traditional RFQ (radio frequency quadrupole) and SFRFQ (separated function RFQ) electrodes into a single cavity. The overall design of the CRS cavity has been completed and the linac is being manufactured currently. In this paper, we aimed to design a frequency tuning system for the CRS cavity, which will be used to explore the electromagnetic field distribution between RFQ and SFRFQ sections in the cavity. The frequency range, variation of Q value, power consumption and electric field distribution were investigated. Based on the beam dynamic program SFRFQDYNv1.0, we analysed the beam transmission properties of the cavity under the unbalanced electric field distribution. The optimized parameters of the tuning system were obtained.

THOAB102

A Pepper-pot Based Device for Diagnostics of the Single-shot Beam

3093

S.X. Peng, J. Chen, J.E. Chen, Z.Y. Guo, P.N. Lu, H.T. Ren, Z.H. Wang, Y. Xu, Z.X. Yuan, T. Zhang, J. Zhao
PKU, Beijing, People's Republic of China
A.L. Zhang
Graduate University, Chinese Academy of Sciences, Beijing, People's Republic of China
J. Zhao
State Key Laboratory of Nuclear Physics and Technology, Beijing, Haidian District, People's Republic of China

Generally the beam emittance can be measured by different Emittance Measurement Units (EMUs), such as the pepper-pot device, the slit-wire type facility and the Allison scanner. However, for a microsecond single-shot ion beam, the pepper-pot device is a suitable choice because of its cut-off single-shot technique without any time-consuming step. A pepper-pot based beam current & profile measurement device, which is a combination of Faraday cup technique and pepper-pot measurement facility, was developed at PKU. It consists of a main Faraday cup with a pepper-pot mask at its bottom, and a Faraday cup array locating 3 mm away from the pepper-pot mask. This device has been tested at the PKU LEBT test bench and the measurement results are consistent with the results acquired by the Allison scanner. By replacing the Faraday cup array with a fluorescent screen and a CCD camera, this device becomes a facility that not only has the ability to measure the total beam current and the beam profile, but also has the capability to measure the beam emittance for CW or pulsed ion beams. Details will be presented in this paper.

Slides THOAB102 [5.332 MB]

THPWO047

The LLRF Measurement and Analysis of the SSC-LINAC RFQ

3875

G. Liu, J.E. Chen, S.L. Gao, Y.R. Lu, Z. Wang, X.Q. Yan, K. Zhu
PKU, Beijing, People's Republic of China
X. Du, Y. He, G. Pan, Y.Q. Yang, X. Yin, Y.J. Yuan, Z.L. Zhang, H.W. Zhao
IMP, Lanzhou, People's Republic of China

Funding: Supported by NSFC(11079001)
The manufacturing process of the SSC-LINAC RFQ went to end and the LLRF measurement has been done. The frequency of the RFQ is 53.557 MHz without tuning, which is not far from the design value 53.667 MHz. The unflatness of the field along the beam axis is less than ±4%, which meets the simulation results. The dipole field is in the acceptable margin as well. The frequency will be adjusted by tuning plungers in operation. In this paper, the field distribution along the cavity has been measured and compared with the modulated electrodes simulation. The difference and its influences on the beam transmission have been analyzed.

THPWO048

A CW High Charge State Heavy Ion RFQ for SSC-LINAC

3878

Y.R. Lu, J.E. Chen, S.L. Gao, G. Liu, Z. Wang, X.Q. Yan, K. Zhu
PKU, Beijing, People's Republic of China
Y. He, L.P. Sun, J.W. Xia, Y.Q. Yang, X. Yin, Y.J. Yuan, Z.L. Zhang, H.W. Zhao
IMP, Lanzhou, People's Republic of China

Funding: Supported by NSFC 11079001
To improve the super heavy ion beam injection efficiency and supply high current heavy ion beam for Separated Sector Cyclotron, A CW RFQ for heavy ion with high charge state has been designed and manufactured in the last two years. This RFQ will operate at 53.667MHz, will accelerate super heavy ions such as 238U³⁴⁺ to 143keV/u. This paper will introduce the SSC-LINAC components, especially the RFQ beam dynamics, full length structure design, tuning and cooling method. Furthermore RF system and RF commissioning with full power for the RFQ power cavity will also be presented.

Paper	Title	Page
MOPEA038	Coherent Wiggler Radiation of Picosecond CW Electron Beam Produced by DC-SRF Photoinjector	160
	S. Huang, J.E. Chen, S. Chen, K.X. Liu, S.W. Quan, Zh.W. Wang, X.D. Wen, F. Zhu PKU, Beijing, People's Republic of China
	The DC-SRF photoinjector at Peking University is capable of providing CW electron beam with the energy of 3-5 MeV. The beam has high repetition rate, picosecond bunch length and high quality, which can be used to produce high repetition rate THz wave by wiggler radiation. Through off-crest acceleration, electron beam from the injector may be bunched, which will lead to coherent enhancement of the radiation power. With current setup of the DC-SRF injector and a 10-period wiggler, THz radiation power of 10s mW to a few watts can be achieved within the wavelength range of 200 μm to 500 μm. In this work, we will present the calculation results about THz radiation produced by the electron beam from DC-SRF photoinjector. The preparation for the experiments will be also described.

MOPEA039	Beam Commissioning and Neutron Radiography on a High Current Deuteron RFQ	163
	Y.R. Lu, J. Chen, J.E. Chen, S.L. Gao, Z.Y. Guo, F.J. Jia, G. Liu, S.X. Peng, H.T. Ren, W.L. Xia, X.Q. Yan, K. Zhu PKU, Beijing, People's Republic of China S.Q. Liu, S. Wang, J. Zhao, B.Y. Zou State Key Laboratory of Nuclear Physics and Technology, Beijing, Haidian District, People's Republic of China
	Funding: Supported by NSFC 11079001 and Peking University The high current deuteron RFQ has been developed and widely used in many projects, especially for accelerator based neutron source and its application. This paper reviews not only the recent developments in the world wide, also presents the beam dynamics, structure design ,RF full power test, beam commissioning of PKUNIFTY, which is consisted of a high current very compact ECR source, a 201.5MHz four-rod deuteron RFQ, thicker beryllium target and its moderating, collimation and neutron radiography system. RF and beam commissioning with duty cycle of 4% show the RFQ inter-vane voltage reaches 70kV at about 240kW, the delivered deuteron peak beam current is about 12mA at 290kW with the beam transmission of about 60%. The improvement of transmission is going on. The initial neutron radiography commissioning has been carried out. The results will promote the future development of small accelerator based neutron source.

MOPFI033	Commissioning Results and Progress of a Helium Injector for Coupled RFQ and SFRFQ Project at Peking University	357
	J. Chen, J.E. Chen, S.L. Gao, Z.Y. Guo, Y.T. Luo, S.X. Peng, H.T. Ren, Z. Wang, Z.H. Wang, W.L. Xia, Y. Xu, A.L. Zhang, T. Zhang, J. Zhao PKU, Beijing, People's Republic of China
	At Peking University (PKU) a new helium injector for coupled radio frequency quadrupole(RFQ) and separated function radio frequency quadrupole(SFRFQ) within one cavity, so called as coupled RFQ & SFRFQ, was designed recently. It will provide a 30keV 20mA He⁺ beam whose emittance is less than 0.15 π.mm.mrad for the accelerator. It is a combination of a 2.45GHz PKU PMECRIS (Permanent Magnet ECRIS) and a 1.16 m long LEBT. Within the 1.16 m LEBT, 2 solenoids, 2 steering magnets, a kicker, a space charge compensation section, a collimator, two vacuum valves, a Faraday cup and an ACCT are installed. The manufacture has been completed and the commissioning is on the way. In this paper we will address the commissioning results and its progress. Haitao Ren, et al., A Helium Injector for Coupled RFQ and SFRFQ Cavity Project at Peking University. Proc. LINAC’12, Paper TUPB034, Israel, 2012

MOPFI034	First Intense H⁻ Beam Generated by a Microwave-driven Pure Volume Source	360
	S.X. Peng, J. Chen, J.E. Chen, Z.Y. Guo, H.T. Ren, Zh.W. Wang, Y. Xu, T. Zhang PKU, Beijing, People's Republic of China A.L. Zhang Graduate University, Chinese Academy of Sciences, Beijing, People's Republic of China J. Zhao State Key Laboratory of Nuclear Physics and Technology, Beijing, Haidian District, People's Republic of China
	The 2.45 GHz Electron cyclotron resonance (ECR) plasma generators have demonstrated their efficiency, reproducibility on producing H⁺, D⁺, O+, N+, He+, Ar+* and He2+ at Peking University(PKU). Recently, modifications on magnet field configuration, discharge chamber structure and extraction system have been done to set-up a microwave-driven pure volume H⁻ ion source. First experiment was done on PKU ion source test bench at the beginning of Nov, 2012. A 15 mA H⁻ ion beam has been produced at 40 keV by this prototype source. This paper describes the source principle and design in detail and reports on the current status of the development work. * H. T. Ren, S. X. Peng*, P. N. Lu, S. Yan, Q. F. Zhou, J. Zhao, Z. X. Yuan, Z. Y. Guo and J. E. Chen, Rev. Sci. Instrum. 83, 02B905 (2012)

MOPFI035	Preliminary Results of H²⁺ Beam Generated by a 2.45 GHz Permanent Magnet ECR Ion Source at PKU	363
	Y. Xu, J. Chen, J.E. Chen, Z.Y. Guo, Y.T. Luo, S.X. Peng, H.T. Ren, Z.H. Wang, T. Zhang, J. Zhao PKU, Beijing, People's Republic of China A.L. Zhang Graduate University, Chinese Academy of Sciences, Beijing, People's Republic of China
	Recently, the need to build an ion source generating high current hydrogen molecular ion H²⁺ beam has been growing rapidly. For example, H²⁺ ion can be used as a pilot beam of the intense deuteron beam during the commission phase of linear accelerators to minimize the activation of components. And it is an effective way to improve the output current of cyclotrons by accelerating H²⁺ and stripping it into H⁺ at the exit of accelerator, instead of accelerating H⁺ beam directly. To obtain high-yield H²⁺ ion beam, experimental and theoretical study was carried out on the 2.45 GHz Peking University permanent magnet electron cyclotron resonance ion source (PKU PMECR). With PMECR II, studies on the size of discharge chamber and the operation pressure were carried out to increase H²⁺ ion fraction. Beam analysis results prove that the H²⁺ can reach 40.5% with suitable operation parameters. More details will be presented in this paper. Zhizhong Song, Shixiang Peng et al., Rev. Sci. Instrum. 77, 03A305 (2006) ** Author to whom correspondence should be addressed. Electronic mail: sxpeng@pku.edu.cn.

MOPME035	Design of a Non-Intercepting Beam Diagnostic Device Using Neutral Beam Fluorescence Method	547
	J. Zhao, J. Chen, J.E. Chen, Z.Y. Guo, S.X. Peng, H.T. Ren, Y. Xu, A.L. Zhang, T. Zhang PKU, Beijing, People's Republic of China H.W. Zhao IMP, Lanzhou, People's Republic of China
	The forward neutral beam from deflecting magntic field carries some characteristic properties of high intensity particle beams, such as profile, emittance etc. Therefore a reliable measurement of neutral beam fluorescence can be used to develop a fast and non-interceptive beam diagnostic tool. A non-intercepting beam emittance (profile) monitor using neutral beam fluorescence method has being constructed at Peking University. As a performance test, an emttiance of an extracted proton beam from a permanent magnetic electron cyclotron resonance (ECR) ion source was successfully measured. The details of design and results of measurement will be presented in this paper.

MOPWO014	Numerical Methods to the Space Charge Compensation (SCC) Effect of the LEBT Beam	915
	S.X. Peng, J. Chen, J.E. Chen, Z.Y. Guo, P.N. Lu, Y.T. Luo, H.T. Ren, Z.H. Wang, Y. Xu, T. Zhang, J. Zhao PKU, Beijing, People's Republic of China A.L. Zhang Graduate University, Chinese Academy of Sciences, Beijing, People's Republic of China
	Numerical simulation as well as experimental researches on space charge compensation for high intensity, low energy ion beam has been done at Peking University (PKU). In this paper we will describe the simulation model proposed at PKU and use it on the PKU ECR single-charged ion source. It consists of a new concept of equivalent density and more consideration of physical process. A series of arithmetical equations is gained through theoretical derivation. Although no numerical solutions have been carried out from our computation, it is foreseeable that the final result will be achieved soon.

TUPEA018	Recent Progress of Laser Plasma Proton Accelerator at Peking University	1199
	X.Q. Yan, J.E. Chen, H.Z. Fu, Y.X. Geng, Z.Y. Guo, C. Lin, Y.R. Lu, Y. Shang, Z.X. Yuan, S. Zhao, K. Zhu PKU, Beijing, People's Republic of China
	Funding: National Natural Science Foundation of China (Grant Nos.10935002, 10835003, 11025523) Recent a project called Laser plasma Proton Accelerator (LAPA) is approved by MOST in China. A prototype of laser driven proton accelerator (1~15MeV) based on the PSA mechanism and plasma lens is going to be built at Peking University in the next five years. It can be used for the applications such as cancer therapy, plasma imaging and fast ignition for inertial confine fusion. The recent progress of LAPA is reported here.

TUPEA019	Proton Acceleration driven by High Energy Density Electrons	1202
	S. Zhao, C. Chao, J.E. Chen, H.Z. Fu, Y.X. Geng, C. Lin, B. Liu, H. Wang, X.Q. Yan PKU, Beijing, People's Republic of China
	Resonance Electrons Driving Ion Acceleration S. Zhao, C. Lin, X. Q. Yan Institute of Heavy Ion Physics, Peking University Proton acceleration driven by resonance electrons is proposed. Energetic electron beam generated through direct laser acceleration in the near critical dense plasma is dense and directional. When interacting with a thin foil target, resonance electrons can transmit the target and drive periodical electrostatic field at the back surface, therefore protons are more efficiently accelerated in a much longer distance in propagation direction of resonance electrons, compared to the classical target normal sheath acceleration. For a Gaussian laser pulse with pulse duration of 80fs, peak intensity I=1.38*10⁸W/cm² , the cutoff energy of the output collimated proton beam is 14MeV, enhanced by a factor of 3 or 4. The scaling law predicts hundreds MeV Proton beam can be generated in laser intensity of 10²⁰W/cm².

TUPWA021	Multi-Pass, Multi-Bunch Beam Breakup of ERLs with 9-cell Tesla Cavities	1769
	S. Chen, J.E. Chen, L.W. Feng, S. Huang, Y.M. Li, K.X. Liu, S.W. Quan, F. Zhu PKU, Beijing, People's Republic of China
	Funding: Supported by the Major State Basic Research Development Program of China under Grant No. 2011CB808303 and No. 2011CB808304 In this paper, multi-pass, multi-bunch beam break-up of some small-scale Energy Recovery Linac(ERL) configuration using 9-cell Tesla cavity is discussed. The threshold currents of different cases are investigated and some factors that influence the threshold currents are discussed.

TUPWA022	Beam Dynamics Design of a 325 MHz RFQ	1772
	F.J. Jia, J.E. Chen, G. Liu, Y.R. Lu, X.Q. Yan PKU, Beijing, People's Republic of China B.Q. Cui, J.H. Li, G.H. Wei CIAE, Beijing, People's Republic of China
	The beam dynamic design of a 325 MHz Radio Frequency Quadrupole (RFQ) is presented in this paper. This 4-vane RFQ will accelerate pulsed proton beam from 30 keV to 3 MeV with repetition frequency of 1 MHz. A 1 MHz chopper and a 5 MHz buncher are arranged in the Low-Energy-Beam-Transport (LEBT) to produce the injected beam. The beam length at the RFQ entrance is about 3 ns, and the energy-spread is about 10%. The code of PARMTEQM is used to simulate RFQ structure. The design should realize high transmission for very high intensity beam meanwhile low emittance growth and relatively short length should be kept.

TUPWA023	Design of the Tuning System for the He⁺ Coupled RFQ-SFRFQ Cavity	1775
	W.L. Xia, J.E. Chen, S.L. Gao, Z.Y. Guo, Y.R. Lu, S.X. Peng, Z. Wang, X.Q. Yan, J. Zhao, K. Zhu PKU, Beijing, People's Republic of China
	Funding: Supported by NSFC 10905003, 11079001, 91026012 Corresponding author: wangzhi@pku.edu.cn The CRS (coupled RFQ-SFRFQ) cavity is a new type linac that couples traditional RFQ (radio frequency quadrupole) and SFRFQ (separated function RFQ) electrodes into a single cavity. The overall design of the CRS cavity has been completed and the linac is being manufactured currently. In this paper, we aimed to design a frequency tuning system for the CRS cavity, which will be used to explore the electromagnetic field distribution between RFQ and SFRFQ sections in the cavity. The frequency range, variation of Q value, power consumption and electric field distribution were investigated. Based on the beam dynamic program SFRFQDYNv1.0, we analysed the beam transmission properties of the cavity under the unbalanced electric field distribution. The optimized parameters of the tuning system were obtained.

THOAB102	A Pepper-pot Based Device for Diagnostics of the Single-shot Beam	3093
	S.X. Peng, J. Chen, J.E. Chen, Z.Y. Guo, P.N. Lu, H.T. Ren, Z.H. Wang, Y. Xu, Z.X. Yuan, T. Zhang, J. Zhao PKU, Beijing, People's Republic of China A.L. Zhang Graduate University, Chinese Academy of Sciences, Beijing, People's Republic of China J. Zhao State Key Laboratory of Nuclear Physics and Technology, Beijing, Haidian District, People's Republic of China
	Generally the beam emittance can be measured by different Emittance Measurement Units (EMUs), such as the pepper-pot device, the slit-wire type facility and the Allison scanner. However, for a microsecond single-shot ion beam, the pepper-pot device is a suitable choice because of its cut-off single-shot technique without any time-consuming step. A pepper-pot based beam current & profile measurement device, which is a combination of Faraday cup technique and pepper-pot measurement facility, was developed at PKU. It consists of a main Faraday cup with a pepper-pot mask at its bottom, and a Faraday cup array locating 3 mm away from the pepper-pot mask. This device has been tested at the PKU LEBT test bench and the measurement results are consistent with the results acquired by the Allison scanner. By replacing the Faraday cup array with a fluorescent screen and a CCD camera, this device becomes a facility that not only has the ability to measure the total beam current and the beam profile, but also has the capability to measure the beam emittance for CW or pulsed ion beams. Details will be presented in this paper.
	Slides THOAB102 [5.332 MB]

THPWO047	The LLRF Measurement and Analysis of the SSC-LINAC RFQ	3875
	G. Liu, J.E. Chen, S.L. Gao, Y.R. Lu, Z. Wang, X.Q. Yan, K. Zhu PKU, Beijing, People's Republic of China X. Du, Y. He, G. Pan, Y.Q. Yang, X. Yin, Y.J. Yuan, Z.L. Zhang, H.W. Zhao IMP, Lanzhou, People's Republic of China
	Funding: Supported by NSFC(11079001) The manufacturing process of the SSC-LINAC RFQ went to end and the LLRF measurement has been done. The frequency of the RFQ is 53.557 MHz without tuning, which is not far from the design value 53.667 MHz. The unflatness of the field along the beam axis is less than ±4%, which meets the simulation results. The dipole field is in the acceptable margin as well. The frequency will be adjusted by tuning plungers in operation. In this paper, the field distribution along the cavity has been measured and compared with the modulated electrodes simulation. The difference and its influences on the beam transmission have been analyzed.

THPWO048	A CW High Charge State Heavy Ion RFQ for SSC-LINAC	3878
	Y.R. Lu, J.E. Chen, S.L. Gao, G. Liu, Z. Wang, X.Q. Yan, K. Zhu PKU, Beijing, People's Republic of China Y. He, L.P. Sun, J.W. Xia, Y.Q. Yang, X. Yin, Y.J. Yuan, Z.L. Zhang, H.W. Zhao IMP, Lanzhou, People's Republic of China
	Funding: Supported by NSFC 11079001 To improve the super heavy ion beam injection efficiency and supply high current heavy ion beam for Separated Sector Cyclotron, A CW RFQ for heavy ion with high charge state has been designed and manufactured in the last two years. This RFQ will operate at 53.667MHz, will accelerate super heavy ions such as 238U³⁴⁺ to 143keV/u. This paper will introduce the SSC-LINAC components, especially the RFQ beam dynamics, full length structure design, tuning and cooling method. Furthermore RF system and RF commissioning with full power for the RFQ power cavity will also be presented.