IPAC2013 - List of Authors (Zhao, Z.T.)

Paper

Title

Page

Transverse Instabilities of Two Twisted Beams in a Storage Ring

172

B.C. Jiang, M.Z. Zhang, Z.T. Zhao
SINAP, Shanghai, People's Republic of China
G.X. Xia
UMAN, Manchester, United Kingdom

Two twisted beams (two beams run on the different closed orbit) in a storage ring which is produced by fast kickers can potentially deliver two bunds of radiations through one insertion device or one bend magnet, in this way doubles the beam line stations. This operation mode needs higher beam current and more RF buckets to be filled to keep the brightness comparable to the single beam operation mode. The resistive wall instability and ion trapping effects is analysed to address the higher current operation possibility. The analyze results show that twisted beams can weaken those two instabilities.

MOPEA045

Performance Optimization and Upgrade of the SSRF Storage Ring

178

Z.T. Zhao, B.C. Jiang, Y.B. Leng, S.Q. Tian, L. Yin, W.Z. Zhang
SINAP, Shanghai, People's Republic of China

The SSRF storage ring achieved its design performance goal in 2008, in the following years its performance was optimized and improved, including implementing top-up operation and low emittance lattice configuration as well as other attempts like fast orbit feedback and low alpha mode. In order to meet the requirements of accommodating more beamlines and high demanding performance in its phase-II beamline project, the SSRF storage ring is being upgraded with a design based on superbend based lattice and a third harmonic RF cavity system. This paper presents the main optimization works and the upgrade design considerations on the SSRF storage ring performance.

TUPEA033

Proposals for Chirped Pulse Amplification in HGHG and CHG at SDUV-FEL

1217

C. Feng, L. Shen, D. Wang, D. Xiang, M. Zhang, Z.T. Zhao
SINAP, Shanghai, People's Republic of China

In this paper, a proposal to generate intense ultra-short free-electron laser (FEL) pulses at Shanghai deep ultraviolet FEL (SDUV-FEL) by combining the chirped pulse amplification (CPA) technique with the high-gain harmonic generation (HGHG) technique is presented. In this proposal, a frequency chirped seed pulse obtained by stretching an ultra-short laser pulse is first used to create frequency-chirped bunching at the laser harmonics in an electron beam; then the frequency chirped harmonic radiation is amplified by an energy chirped electron beam; finally the output radiation pulse which inherits the properties of the seed pulse is compressed to provide an ultra-intense ultra-short radiation pulse. The feasibility and performance of this CPA-HGHG scheme are studied with start-to-end simulations using the parameters of the SDUV-FEL.

TUPEA038

Pre-chirp Control Broadband Non-collinear Optical Parametric Amplifier for the Future Laser Weak-field Accelerator

1223

L. Shen, C. Feng, L. Feng, D. Wang, H.F. Yao, W.Y. Zhang, Z.T. Zhao
SINAP, Shanghai, People's Republic of China

Ultra-short pulse has been proved to be a very useful tool for accelerating electron close to GeV now. But limited by gain narrowing effect, conventional CPA technology is quite hard to get less than 30fs at high energy level. Non-collinear optical parametric amplification (NOPA) looks more and more attractive for generating super-broadbandwidth pulses which is possible to be compressed to ultra-short pulses. Previous NOPAs, pumped by 400nm pulses, were using BBO crystals to reach shorter signal pulse durations. But the associated spectral bandwidths are still strongly linked with higher order nonlinear effects. which make it quite difficult to get higher energy with short pulse duration. Here we proposed to use pre-chirped few nm bandwidths around 515nm pumped pulses to amplify ultra-short pulses centered at 800nm. In our setup, we have found just one dramatical geometry configuration which support that we have possibility to get amplification from 720nm to 900nm, which will support to less than 10fs by well re-compression. This design is well adapted for BBO crystals. But the idea could be used also for other crystals.

TUPWO031

Double-mini-beta Optics for the SSRF Storage Ring

1943

S.Q. Tian, B.C. Jiang, M.Z. Zhang, Z.T. Zhao
SINAP, Shanghai, People's Republic of China

The two long straight sections of the SSRF storage ring will be installed by dual canted in-vacuum insertion devices in the near future. In order to get high brightness and maintain good machine performance, the vertical beta function must be reduced by a triplet of quadrupole between the two source points, which is the so-called double-mini-beta optics. We have designed this kind of optics for SSRF, and the results are presented in this paper.

TUPWO033

Effects Estimation of Superconducting Wiggler in SSRF

1946

Q.L. Zhang, B.C. Jiang, S.Q. Tian, W.Z. Zhang, Z.T. Zhao
SINAP, Shanghai, People's Republic of China

Superconducting wiggler (SW) may greatly impact on the beam dynamics in a storage ring. The effects of a 4.5T SW has been studied in SSRF including impaction on the emittance and the energy spread. To keep an undegraded storage ring performance, a local achromatic lattice is considered. The combat between the damping effect of the SW and emittance growth of local achromatic lattice is the main concern of this paper. Other effects (tune shift, beta beating, dynamics aperture, etc.) with the SW are also simulated and optimized in this paper.

WEODB102

Generating Polarization Controllable FELs at Dalian Coherent Light Source

2071

T. Zhang, H.X. Deng, D. Wang, Z.T. Zhao
SINAP, Shanghai, People's Republic of China
D.X. Dai, G.R. Wu, X.M. Yang, W.Q. Zhang
DICP, Dalian, People's Republic of China

Funding: 973 Program of China (2011CB808300), NSFC 11175240 and 11205234.
The property of the FEL polarization is of great importance to the user community. FEL pulses with ultra-high intensity and flexible polarization control ability will absolutely open up new scientific realms. In this paper, several polarization control approaches are presented to investigate the great potential on Dalian coherent light source, which is a government-approved novel FEL user facility with the capability of wavelength continuously tunable in the EUV regime of 50-150 nm. The numerical simulations show that both circularly polarized FELs with highly modulating frequency and 100 microjoule level pulse energy could be generated at Dalian coherent light source*.
*T. Zhang, et al., FEL Polarization Control Studies on Dalian Coherent Light Source, Chinese Physics C, 2013, to be published.

Slides WEODB102 [6.131 MB]

WEPWO036

Conceptual Design of a Superfluid Superconducting Third Harmonic RF System for the SSRF Storage Ring

2381

H.T. Hou, J.F. Liu, Z.T. Zhao
SINAP, Shanghai, People's Republic of China
J.F. Liu
Shanghai KEY Laboratory of Cryogenics & Superconducting RF Technology, Shanghai, People's Republic of China

Harmonic cavity can improve the beam quality through bunch size lengthening which includes providing Landau damping, suppressing coupled bunch instability and microwave instability, enhancing the beam current per bunch besides the beam lifetime improvement. A passive third harmonic superconducting cavity operating at super fluid liquid helium has been proposed for the SSRF storage ring with compromise on the required harmonic voltage, limited installation space and dissipated cryogenic power. This paper will mainly present the conceptual design of the harmonic rf system including the requirement of SSRF, a brief review on beam dynamics of harmonic rf system and the harmonic cavity choice.

WEPFI038

R&D of New C-band Accelerating Structure for SXFEL Facility

2785

W. Fang, Q. Gu, Z.T. Zhao
SINAP, Shanghai, People's Republic of China
L. Chen, X. Sheng
BVERI, Beijing, People's Republic of China
D.C. Tong
TUB, Beijing, People's Republic of China

C-band high gradient accelerating structure is crucial technology for Shanghai Soft X-ray FEL facility. Based on the prototype, the optimized C-band accelerating structure is proposed, and the experimental model is ready for high power test. In this paper, optimization design and some experiment results are presented, also design, fabrication and cold test of experimental model are introduced.

WEPFI039

New X-band Deflecting Cavity Design for Ultra-short Bunch Length Measure of FEL at SINAP

2788

J.H. Tan, W. Fang, Q. Gu, Z.T. Zhao
SINAP, Shanghai, People's Republic of China

For the development of Free Electron Lasers (FEL) at SINAP, ultra-short bunch is the crucial requirement for excellent lasing performance. It’s big challenge for deflecting cavity to measure the length of ultra-short bunch, and higher deflecting gradient is required for higher measurement resolution. X-band travelling wave deflecting structure has features of higher deflecting voltage and compact structure, which is good performance at ultra-short bunch length measuring. In this paper, a new X-band deflecting structure was designed, operated at HEM11- 2π/3 mode. For suppressing the polarization of deflection plane of the HEM11 mode, two symmetrical caves are added on the cavity wall to separate two polarized modes. More details of design and simulation results are presented in this paper.

WEPFI040

R&D of C-band Pulse Compression for Soft X-ray FEL at SINAP

2791

C.P. Wang, W. Fang, Q. Gu, W.C. Wang, Z.T. Zhao
SINAP, Shanghai, People's Republic of China

A compact Soft X-ray Free Electron Lasers facility is presently being constructed at SINAP, and 8 C-band accelerating structure unit are required for third-stage including 4 pulse compressors. The field mode of C-band SLED is TE0.1.15 with high quality factor Q, and the coupling coefficient is 8.5. Based on the design, the power pulse of klystron is compressed from 2.5μs to 0.5μs, and finally the power gain is about 3.1. In this paper, the details and simulation of 3-dB coupler, mode convertors and the resonant cavities are presented, meanwhile some cold test results of cavity are also analyzed at the end of this paper.

Paper	Title	Page
MOPEA043	Transverse Instabilities of Two Twisted Beams in a Storage Ring	172
	B.C. Jiang, M.Z. Zhang, Z.T. Zhao SINAP, Shanghai, People's Republic of China G.X. Xia UMAN, Manchester, United Kingdom
	Two twisted beams (two beams run on the different closed orbit) in a storage ring which is produced by fast kickers can potentially deliver two bunds of radiations through one insertion device or one bend magnet, in this way doubles the beam line stations. This operation mode needs higher beam current and more RF buckets to be filled to keep the brightness comparable to the single beam operation mode. The resistive wall instability and ion trapping effects is analysed to address the higher current operation possibility. The analyze results show that twisted beams can weaken those two instabilities.

MOPEA045	Performance Optimization and Upgrade of the SSRF Storage Ring	178
	Z.T. Zhao, B.C. Jiang, Y.B. Leng, S.Q. Tian, L. Yin, W.Z. Zhang SINAP, Shanghai, People's Republic of China
	The SSRF storage ring achieved its design performance goal in 2008, in the following years its performance was optimized and improved, including implementing top-up operation and low emittance lattice configuration as well as other attempts like fast orbit feedback and low alpha mode. In order to meet the requirements of accommodating more beamlines and high demanding performance in its phase-II beamline project, the SSRF storage ring is being upgraded with a design based on superbend based lattice and a third harmonic RF cavity system. This paper presents the main optimization works and the upgrade design considerations on the SSRF storage ring performance.

TUPEA033	Proposals for Chirped Pulse Amplification in HGHG and CHG at SDUV-FEL	1217
	C. Feng, L. Shen, D. Wang, D. Xiang, M. Zhang, Z.T. Zhao SINAP, Shanghai, People's Republic of China
	In this paper, a proposal to generate intense ultra-short free-electron laser (FEL) pulses at Shanghai deep ultraviolet FEL (SDUV-FEL) by combining the chirped pulse amplification (CPA) technique with the high-gain harmonic generation (HGHG) technique is presented. In this proposal, a frequency chirped seed pulse obtained by stretching an ultra-short laser pulse is first used to create frequency-chirped bunching at the laser harmonics in an electron beam; then the frequency chirped harmonic radiation is amplified by an energy chirped electron beam; finally the output radiation pulse which inherits the properties of the seed pulse is compressed to provide an ultra-intense ultra-short radiation pulse. The feasibility and performance of this CPA-HGHG scheme are studied with start-to-end simulations using the parameters of the SDUV-FEL.

TUPEA038	Pre-chirp Control Broadband Non-collinear Optical Parametric Amplifier for the Future Laser Weak-field Accelerator	1223
	L. Shen, C. Feng, L. Feng, D. Wang, H.F. Yao, W.Y. Zhang, Z.T. Zhao SINAP, Shanghai, People's Republic of China
	Ultra-short pulse has been proved to be a very useful tool for accelerating electron close to GeV now. But limited by gain narrowing effect, conventional CPA technology is quite hard to get less than 30fs at high energy level. Non-collinear optical parametric amplification (NOPA) looks more and more attractive for generating super-broadbandwidth pulses which is possible to be compressed to ultra-short pulses. Previous NOPAs, pumped by 400nm pulses, were using BBO crystals to reach shorter signal pulse durations. But the associated spectral bandwidths are still strongly linked with higher order nonlinear effects. which make it quite difficult to get higher energy with short pulse duration. Here we proposed to use pre-chirped few nm bandwidths around 515nm pumped pulses to amplify ultra-short pulses centered at 800nm. In our setup, we have found just one dramatical geometry configuration which support that we have possibility to get amplification from 720nm to 900nm, which will support to less than 10fs by well re-compression. This design is well adapted for BBO crystals. But the idea could be used also for other crystals.

TUPWO031	Double-mini-beta Optics for the SSRF Storage Ring	1943
	S.Q. Tian, B.C. Jiang, M.Z. Zhang, Z.T. Zhao SINAP, Shanghai, People's Republic of China
	The two long straight sections of the SSRF storage ring will be installed by dual canted in-vacuum insertion devices in the near future. In order to get high brightness and maintain good machine performance, the vertical beta function must be reduced by a triplet of quadrupole between the two source points, which is the so-called double-mini-beta optics. We have designed this kind of optics for SSRF, and the results are presented in this paper.

TUPWO033	Effects Estimation of Superconducting Wiggler in SSRF	1946
	Q.L. Zhang, B.C. Jiang, S.Q. Tian, W.Z. Zhang, Z.T. Zhao SINAP, Shanghai, People's Republic of China
	Superconducting wiggler (SW) may greatly impact on the beam dynamics in a storage ring. The effects of a 4.5T SW has been studied in SSRF including impaction on the emittance and the energy spread. To keep an undegraded storage ring performance, a local achromatic lattice is considered. The combat between the damping effect of the SW and emittance growth of local achromatic lattice is the main concern of this paper. Other effects (tune shift, beta beating, dynamics aperture, etc.) with the SW are also simulated and optimized in this paper.

WEODB102	Generating Polarization Controllable FELs at Dalian Coherent Light Source	2071
	T. Zhang, H.X. Deng, D. Wang, Z.T. Zhao SINAP, Shanghai, People's Republic of China D.X. Dai, G.R. Wu, X.M. Yang, W.Q. Zhang DICP, Dalian, People's Republic of China
	Funding: 973 Program of China (2011CB808300), NSFC 11175240 and 11205234. The property of the FEL polarization is of great importance to the user community. FEL pulses with ultra-high intensity and flexible polarization control ability will absolutely open up new scientific realms. In this paper, several polarization control approaches are presented to investigate the great potential on Dalian coherent light source, which is a government-approved novel FEL user facility with the capability of wavelength continuously tunable in the EUV regime of 50-150 nm. The numerical simulations show that both circularly polarized FELs with highly modulating frequency and 100 microjoule level pulse energy could be generated at Dalian coherent light source. T. Zhang, et al., FEL Polarization Control Studies on Dalian Coherent Light Source, Chinese Physics C, 2013, to be published.
	Slides WEODB102 [6.131 MB]

WEPWO036	Conceptual Design of a Superfluid Superconducting Third Harmonic RF System for the SSRF Storage Ring	2381
	H.T. Hou, J.F. Liu, Z.T. Zhao SINAP, Shanghai, People's Republic of China J.F. Liu Shanghai KEY Laboratory of Cryogenics & Superconducting RF Technology, Shanghai, People's Republic of China
	Harmonic cavity can improve the beam quality through bunch size lengthening which includes providing Landau damping, suppressing coupled bunch instability and microwave instability, enhancing the beam current per bunch besides the beam lifetime improvement. A passive third harmonic superconducting cavity operating at super fluid liquid helium has been proposed for the SSRF storage ring with compromise on the required harmonic voltage, limited installation space and dissipated cryogenic power. This paper will mainly present the conceptual design of the harmonic rf system including the requirement of SSRF, a brief review on beam dynamics of harmonic rf system and the harmonic cavity choice.

WEPFI038	R&D of New C-band Accelerating Structure for SXFEL Facility	2785
	W. Fang, Q. Gu, Z.T. Zhao SINAP, Shanghai, People's Republic of China L. Chen, X. Sheng BVERI, Beijing, People's Republic of China D.C. Tong TUB, Beijing, People's Republic of China
	C-band high gradient accelerating structure is crucial technology for Shanghai Soft X-ray FEL facility. Based on the prototype, the optimized C-band accelerating structure is proposed, and the experimental model is ready for high power test. In this paper, optimization design and some experiment results are presented, also design, fabrication and cold test of experimental model are introduced.

WEPFI039	New X-band Deflecting Cavity Design for Ultra-short Bunch Length Measure of FEL at SINAP	2788
	J.H. Tan, W. Fang, Q. Gu, Z.T. Zhao SINAP, Shanghai, People's Republic of China
	For the development of Free Electron Lasers (FEL) at SINAP, ultra-short bunch is the crucial requirement for excellent lasing performance. It’s big challenge for deflecting cavity to measure the length of ultra-short bunch, and higher deflecting gradient is required for higher measurement resolution. X-band travelling wave deflecting structure has features of higher deflecting voltage and compact structure, which is good performance at ultra-short bunch length measuring. In this paper, a new X-band deflecting structure was designed, operated at HEM11- 2π/3 mode. For suppressing the polarization of deflection plane of the HEM11 mode, two symmetrical caves are added on the cavity wall to separate two polarized modes. More details of design and simulation results are presented in this paper.

WEPFI040	R&D of C-band Pulse Compression for Soft X-ray FEL at SINAP	2791
	C.P. Wang, W. Fang, Q. Gu, W.C. Wang, Z.T. Zhao SINAP, Shanghai, People's Republic of China
	A compact Soft X-ray Free Electron Lasers facility is presently being constructed at SINAP, and 8 C-band accelerating structure unit are required for third-stage including 4 pulse compressors. The field mode of C-band SLED is TE0.1.15 with high quality factor Q, and the coupling coefficient is 8.5. Based on the design, the power pulse of klystron is compressed from 2.5μs to 0.5μs, and finally the power gain is about 3.1. In this paper, the details and simulation of 3-dB coupler, mode convertors and the resonant cavities are presented, meanwhile some cold test results of cavity are also analyzed at the end of this paper.