IBIC2012 - List of Authors (Leng, Y.B.)

Paper

Title

Page

Study of Beam Length Measurement based on TM010 Mode

162

R.X. Yuan, Y.B. Leng, L.Y. Yu, W.M. Zhou
SINAP, Shanghai, People's Republic of China

Beam length measurement in frequency domain is a familiar method, and the resolution is seriously limited by the system signal-noise-ratio (SNR) and the beam length measured. Usually this method can only obtain the resolution about ~10ps with beam length ~30ps when using signal from button or stripline BPM. But in FEL case, the beam length is the ps or sub-ps order. The paper discusses the probability of beam length measurement based on the TM010 mode in FEL case. When adopting High Order Mode(HOM) reject and system gain control, the system SNR can arrive at 110dB and the resolution can achieve 30fs with beam length ps or sub-ps.

MOPB53

Hartmann Screen and Wavefront Sensor System for Extracting Mirror at SSRF

191

J. Chen, Y.B. Leng, K.R. Ye
SINAP, Shanghai, People's Republic of China

A Be mirror was used to extract visible synchrotron radiation light from bending magnet at SSRF. The surface of mirror was deformed because of X-ray heat. A set of Hartmann Screen Test was used to measure the surface of the mirror. Another equipment named The Shack-Hartmann wavefront sensor system was introduced to get more precision data. The result of two kind of test match each other well.

MOPB70

The Synchrotron Radiation Diagnostic Line at SSRF

232

J. Chen, Z.C. Chen, G.Q. Huang, Y.B. Leng, K.R. Ye, W.M. Zhou
SINAP, Shanghai, People's Republic of China

The synchrotron radiation photon beam line has been operated since 2009 at Shanghai Synchrotron Radiation Facility. There are two diagnostic beam lines of the storage ring behind bending magnet, which is employed conventional X-ray and visible imaging techniques. A synchrotron radiation (SR) interferometer using visible light region in order to measure the small transverse electron beam size (about 22μm); low emittance and a low coupling. A small off-axis mirror is set for the convenience of the observation. Wave front testing is used for interferometer to calibrate the deformation effect of optical components. An X-ray pin-hole camera is also employed in the diagnostics beamline of the ring to characterize beam. Typically the point spread function of the X-ray pinhole camera is calculated via analytical or numerical method. Those two methods check each other. As a result, the measurement with SR system has quite enough resolution of itself even though the absolute beam size acquired. The existed system suffers with dynamic problem for beam physics studies. It has been measured 2.8nm.rad in small emittance mode at SSRF.

TUPA12

A DBPM Calibration Method Implemented on FPGA

358

X.D. Sun, Y.B. Leng
SINAP, Shanghai, People's Republic of China

An calibration method on the four channels of DBPM is discussed . Using interpolation, the method is implemented on FPGA , which can handle the data on-line. The calibration algorithm is mono-channel dependent and is intended to solve the beam current dependence problem and increase resolution. Orientations of the method is presented. Basic design diagrams of the pipelined FPGA modules are listed and comparisons are made before and after the calibration

TUPA22

Design of RF Front End for Cavity Beam Position Monitor based on ICs

383

B.P. Wang, Z.C. Chen, Y.B. Leng, L.Y. Yu, R.X. Yuan, W.M. Zhou
SINAP, Shanghai, People's Republic of China

RF front end has the significant impact on the performance of cavity beam position monitor (CBPM) which is indispensable beam instrumentation component in free electron laser(FEL) or linear collider facility. With many new advances in data converter and radio technology, complex RF front end design has been greatly simplified. Now based on digital intermediate frequency (IF) receiver architecture, a new RF front end for (CBPM) has been designed and fabricated using surface mount component on print circuit board (PCB). The front end contains analog-digital converter used to digitize the IF signals. The whole system would be integrated to a digital board developed by our lab to produce the dedicated signal processor for CBPM. There is an Xilinx Vertex-5 FPGA device on the digital board and relevant signal processing algorithm has been implemented on it using VHDL. The details about design and test results would be introduced blow.

TUPB81

Design of the Beam Profile Monitors for the SXFEL Facility

534

L.Y. Yu, J. Chen, Y.B. Leng, K.R. Ye, W.M. Zhou
SINAP, Shanghai, People's Republic of China

The Shanghai X-ray Free Electron Laser Facility will begin construction at next year. The linac electron beam energy is 0.84 GeV. Over 50 beam profile monitors with OTR and YaG screen will be installed along the linac and undulators. The profile monitor system design is a challenging task, since the system has to measure transverse electron beam sizes from millimeter down to 40μm scale with a 20μm resolution and 50μm repeat positioning accuracy. This paper describes the design of the mechanical detector , the integrated step-servo motor controlling system, the beam imaging system, as well as the software system.

MOCB03

Modeling and Performance Evaluation of DCCTs in SSRF

16

Z.C. Chen, Y.B. Leng, Y. Xiong, W.M. Zhou
SSRF, Shanghai, People's Republic of China

Direct Current Current Transformer (DCCT) is the most commonly used high precision current monitor in modern particle accelerators including Shanghai Synchrotron Radiation Facility (SSRF). Three types of noise have been observed in the output signal of the DCCT in the storage ring of SSRF: power line noise, beam current related narrow band noise and random square wave noise from nowhere. This article will discuss the noise removal algorithms in SSRF and the performance of the DCCTs afterwards.

Slides MOCB03 [1.436 MB]

TUPA07

BPM Selection for Beam Current Monitoring in SSRF

341

Z.C. Chen, Y.B. Leng, Y.B. Yan
SSRF, Shanghai, People's Republic of China

Although Direct Current Current Transformer (DCCT) is the general solution of beam current monitor, Beam Position Monitor (BPM) sum signals may still surpass it in some aspects such as the faster data rate and higher resolution in low current situations. Nevertheless, an additional monitor should be harmless. Meanwhile, the DCCTs in the storage ring of Shanghai Synchrotron Radiation Facility (SSRF) have been suffering from various noise and the signals from the BPMs could be an aid to provide the beam current more accurately. There're 140 BPMs in the storage ring in SSRF but not all of them are suitable for this particular usage. This article focuses on the methods used here to dynamicly choose the BPMs that meet the criteria.

TUPA11

SSRF BPM System Optimization and Upgrade

355

Y.B. Yan, Y.B. Leng
SSRF, Shanghai, People's Republic of China
L.Y. Yu, W.M. Zhou
SINAP, Shanghai, People's Republic of China

The beam position monitor (BPM) system at SSRF was fully equipped with Libera Electrons. It have operated steadily for nearly five years. During the summer shutdown of 2012 more than 50 Libera Electrons were upgraded to Libera Brilliance which are used mainly for fast obit feedback system. The software of whole system is upgraded from 1.42 to 2.07. Some other hardware and software optimizations are carried out. After this upgrade, the stability and performance have been improved significantly. This paper introduces the details of the optimization and upgrade.

TUPB85

Spectrum of Multi-bunch Position Model and Parameter Acquisition Algorithm

540

Y. Yang, Y.B. Leng
SSRF, Shanghai, People's Republic of China
B.P. Wang
SINAP, Shanghai, People's Republic of China

Based on the spectrum of turn-by-turn model for the storage ring, spectrum of multi-bunch position model was derived through some assumptions. Spectrum of excited electron beam position was analyzed in Shanghai Synchrotron Radiation Facility(SSRF) and Genetic Algorithm was used to obtain the model parameters when fitting multi-curve data. Results show that, after 100 times iteration, all the correlation of fitted data and original data can be up to 95%, and the model can accurate estimate a bimodal split of the spectrum curve.

Paper	Title	Page
MOPA45	Study of Beam Length Measurement based on TM010 Mode	162
	R.X. Yuan, Y.B. Leng, L.Y. Yu, W.M. Zhou SINAP, Shanghai, People's Republic of China
	Beam length measurement in frequency domain is a familiar method, and the resolution is seriously limited by the system signal-noise-ratio (SNR) and the beam length measured. Usually this method can only obtain the resolution about ~10ps with beam length ~30ps when using signal from button or stripline BPM. But in FEL case, the beam length is the ps or sub-ps order. The paper discusses the probability of beam length measurement based on the TM010 mode in FEL case. When adopting High Order Mode(HOM) reject and system gain control, the system SNR can arrive at 110dB and the resolution can achieve 30fs with beam length ps or sub-ps.

MOPB53	Hartmann Screen and Wavefront Sensor System for Extracting Mirror at SSRF	191
	J. Chen, Y.B. Leng, K.R. Ye SINAP, Shanghai, People's Republic of China
	A Be mirror was used to extract visible synchrotron radiation light from bending magnet at SSRF. The surface of mirror was deformed because of X-ray heat. A set of Hartmann Screen Test was used to measure the surface of the mirror. Another equipment named The Shack-Hartmann wavefront sensor system was introduced to get more precision data. The result of two kind of test match each other well.

MOPB70	The Synchrotron Radiation Diagnostic Line at SSRF	232
	J. Chen, Z.C. Chen, G.Q. Huang, Y.B. Leng, K.R. Ye, W.M. Zhou SINAP, Shanghai, People's Republic of China
	The synchrotron radiation photon beam line has been operated since 2009 at Shanghai Synchrotron Radiation Facility. There are two diagnostic beam lines of the storage ring behind bending magnet, which is employed conventional X-ray and visible imaging techniques. A synchrotron radiation (SR) interferometer using visible light region in order to measure the small transverse electron beam size (about 22μm); low emittance and a low coupling. A small off-axis mirror is set for the convenience of the observation. Wave front testing is used for interferometer to calibrate the deformation effect of optical components. An X-ray pin-hole camera is also employed in the diagnostics beamline of the ring to characterize beam. Typically the point spread function of the X-ray pinhole camera is calculated via analytical or numerical method. Those two methods check each other. As a result, the measurement with SR system has quite enough resolution of itself even though the absolute beam size acquired. The existed system suffers with dynamic problem for beam physics studies. It has been measured 2.8nm.rad in small emittance mode at SSRF.

TUPA12	A DBPM Calibration Method Implemented on FPGA	358
	X.D. Sun, Y.B. Leng SINAP, Shanghai, People's Republic of China
	An calibration method on the four channels of DBPM is discussed . Using interpolation, the method is implemented on FPGA , which can handle the data on-line. The calibration algorithm is mono-channel dependent and is intended to solve the beam current dependence problem and increase resolution. Orientations of the method is presented. Basic design diagrams of the pipelined FPGA modules are listed and comparisons are made before and after the calibration

TUPA22	Design of RF Front End for Cavity Beam Position Monitor based on ICs	383
	B.P. Wang, Z.C. Chen, Y.B. Leng, L.Y. Yu, R.X. Yuan, W.M. Zhou SINAP, Shanghai, People's Republic of China
	RF front end has the significant impact on the performance of cavity beam position monitor (CBPM) which is indispensable beam instrumentation component in free electron laser(FEL) or linear collider facility. With many new advances in data converter and radio technology, complex RF front end design has been greatly simplified. Now based on digital intermediate frequency (IF) receiver architecture, a new RF front end for (CBPM) has been designed and fabricated using surface mount component on print circuit board (PCB). The front end contains analog-digital converter used to digitize the IF signals. The whole system would be integrated to a digital board developed by our lab to produce the dedicated signal processor for CBPM. There is an Xilinx Vertex-5 FPGA device on the digital board and relevant signal processing algorithm has been implemented on it using VHDL. The details about design and test results would be introduced blow.

TUPB81	Design of the Beam Profile Monitors for the SXFEL Facility	534
	L.Y. Yu, J. Chen, Y.B. Leng, K.R. Ye, W.M. Zhou SINAP, Shanghai, People's Republic of China
	The Shanghai X-ray Free Electron Laser Facility will begin construction at next year. The linac electron beam energy is 0.84 GeV. Over 50 beam profile monitors with OTR and YaG screen will be installed along the linac and undulators. The profile monitor system design is a challenging task, since the system has to measure transverse electron beam sizes from millimeter down to 40μm scale with a 20μm resolution and 50μm repeat positioning accuracy. This paper describes the design of the mechanical detector , the integrated step-servo motor controlling system, the beam imaging system, as well as the software system.

MOCB03	Modeling and Performance Evaluation of DCCTs in SSRF	16
	Z.C. Chen, Y.B. Leng, Y. Xiong, W.M. Zhou SSRF, Shanghai, People's Republic of China
	Direct Current Current Transformer (DCCT) is the most commonly used high precision current monitor in modern particle accelerators including Shanghai Synchrotron Radiation Facility (SSRF). Three types of noise have been observed in the output signal of the DCCT in the storage ring of SSRF: power line noise, beam current related narrow band noise and random square wave noise from nowhere. This article will discuss the noise removal algorithms in SSRF and the performance of the DCCTs afterwards.
	Slides MOCB03 [1.436 MB]

TUPA07	BPM Selection for Beam Current Monitoring in SSRF	341
	Z.C. Chen, Y.B. Leng, Y.B. Yan SSRF, Shanghai, People's Republic of China
	Although Direct Current Current Transformer (DCCT) is the general solution of beam current monitor, Beam Position Monitor (BPM) sum signals may still surpass it in some aspects such as the faster data rate and higher resolution in low current situations. Nevertheless, an additional monitor should be harmless. Meanwhile, the DCCTs in the storage ring of Shanghai Synchrotron Radiation Facility (SSRF) have been suffering from various noise and the signals from the BPMs could be an aid to provide the beam current more accurately. There're 140 BPMs in the storage ring in SSRF but not all of them are suitable for this particular usage. This article focuses on the methods used here to dynamicly choose the BPMs that meet the criteria.

TUPA11	SSRF BPM System Optimization and Upgrade	355
	Y.B. Yan, Y.B. Leng SSRF, Shanghai, People's Republic of China L.Y. Yu, W.M. Zhou SINAP, Shanghai, People's Republic of China
	The beam position monitor (BPM) system at SSRF was fully equipped with Libera Electrons. It have operated steadily for nearly five years. During the summer shutdown of 2012 more than 50 Libera Electrons were upgraded to Libera Brilliance which are used mainly for fast obit feedback system. The software of whole system is upgraded from 1.42 to 2.07. Some other hardware and software optimizations are carried out. After this upgrade, the stability and performance have been improved significantly. This paper introduces the details of the optimization and upgrade.

TUPB85	Spectrum of Multi-bunch Position Model and Parameter Acquisition Algorithm	540
	Y. Yang, Y.B. Leng SSRF, Shanghai, People's Republic of China B.P. Wang SINAP, Shanghai, People's Republic of China
	Based on the spectrum of turn-by-turn model for the storage ring, spectrum of multi-bunch position model was derived through some assumptions. Spectrum of excited electron beam position was analyzed in Shanghai Synchrotron Radiation Facility(SSRF) and Genetic Algorithm was used to obtain the model parameters when fitting multi-curve data. Results show that, after 100 times iteration, all the correlation of fitted data and original data can be up to 95%, and the model can accurate estimate a bimodal split of the spectrum curve.