117464950
Study on the multi-pass, multi-bunch beam breakup for 9-cell TESLA cavities in ERL *
Generally, Energy Recovery Linac (ERL) needs special designed high current superconducting RF cavities. In this paper, the threshold current of BBU for compact ERL facilities with 9-cell Tesla type cavities are investigated. The results show that it is feasible to adopt 9-cell Tesla cavity for compact ERL test facilities with just a few cavities and beam current around tens mA.
110104367
OPTICAL DESIGN OF THE ENERGY RECOVERY LINAC FEL AT PEKING UNIVERSITY
Peking University is currently designing an Energy Recovery Linac FEL (PKU-ERL-FEL). The system is consisted of a DC-SC photocathode injector, a superconducting linac which is composed of two nine cell TESLA-type cavities, an undulator and beam transport system. The objectives of the PKU-ERL-FEL are providing infrared FEL and building a test-bed for the study of beam dynamics and accelerator technology for energy recovery. In this paper the main parameters of the PKU-ERL-FEL are described and the optical design for the beam transport of PKU-ERL-FEL is presented. The simulation is carried out using the typical particle tracking codes such as elegant.
121908829
Amplitude and phase stability studies in a DC superconducting injector
The DC superconducting injector will be used in the PKU-THz facility which consists of a DC-gun and a 3+1/2-cell superconducting cavity. The cavity must accelerate the electron beam to 5.82 MeV which is susceptible to perturbations because of its narrow bandwidth. In this paper, the sources and influences of the perturbations in the 3+1/2-cell cavity are discussed. It is shown that the control system is essential for the cavity. The design of a feedback based digital RF low level control system for the 3+1/2-cell cavity is accomplished.
122621857
Cold RF test and associated mechanical features correlation of a TESLA-style 9-cell superconducting niobium cavity built in China
The RF performance of a 1.3 GHz 9-cell superconducting niobium cavity was evaluated at cryogenic temperatures following surface processing by using the standard ILC-style recipe. The cavity is a TESLA-style 9-cell superconducting niobium cavity, with complete end group components including a higher order mode coupler, built in China for practical applications. An accelerating gradient of 28.6 MV/m was achieved at an unloaded quality factor of 4 × 109. The morphological property of mechanical features on the RF surface of this cavity was characterized through optical inspection. Correlation between the observed mechanical features and the RF performance of the cavity is attempted.
123774404
Stable Operation of the 2 K Cryogenic System for the Superconducting Accelerator at Peking University
A superconducting energy recovery linac test facility (PKU-SETF) was built at Peking University, and a 2K cryogenic system, which is the first closed-loop 2K cryogenic system for a superconducting accelerator in China, was constructed for the 1.3 GHz 3+1/2 cell dc-SRF injector. The main accelerator consists of two nine-cell TESLA-type superconducting cavities of the PKU-SETF The commissioning and stable operation of this 2 K cryogenic system was carried out. A helium pressure stability of better than ±0.1 mbar and a total refrigeration capacity of 65 W at a temperature of 2K was reached.
120411181
Recent progress in techniques utilized for particle accelerator
Particle accelerators are widely used in scientific research and industry. Recently, techniques utilized for accelerator are developed rapidly in China. We briefly review the recent progress in this field and primarily focus on superconducting RF, innovative structures for particle production and acceleration and beam diagnosis. Several advanced compact user facilities are also introduced.
111206305
STABILITY STUDY OF SUPERCONDUCTOR MAGNET POWER SUPPLIES AT TLS
In this paper, performance of three power supplies schemes driving the newly-developed Superconducting Wave Length Shifter Magnet at TLS is investigated. Due to the inherent structure of the Superconducting Magnet, the main and two accessory trimming power supplies are physically correlated with each others. Due to the inherent structure, in order to achieve high performance control of the magnet, slew rate control of the main power supply and the proper operation sequence have to be properly managed, otherwise, small current disturbance can occurs, which may degrade the stability of the performance of Superconducting Magnet.
110529856
REDUCING OUTPUT CURRENT RIPPLE OF POWER SUPPLY WITH COMPONENT REPLACEMENT
Correction magnets of synchrotron storage ring are served with linear power supplies (correction power supply) with 100 ppm output current ripple in National Synchrotron Radiation Research Center. Reducing output current ripple of correction power supply might reduce perturbation of beam position of storage ring. Replacing correction power supplies with lower output current ripple ones is straightforward but costs lots of money. Without adding any other circuit and electronic component, some components of correction power supply are replaced by ones with more precious and lower output fluctuation; so that the same circuitry structure of correction power supply is kept without increasing its complexity and could reach 25 ppm output current ripple
73583477
TPS DIGITAL CORRECTOR MAGNET POWER CONVERTER BASED ON FPGA
This paper is to realize digital corrector magnet power supply based on FPGA. The purpose of the study is to implement digital PID controller by using Xilinx programmable gate array (FPGA), in hope of enhancing output performance and reducing circuit size. The ±10A/± 48V output corrector magnet digital FPGA power converter uses a full bridge configuration, the switching frequency of power MOSFET is 40 kHz, in which each bridge leg has its own independent PWM controller and the output current bandwidth is 1kHz when connected with the corrector magnet load. Using a DCCT as the current feedback component, the output current ripple of this converter could be lower than 10ppm. In this paper, the hardware structure and control method of the corrector magnet power converter will be described and the test results will be demonstrated.
210986666
TPS FAST CORRECTOR MAGNET POWER CONVERTER
M With the increasing demand of the current output accuracy on the TPS(Taiwan Photon Source) project, the MCOR 30 correction power supplies used in current TLS ring are no longer sufficient to meet the TPS requirement. Therefore, power supply group develops a high-precision low output current corrector magnet power supply with a DCCT as an output current feedback component for the future TPS ring. During the research and development experiment phase, we found the DCCT is more possible damaged than the other components. The implementation of the fast corrector magnet power converter is with keeping the architecture of the highprecision low output current power supply, but the DCCT output current feedback component is replaced with a current sensing Shunt resistor. This paper will discuss the design methods of utilizing several different types current sensing Shunt resistor to reduce the cost of power supply and the probability of damage, and improve frequency response of power supply.[1]
110332574
Precision current monitor system for the power supplies at SRRC
At SRRC, a precision output current monitoring system is installed to monitor the output performance of all the booster/storage ring power supplies. Accurate DC current transformers (DCCTs) are attached to the output terminal of every power supply system. Each transformer's gain/offset are carefully calibrated against a high precision current source and approximated using high-order polynomial curve fitting. The output of each DCCT is connected to a multi-channel data logger for realtime data collection, the collected data are calibrated using the interpolated DCCT gain/offset value. A PC station is set up to serve as host to store the current output for real-time monitoring. This monitoring system provides a precise real-time database for rapid fault diagnosing whenever there is malfunction of the beam operation.