195748264
PERFORMANCE OF A PFN KICKER POWER SUPPLY FOR TPS PROJECT
A test unit of a pulse-forming-network (PFN) kicker power supply has been designed and fabricated for Taiwan Photon Source (TPS) beam injection/extraction of the booster ring. In order to fulfill the requirements, the performance of the designed unit has been bench tested and the results are examined for evaluation purpose. The pulse-to-pulse stability and the flattop specifications are specified according to the beam injection/extraction requirements. Effort has been made to enhance the rise/fall time of the delivered pulse current. The engineering evaluation and its possible application for beam diagnostics purpose are briefly discussed.
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.
73599484
High efficiency linear power supply with a preregulator controlled by keeping constant R/sub DS/ of MOSFET
In Synchrotron Radiation Research Center (SRRC) more than ninety linear power supplies with 100 ppm long-term stability are served for correction magnets. To increase the well-known efficiency problem of linear power supply, inside a customer-made bipolar linear power supply a homemade pre-regulator circuitry is in series in front of power stage. By using constant V/sub DS/ controlled pre-regulator, the power consumption of linear power supply itself could be reduced and the efficiency changes with respect to the output power. On the other hand, with constant R/sub DS/ controlled pre-regulator, the efficiency is even higher and is the ratio of load resistance and R/sub DS/. Design and performance of the pre-regulator circuitry are demonstrated.
55337938
DESIGN AND MODELING OF THE STEP DOWN PIEZO TRANSFORMER
The energy conversion and the step down voltage waveform of the piezo transformer are required to achieve optimal working condition of the resonant frequency. To meet this requirement, a reliable and precise instrument is needed to scan the resonant point of the piezo transformer such that its output power performance can meet the required specification. In this paper, the design and model of a new step down piezo transformer deployed in NSRRC is described. This step down piezo transformer is capable of delivering energy conversion with high efficiency performance, which is better than traditional transformer, and the voltage transfer ratio is correct. Using the simulation circuit model to develop driver circuit of it is also included in the design of this new step down transformer. It has been tested and proven to be working well in power conversion with excellent efficiency and reliability.
55506316
The Design and Fabrication of the Kicker Power Supply for TPS Project
The preliminary test results of the kicker power supply for TPS (Taiwan Photon Source) project will be presented in this report. The achieved capability of this test unit demonstrates that it fulfills the design requirement of providing half-sine pulsed current of 2.5 kA (peak), 5.2 μs (base-width), with jitter < 1 ns (peak-to-peak). Both units of using thyratron and IGBT switches are built with the same requirements. The technical considerations of both units for this particular application will be discussed. INTRODUCTION The Taiwan Photon Source (TPS) under construction consists of a 150 MeV electron linac, a 3 GeV full energy booster, and a 3 GeV storage ring. The storage ring is planned to operate top-up at 400 mA. The top-up filling process will take place periodically within about every 100 seconds. In order to fulfill this requirement, the injection kickers will be triggered repeatedly at the same repetition rate. This proposed topup operation mode requires stringent performance of the 4 injection kickers for good stability on pulse amplitude and jitter, and in particular, pulse-shape matching among these 4 kickers. Test units of the kicker pulser have been built to examine their feasibility. Pulsers using both thyratron and IGBT switches have been tested. The results show that both units fulfill the pulser requirements on amplitude and jitter stability. The system configuration and the test results are briefly described in this report. PERFORMANCE REQUIREMENTS The circumference of the TPS storage ring is 518.4 m [1]. Beam injection will be taken place at a 10 m long straight section. The proposed injection scheme demand a 5.2 μs (base-width) half-sine pulse for the injection kickers in order to perform four-turn injection process [2]. The estimated parameters had been applied to examine and evaluate the feasibility of building pulse power supply for kicker in house. The design of the prototype kicker magnet requires the driving peak current to be 2.5 kA. The suggested stability goals of both pulse amplitude and jitter for the test unit are given as 0.5% and 2 ns, respectively. Since top-up mode will be implemented in the future for routine user operation, performance on high reliability and small long term drift of the test unit are required. The stability will be examined and analyzed for this purpose. The estimated parameters for evaluating kicker pulser test unit are given in Table 1. Table 1: Parameters for evaluating kicker pulser test unit straight section (m) 10 magnet length (m) 0.6
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.
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.
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.
118620211
Relativistic Correction to Color Octet J/psi Production at Hadron Colliders
The relativistic corrections to the color-octet $J/\psi$ hadroproduction at the Tevatron and LHC are calculated up to $\mathcal{O}(v^2)$ in nonrelativistic QCD factorization frame. The short distance coefficients are obtained by matching full QCD with NRQCD results for the partonic subprocess $g+g\to J/\psi ({}^1S_0^{[8]},{}^3S_1^{[8]}, {}^3P_J^{[8]})+g$, $q+\bar{q}\to J/\psi ({}^1S_0^{[8]},{}^3S_1^{[8]}, {}^3P_J^{[8]})+g$ and $g+q({\bar{q}})\to J/\psi ({}^1S_0^{[8]},{}^3S_1^{[8]}, {}^3P_J^{[8]})+q({\bar{q}})$. The short distance coefficient ratios of relativistic correction to leading order for color-octet states ${^1}S_{0}^{[8]}$, ${^3}S_{1}^{[8]}$, and ${^3}P_{J}^{[8]}$ at large $p_T$ are approximately -5/6, -11/6, and -31/30, respectively, for each subprocess, and it is 1/6 for color-singlet state ${^3}S_{1}^{[1]}$. If the higher order long distance matrix elements are estimated through velocity scaling rule with adopting $v^2=0.23$ and the lower order long distance matrix elements are fixed, the leading order cross sections of color-octet states are reduced by about a factor of $20\sim40%$ at large $p_T$ at both the Tevatron and the LHC. Comparing with QCD radiative corrections to color-octet states, relativistic correction is ignored along with $p_T$ increasing. Using long distance matrix elements extracted from the fit to $J/\psi$ production at the Tevatron, we can find the unpolarization cross sections of $J/\psi$ production at the LHC taking into account both QCD and relativistic corrections are changed by about $20\sim50%$ of that considering only QCD corrections. These results indicate that relativistic corrections may play an important role in $J/\psi$ production at the Tevatron and the LHC.
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.
124456966
The NLO Calculations of Heavy Quarkonium Production at B Factories
We calculated the next to leading order quantum chromodynamics corrections of J/ψ production at B factories. The next to leading order corrections are very important for heavy quarkonium production at B factories. The next to leading order cross sections can be compared with the B factories data. Some detail of the next to leading order calculations within the non-relativistic quantum chromodynamics factorization framework are given here.