| Paper | Title | Page |
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| MOPAN114 | A Linear MOSFET Regulator for Improving Performance of the Booster Ramping Power Supplies at the APS | 434 |
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Funding: Work supported by U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-06CH11357. Due to the circuit topology of ramping power supplies used in the APS Booster ring, they are unable to follow the linear current ramp to the desired accuracy of 0.1%. In addition, those supplies are also sensitive to AC line perturbation. To improve the performance, a linear regulator using paralleled MOSFET devices in series with the power supply is proposed. The control algorithm uses a real-time current feedback loop to force the MOSFETs to work in the linear operation mode. By using this linear MOSFET regulator, the MOSFETs' drain to source voltage, and hence the voltage imposed on magnets can be regulated very quickly. As a result, the regulation of the magnet current can be improved significantly. So far the simulation results show that with the linear regulator the current regulation can be improved to better than 0.1%. Because of the high bandwidth of the linear regulator, it can reduce the harmonic content in the output current as well as the noises due to the AC line disturbance. A sextupole power supply has been set up to verify the proposed topology. This paper discusses the circuit topology, the regulation algorithm, and the experiment results. |
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| TUPMN058 | The Operation Status of HLS (Hefei Light Source) | 1058 |
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| National Synchrotron Radiation Lab, University of Science and Technology of China, P. R.China HLS(Hefei Light Source) is a dedicated synchrotron radiation research facility, spectrally strongest in Vacuum Ultra Violet and Soft X-ray. Designed and constructed in 1980's, accepted to regular service in 1991. From 1999 to 2004, the National Synchrotron Radiation Lab carried out its Phase II Project, in which quite a few sub-systems of HLS storage ring were upgraded and 8 new beamline were constructed. After the project, the performance of HLS is improved considerably. In this paper, the operation status and performance of storage ring in recent years were presented. With some measures, the operation beam intensity is about 300mA, beam lifetime is higher than before, orbit stability is met requirement of users, and the capability to provide synchrotron radiation exceeds the design value. | ||
| TUPMN059 | The Nonlinear Effects of Fringe Fields in HLS | 1061 |
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| As a small low energy electron storage ring, the fringe field effects on linear and nonlinear properties maybe can not be ignored. In this paper, the fringe field of dipole magnets and quadrupole magnets on linear optics parameters and nonlinear driving terms of general purpose operation mode in HLS storage ring were analyzed and calculated. The results showed that, for GPLS mode, the fringe field of dipole and quadrupole is the main source of tune shift with amplitude. The fringe field of dipole contributes non-ignorable part to vertical chromaticity. Similar behavour is also displayed in non linear driving terms. | ||
| TUPMN060 | A Low Emittance Lattice Design for HLS Storage Ring | 1064 |
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| Lower beam emittance is the most effective measure to higher brilliance of light source. To enhance performance of HLS ring, a new low emittance lattice was studied and introduced in this paper. The scale of new lattice is designed according to the current ground settlement of HLS ring, but the focusing structure and mangets were changed. The new designed lattice has two operation mode, low emittance mode and low momentum compaction mode. In this paper, the linear lattice function and dynamic aperutre of the new designed lattice was briefly introduced. Caculation results showed that, after upgrade, the brilliance of HLS storage ring can approach the level of third order light source. | ||
| TUPMN061 | An Upgrade Proposal of Injection Bump System for HLS | 1067 |
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| The current injection bump system of Hefei Light Source was designed eight years ago, and operated five years ago. In this paper, the advantages and shortcomings of current bump system were analyzed, and reasonalbe design objective was summed up. According to new design goal, a new physical design of bump system for HLS ring was completed. The acceptance of injected beam and perturbation on stored beam were analyzed. At same time, the ELEGANT software was used to simulate the injection process under new designed bump system. The results showed that, with new designed bump system, the injection rate would be higher than 90%, and the perturbation on orbit of stored beam would be small enough. | ||
| THPMN042 | Design of a 200keV High Pulse Current Electron Beam Facility | 2811 |
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| In the paper, design of a 200keV high pulse current electron beam facility is introduced, which is used to generate plasma by interaction between electron beam and gas. Physical parameters of the beam have been selected to satisfy the plasma experiment's need. LaB6 is chosen as cathode because of its high efficient emission and long lifetime. Temperature distribution simulation in the facility has been finished with I-deas code. Because the maximum working temperature in the system is 2400°C, grid is made of heat-resistant metal Mo. In order to get high pulse current and line shaping electron beam, shape of electrodes has been optimized. Electric field distribution in the system and process of electron beam emission have been simulated with opera-3d, which considering space charge effects. Ceramic flange's electrics and mechanics properties have also been analyzed. Metal foil window is made of titanium with 40μm thickness. Relationship between initial energy and energy loss of the electron beam has been obtained by MC simulation during passing through the window. Making of the facility has been finished and some parameters have been measured through testing experiments. | ||
| THPAN055 | Theoretical Study of Medium Emittance Lattice at HLS | 3351 |
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Funding: Supported by National Natural Science Foundation of China, No. 10175062 & No.17175100
A method of injection analysis of small electron storage ring is introduced, and several medium emittance lattices are proposed. By analyzing the injection, working point of the lattice is selected at the vicinity of half integer resonance lines, and emittance is around 60nmrad, the linear and nonlinear properties can be satisfied for injection and store.
LIU Zu-Ping, Li Wei-Min. Progress of the NSRL Phase Two Project. In proceedings of the Second Asia Particle Accelerator Conference, Beijing, China, 2001, 235-238 |