Study On HLS Full Energy Injection And R&D Of New Type Kicker Pulse Generator

Hefei Light Source (HLS) is a dedicated synchrotron radiation research facility, spectrally strongest in Vacuum Ultra Violet and Soft X-ray. The electron beams are accelerated to 200MeV by Linac, then injected to storage ring and increased to 800MeV using an energy ramping system. The injection system has been stably operated for many years, higher beam accumulation rate and current intensity has been achieved. However the injection process is very sensitive to injected beam parameters and the error tolerance is tight. In the ramping process, the main system equipments of the machine which include RF cavity and power supplies of main magnets were kept changing with the beam energy increasing. It was regarded as a source of closed orbit drift. And now, HLS storage ring beam was refilled every several hours, it makes the beam current keep changing in large range and the elements of the beamline were seriously suffered thermal load effection. The spot position of synchrotron radiation is hard to maintain high stability and it can't meet the requirements of some experiments.Improving the brightness, stability and life of light sources is the goal of Hefei Light Source development. There are some plans of upgrading energy injection were proposed during the course of HLS's construction. In 2007, National Synchrotron Radiation Laboratory in Hefei had applied for the development of soft X-ray free electron laser experimental device (Hefei soft X-ray free electron laser Test Facility, ab.HTF). The thesis had initially connected with the project. Although the application was failed, full energy injection is a long-term plan. To eliminate the existing deficiencies of the current injection system, a new full energy injection system was designed. To obtain good injection efficiency, the optimum horizontal beta function of transfer line at the injection point was calculated. Optimizedβ-injection is preferable to occupy minimal phase space in the storage ring in comparison to matchedβ-injection. AT software based on MATLAB was used to design bump system and simulate injection process. We have done systematic study of the capture efficiency of the injected beam in the HLS storage. A tolerances range of the injection system was given. According to the characteristics of HLS, the potential possibility of Top-up injection was further studied, the feasible parameters were calculated out. The perturbation on store beams in injection process was estimated and simulated. In order to achieve high injection efficiency, two new injection methods were proposed, they are mismacth injection and off-momentum injection.The long-time performance and reliability of kicker power supply directly effects on injection efficiency and the stability of store beam that is an important issue for operation of machine. With in increasing the performance of accelerator and especially adoption of the Top-up injection model, the requirement for high current and the reproduction of current waveform of pulsed power supply is becoming higher and higher. Therefore there is challenge to design and manufacture the pulsed power supply, especially kicker pulse generator. The current kicker pulse modulator is simplied PFN type based on thyratron. The life-time of the vacuum switching device is short, and the operation reliability of traditional thyratron switches can't satisfied with the requirement of new injection system. Therefore, we designed a new type of magnetic coupling IGBT solid kicker pulse generator. A multi-channel trigger of high voltage IGBT (Insulated gate bipolar transistor) driver based on FPGA (Field-programmable gate array) has been developed. The thyratron, PFN and high voltage power supply were replaced by solid-state switches, new magnetic material and new circuit topology in the design. Reducing the rise and fall time, increasing efficiency and power density, overcoming the life-time limit of switches and making the pulse width adjustable are the results of the research. It has met requirement and satisfied the needs for injection system upgrade and even Top-up injection. The fruit of the research work will not only be applied directly to accelerator area, but also will be extended to other relevant fields, such as radar transmitter, industrial irradiation and medical accelerator.In sum, the main contents of this thesis are as following: the optimal physical design and tracking simulation of the full energy injection systems, analysis of the feasibility of top-up injection, development of a new type kicker pulse generator and related key technology. There are good physical and technical basis for the future development of Hefei Light source.