Development And Application Of Injector Beam Position Monitor System At HLS Ⅱ

Beam position measurement system is an important subsystem for the accelerator beam measurement system. Strip-line Beam Position Monitor (BPM) can be used for non-intercepting beam position measurement. Due to this fact, it is feasible to measure online beam position and current in real-time, and this is advantageous to improve the beam quality of the injector and injection efficiency. A beam position measurement system based on Strip-line BPM and digital beam position processor is developed for the upgraded Hefei Light Source (HLSII) injector as a reliable diagnostic tool for the commissioning and operation of HLSII injector.Firstly, the concerning theory relative to stripline beam position monitor is introduced. The signal of the stripline pick-up induced by the beam is introduced. Informations about beam position, current and energy spread can be extracted with different treatment to the induced signal of the four electodes. Also, the coupling effect of electrodes on these measurements is analyzed. We describe the different signal treatments for beam position measurement based on the electrode signals. The related theory of signal processing in frequency domain is also briefly described.In order to meet the demand of the HLSII injector BPM system, main parameters of stripline BPM are simulated and calculated. Using the boundary element method, we simulate the BPM sensitivity, fitting formula for Mapping, sum signal and gain coefficient of the electrode, etc. By simulating the stripline BPM in Microwave Studio (CST), the effects of electrode coupling on each measured parameter are estimated. The stripline BPMs’ parameters are calibrated in a full-automatic off-line calibration platform. Results show that the measured parameters are in agreement with simulation results.The signal acquisition and processing of HLSII injector beam position measurement system is introduced. A series tests are made on the hardware:the performance and off-line resolution of the Libera Brilliance Single Pass; the inconsistency for the four channels of Libera Brilliance Single Pass; the performance of cable. Test results show that the performance of all the hardware are satisfied for the beam position measurement of the HLSII injector. An integral operator interface is developed based on the CSS_BOY and fullly tested. Results show that the program is sufficient stability for continuous running.At last, related experimental researches on HLS injector and HLSII injector are respcetively done. The results of beam position measurement for the HLS injector show that the perfomence of Libera Brilliance Single Pass is better than the exsiting system. Results of HLSII injector shows that the system meet the design requirements. Moreover, beam-based calibration and gain coefficient calibration of the electrodes based on the BPM system on the HLSII injector are made respectively. In finally, the SUM signal and energy spread of the online beam are measured.Investigation of this subject is supported by National Natural Science Foundation project11175173,11375178,11105141, and the HLS major maintenance and reconstruction project.