Beam current dependence resulted from nonlinearity and asymmetry of the four channels of digital BPM(Beam Position Monitor) processor deteriorates the BPM performance.A systematic solution based on signal source calib...Beam current dependence resulted from nonlinearity and asymmetry of the four channels of digital BPM(Beam Position Monitor) processor deteriorates the BPM performance.A systematic solution based on signal source calibration tactics has been carried out to rectify this defect.It is optimized for implementation in FPGA.Mathematical illustrations of the calibration method,hardware and software design and implementation are presented.A signal source circuit using frequency synthesis technique is designed as calibration standard.Data acquisition system using JAVA web technology and Ethernet is introduced.Integrated FPGA implementation code architecture is presented,and experimental test results show that the method implemented in FPGA is feasible.Compared to other methods,our approach can rectify the nonlinearity and asymmetry simultaneously.The whole solution is integrated into the DBPM processor and can be executed online.展开更多
The Shanghai advanced proton therapy facility is a proton cancer treatment device designed and built by the Shanghai Institute of applied physics at the Chinese academy of sciences.The accelerator part comprises a pro...The Shanghai advanced proton therapy facility is a proton cancer treatment device designed and built by the Shanghai Institute of applied physics at the Chinese academy of sciences.The accelerator part comprises a proton linear accelerator(linac)injector and a circular synchrotron.An alternating current current transformer(ACCT)is used for non-intercepting beam current measurement at the drift tube linac exit.According to the beam characteristics,the ACCT is required to complete real-time beam current and pulse width measurements at currents of3-30 mA,frequencies of 1-10 Hz,and pulse widths of40-400μs.In this paper,we report the design and development of an ACCT.The designed ACCT was simulated using CST Microwave Studio,and calibrated using an oscilloscope and signal generator.Variations in the output signal of the ACCT were investigated as a function of ceramic gap size,number of coil turns,and resistance.According to the simulation and experimental results,the optimal number of coil turns was found to be 30.In addition,a low-pass filter was adopted to filter the noise introduced during long-distance signal transmission using a coaxial cable with the length of 20 m.The calibration results show that the corresponding rise time of the ACCT is 800 ns with the sensitivity of 8.2 V/A and a droop of less than 1%,meeting the design requirements.展开更多
基金Supported by the National Natural Science Foundation of China(No.11075198)
文摘Beam current dependence resulted from nonlinearity and asymmetry of the four channels of digital BPM(Beam Position Monitor) processor deteriorates the BPM performance.A systematic solution based on signal source calibration tactics has been carried out to rectify this defect.It is optimized for implementation in FPGA.Mathematical illustrations of the calibration method,hardware and software design and implementation are presented.A signal source circuit using frequency synthesis technique is designed as calibration standard.Data acquisition system using JAVA web technology and Ethernet is introduced.Integrated FPGA implementation code architecture is presented,and experimental test results show that the method implemented in FPGA is feasible.Compared to other methods,our approach can rectify the nonlinearity and asymmetry simultaneously.The whole solution is integrated into the DBPM processor and can be executed online.
基金supported by the Ministry of Education of the People's Republic of China(MOE)(No.021312921002)。
文摘The Shanghai advanced proton therapy facility is a proton cancer treatment device designed and built by the Shanghai Institute of applied physics at the Chinese academy of sciences.The accelerator part comprises a proton linear accelerator(linac)injector and a circular synchrotron.An alternating current current transformer(ACCT)is used for non-intercepting beam current measurement at the drift tube linac exit.According to the beam characteristics,the ACCT is required to complete real-time beam current and pulse width measurements at currents of3-30 mA,frequencies of 1-10 Hz,and pulse widths of40-400μs.In this paper,we report the design and development of an ACCT.The designed ACCT was simulated using CST Microwave Studio,and calibrated using an oscilloscope and signal generator.Variations in the output signal of the ACCT were investigated as a function of ceramic gap size,number of coil turns,and resistance.According to the simulation and experimental results,the optimal number of coil turns was found to be 30.In addition,a low-pass filter was adopted to filter the noise introduced during long-distance signal transmission using a coaxial cable with the length of 20 m.The calibration results show that the corresponding rise time of the ACCT is 800 ns with the sensitivity of 8.2 V/A and a droop of less than 1%,meeting the design requirements.
