An L band RF linac is now under installation at CIAE to provide intense electronbeam for a far-infrared free-electron laser oscillator.This linac consists of a DC thermionicgun,a subharmonic prebuncher,a buncher,an ac...An L band RF linac is now under installation at CIAE to provide intense electronbeam for a far-infrared free-electron laser oscillator.This linac consists of a DC thermionicgun,a subharmonic prebuncher,a buncher,an accelerating section and a beam transport line.From the INEX(Integrated Numerical Experiment)conducted for prediction of the perfor-mance of the complex and the comparison of some of the simulation results with available ex-perimental data,it shows that the beam quality can satisfy our FEL requirements.展开更多
A 53.667 MHz CW(continuous-wave) heavy ion IH-DTL has been designed for the SSC-LINAC injector of HIRFL-CSR(Heavy Ions Research Facility at Lanzhou-Cooling Storage Ring). It accelerates ions with maximum mass-to-charg...A 53.667 MHz CW(continuous-wave) heavy ion IH-DTL has been designed for the SSC-LINAC injector of HIRFL-CSR(Heavy Ions Research Facility at Lanzhou-Cooling Storage Ring). It accelerates ions with maximum mass-to-charge ratio of 7.0 from 143 to 295 ke V/u. Low-power RF measurement of the IH-DTL1 has been taken to investigate the RF performance and the quality of the electric field distribution on the beam axis.The measured Q_0 value and the shunt impedance are 10,400 and 198 MX/m, respectively. The electric field distributions on and around the beam axis were evaluated and compared with the design value. By a new approach,the dipole field component is also estimated. The beam dynamics simulation using measured field distribution was presented in this paper. Based on the dynamics analysis in both transverse and longitudinal phase space, the field distribution can meet the design requirement. Finally, the RF conditioning and very first beam commissioning on the IH-DTL1 were finished. The beam test results agree well with the simulation results; what's more, the property of the variable output beam energy about the separated functions DTL was verified.展开更多
A 325 MHz aluminum prototype of a spatially periodic RF quadrupole focusing linac was developed at the Institute of Modern Physics,Chinese Academy of Sciences,as a promising candidate for the front end of a high-curre...A 325 MHz aluminum prototype of a spatially periodic RF quadrupole focusing linac was developed at the Institute of Modern Physics,Chinese Academy of Sciences,as a promising candidate for the front end of a high-current linac.It consists of an alternating series of crossbar H-type drift tubes and RF quadrupole sections.Owing to its special geometry,cavity fabrication is a major hurdle for its engineering development and application.In this paper,we report the detailed mechanical design of this structure and describe its fabrication process,including machining,assembly,and inspection.The field distribution was measured by the bead-pull technique.The results show that the field errors of both the accelerating and focusing fields are within an acceptable range.A tuning scheme for this new structure is proposed and verified.The cold test process and results are presented in detail.The development of this prototype provides valuable guidance for the application of the spatially periodic RF quadrupole structure.展开更多
The Radio Frequency Quadrupole (RFQ) accelerator invented by Kapchinskii and Tepliakov can focus, bunch, and accelerate charged-particle beams simultaneously. Typically, it operates at frequencies up to 500 MHz, for l...The Radio Frequency Quadrupole (RFQ) accelerator invented by Kapchinskii and Tepliakov can focus, bunch, and accelerate charged-particle beams simultaneously. Typically, it operates at frequencies up to 500 MHz, for low particle velocities ( β ). The first attempt to design cylindrical RFQ for electrons in the GHz region was done using 3 GHz at Frascati in 1990. In this paper, an analytical approximation of the electromagnetic field is given, and linearized in the beam region for a rectangular Electron Radio Frequency Quadrupole (ERFQ). The differences between the proton-RFQ and the electron-RFQ are discussed. Then, it will be shown that contrary to the quadrupoles for protons or heavy-ions, the ERFQ is suited for electron velocities in the range 0.5 - 0.7 c, and possible applications are given. Finally, it is illustrated, with numerical field computations that this approach gives sufficient accuracy at 10 GHz.展开更多
将滑模极值搜索算法引入基于腔体反射信号的SSC-LINAC射频四极场加速器(Radio Frequency Quadrupole, RFQ)腔体频率稳定系统设计中,结合Lyapunov稳定性理论和SSC-LINAC RFQ高频系统的特点,对滑模极值搜索算法的控制增益和参考信号进行改...将滑模极值搜索算法引入基于腔体反射信号的SSC-LINAC射频四极场加速器(Radio Frequency Quadrupole, RFQ)腔体频率稳定系统设计中,结合Lyapunov稳定性理论和SSC-LINAC RFQ高频系统的特点,对滑模极值搜索算法的控制增益和参考信号进行改进;通过求解微分方程,得到腔体反射信号关于时间和调谐杆位置的函数。通过软件仿真和设计硬件系统,对基于滑模极值搜索算法的调谐过程进行仿真与实际测试,结果显示,所设计的频率稳定系统能够在较短时间内实现SSC-LINAC RFQ腔体功率自动馈入过程且频率稳定度满足设计指标要求,通过了长时间稳定性试验。证明了将滑模极值搜索算法应用于高频谐振腔调谐工作的可行性。展开更多
To study the new RF control methods, a mathematic model of the RF system for the normal conducting linac is built and implemented with the software of Matlab. The model contains some typical units of the RF system, su...To study the new RF control methods, a mathematic model of the RF system for the normal conducting linac is built and implemented with the software of Matlab. The model contains some typical units of the RF system, such as the klystron, the SLED and the traveling wave accelerating tube. Finally, the model is used to study the working point of the SLED and the adaptive feed forward algorithm for the RF control system. Simulation shows that the model works well as expected.展开更多
基金The project supported by the Nuclear Industry Science Foundation of China
文摘An L band RF linac is now under installation at CIAE to provide intense electronbeam for a far-infrared free-electron laser oscillator.This linac consists of a DC thermionicgun,a subharmonic prebuncher,a buncher,an accelerating section and a beam transport line.From the INEX(Integrated Numerical Experiment)conducted for prediction of the perfor-mance of the complex and the comparison of some of the simulation results with available ex-perimental data,it shows that the beam quality can satisfy our FEL requirements.
基金supported by the National Natural Science Foundation of China(Nos.11375243 and 11405237)the Guangdong Innovative and Entrepreneurial Research Team Program(No.2016ZT06G373)
文摘A 53.667 MHz CW(continuous-wave) heavy ion IH-DTL has been designed for the SSC-LINAC injector of HIRFL-CSR(Heavy Ions Research Facility at Lanzhou-Cooling Storage Ring). It accelerates ions with maximum mass-to-charge ratio of 7.0 from 143 to 295 ke V/u. Low-power RF measurement of the IH-DTL1 has been taken to investigate the RF performance and the quality of the electric field distribution on the beam axis.The measured Q_0 value and the shunt impedance are 10,400 and 198 MX/m, respectively. The electric field distributions on and around the beam axis were evaluated and compared with the design value. By a new approach,the dipole field component is also estimated. The beam dynamics simulation using measured field distribution was presented in this paper. Based on the dynamics analysis in both transverse and longitudinal phase space, the field distribution can meet the design requirement. Finally, the RF conditioning and very first beam commissioning on the IH-DTL1 were finished. The beam test results agree well with the simulation results; what's more, the property of the variable output beam energy about the separated functions DTL was verified.
基金This work was supported by the NSAF Joint Foundation of China(No.U1730122)。
文摘A 325 MHz aluminum prototype of a spatially periodic RF quadrupole focusing linac was developed at the Institute of Modern Physics,Chinese Academy of Sciences,as a promising candidate for the front end of a high-current linac.It consists of an alternating series of crossbar H-type drift tubes and RF quadrupole sections.Owing to its special geometry,cavity fabrication is a major hurdle for its engineering development and application.In this paper,we report the detailed mechanical design of this structure and describe its fabrication process,including machining,assembly,and inspection.The field distribution was measured by the bead-pull technique.The results show that the field errors of both the accelerating and focusing fields are within an acceptable range.A tuning scheme for this new structure is proposed and verified.The cold test process and results are presented in detail.The development of this prototype provides valuable guidance for the application of the spatially periodic RF quadrupole structure.
文摘The Radio Frequency Quadrupole (RFQ) accelerator invented by Kapchinskii and Tepliakov can focus, bunch, and accelerate charged-particle beams simultaneously. Typically, it operates at frequencies up to 500 MHz, for low particle velocities ( β ). The first attempt to design cylindrical RFQ for electrons in the GHz region was done using 3 GHz at Frascati in 1990. In this paper, an analytical approximation of the electromagnetic field is given, and linearized in the beam region for a rectangular Electron Radio Frequency Quadrupole (ERFQ). The differences between the proton-RFQ and the electron-RFQ are discussed. Then, it will be shown that contrary to the quadrupoles for protons or heavy-ions, the ERFQ is suited for electron velocities in the range 0.5 - 0.7 c, and possible applications are given. Finally, it is illustrated, with numerical field computations that this approach gives sufficient accuracy at 10 GHz.
文摘To study the new RF control methods, a mathematic model of the RF system for the normal conducting linac is built and implemented with the software of Matlab. The model contains some typical units of the RF system, such as the klystron, the SLED and the traveling wave accelerating tube. Finally, the model is used to study the working point of the SLED and the adaptive feed forward algorithm for the RF control system. Simulation shows that the model works well as expected.
