基于直接等离子体注入(Direct Plasma Injection Scheme,DPIS)的方法,设计并建造了一台低能段离子加速装置;目前实验上利用该方法成功地加速了峰值流强为11.28 m A,能量为593 ke V/u的C6+脉冲束流。考虑到激光离子源产生的束流为脉冲束...基于直接等离子体注入(Direct Plasma Injection Scheme,DPIS)的方法,设计并建造了一台低能段离子加速装置;目前实验上利用该方法成功地加速了峰值流强为11.28 m A,能量为593 ke V/u的C6+脉冲束流。考虑到激光离子源产生的束流为脉冲束,且具有能散大,强度高等特点,给低能传输线(LEBT)的设计带来很大的困难,而DPIS方法则简单易行,可有效地提高注入效率;因此该装置将激光离子源与RFQ直接连接在一起,将离子源产生的等离子体直接注入到RFQ,并没有采用传统的LEBT。并采用IGUN程序对该注入方法进行了模拟,计算确定了离子源引出的强流脉冲束的参数以及注入效率,模拟的结果与实验的测量值一致。展开更多
To investigate the feasibility of using a form cutter to machine the Radial Matcher Section （RMS） of tile Radio Frequency Quadrupole （RFQ） for the Accelerator Driven System （ADS） project at Institute of Modern P...To investigate the feasibility of using a form cutter to machine the Radial Matcher Section （RMS） of tile Radio Frequency Quadrupole （RFQ） for the Accelerator Driven System （ADS） project at Institute of Modern Physics, Chinese Academy of Sciences （IMP, CAS）, the influence of RMS end shape on the RFQ cavity frequency is studied. The results indicate that using a form cutter to machine the RMS of an RFQ will indeed influence the cavity frequency. The RMS end shape will give more influence to a shorter RFQ cavity. For the 4.2 m ADS RFQ, the influence is negligible, which means that a form cutter can be used to machine the RMS.展开更多
A high current RFQ （radio frequency quadrupole） is being studied at the Institute of Modern Physics, CAS for the direct plasma injection scheme. Shunt impedance is an important parameter when designing a ＆rod RFQ c...A high current RFQ （radio frequency quadrupole） is being studied at the Institute of Modern Physics, CAS for the direct plasma injection scheme. Shunt impedance is an important parameter when designing a ＆rod RFQ cavity, it reflects the RF efficiency of the cavity, and has a direct influence on the cost of the structure. Voltage distribution of a RFQ cavity has an effect on beam transmission, and particles would be lost if the actual voltage distribution is not as what it should be. The influence of cell length, stem thickness and height on shunt impedance and voltage distribution have been studied, in particular the effect of projecting electrodes has been investigated in detail.展开更多
A new special coupler with a kind of bowl-shaped ceramic window for a proton linear accelerator named the Chinese Accelerator Driven System （C-ADS） at the Institute of Modern Physics （IMP） has been simulated and c...A new special coupler with a kind of bowl-shaped ceramic window for a proton linear accelerator named the Chinese Accelerator Driven System （C-ADS） at the Institute of Modern Physics （IMP） has been simulated and constructed and a continuous wave （CW） beam commissioning through a four-meter long radio frequency quadruple （RFQ） was completed by the end of July 2014. In the experiments of conditioning and beam, some problems were promoted gradually such as sparking and thermal issues. Finally, two new couplers were passed with almost 110 kW CW power and 120 kW pulsed mode, respectively. The 10 mA intensity beam experiments have now been completed, and the couplers during the operation had no thermal or electro-magnetic problems. The detailed design and results are presented in the paper.展开更多
A 162.5 MHz, 2.1 MeV radio frequency quadruples （RFQ） structure is being designed for the Injector Scheme Ⅱ of the China Accelerator Driven Sub-critical System （C-ADS） linac. The RFQ will operate in continuous wa...A 162.5 MHz, 2.1 MeV radio frequency quadruples （RFQ） structure is being designed for the Injector Scheme Ⅱ of the China Accelerator Driven Sub-critical System （C-ADS） linac. The RFQ will operate in continuous wave （CW） mode as required. For the CW normal conducting machine, the heat management will be one of the most important issues, since the temperature fluctuation may cause cavity deformation and lead to the resonant frequency shift. Therefore a detailed multi-physics analysis is necessary to ensure that the cavity can stably work at the required power level. The multi-physics analysis process includes RF electromagnetic analysis, thermal analysis, mechanical analysis, and this process will be iterated for several cycles until a satisfactory solution can be found. As one of the widely accepted measures, the cooling water system is used for frequency fine tunning, so the tunning capability of the cooling water system is also studied under different conditions. The results indicate that with the cooling water system, both the temperature rise and the frequency shift can be controlled at an acceptable level.展开更多
Superconducting quarter-wave resonators,due to their compactness and their convenient shape for tuning and coupling,are very attractive for low-β beam acceleration.In this paper,two types of cavities with different g...Superconducting quarter-wave resonators,due to their compactness and their convenient shape for tuning and coupling,are very attractive for low-β beam acceleration.In this paper,two types of cavities with different geometry have been numerically simulated the first type with larger capacitive load in the beam line and the second type of lollipop-shape for 100 MHz,β=0.06 beams then the relative electromagnetic parameters and geometric sizes have been compared.It is found that the second type,whose structural design is optimized with the conical stem and shaping drift-tube,can support the better accelerating performance.At the end of the paper,some structural deformation effects on frequency shifts and appropriate solutions have been discussed.展开更多
A re-buncher with spiral arms for a heavy ion linear accelerator named as SSC-LINAC at HIRFL （the heavy ion research facility of Lanzhou） has been constructed. The re-buncher, which is used for beam longitudinal mod...A re-buncher with spiral arms for a heavy ion linear accelerator named as SSC-LINAC at HIRFL （the heavy ion research facility of Lanzhou） has been constructed. The re-buncher, which is used for beam longitudinal modulation and matching between the RFQ and DTL, is designed to be operated in continuous wave （CW） mode at the Medium-Energy Beam-Transport （MEBT） line to maintain the beam intensity and quality. Because of the longitudinal space limitation, the re-buncher has to be very compact and will be built with four gaps. We determined the key parameters of the re-buncher cavity from the simulations using Microwave Studio software, such as the resonant frequency, the quality factor Q and the shunt impedance. The detailed design of a 53.667 MHz spiral cavity and measurement results of its prototype will be presented.展开更多
In order to realize high energy density physics and plasma physics research at HIRFL-CSR, a magnetic alloy （MA）-loaded cavity has been studied. According to the theoretical calculation and simulation for the MA-load...In order to realize high energy density physics and plasma physics research at HIRFL-CSR, a magnetic alloy （MA）-loaded cavity has been studied. According to the theoretical calculation and simulation for the MA-loaded cavity, we achieved a better result. The MA-loaded cavity had a higher μQf value, with a higher shunt impedance and a higher accelerating gradient. The accelerating gradient was about 95 kV/m at 1.8003 MHz, 130 kV/m at 0.9000 MHz. Compared with the ferrite-loaded cavities that are used at HIRFL-CSR, with about 10 kV/m accelerating gradient, the MA-loaded cavity obviously has an advantage. The results of the theoretical calculation and the simulation, which meet the design requirements are in good agreement.展开更多
A 162.5 MHz four-vane radio frequency quadruple（RFQ） accelerator has been developed at the Institute of Modern Physics（IMP） for Injector II of the China ADS linac. The RFQ will operate in continuous wave mode at 1...A 162.5 MHz four-vane radio frequency quadruple（RFQ） accelerator has been developed at the Institute of Modern Physics（IMP） for Injector II of the China ADS linac. The RFQ will operate in continuous wave mode at 100 k W. For the designed 10 mA beam, the additional RF power dissipation will induce a very large reflection of power. A water-temperature controlling system will be used to reduce the power reflection by tuning the frequency of the RFQ. The tuning capability of the water temperature is studied under different configurations of cooling water.Simulations and experiment are compared in this paper. The experimental results agree well with simulation using ANSYS. This can be used as a reference to tune the RFQ in beam commissioning.展开更多
文摘基于直接等离子体注入(Direct Plasma Injection Scheme,DPIS)的方法,设计并建造了一台低能段离子加速装置;目前实验上利用该方法成功地加速了峰值流强为11.28 m A,能量为593 ke V/u的C6+脉冲束流。考虑到激光离子源产生的束流为脉冲束,且具有能散大,强度高等特点,给低能传输线(LEBT)的设计带来很大的困难,而DPIS方法则简单易行,可有效地提高注入效率;因此该装置将激光离子源与RFQ直接连接在一起,将离子源产生的等离子体直接注入到RFQ,并没有采用传统的LEBT。并采用IGUN程序对该注入方法进行了模拟,计算确定了离子源引出的强流脉冲束的参数以及注入效率,模拟的结果与实验的测量值一致。
基金Supported by"Strategic Priority Research Program"of the Chinese Academy of Sciences(XDA03020500)NSFC(110790001)
文摘To investigate the feasibility of using a form cutter to machine the Radial Matcher Section （RMS） of tile Radio Frequency Quadrupole （RFQ） for the Accelerator Driven System （ADS） project at Institute of Modern Physics, Chinese Academy of Sciences （IMP, CAS）, the influence of RMS end shape on the RFQ cavity frequency is studied. The results indicate that using a form cutter to machine the RMS of an RFQ will indeed influence the cavity frequency. The RMS end shape will give more influence to a shorter RFQ cavity. For the 4.2 m ADS RFQ, the influence is negligible, which means that a form cutter can be used to machine the RMS.
文摘A high current RFQ （radio frequency quadrupole） is being studied at the Institute of Modern Physics, CAS for the direct plasma injection scheme. Shunt impedance is an important parameter when designing a ＆rod RFQ cavity, it reflects the RF efficiency of the cavity, and has a direct influence on the cost of the structure. Voltage distribution of a RFQ cavity has an effect on beam transmission, and particles would be lost if the actual voltage distribution is not as what it should be. The influence of cell length, stem thickness and height on shunt impedance and voltage distribution have been studied, in particular the effect of projecting electrodes has been investigated in detail.
基金Supported by Strategic Priority Research Program of Chinese Academy of Sciences(XDA03020500)
文摘A new special coupler with a kind of bowl-shaped ceramic window for a proton linear accelerator named the Chinese Accelerator Driven System （C-ADS） at the Institute of Modern Physics （IMP） has been simulated and constructed and a continuous wave （CW） beam commissioning through a four-meter long radio frequency quadruple （RFQ） was completed by the end of July 2014. In the experiments of conditioning and beam, some problems were promoted gradually such as sparking and thermal issues. Finally, two new couplers were passed with almost 110 kW CW power and 120 kW pulsed mode, respectively. The 10 mA intensity beam experiments have now been completed, and the couplers during the operation had no thermal or electro-magnetic problems. The detailed design and results are presented in the paper.
基金Supported by National Natural Science Foundation of China(91026001)
文摘A 162.5 MHz, 2.1 MeV radio frequency quadruples （RFQ） structure is being designed for the Injector Scheme Ⅱ of the China Accelerator Driven Sub-critical System （C-ADS） linac. The RFQ will operate in continuous wave （CW） mode as required. For the CW normal conducting machine, the heat management will be one of the most important issues, since the temperature fluctuation may cause cavity deformation and lead to the resonant frequency shift. Therefore a detailed multi-physics analysis is necessary to ensure that the cavity can stably work at the required power level. The multi-physics analysis process includes RF electromagnetic analysis, thermal analysis, mechanical analysis, and this process will be iterated for several cycles until a satisfactory solution can be found. As one of the widely accepted measures, the cooling water system is used for frequency fine tunning, so the tunning capability of the cooling water system is also studied under different conditions. The results indicate that with the cooling water system, both the temperature rise and the frequency shift can be controlled at an acceptable level.
文摘Superconducting quarter-wave resonators,due to their compactness and their convenient shape for tuning and coupling,are very attractive for low-β beam acceleration.In this paper,two types of cavities with different geometry have been numerically simulated the first type with larger capacitive load in the beam line and the second type of lollipop-shape for 100 MHz,β=0.06 beams then the relative electromagnetic parameters and geometric sizes have been compared.It is found that the second type,whose structural design is optimized with the conical stem and shaping drift-tube,can support the better accelerating performance.At the end of the paper,some structural deformation effects on frequency shifts and appropriate solutions have been discussed.
基金Supported by Pioneering and Interdisciplinary Research of Big Sciences (Y115210YQ0)
文摘A re-buncher with spiral arms for a heavy ion linear accelerator named as SSC-LINAC at HIRFL （the heavy ion research facility of Lanzhou） has been constructed. The re-buncher, which is used for beam longitudinal modulation and matching between the RFQ and DTL, is designed to be operated in continuous wave （CW） mode at the Medium-Energy Beam-Transport （MEBT） line to maintain the beam intensity and quality. Because of the longitudinal space limitation, the re-buncher has to be very compact and will be built with four gaps. We determined the key parameters of the re-buncher cavity from the simulations using Microwave Studio software, such as the resonant frequency, the quality factor Q and the shunt impedance. The detailed design of a 53.667 MHz spiral cavity and measurement results of its prototype will be presented.
文摘In order to realize high energy density physics and plasma physics research at HIRFL-CSR, a magnetic alloy （MA）-loaded cavity has been studied. According to the theoretical calculation and simulation for the MA-loaded cavity, we achieved a better result. The MA-loaded cavity had a higher μQf value, with a higher shunt impedance and a higher accelerating gradient. The accelerating gradient was about 95 kV/m at 1.8003 MHz, 130 kV/m at 0.9000 MHz. Compared with the ferrite-loaded cavities that are used at HIRFL-CSR, with about 10 kV/m accelerating gradient, the MA-loaded cavity obviously has an advantage. The results of the theoretical calculation and the simulation, which meet the design requirements are in good agreement.
基金Supported by National Natural Science Foundation of China(91026001)
文摘A 162.5 MHz four-vane radio frequency quadruple（RFQ） accelerator has been developed at the Institute of Modern Physics（IMP） for Injector II of the China ADS linac. The RFQ will operate in continuous wave mode at 100 k W. For the designed 10 mA beam, the additional RF power dissipation will induce a very large reflection of power. A water-temperature controlling system will be used to reduce the power reflection by tuning the frequency of the RFQ. The tuning capability of the water temperature is studied under different configurations of cooling water.Simulations and experiment are compared in this paper. The experimental results agree well with simulation using ANSYS. This can be used as a reference to tune the RFQ in beam commissioning.
