The Peking University neutron imaging facility (PKUNIFTY), an RFQ-based neutron source, aims at developing industrial applications. During the past 3 y operation, some problems have appeared, such as RF sparking for t...The Peking University neutron imaging facility (PKUNIFTY), an RFQ-based neutron source, aims at developing industrial applications. During the past 3 y operation, some problems have appeared, such as RF sparking for the RFQ high power operation, full power level instability of RF transmitter, and the misalignment of RFQ electrodes assembling and deformation. The PKUNIFTY upgrade endeavors to adopt a modest inter-voltage beam dynamics design. The new beam dynamics design of 201.5MHz RFQ of PKUNIFTY, which accelerates 35mA of D+ from 50 keV to 2.0MeV at 10% duty factor, is performed. The averaged D+ beam will be about 3 mA. The source will deliver a fast neutron yield of 2.5x10(12) n/s via the deuteron-beryllium reaction, which is about 10 times higher than the current status.展开更多
A four-rod radio frequency quadruple (RFQ) accelerator is designed,manufactured,installed and commissioned for the Peking University Neutron Imaging Facility (PKUNIFTY).This 2699.6-mm-long RFQ accelerator with the mea...A four-rod radio frequency quadruple (RFQ) accelerator is designed,manufactured,installed and commissioned for the Peking University Neutron Imaging Facility (PKUNIFTY).This 2699.6-mm-long RFQ accelerator with the mean aperture radius of 3.88mm is operating at 201.5MHz in pulse mode.An inter-electrode voltage of 70kV is needed to accelerate the injected 50keV 40mA D+ ions up to 2MeV.We present the rf system,high rf power feeder design,lowver rf measurements and higher rf power test.Especially,the rf commissioning was carried out with rf power up to ~280 k W and duty factor of 4%.The measured x-ray spectrum shows that the rf inter-electrode voltage reaches 70.7 kV.It is found that the specific shunt impedance of the RFQ cavity reaches 52.7kΩ.m.展开更多
A four-rod radio frequency quadruple （RFQ） cavity has been built for the Peking University Neutron Imaging Facility （PKUNIFTY）. The rf tuning of such a cavity is important to make the field distribution flat and t...A four-rod radio frequency quadruple （RFQ） cavity has been built for the Peking University Neutron Imaging Facility （PKUNIFTY）. The rf tuning of such a cavity is important to make the field distribution flat and to tune the cavity’s resonant frequency to its operating value. Plate tuners are used to tune the RFQ, which have an effect on both the cavity frequency and field distribution. The rf performance of the RFQ and the effect of plate tuners are simulated. Based on the simulation, a code RFQTUNING is designed, which gives a fast way to tune the cavity. With the aid of the code the cavity frequency is tuned to 201.5 MHz and the flatness deviation of the field distribution is reduced to less than 5%.展开更多
A mini-vane four-rod radio frequency quadruple (RFQ) accelerator has been built for neutron imaging. The RFQ will operate at 201.5 MHz, and its length is 2.7 m. The original electric field distribution along the elect...A mini-vane four-rod radio frequency quadruple (RFQ) accelerator has been built for neutron imaging. The RFQ will operate at 201.5 MHz, and its length is 2.7 m. The original electric field distribution along the electrodes is not flat. The resonant frequency needs to be tuned to the operating value. And the frequency needs to be compensated for temperature change during high power RF test and beam test. As tuning such a RFQ is difficult, plate tuners and stick tuners are designed. This paper will present the tuners design, the tuning procedure, and the RF properties of the RFQ.展开更多
Radio frequency quadrupoles(RFQs),which are crucial components of proton injectors,significantly affect the performance of proton accelerator facilities.An RFQ with a high frequency of 714 MHz dedicated to compact pro...Radio frequency quadrupoles(RFQs),which are crucial components of proton injectors,significantly affect the performance of proton accelerator facilities.An RFQ with a high frequency of 714 MHz dedicated to compact proton injectors for medi-cal applications is designed in this study.The RFQ is designed to accelerate proton beams from 50 keV to 4 MeV within a short length of 2 m and can be matched closely with the downstream drift tube linac to capture more particles through a preliminary optimization.To develop an advanced RFQ,challenging techniques,including fabrication and tuning method,must be evaluated and verified using a prototype.An aluminium prototype is derived from the conceptual design of the RFQ and then redesigned to confirm the radio frequency performance,fabrication procedure,and feasibility of the tuning algorithm.Eventually,a new tuning algorithm based on the response matrix and least-squares method is developed,which yields favorable results based on the prototype,i.e.,the errors of the dipole and quadrupole components reduced to a low level after several tuning iterations.Benefiting from the conceptual design and techniques obtained from the prototype,the formal mechanical design of the 2-m RFQ is ready for the next manufacturing step.展开更多
To validate the design rationality of the power coupler for the RFQ cavity and minimize cavity contamination,we designed a low-loss offline conditioning cavity and conducted high-power testing.This offline cavity feat...To validate the design rationality of the power coupler for the RFQ cavity and minimize cavity contamination,we designed a low-loss offline conditioning cavity and conducted high-power testing.This offline cavity features two coupling ports and two tuners,operating at a frequency of 162.5 MHz with a tuning range of 3.2 MHz.Adjusting the installation angle of the coupling ring and the insertion depth of the tuner helps minimize cavity losses.We performed electromagnetic structural and multiphysics simulations,revealing a minimal theoretical power loss of 4.3%.However,when the cavity frequency varied by110 kHz,theoretical power losses increased to10%,necessitating constant tuner adjustments during conditioning.Multiphysics simulations indicated that increased cavity temperature did not affect frequency variation.Upon completion of the offline high-power conditioning platform,we measured the transmission performance,revealing a power loss of 6.3%,exceeding the theoretical calculation.Conditioning utilized efficient automatic range scanning and standing wave resonant methods.To fully condition the power coupler,a 15°phase difference between two standing wave points in the condition-ing system was necessary.Notably,the maximum continuous wave power surpassed 20 kW,exceeding the expected target.展开更多
SSC-Linac RFQ(Separated Sector Cyclotron Linac Radio Frequency Quadrupolec)是中国科学院近代物理研究所和北京大学共同研制的国内首台高电荷态强流重离子连续波四杆型加速器,机械加工的高精度是RFQ能否顺利出束的关键步骤之一。...SSC-Linac RFQ(Separated Sector Cyclotron Linac Radio Frequency Quadrupolec)是中国科学院近代物理研究所和北京大学共同研制的国内首台高电荷态强流重离子连续波四杆型加速器,机械加工的高精度是RFQ能否顺利出束的关键步骤之一。为了检测其机械形位公差,采用了激光跟踪仪和关节测量臂合理组合应用的测量新方法,使两种高精度的测量仪器能扬长避短,克服了大尺度工件形位公差传统测量方法的不足,使其在测量过程中发挥其最优的使用性和操作性,有效地提高了工作效率,从而保证RFQ高精度的测量结果。展开更多
中国散裂中子源研发了一台射频四极RFQ(Radio Frequency Quadrupole)强流质子加速器。为保证RFQ顺利出束,对加工焊接阶段、RF调谐调场、高功率RF(Radio Frequency)老练过程中出现的问题进行了分析,给出了解决办法,并进行了调束实验。三...中国散裂中子源研发了一台射频四极RFQ(Radio Frequency Quadrupole)强流质子加速器。为保证RFQ顺利出束,对加工焊接阶段、RF调谐调场、高功率RF(Radio Frequency)老练过程中出现的问题进行了分析,给出了解决办法,并进行了调束实验。三坐标测量测得RFQ精加工后的加工公差约在20μm,RFQ腔体无载品质因子Q0大于7 679,约为理论无载Q0值的80%。RFQ腔内RF电场分布的平整度好于2.5%,RFQ高功率RF老练入腔功率达到450 k W,是理论腔耗390 k W的1.15倍,且保持连续12 h不打火。在RFQ调束实验中,RFQ出口得到3 Me V、28 m A的负氢束流,满足中国散裂中子源的要求。展开更多
射频四极场(Radio frequency quodrupole,RFQ)加速器是一种非常适于用作MeV级能量离子注入的加速器。它具有束流强、体积小、使用方便、离子源处在地电位,还可同时加速正、负两种离子等优点。本文介绍了RFQ加速器在国际上的发展状况及...射频四极场(Radio frequency quodrupole,RFQ)加速器是一种非常适于用作MeV级能量离子注入的加速器。它具有束流强、体积小、使用方便、离子源处在地电位,还可同时加速正、负两种离子等优点。本文介绍了RFQ加速器在国际上的发展状况及其基本原理、北京大学研制的1 MeV RFQ加速器的具体结构、性能以及一种新型RFQ-SFRFQ组合加速器的特点。展开更多
基金Supported by the National Basic Research Program of China under Grant No 2014CB845503
文摘The Peking University neutron imaging facility (PKUNIFTY), an RFQ-based neutron source, aims at developing industrial applications. During the past 3 y operation, some problems have appeared, such as RF sparking for the RFQ high power operation, full power level instability of RF transmitter, and the misalignment of RFQ electrodes assembling and deformation. The PKUNIFTY upgrade endeavors to adopt a modest inter-voltage beam dynamics design. The new beam dynamics design of 201.5MHz RFQ of PKUNIFTY, which accelerates 35mA of D+ from 50 keV to 2.0MeV at 10% duty factor, is performed. The averaged D+ beam will be about 3 mA. The source will deliver a fast neutron yield of 2.5x10(12) n/s via the deuteron-beryllium reaction, which is about 10 times higher than the current status.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11079001 and 10775009.
文摘A four-rod radio frequency quadruple (RFQ) accelerator is designed,manufactured,installed and commissioned for the Peking University Neutron Imaging Facility (PKUNIFTY).This 2699.6-mm-long RFQ accelerator with the mean aperture radius of 3.88mm is operating at 201.5MHz in pulse mode.An inter-electrode voltage of 70kV is needed to accelerate the injected 50keV 40mA D+ ions up to 2MeV.We present the rf system,high rf power feeder design,lowver rf measurements and higher rf power test.Especially,the rf commissioning was carried out with rf power up to ~280 k W and duty factor of 4%.The measured x-ray spectrum shows that the rf inter-electrode voltage reaches 70.7 kV.It is found that the specific shunt impedance of the RFQ cavity reaches 52.7kΩ.m.
基金Supported by National Natural Science Foundation of China (10735020)National Basic Research Program of China(2010CB833106)
文摘A four-rod radio frequency quadruple （RFQ） cavity has been built for the Peking University Neutron Imaging Facility （PKUNIFTY）. The rf tuning of such a cavity is important to make the field distribution flat and to tune the cavity’s resonant frequency to its operating value. Plate tuners are used to tune the RFQ, which have an effect on both the cavity frequency and field distribution. The rf performance of the RFQ and the effect of plate tuners are simulated. Based on the simulation, a code RFQTUNING is designed, which gives a fast way to tune the cavity. With the aid of the code the cavity frequency is tuned to 201.5 MHz and the flatness deviation of the field distribution is reduced to less than 5%.
基金supported by the National Natural Science Foundation of China (Grant No. 107035020)the National Basic Research Program of China (Grant No. 2010CB833106)
文摘A mini-vane four-rod radio frequency quadruple (RFQ) accelerator has been built for neutron imaging. The RFQ will operate at 201.5 MHz, and its length is 2.7 m. The original electric field distribution along the electrodes is not flat. The resonant frequency needs to be tuned to the operating value. And the frequency needs to be compensated for temperature change during high power RF test and beam test. As tuning such a RFQ is difficult, plate tuners and stick tuners are designed. This paper will present the tuners design, the tuning procedure, and the RF properties of the RFQ.
基金This work was supported by National Natural Science Foundation of China(No.12222513).
文摘Radio frequency quadrupoles(RFQs),which are crucial components of proton injectors,significantly affect the performance of proton accelerator facilities.An RFQ with a high frequency of 714 MHz dedicated to compact proton injectors for medi-cal applications is designed in this study.The RFQ is designed to accelerate proton beams from 50 keV to 4 MeV within a short length of 2 m and can be matched closely with the downstream drift tube linac to capture more particles through a preliminary optimization.To develop an advanced RFQ,challenging techniques,including fabrication and tuning method,must be evaluated and verified using a prototype.An aluminium prototype is derived from the conceptual design of the RFQ and then redesigned to confirm the radio frequency performance,fabrication procedure,and feasibility of the tuning algorithm.Eventually,a new tuning algorithm based on the response matrix and least-squares method is developed,which yields favorable results based on the prototype,i.e.,the errors of the dipole and quadrupole components reduced to a low level after several tuning iterations.Benefiting from the conceptual design and techniques obtained from the prototype,the formal mechanical design of the 2-m RFQ is ready for the next manufacturing step.
基金supported by the Chinese initiative accelerator driven subcritical system and the hundred talents plan of the Chinese Academy of Sciences(No.E129841Y).
文摘To validate the design rationality of the power coupler for the RFQ cavity and minimize cavity contamination,we designed a low-loss offline conditioning cavity and conducted high-power testing.This offline cavity features two coupling ports and two tuners,operating at a frequency of 162.5 MHz with a tuning range of 3.2 MHz.Adjusting the installation angle of the coupling ring and the insertion depth of the tuner helps minimize cavity losses.We performed electromagnetic structural and multiphysics simulations,revealing a minimal theoretical power loss of 4.3%.However,when the cavity frequency varied by110 kHz,theoretical power losses increased to10%,necessitating constant tuner adjustments during conditioning.Multiphysics simulations indicated that increased cavity temperature did not affect frequency variation.Upon completion of the offline high-power conditioning platform,we measured the transmission performance,revealing a power loss of 6.3%,exceeding the theoretical calculation.Conditioning utilized efficient automatic range scanning and standing wave resonant methods.To fully condition the power coupler,a 15°phase difference between two standing wave points in the condition-ing system was necessary.Notably,the maximum continuous wave power surpassed 20 kW,exceeding the expected target.
文摘SSC-Linac RFQ(Separated Sector Cyclotron Linac Radio Frequency Quadrupolec)是中国科学院近代物理研究所和北京大学共同研制的国内首台高电荷态强流重离子连续波四杆型加速器,机械加工的高精度是RFQ能否顺利出束的关键步骤之一。为了检测其机械形位公差,采用了激光跟踪仪和关节测量臂合理组合应用的测量新方法,使两种高精度的测量仪器能扬长避短,克服了大尺度工件形位公差传统测量方法的不足,使其在测量过程中发挥其最优的使用性和操作性,有效地提高了工作效率,从而保证RFQ高精度的测量结果。
文摘中国散裂中子源研发了一台射频四极RFQ(Radio Frequency Quadrupole)强流质子加速器。为保证RFQ顺利出束,对加工焊接阶段、RF调谐调场、高功率RF(Radio Frequency)老练过程中出现的问题进行了分析,给出了解决办法,并进行了调束实验。三坐标测量测得RFQ精加工后的加工公差约在20μm,RFQ腔体无载品质因子Q0大于7 679,约为理论无载Q0值的80%。RFQ腔内RF电场分布的平整度好于2.5%,RFQ高功率RF老练入腔功率达到450 k W,是理论腔耗390 k W的1.15倍,且保持连续12 h不打火。在RFQ调束实验中,RFQ出口得到3 Me V、28 m A的负氢束流,满足中国散裂中子源的要求。
文摘射频四极场(Radio frequency quodrupole,RFQ)加速器是一种非常适于用作MeV级能量离子注入的加速器。它具有束流强、体积小、使用方便、离子源处在地电位,还可同时加速正、负两种离子等优点。本文介绍了RFQ加速器在国际上的发展状况及其基本原理、北京大学研制的1 MeV RFQ加速器的具体结构、性能以及一种新型RFQ-SFRFQ组合加速器的特点。
