The ongoing Jinping Underground Nuclear Astrophysics Experiment(JUNA)takes advantage of the ultralow background in Jinping Underground Laboratory(CJPL)of China,high current accelerator driven by an ECR source and high...The ongoing Jinping Underground Nuclear Astrophysics Experiment(JUNA)takes advantage of the ultralow background in Jinping Underground Laboratory(CJPL)of China,high current accelerator driven by an ECR source and highly sensitive detector to study directly a number of important reactions for the first time within their relevant stellar energy range.展开更多
To meet the requirements of developing SFRFQ and upgrading the 1 MeV ISR RFQ accelerator,an ECR O^+ ion source and LEBT system have been developed.Using two Einzel Lenses to focus the beam,more than 3mA O^+ beam with ...To meet the requirements of developing SFRFQ and upgrading the 1 MeV ISR RFQ accelerator,an ECR O^+ ion source and LEBT system have been developed.Using two Einzel Lenses to focus the beam,more than 3mA O^+ beam with the energy of 22keV can be obtained at the end of LEBT.Its normalized root-mean-square emittance is about 0.12πmm·mrad.展开更多
Physical designing of the pre-chopper in CSNS LEBT is carried out, which includes the deflecting voltage, the length and the width of the deflecting plates, and the gap between the deflecting plates. The most outstand...Physical designing of the pre-chopper in CSNS LEBT is carried out, which includes the deflecting voltage, the length and the width of the deflecting plates, and the gap between the deflecting plates. The most outstanding feature of the design is that both the gap and the width vary with the beam envelope size. So both the requried deflecting voltage and the loaded capacitance are lowered. In order to avoid destruction of the space charge neutralization by the pre-chopper in the whole LEBT, an electron-trapping electrode is arranged to confine the electrostatic field of the pre-chopper to the local area. To examine the reliability of the pre-chopping design in CSNS LEBT, a similar pre-chopping design in ADS RFQ LEBT is set up and an experiment on the pre-chopper is prepared. 3-dimensional simulations are carried out to determine the loaded capacitance and the applied voltage of the electron-trapping electrode.展开更多
The concept for a 2 charge state injector for a'RIA type'accelerator has been presented.Progress toward an operational prototype 2Q-LEBT system at Argonne National Laboratory(ANL)is under way. The existing BIE...The concept for a 2 charge state injector for a'RIA type'accelerator has been presented.Progress toward an operational prototype 2Q-LEBT system at Argonne National Laboratory(ANL)is under way. The existing BIE 100 all permanent magnet ECR has been placed on a high voltage platform capable of a combined>100kV with q/m separation at ground level.Remote control of the devices on the platform has been implemented.Other components of the facility are currently being tested.The components of an achromatic bending system are currently being procured.This paper will present recent work at the facility as well as preliminary development of solid materials using the BIE 100.展开更多
An ECR O^+ ion source and LEBT system have been developed for the upgrade of 1MeV Integral Split Ring RFQ at Peking University.To satisfy the requirement of RFQ,a more than 10mA oxygen beam has been extracted at 22kV ...An ECR O^+ ion source and LEBT system have been developed for the upgrade of 1MeV Integral Split Ring RFQ at Peking University.To satisfy the requirement of RFQ,a more than 10mA oxygen beam has been extracted at 22kV through a 5mm diameter aperture.Its normalized root-mean-square emmitance is less than 0.1π·mm·mrad,which is required by RFQ accelerator.The LEBT matching section is redesigned upon the bench test results.The preliminary results will be presented in this paper.展开更多
The transport characteristics of a space chargedominated multi-species deuterium beam consisting of D_1^+,D_2^+, and D_3^+ particles in an electrostatic low-energy beam line are studied. First, the envelope equations ...The transport characteristics of a space chargedominated multi-species deuterium beam consisting of D_1^+,D_2^+, and D_3^+ particles in an electrostatic low-energy beam line are studied. First, the envelope equations of the primary D_1^+ beam are derived considering the space charge effects caused by all particles. Second, the evolution of the envelope of the multi-species deuterium beam is simulated using the PIC code TRACK, with the results showing a significant effect of the unwanted beam on the transport of the primary beam. Finally, different injected beam parameters are used to study beam matching, and a new beam extraction system for the existing duoplasmatron source is designed to obtain the ideal injected beam parameters that allow a D_1^+ beam of up to 50 m A to pass unobstructed through the electrostatic low-energy beam transport line in the presence of an unwanted(D_2^+, D_3^+)beam of 20 m A; at the same time, distortions of the beam emittance and particle distributions are observed.展开更多
The Low Energy Accelerator Facility(LEAF)consists of a ECR ion source,a LEBT,an RFQ,a MEBT and three terminals.The cooling water system for high-power equipments like RFQ and power supply had designed to guarantee sta...The Low Energy Accelerator Facility(LEAF)consists of a ECR ion source,a LEBT,an RFQ,a MEBT and three terminals.The cooling water system for high-power equipments like RFQ and power supply had designed to guarantee stable operation for LEAF.A water leakage monitoring system was designed and implemented in 2018,which could pre-warning the water leakage status of the water cooling system along the beam line and the water pump house in real time to prevent equipment damage caused by water leakage accident.展开更多
ADS Injector-II linear accelerator is mainly composed of ECR ion source,LEBT,RFQ,MEBT,a superconducting accelerating segment and HEBT.The superconducting accelerating segment is composed of two HWR010 cavity cryomodul...ADS Injector-II linear accelerator is mainly composed of ECR ion source,LEBT,RFQ,MEBT,a superconducting accelerating segment and HEBT.The superconducting accelerating segment is composed of two HWR010 cavity cryomodules,a taper cavity cryomodule and a spoke cavity cryomodule(CM1+CM2+CM3+CM4),which has accelerated the proton beam to 25 MeV in Jun.2017.展开更多
The superconducting Ion Linac(iLinac)of High Intensity Heavy-ion Accelerator Facility(HIAF)is composed of an ECR ion source,low energy beam transport line(LEBT),81.25 MHz radio frequency quadrupole(RFQ)accelerator,med...The superconducting Ion Linac(iLinac)of High Intensity Heavy-ion Accelerator Facility(HIAF)is composed of an ECR ion source,low energy beam transport line(LEBT),81.25 MHz radio frequency quadrupole(RFQ)accelerator,medium energy beam transport line(MEBT)and superconducting section composed by Quarter Wave Resonators(QWR007)and Half Wave Resonators(HWR015).The ^(238)U^(35+)beam is accelerated by the RFQ accelerator from 0.014 to 0.8 MeV/u and then to 17 MeV/u by 96 SC cavities.The layout of the linac is shown in Fig.1.展开更多
Background The beam chopper system of China Spallation Neutron Source(CSNS)is used to pulsed chop the negative hydrogen ion beam from ion source;in order to meet the beam time structure of rapid cycling synchrotron(RC...Background The beam chopper system of China Spallation Neutron Source(CSNS)is used to pulsed chop the negative hydrogen ion beam from ion source;in order to meet the beam time structure of rapid cycling synchrotron(RCS),it is the key to control emittance growth of low energy beam and decrease beam loss during the beam injection process from the linac to RCS.After beam chopped,the particle beam is required to deviate completely and then lose at entrance of radiofrequency quadrupole(RFQ)cavity;considering high duty cycle of ion source and beam high chop rate,the effect of deflected particles on RFQ is difficult to predict.Purpose A bipolar beam chopper pulse power supply is developed,which makes the beam spot at the entrance of RFQ twice that of unipolar beam chopper power supply,and reduces the damage of deflected particles to RFQ cavity and vacuum.Methods The beam chopper power supply provides a fast high voltage pulse source;two fast reversing switches are used to quickly change the polarity of the output high voltage pulse in 40 ms.Results and conclusion The power supply has been installed in the low beam energy transport line(LEBT),the output high voltage pulse is±6 kV,frequency is about 1 MHz,and the pulse edge is less than 10 ns.展开更多
研制了一套强流质子源及低能传输线(LEBT)注入器用于ADS质子直线加速器。质子源产生35 ke V强流束经过低能传输段聚焦进入射频四极(RFQ)入口。低能传输段不匹配是强流RFQ中引起束流丢失的主要原因。不同加速段的束流匹配是减少束流损失...研制了一套强流质子源及低能传输线(LEBT)注入器用于ADS质子直线加速器。质子源产生35 ke V强流束经过低能传输段聚焦进入射频四极(RFQ)入口。低能传输段不匹配是强流RFQ中引起束流丢失的主要原因。不同加速段的束流匹配是减少束流损失与抑制发射度增长的重要手段。束流损失导致RFQ电极表面受热变形进而引起高频打火,降低RFQ长期运行的稳定性。针对以上问题,研究LEBT发射度在不同的实验条件下如何实现加速器更好的匹配。研究结果表明,LEBT出口束流在35 ke V,10 m A下,束流发射度小于0.2πmm·mrad,当LEBT螺线管电流为210和270 A时,束流在RFQ入口满足匹配条件。展开更多
The design of the China Spallation Neutron Source （CSNS） low-energy beam transport （LEBT） line, which locates between the ion source and the radio-frequency quadrupole （RFQ）, has been completed with the TRACE3D ...The design of the China Spallation Neutron Source （CSNS） low-energy beam transport （LEBT） line, which locates between the ion source and the radio-frequency quadrupole （RFQ）, has been completed with the TRACE3D code. The design aims at perfect matching, primary chopping, a small emittance growth and sufficient space for beam diagnostics. The line consists of three solenoids, three vacuum chambers, two steering magnets and a pre-chopper. The total length of LEBT is about 1.74 m. This LEBT is designed to transfer 20 mA of H-pulsed beam from the ion source to the RFQ. An induction cavity is adopted as the pre-chopper. The electrostatic octupole steerer is discussed as a candidate. A four-quadrant aperture for beam scraping and beam position monitoring is designed.展开更多
A new SSC （Separated Sector Cyclotron）-Linac is being designed to serve as an injector for the SSC at the HIRFL （Heavy Ion Research Facility Lanzhou）. The beam intensity at the LEBT （Low Energy Beam Transport） f...A new SSC （Separated Sector Cyclotron）-Linac is being designed to serve as an injector for the SSC at the HIRFL （Heavy Ion Research Facility Lanzhou）. The beam intensity at the LEBT （Low Energy Beam Transport） for the heavy ions after the selection is typically low and the space charge effects are inconspicuous. The space charge effects become obvious when the beam current increases to a few hundred microamperes. The emittance growth deriving from the space charge effects may be particularly troublesome for the following linac and cyclotron. An optical system containing three solenoids has been designed for the LEBT to limit the beam emittance and to avoid the unnecessary beam loss in the cyclotron, as well as for the purpose of immunizing the LEBT emittance growth due to the space charge effects. The results of the PIC （Particle- In-Cell） mode simulation illustrate that this channel could limit the beam emittance growth and increase the beam brightness.展开更多
文摘The ongoing Jinping Underground Nuclear Astrophysics Experiment(JUNA)takes advantage of the ultralow background in Jinping Underground Laboratory(CJPL)of China,high current accelerator driven by an ECR source and highly sensitive detector to study directly a number of important reactions for the first time within their relevant stellar energy range.
文摘To meet the requirements of developing SFRFQ and upgrading the 1 MeV ISR RFQ accelerator,an ECR O^+ ion source and LEBT system have been developed.Using two Einzel Lenses to focus the beam,more than 3mA O^+ beam with the energy of 22keV can be obtained at the end of LEBT.Its normalized root-mean-square emittance is about 0.12πmm·mrad.
文摘Physical designing of the pre-chopper in CSNS LEBT is carried out, which includes the deflecting voltage, the length and the width of the deflecting plates, and the gap between the deflecting plates. The most outstanding feature of the design is that both the gap and the width vary with the beam envelope size. So both the requried deflecting voltage and the loaded capacitance are lowered. In order to avoid destruction of the space charge neutralization by the pre-chopper in the whole LEBT, an electron-trapping electrode is arranged to confine the electrostatic field of the pre-chopper to the local area. To examine the reliability of the pre-chopping design in CSNS LEBT, a similar pre-chopping design in ADS RFQ LEBT is set up and an experiment on the pre-chopper is prepared. 3-dimensional simulations are carried out to determine the loaded capacitance and the applied voltage of the electron-trapping electrode.
基金Supported by the U.S.Department of Energy,Office of Nuclear Physics,under Contract No.W-31-109-ENG-38
文摘The concept for a 2 charge state injector for a'RIA type'accelerator has been presented.Progress toward an operational prototype 2Q-LEBT system at Argonne National Laboratory(ANL)is under way. The existing BIE 100 all permanent magnet ECR has been placed on a high voltage platform capable of a combined>100kV with q/m separation at ground level.Remote control of the devices on the platform has been implemented.Other components of the facility are currently being tested.The components of an achromatic bending system are currently being procured.This paper will present recent work at the facility as well as preliminary development of solid materials using the BIE 100.
文摘An ECR O^+ ion source and LEBT system have been developed for the upgrade of 1MeV Integral Split Ring RFQ at Peking University.To satisfy the requirement of RFQ,a more than 10mA oxygen beam has been extracted at 22kV through a 5mm diameter aperture.Its normalized root-mean-square emmitance is less than 0.1π·mm·mrad,which is required by RFQ accelerator.The LEBT matching section is redesigned upon the bench test results.The preliminary results will be presented in this paper.
基金supported by the Fundamental Research Funds for the Central Universities(No.lzujbky-2017-93)the National Natural Science Foundation of China(Nos.11375077,11027508,and21327801)the National Key Scientific Instrument and Equipment Development Projects(No.2013YQ04086101)
文摘The transport characteristics of a space chargedominated multi-species deuterium beam consisting of D_1^+,D_2^+, and D_3^+ particles in an electrostatic low-energy beam line are studied. First, the envelope equations of the primary D_1^+ beam are derived considering the space charge effects caused by all particles. Second, the evolution of the envelope of the multi-species deuterium beam is simulated using the PIC code TRACK, with the results showing a significant effect of the unwanted beam on the transport of the primary beam. Finally, different injected beam parameters are used to study beam matching, and a new beam extraction system for the existing duoplasmatron source is designed to obtain the ideal injected beam parameters that allow a D_1^+ beam of up to 50 m A to pass unobstructed through the electrostatic low-energy beam transport line in the presence of an unwanted(D_2^+, D_3^+)beam of 20 m A; at the same time, distortions of the beam emittance and particle distributions are observed.
文摘The Low Energy Accelerator Facility(LEAF)consists of a ECR ion source,a LEBT,an RFQ,a MEBT and three terminals.The cooling water system for high-power equipments like RFQ and power supply had designed to guarantee stable operation for LEAF.A water leakage monitoring system was designed and implemented in 2018,which could pre-warning the water leakage status of the water cooling system along the beam line and the water pump house in real time to prevent equipment damage caused by water leakage accident.
文摘ADS Injector-II linear accelerator is mainly composed of ECR ion source,LEBT,RFQ,MEBT,a superconducting accelerating segment and HEBT.The superconducting accelerating segment is composed of two HWR010 cavity cryomodules,a taper cavity cryomodule and a spoke cavity cryomodule(CM1+CM2+CM3+CM4),which has accelerated the proton beam to 25 MeV in Jun.2017.
文摘The superconducting Ion Linac(iLinac)of High Intensity Heavy-ion Accelerator Facility(HIAF)is composed of an ECR ion source,low energy beam transport line(LEBT),81.25 MHz radio frequency quadrupole(RFQ)accelerator,medium energy beam transport line(MEBT)and superconducting section composed by Quarter Wave Resonators(QWR007)and Half Wave Resonators(HWR015).The ^(238)U^(35+)beam is accelerated by the RFQ accelerator from 0.014 to 0.8 MeV/u and then to 17 MeV/u by 96 SC cavities.The layout of the linac is shown in Fig.1.
基金supported by Beijing Natural Science Foundation(Project Nos.3214065).
文摘Background The beam chopper system of China Spallation Neutron Source(CSNS)is used to pulsed chop the negative hydrogen ion beam from ion source;in order to meet the beam time structure of rapid cycling synchrotron(RCS),it is the key to control emittance growth of low energy beam and decrease beam loss during the beam injection process from the linac to RCS.After beam chopped,the particle beam is required to deviate completely and then lose at entrance of radiofrequency quadrupole(RFQ)cavity;considering high duty cycle of ion source and beam high chop rate,the effect of deflected particles on RFQ is difficult to predict.Purpose A bipolar beam chopper pulse power supply is developed,which makes the beam spot at the entrance of RFQ twice that of unipolar beam chopper power supply,and reduces the damage of deflected particles to RFQ cavity and vacuum.Methods The beam chopper power supply provides a fast high voltage pulse source;two fast reversing switches are used to quickly change the polarity of the output high voltage pulse in 40 ms.Results and conclusion The power supply has been installed in the low beam energy transport line(LEBT),the output high voltage pulse is±6 kV,frequency is about 1 MHz,and the pulse edge is less than 10 ns.
文摘研制了一套强流质子源及低能传输线(LEBT)注入器用于ADS质子直线加速器。质子源产生35 ke V强流束经过低能传输段聚焦进入射频四极(RFQ)入口。低能传输段不匹配是强流RFQ中引起束流丢失的主要原因。不同加速段的束流匹配是减少束流损失与抑制发射度增长的重要手段。束流损失导致RFQ电极表面受热变形进而引起高频打火,降低RFQ长期运行的稳定性。针对以上问题,研究LEBT发射度在不同的实验条件下如何实现加速器更好的匹配。研究结果表明,LEBT出口束流在35 ke V,10 m A下,束流发射度小于0.2πmm·mrad,当LEBT螺线管电流为210和270 A时,束流在RFQ入口满足匹配条件。
文摘The design of the China Spallation Neutron Source （CSNS） low-energy beam transport （LEBT） line, which locates between the ion source and the radio-frequency quadrupole （RFQ）, has been completed with the TRACE3D code. The design aims at perfect matching, primary chopping, a small emittance growth and sufficient space for beam diagnostics. The line consists of three solenoids, three vacuum chambers, two steering magnets and a pre-chopper. The total length of LEBT is about 1.74 m. This LEBT is designed to transfer 20 mA of H-pulsed beam from the ion source to the RFQ. An induction cavity is adopted as the pre-chopper. The electrostatic octupole steerer is discussed as a candidate. A four-quadrant aperture for beam scraping and beam position monitoring is designed.
基金Supported by National Natural Science Foundation of China (10635090)
文摘A new SSC （Separated Sector Cyclotron）-Linac is being designed to serve as an injector for the SSC at the HIRFL （Heavy Ion Research Facility Lanzhou）. The beam intensity at the LEBT （Low Energy Beam Transport） for the heavy ions after the selection is typically low and the space charge effects are inconspicuous. The space charge effects become obvious when the beam current increases to a few hundred microamperes. The emittance growth deriving from the space charge effects may be particularly troublesome for the following linac and cyclotron. An optical system containing three solenoids has been designed for the LEBT to limit the beam emittance and to avoid the unnecessary beam loss in the cyclotron, as well as for the purpose of immunizing the LEBT emittance growth due to the space charge effects. The results of the PIC （Particle- In-Cell） mode simulation illustrate that this channel could limit the beam emittance growth and increase the beam brightness.
