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
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 B...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
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
A new SSC-linac system （injector into separated sector cyclotron） is being designed in the HIRFL （heavy ion research facility of Lanzhou）. As part of SSC-Linac, the LEBT （low energy beam transport） consists of s...A new SSC-linac system （injector into separated sector cyclotron） is being designed in the HIRFL （heavy ion research facility of Lanzhou）. As part of SSC-Linac, the LEBT （low energy beam transport） consists of seven solenoids, four quadrupoles, a bending magnet and an extra multi-harmonic buncher. The total length of this segment is about 7 meters. The beam dynamics in this LEBT has been studied using three-dimensional PIC （particle-in-cell） code BEAMPATH. The simulation results show that the continuous beam from the ion source is first well analyzed by a charge-to-mass selection system, and the beam of the selected charge-to-mass ratio is then efficiently pre-bunched by a multi-harmonic buncher and optimally matched into the RFQ （radio frequency quadrupole） for further acceleration. The principles and effects of the solenoid collimation channel are discussed, and it could limit the beam emittance by changing the aperture size.展开更多
Introduction Operation target beam power of China Spallation Neutron Source(CSNS),as the China's first 100 kW beam power pulsed neutron source,is now larger than 80 kW.During the beam power upgrading process of CS...Introduction Operation target beam power of China Spallation Neutron Source(CSNS),as the China's first 100 kW beam power pulsed neutron source,is now larger than 80 kW.During the beam power upgrading process of CSNS to 50 kW from 2018 to 2019,many improvements have been made for the front end of CSNS.Results The improvements mainly focus on solving the problems of ion source instability and the radio frequency quadrupole(RFQ)sparking caused by the pre-chopped beam into RFQ.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.
基金Supported by National Natural Science Foundation of China （10635090）
文摘A new SSC-linac system （injector into separated sector cyclotron） is being designed in the HIRFL （heavy ion research facility of Lanzhou）. As part of SSC-Linac, the LEBT （low energy beam transport） consists of seven solenoids, four quadrupoles, a bending magnet and an extra multi-harmonic buncher. The total length of this segment is about 7 meters. The beam dynamics in this LEBT has been studied using three-dimensional PIC （particle-in-cell） code BEAMPATH. The simulation results show that the continuous beam from the ion source is first well analyzed by a charge-to-mass selection system, and the beam of the selected charge-to-mass ratio is then efficiently pre-bunched by a multi-harmonic buncher and optimally matched into the RFQ （radio frequency quadrupole） for further acceleration. The principles and effects of the solenoid collimation channel are discussed, and it could limit the beam emittance by changing the aperture size.
文摘Introduction Operation target beam power of China Spallation Neutron Source(CSNS),as the China's first 100 kW beam power pulsed neutron source,is now larger than 80 kW.During the beam power upgrading process of CSNS to 50 kW from 2018 to 2019,many improvements have been made for the front end of CSNS.Results The improvements mainly focus on solving the problems of ion source instability and the radio frequency quadrupole(RFQ)sparking caused by the pre-chopped beam into RFQ.
