A radial sputter probe has been developed for the AECR-U as an additional method of producing metal ion beams.Negative voltage is applied to the probe to incite collisions with target atoms,thereby sputtering material...A radial sputter probe has been developed for the AECR-U as an additional method of producing metal ion beams.Negative voltage is applied to the probe to incite collisions with target atoms,thereby sputtering material into the plasma.The sputter probe is positioned through one of the 6 radial access slots between the permanent hexapole structure of the AECR-U.The probe position can be varied with respect to the inner edge of the hexapole magnet structure.Charge state distributions and peak beam intensities at bias voltages up to-5kV were obtained for gold samples at varying distances of the probe with respect to the plasma.For high charge states production the radial position with respect to the plasma was more sensitive than for the medium and lower charge states.For high charge state ion production the probe was optimized at a distance of 0.6cm inside the chamber wall(4.1cm from the center of the chamber).Stable beams with peak intensities of up to 28eμA of Au^(24+) and 1.42eμA of Au^(41+) have been produced using the sputter probe technique. In addition,a solid state circuit under development by Scientific Solutions,Inc which provides a bandwidth up to 100MHz was used to drive the 14GHz klystron amplifier for the LBNL AECR-U ion source.Various broadband and discrete heating modes were tested and the results for high charge state ion production were compared with single frequency heating.展开更多
The next generation,superconducting ECR ion source VENUS(Versatile ECR ion source for NUclear Science) has operated with 28GHz since 2004,and has produced world record ion beam intensities. The VENUS project is focuse...The next generation,superconducting ECR ion source VENUS(Versatile ECR ion source for NUclear Science) has operated with 28GHz since 2004,and has produced world record ion beam intensities. The VENUS project is focused on two main objectives.First,for the 88-Inch Cyclotron,VENUS will serve as the third injector source boosting both the energy and intensity of beams available from the facility.Secondly, VENUS also serves as the prototype injector source for a high intensity heavy ion beam driver linac for a next generation radioactive ion beam facility,where the goal is to produce intense beams of medium to low charge states ions such as 240eμA of Xe^(20+) or 250eμA of U^(28+to34+).These high intensity ion beam requirements present a challenge for the beam transport system since the total currents extracted from the ECR ion source reach several mA.Therefore in parallel to ion beam developments,we are also enhancing our ion beam diagnostics devices and are conducting an extensive ion beam simulation effort to improve the understanding of the ion beam transport from the VENUS ECR ion source.The paper will give an overview of recent experiments with the VENUS ECR ion source.Since the last ECR ion source workshop in Berkeley in 2004,we have installed a new plasma chamber,which includes X-ray shielding.This enables us to operate the source reliably at high power 28GHz operation.With this new chamber several high intensity beams(such as 2.4mA of O^(6+),600eμA of O^(7+),1mA of Ar^(9+),etc.)have been produced.In addition,we have started the development of high intensity uranium beams.For example,200eμA of U^(33+) and V^(34+) have been produced so far.In respect to high charge state ions,leμA of Ar^(18+),133eμA of Ar^(16+),and 4.9eμA of U^(47+) have been measured.In addition,ion beam profile measurements are presented with,and without the sextupole magnetic field energized.These experimental results are being compared with simulations using the WARP code.展开更多
To go beyond the present and planned third generation ECR ion sources operating at microwave frequencies between 20 and 30GHz to a fourth generation of sources operating above 50GHz offers new oppor- tunities and chal...To go beyond the present and planned third generation ECR ion sources operating at microwave frequencies between 20 and 30GHz to a fourth generation of sources operating above 50GHz offers new oppor- tunities and challenges.Based on the experimentally demonstrated frequency scaling,a doubling in operating frequency could provide more intense high charge state beams with higher charge states.The technical chal- lenges include the development of magnetic structures capable of producing 8T solenoid field and 4T sextupole fields,production and coupling of high power microwave power to heat the plasma,extraction of intense mul- tiple charge ion beams from a region of strong magnetic field and shielding of bremstrahlung from the hot electrons.In this paper,the status of high field superconducting magnets now under development for acceler- ator applications,gyrotrons for microwave power and other technical aspects that would be incorporated into a fourth generation ECR ion source are explored and applied to a conceptual design.展开更多
基金Supported by the Director,Office of Energy Research,Office of High Energy and Nuclear Physics,Nuclear Physics Division of the U.S.Department of Energy under Contract DE AC03-76SF00098
文摘A radial sputter probe has been developed for the AECR-U as an additional method of producing metal ion beams.Negative voltage is applied to the probe to incite collisions with target atoms,thereby sputtering material into the plasma.The sputter probe is positioned through one of the 6 radial access slots between the permanent hexapole structure of the AECR-U.The probe position can be varied with respect to the inner edge of the hexapole magnet structure.Charge state distributions and peak beam intensities at bias voltages up to-5kV were obtained for gold samples at varying distances of the probe with respect to the plasma.For high charge states production the radial position with respect to the plasma was more sensitive than for the medium and lower charge states.For high charge state ion production the probe was optimized at a distance of 0.6cm inside the chamber wall(4.1cm from the center of the chamber).Stable beams with peak intensities of up to 28eμA of Au^(24+) and 1.42eμA of Au^(41+) have been produced using the sputter probe technique. In addition,a solid state circuit under development by Scientific Solutions,Inc which provides a bandwidth up to 100MHz was used to drive the 14GHz klystron amplifier for the LBNL AECR-U ion source.Various broadband and discrete heating modes were tested and the results for high charge state ion production were compared with single frequency heating.
基金Supported by the Director,Office of Energy Research,Office of High Energy and Nuclear Physics,Nuclear Physics Division of the U.S.Department of Energy under Contract DE AC03-76SF00098
文摘The next generation,superconducting ECR ion source VENUS(Versatile ECR ion source for NUclear Science) has operated with 28GHz since 2004,and has produced world record ion beam intensities. The VENUS project is focused on two main objectives.First,for the 88-Inch Cyclotron,VENUS will serve as the third injector source boosting both the energy and intensity of beams available from the facility.Secondly, VENUS also serves as the prototype injector source for a high intensity heavy ion beam driver linac for a next generation radioactive ion beam facility,where the goal is to produce intense beams of medium to low charge states ions such as 240eμA of Xe^(20+) or 250eμA of U^(28+to34+).These high intensity ion beam requirements present a challenge for the beam transport system since the total currents extracted from the ECR ion source reach several mA.Therefore in parallel to ion beam developments,we are also enhancing our ion beam diagnostics devices and are conducting an extensive ion beam simulation effort to improve the understanding of the ion beam transport from the VENUS ECR ion source.The paper will give an overview of recent experiments with the VENUS ECR ion source.Since the last ECR ion source workshop in Berkeley in 2004,we have installed a new plasma chamber,which includes X-ray shielding.This enables us to operate the source reliably at high power 28GHz operation.With this new chamber several high intensity beams(such as 2.4mA of O^(6+),600eμA of O^(7+),1mA of Ar^(9+),etc.)have been produced.In addition,we have started the development of high intensity uranium beams.For example,200eμA of U^(33+) and V^(34+) have been produced so far.In respect to high charge state ions,leμA of Ar^(18+),133eμA of Ar^(16+),and 4.9eμA of U^(47+) have been measured.In addition,ion beam profile measurements are presented with,and without the sextupole magnetic field energized.These experimental results are being compared with simulations using the WARP code.
基金Supported by U.S.Department of Energy under Contract No.DE-AC02-05CH11231
文摘To go beyond the present and planned third generation ECR ion sources operating at microwave frequencies between 20 and 30GHz to a fourth generation of sources operating above 50GHz offers new oppor- tunities and challenges.Based on the experimentally demonstrated frequency scaling,a doubling in operating frequency could provide more intense high charge state beams with higher charge states.The technical chal- lenges include the development of magnetic structures capable of producing 8T solenoid field and 4T sextupole fields,production and coupling of high power microwave power to heat the plasma,extraction of intense mul- tiple charge ion beams from a region of strong magnetic field and shielding of bremstrahlung from the hot electrons.In this paper,the status of high field superconducting magnets now under development for acceler- ator applications,gyrotrons for microwave power and other technical aspects that would be incorporated into a fourth generation ECR ion source are explored and applied to a conceptual design.
