ECR离子源金属离子的产生

讨论了ECR离子源金属供料方法,在145GHzECR离子源上应用炉子加热和MIVOC法获得了⁴⁰Ca¹¹⁺140eμA和⁵⁶Fe¹⁰⁺65eμA,并对实验过程和结果作了分析.     

NIRS的ECR离子源现状

Four ECR ion sources have been operated in National Institute of Radiological Sciences(NIRS). Two ECR ion sources supply various ion species for the Heavy Ion Medical Accelerator in Chiba(HIMAC). The 10GHz NIRS-ECR ion source mainly produces C~(2 ) ions for the heavy-ion therapy.Ions of Si,Ar,Fe,Kr and Xe are usually produced by the 18GHz NIRS-HEC ion source for physical and biological experiments.The other two compact ECR ion sources with all permanent magnet configuration have been developed for the new generation carbon therapy facility.One of these,the Kei-source,is a prototype which has been installed to the NIRS-930 cyclotron for axial injection.The other source,Kei2-source,is a demonstration source and utilized for the new generation Linac.In addition,both Kei sources have been used to study fundamental properties. In this paper,present status of the ion sources and recent developments are reported.     

一种改进型ECR离子源的设计计算

本文介绍了具有ω_ecr共振面,2ω_rf闭合等值面的ECR离子源的设计思想.文章同时给出了二峰值约为0.8T的轴向磁镜场和最大场强为0.8T的径向六极约束磁场的设计计算数据.设计结果表明这种改进型ECR离子源的ω_ecr共振面在轴向展宽比现在引进的CAPRICE型离子源的ω_ecr共振面在轴向展宽有极大提高,并产生闭合的2ω_rf等值面.这些设计参数表征着高电荷态的离子束强度将有很大提高.     

ECR离子源六极永磁体的设计研究

分别从材料、结构、尺寸等方面全面地研究了Halbach结构六极永磁铁的设计方法.针对个别磁块可能存在的退磁问题给出了相应的解决方案.通过优化结构,使六极磁铁在离子源等离子体弧腔内壁产生的磁场达到最大.用POISSON,PERMAG,TOSCA等多个磁场模拟程序计算模拟了六极磁场的大小与分布,并给出了一些相应的曲线     

高频ECR离子源的最新进展

As they are first optimized for their ion losses,ECRISs are always under a fundamental compromise: having high losses and strong confinement at the same time.To help ECR ion source developers in the design or improvement of existing machines,general comments are presented in a review article being soon published. In this 160 pages contribution,fundamental aspects of ECRISs are presented,with a discussion of electron temperature and confinement and ion confinement.Then,as microwaves play a key role in these machines, a chapter presents major guidelines for microwave launching and coupling to ECR plasma.Moreover,once ECR plasma is created,understanding this plasma is important in ion sourcery;and a section is dedicated to plasma diagnostics with an emphasis on the determination of electron and ion density and temperature by vacuum ultraviolet(VUV)spectroscopy.Another chapter deals with the role of magnetic confinement and presents updated scaling laws.Next chapter presents different types of ECRISs designed according to the main parameters previously described.Finally,some industrial applications of ECRISs and ECR plasmas in general are presented like ion implantation and photon lithography.Some hints taken from this review article are presented in the following article.     

单粒子态ECR离子源

介绍了一台2.45GHz电子回旋共振(ECR)单电荷离子源的磁场场形,以及它和总束流的关系.并且比较了国际上现有的几台同类型离子源的磁场场形.由此得出了关于2.45GHzECR离子源磁场场形的一些结论.     

超导ECR离子源DECRIS-SC2

A new compact version of the"liquid He-free"superconducting Electron Cyclotron Resonance Ion Source,to be used as an injector for the U-400M cyclotron,is presently under construction at the FLNR in collaboration with LHE(JINR).The axial magnetic field of the source is created by the superconducting magnet,and the NdFeB hexapole is used for the radial plasma confinement.The microwave frequency of 14GHz will be used for ECR plasma heating.The DECRIS-SC2 superconducting magnet is designed for the induction of a magnetic field on the axis of the source of up to 1.4T(extraction side)and 1.9T(injection side) at nominal current of 75A.Cooling of the coils is carried out by CM cryocooler with cooling power of 1W at the temperature 4.5K.The basic design features of the superconducting magnet and of the ion source are presented.The main parts of the source are in production.The first beam test of the source is expected in the beginning of 2007.     

SECRAL超导磁体系统的结构分析

An advanced superconducting ECR ion source named SECRAL has been constructed at Institute of Modern Physics of Chinese Academy of Sciences,whose superconducting magnet assembly consists of three axial solenoid coils and six sextupole coils with a cold iron structure as field booster and clamp.In order to investigate the structure of sextupole coils and to increase the structural reliabilities of the magnet system, global and local structural analysis have been performed in various operation scenarios.Winding pack and support structure design of magnet system,mechanical calculation and stress analysis are given in this paper. From the analysis results,it has been found that the magnet system is safe in the referential operation scenarios and the configuration of the magnet complies with design requirements of the SECRAL.     

RIKEN超导ECR离子源磁体系统的设计

Superconducting magnet system for a 28GHz ECR ion source has been designed.The maximum axial magnetic fields are 4T at the rf injection side and 2T at the beam extraction side,respectively.The hexapole magnetic field is about 2T on the inner surface of the plasma chamber.The superconducting coils consist of six solenoids and six racetrack windings for a hexapole field.Two kinds of coil arrangements were investigated:one is an arrangement in which the hexpole coil is located in the bore of the solenoids,and another is the reverse of it.The coils use NbTi-Copper conductor and are bath-cooled in liquid helium.The six solenoids are excited with individual power supplies to search for the optimal axial field distribution.The current leads use high Tc material and the cryogenic system is operated in LHe re-condensation mode using small refrigerators.The thermal insulated supports of the cold mass have also been designed based on the calculated results of the magnetic force.The heat loads to 70K and LHe stages were estimated from the design of the supports,the current leads and so on.     

一台2.45GHz强流中子源

A 2.45GHz microwave-driven ion source is being used to provide 40mA of deuterium ion beam (peak current) for an RFQ accelerator as part of a neutron source system.We have also designed a 60kV electrostatic LEBT using computer simulations.In our experiment,we measured the hydrogen and deuterium ion beam currents as functions of discharge power,gas flow,and magnetic field strength.The required beam current was obtained using leas than 700W of net microwave power with a gas flow of less than 1.5sccm.From the rise time data,it was determined that in order to obtain a high percentage of atomic ions in the beam, the beam extraction should start after 1ms of switching on the microwave power.At steady state,the proton fraction was above 90%.     

SECRAL在18GHz频率下产生强流高电荷态离子束的初步结果

A Superconducting ECR ion source with Advanced design in Lanzhou (SECRAL) was successfully built to produce intense beams of highly charged ions for Heavy Ion Research Facility in Lanzhou (HIRFL).The ion source has been optimized to be operated at 28GHz for its maximum performance.The superconducting magnet confinement configuration of the ion source consists of three axial solenoid coils and six sextupole coils with a cold iron structure as field booster and clamping.For 28GHz operation,the magnet assembly can produce peak mirror fields on axis 3.6T at injection,2.2T at extraction and a radial sextupole field of 2.0T at plasma chamber wall.A unique feature of SECRAL is that the three axial solenoid coils are located inside of the sextupole bore in order to reduce the interaction forces between the sextupole coils and the solenoid coils. During the ongoing commissioning phase at 18GHz with a stainless steel chamber,tests with various gases and some metals have been conducted with microwave power less than 3.2kW and it turned out the performance is very promising.Some record ion beam intensities have been produced,for instance,810eμA of O~(7 ),505eμA of Xe~(20 ),306eμA of Xe~(27 ),21eμA of Xe~(34 ),2.4eμA of Xe~(38 ) and so on.To reach better results for highly charged ion beams,further modifications such as an aluminium chamber with better cooling,higher microwave power and a movable extraction system will be done,and also emittance measurements are being prepared.     

强流高电荷态Pb离子束的产生与优化研究

随着原子物理及表面物理研究的发展,电荷态金属离子束的需求日益增多. 近来,中国科学院近代物理研究所,14.5GHz LECR3,离子源实验平台上, 以炉子法产生的铅离子束作为研究对象, 进行了一系列,ECR,离子源关键参数(如：磁场、炉子功率、掺气等)影响高电荷态铅离子束产额的实验研究, 在此基础上, 调整优化了,LECR3,离子源的状态参数, 从而获得了强流高电荷态铅离子束,18eμa ²⁰⁷Pb³⁰⁺,和6.7eμa ²⁰⁷Pb³⁷⁺.     

ECR离子源束流发射度的实验研究

利用最新自行研制的电扫描发射度探测系统, 在ECR离子源上进行了一系列关于ECR离子源引出束流发射度的研究. 这套电扫描发射度探测系统安装在中国科学院近代物理研究所(兰州)的LECR3试验平台的束运线上. 试验中, 通过测量相关参数, 研究了磁场、微波、掺气效应及负偏压效应等对引出束流发射度的影响. 利用实验所得的结果与关于ECR等离子体和离子源束流发射度的半经验理论, 分析推导了离子源各可调参数与ECR等离子体的直接关系, 这为分析探索ECR离子源的工作机制提供了一定的参考依据.     

宽带微波馈入对于具有常规磁场构型的ECR离子源性能的提高

As clearly demonstrated at several laboratories,the performances of electron-cyclotron resonance (ECR)ion sources can be enhanced by increasing the physical sizes(volumes)of embedded ECR zones.En- larged ECR zones have been achieved by engineering the central magnetic field region of these sources so they are uniformly-distributed"volumes"in resonance with single-frequency rf power.Alternatively,the number of ECR surfaces in conventional minimum-B geometry sources can be increased by heating their plasmas with multiple,discrete frequency microwave radiation.Broadband rf power offers a simple,low cost and arguably more effective means for increasing the physical sizes of the ECR zones within the latter source type.In this article,theoretical arguments are made in support of the volume effect and the charge-state enhancing ef- fects of broadband microwave radiation(bandwidth:200MHz)plasma heating are demonstrated by comparing the high-charge-states of Ar ion beams,produced by powering a conventional minimum-B geometry,6.4GHz ECR ion source,equipped with a biased disk,with those produced by conventional bandwidth(bandwidth:～1.5MHz)radiation.     

VENUS离子源的最新结果(28GHz)

The nest 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 intesities. The VENUS project is focused on two main objectives. First, for the 88-Inch Cyclotron,VENUS will serve as the third injector soures boosting both the energy and itensity of beams available form the facility.Seconly,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 U28 to 34 . These high intensity ion beam requerements present a challenge for the beam transport system since the total currents extracte from the ECR ion source reach several mA. Therefore in parallel to io beam develoments,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 ransprot form 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 ofO6 ,600eμA of Ar9 ,etc.) have been produced. In addition, we have started the developent of high intensity uranium beams. For example, 200eμA of U33 and U34 have been produced so far. In respect to high charge state ions,leμA of Ar18 ,133eμA of Ar16 ,and 4.9eμA of U47 have been measured. In addition,ion beam profile meaurements are presented with ,and without the sextupole magnetic field energized. These expeerimental results are being compared with simulations using the WARP code.     

用于1MeV 分离作用RFQ加速器改造的ECR氧离子源及LEBT系统的研制

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.