Production of intense highly charged ion beams by IMP 14.5 GHz electron cyclotron resonance ion source

A new 14.5 GHz Electron Cyclotron Resonance (ECR) ion source has been constructed over the last two years. The source was designed and tested by making use of the latest results from ECR ion source development, such as high mirror magnetic field, large plasma volume, and biased probe. 140uA of O^7+, 185uA of Ar^11+ and 50uA of Xe^26+ could be produced with a RF power of 800 W. The intense beams of highly charged metallic ions are produced by means of the method of a metal evaporation oven and volatile compound through axial access. The test results are 130uA of Ca^11+, 70uA of Ca^12+ and 65uA of Fe^lo+. The ion source has been put into operation for the cyclotron at the institute of Modern Physics (IMP).

Charge state effect on the K-shell ionization of iron by xenon ions near the Bohr velocity

Fe K-shell ionization cross sections induced by 2.4-6.0 MeV Xe^20＋ are measured and compared with different binary- encounter-approximation （BEA） models. The results indicate that the BEA model corrected both by the Coulomb repulsion and by the effective nuclear charge （Zeff） agrees well with the experimental data. Comparison of Fe K-shell X-ray emission induced by 5 MeV xenon ions with different initial charge states （20＋, 22＋, 26＋, 30＋） verifies the applicability of the effective nuclear charge （Zeff） correction for the BEA model. It is found that Zeff correction is reasonable to describe direct ionization induced by xenon ions with no initial M-shell vacancies. However, when the M shell is opened, the Zeff corrected BEA model is unable to explain the inner-shell ionization, and the electron transfer by molecular-orbital promotion should be considered.

Continuous operation of 2.45-GHz microwave proton source for 306 hours with more than 50 mA DC beam

This paper describes a long-term operation of the 2.45-GHz microwave proton source at Peking University. The DC proton beam of 50–55 mA with energy of 35 keV has been run for 306 hours continuously. Total beam availability,defined as 35-keV beam-on time divided by elapsed time, is higher than 99%. Water cooling machine failures cause all the downtime, and no plasma generator failure or high voltage breakdown is observed. The longest uninterrupted run time is122 hours.

Charge Breeding Simulations in a Hollow Electron Beam

Charge breeding technique is used for RIB （radioactive ion beam） production in order of optimizing the re-acceleration of the radioactive isotopes produced by a primary beam in a thick target. Charge breeding is achieved by means of a device capable of increasing the ion charge state from 1＋ to a desired value n＋. In some experiments, a continuous RIB of a given energy may be required. To reach this goal, a charge breeding device based on a hollow gun EBIS （electron beam ion source） has been proposed by the author recently. That EBIS, in principle, can be capable to realize a CW （continuous wave） operation. A sufficiently high focusing magnetic field could reduce to zero the hole radius in the EBIS electron beam. However, a smaller efficiency in the ion charge state increase should be expected. A code developed for studying the ion selective containment in a EBIS has been modified and used to simulate the ion charge state breeding. The effects of the hollow electron beam on the breeding rate have been studied.

高电荷态ECR离子源

综述了中国科学院近代物理研究所近几年来高电荷态ECR离子源的最新进展。

蒸发冷却技术在高电荷态ECR离子源磁体上的应用——LECR4

高电荷态ECR离子源磁体的功率密度高、发热量大,磁体线圈的高效冷却是制约性能进一步提升的关键技术之一,是离子源磁体技术研究的重要内容。本文介绍了基于蒸发冷却技术的近代物理研究所第四代高电荷态ECR离子源(LECR4)的研制工作。该离子源磁体线圈采用饼式单元结构,利用线饼单元间的窄隙作为冷却工质的流动通道,液态蒸发冷却工质在通道内吸收线圈热量并汽化,气态的工质向上流动进入冷凝器而冷凝。基于冷却工质的相变过程,建立自循环蒸发冷却热力循环,实现对磁体线圈热量的传输。设计制作完成的LECR4离子源进行了系统试验,试验结果表明,采用自循环蒸发冷却方式的离子源磁体线圈长期稳定运行在60℃左右,各项磁场指标均达到设计要求。

高性能全永磁ECR离子源LAPECR2的研制

研制了一台体积和重量都较大、设计性能较高的全永磁电子回旋共振(Electron cyclotron resonance, ECR)离子源LAPECR2(Lanzhou all permanent magnetic ECR ion source No．2)。该离子源将用于中国科学院近代物理研究所320 kV高压平台,为其提供强流高电荷态离子束流。LAPECR2的研制采用全新的全永磁磁体结构设计,通过采用高性能的NdFeB永磁材料、优化的磁结构设计以及精确的计算,实测源体的磁场参数能达到高性能ECR离子源的设计要求。离子源采用较高频率的14．5 GHz微波馈入加热等离子体,波导直接馈入离子源以增强馈入微波的稳定性与效率。此外,还大量采用了一些有利于提高离子源高电荷态离子产额的关键技术,如铝内衬等离子体弧腔、负偏压盘、铝制等离子体电极、三电极引出系统、辅助掺气等。

双频加热的LECR3离子源设计及初步的调试

研制成功了一台新的ECR(ElectronCyclotronResonance)离子源LECR3(LanzhouECRNo .3)。该离子源能为原子核物理与表面物理研究提供高电荷态离子束流 ,LECR3的设计主要基于IMP(InstituteofModernPhysics)的 14 .5GHzECR离子源 (LanzhouECRNo .2 ) ,但采用了双频加热、波导直接馈入微波功率及铝制等离子体弧腔等新技术和新方法。另外 ,LECR3的弧腔容积比LECR2的大 ,增加可注入的微波功率 ,可有效地增加引出的高电荷态离子束流的强度。虽然增大了弧腔的内径 ,但仍然保持径向六极磁铁在弧腔内壁上产生最大磁场强度与LECR2的同样大小。

永磁强流ECR离子源

文章介绍一台2.45GHz永磁强流ECR离子源,其直径为10cm,长10cm,重量不足5kg,可工作在直流模式和脉冲模式。脉冲模式引出的氢离子束峰值流强大于100mA,束流密度达到500mA/cm2;直流模式引出束流达到60mA,束流密度为300mA/cm2。两种模式的质子比均达到80%。

金属筒在ECR2高电荷态离子源中的应用

叙述了用金属筒来增强ECR2离子源的高电荷态离子束流强度。铝筒的增强效果最为显著。与锆简相比，Ar(8+)离子的束流强度从245μA增至330μA，Ar(9+)离子从125μA增至150μA。

高电荷态ECR2离子源

介绍了兰州重粒子加速器ＥＣＲ２离子源的结构特点，给出该离子源的调试结果。

强流高电荷态全永磁ECR离子源LAPECR2的初步调试

研制成功了一台强流高电荷态全永磁ECR(Electron Cyclotron Resonance)离子源LAPECR2(Lanzhou All Permanent Magnet ECR Ion Source No.2)。该离子源在完成磁体装配后已成功在近代物理研究所320 kV高压平台上安装就位,与后束运线完成对接组装。离子源于2005年7月在14.5 GHz实现了第一次成功起弧,并引出较强的混合束流。目前离子源已与后束线以及部分实验终端完成了联调,在实验终端能够获得强流较高电荷态的离子束流。本文将着重论述该全永磁源的结构技术特点和主要参数指标。本文还着重论述了LAPECR2离子源在14.5 GHz微波功率馈入条件下的初步调试结果,在此基础上对束流向实验终端联调的实验结果进行了讨论,着重分析了影响束流引出与传输效率的主要因素。

EPICS实现ECR离子源高压电源控制

本文在EPICS架构下设计了ECR离子源高压电源的控制逻辑结构,开发了支持其控制器的Record类型,完成了其IOC端的代码实现,实现了ECR离子源高压电源的控制并在现场运行。

ECR离子源高电荷态金属离子产生的MIVOC法实验研究

为满足兰州重离子加速器的实验要求,先后在中国科学院近代物理研究所14.5GHz(LECR2)及10GHz+14.5GHz(LECR3)高电荷态ECR离子源上使用MIVOC(Metallic ion fromvolatile compounds)方法进行了高电荷态金属离子产生的实验研究。主要研究了铁和镍的各种高电荷态离子的产生,具有代表性的是210eμA的Fe11+、175eμA的Fe12+、142eμA的Fe13+、25eμA的Fe16+、64eμA的Ni10+、57eμA的Ni13+、31eμA的Ni15+和15eμA的Ni16+。本文将分别给出两种金属离子产生的多电荷态束流谱图,并对实验装置的安排、实验现象及结果进行讨论与总结。

高电荷态ECR离子源的金属离子产生

简单介绍了采用炉子加热、挥发性金属化合物和溅射产生ECR离子源的金属离子的3种方法和实验结果,主要研究了铜、锌、镍和铁等多种电荷态离子的产生.对3种方法分别进行了探讨.

CIAE强流ECR离子源研制

本文介绍了研制的一台强流ECR微波离子源,其能从7mm直径的圆孔引出大于150mA的氢离子束(75keV),质子比达90%。该离子源采用独特的结构提高了离子源寿命。离子源在75keV、110mA束流条件下连续工作超过220h,束流中断2次,不间断工作时间超过150h。

ECR高电荷态离子源——CAPRICE的调试

本文介绍了10GH_z CAPRICE离子源的实验装置结构、工作原理及运行中各参数对引出束流的影响,同时给出了N、O、Ne、Ar四种元素的高电荷态束流大小及其离子束的连续谱。结果是满意的。

全永磁ECR离子源研究进展

ECR(电子回旋共振)离子源是产生稳定的强流多电荷态离子束流最有效装置。全永磁ECR离子源因其独特的特点为很多中小型多电荷态离子束流实验平台与离子注入机等系统所采用,为后者产生重复性好、稳定性强的多电荷态离子束流。本文着重论述了中国科学院近代物理研究所研制的几台全永磁多电荷态ECR离子源及其特性与典型性能,如能产生强流高电荷态离子束流的高性能全永磁离子源LAPECR2,能产生强流中低电荷态离子束流的LAPECR1,能产生多电荷态重金属离子束流的LAPECR1-M等。这些性能稳定的离子源为提高近代物理研究所相关试验平台的性能提供了关键的束流品质保障。

用连续激光在ECR离子源中产生金属离子研究

研究了用连续激光在ECR离子源中产生金属离子的方法,在中国科学院近代物理研究所的高电荷态离子源ECR2上。

First Results of SECRAL at 18GHz for Intense Beam Production of Highly Charged Ions

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.