高电荷态金属离子的产生实验研究

　为满足兰州重离子加速器的实验要求,在14.5GHz高电荷态ECR离子源上做了一系列产生金属离子的实验,尝试了多种方法,包括炉子加热及MIVOC(MetallicIonformVolatileCompounds)两种方法,其中,用炉子做的结果较理想。实验主要研究了铜、锌、镍多种电荷态离子的产生,具有代表性的是39euA的Cu13+,30euA的Zn15+和29euA的Ni10+。分别给出了这三种金属离子产生的多电荷态束流峰谱图,以及实验的一些其它现象及结果,并对其进行了讨论与总结。

~(40)Ar~(10+)轰击Al和Si固体表面形成的200～1000nm光谱

报道了利用兰州重离子加速器国家实验室ECR离子源提供的高电荷态离子~(40)Ar~(10+)入射到Al和p型Si表面所产生的Al,Si,Ar原子的200～1000nm特征光谱的实验测量结果。结果表明,低速高电荷态离子与团体表面原子相互作用可有效地激发靶原子和靶离子的特征谱线,而且由于发射二次电子的无辐射退激与辐射光子退激过程的竞争,使得在p型Si表面上Ar原子的光谱强度总体大于在Al表面上的光谱强度。

高电荷态离子与表面相互作用

论述了高电荷态离子与表面相互作用的过程 ,说明了发射电子、发射光子、负离子、中性粒子、正离子的散射和发射的物理机理以及应用前景 .介绍了在兰州重离子国家实验室ECR源建立高电荷态离子与表面相互作用的原子物理平台的重要意义和将要开展的工作

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。

2.45GHz单电荷态电子回旋共振离子源

描述了一台 2 .4 5GHz单电荷态电子回旋共振 (ECR)离子源的原理、结构与应用。介绍了其微波系统与磁场结构。在微波输入功率约 6 0 0W ,引出高压 2 2kV ,引出孔径为6mm时 ,该离子源的总束流I(H1++H2 ++H3+)可达 90mA。

Study of the interaction of highly charged ions with SiO2 surface

Highly charged ions (HCIs) AO(q+)/Pbq+ are extracted from ECR source and impacted on solid surface Of SiO2 Sputtering yield as a function of incident angle is measured by multi-channel plate (MCP). The results have been fitted by a new formula. We proposed the cooperation model to explain the formula. The results demonstrate that the potential assisted kinetic sputtering yield increases with the charge state and potential sputtering (PS) could be induced by impact of HCIs. At larger incident angles, the sputtering yield is dominated by elastic collision between HCIs and material atoms. It is found that, smaller the incident angle, larger the contribution from the potential sputtering. (C) 2009 Elsevier B.V. All rights reserved.

36-segmented high magnetic field hexapole magnets for electron cyclotron resonance ion source

Two high magnetic field hexapoles for electron cyclotron resonance ion source (ECRIS) have successfully fabricated to provide sufficient radial magnetic confinement to the ECR plasma. The highest magnetic field at the inner pole tip of one of the magnets exceeds 1.5 T, with the inner diameter (i.d.)=74 mm. The other hexapole magnet provides more than 1.35 T magnetic field at the inner pole tip, and the i.d. is 84 mm. In this article, we discuss the necessity to have a good radial magnetic field confinement and the importance of a Halbach hexapole to a high performance ECRIS. The way to design a high magnetic field Halbach structure hexapole and one possible solution to the self-demagnetization problem are both discussed. Based on the above discussions, two high magnetic field hexapoles have been fabricated to be utilized on two high performance ECRISs in Lanzhou. The preliminary results obtained from the two ECR ion sources are given

Experiments and modification on electron cyclotron resonance ion sources at the Institute of Modern Physics

Uranium ion beams were produced from electron cyclotron resonance (ECR) ion sources by sputtering method this year at the Institute of Modern Physics. At first, we chose the Lanzhou ECR No. 3 ion source to implement the production experiment of U ion beams. Finally, 11 e mu A of U28+, 5 e mu A of U32+, and 1.5 e mu A of U35+ were obtained. A U26+ ion beam produced by the LECR2 ion source was accelerated successfully by the cyclotron. This means that the Heavy Ion Research Facility in Lanzhou (HIRFL) has accomplished the acceleration of the ion beam of the heaviest element according to the designed parameters. The Lanzhou ECR ion source No. 2 (LECR2), which was built in 1997, has served the HIRFL for eight years and needed to be upgraded to provide more intense high charge state ion beams for HIRFL cooling storage ring. We started the upgrading project of LECR2 last year, and the modified design just has been finished. (c) 2006 American Institute of Physics.

A latest developed all permanent magnet ECRIS for atomic physics research at IMP

Electron cyclotron resonance (ECR) ion sources have been used for atomic physics research for a long time. With the development of atomic physics research in the Institute of Modern Physics (IMP), additional high performance experimental facilities are required. A 300 kV high voltage (HV) platform has been under construction since 2003, and an all permanent magnet ECR ion source is supposed to be put on the platform. Lanzhou all permanent magnet ECR ion source No. 2 (LAPECR2) is a latest developed all permanent magnet ECRIS. It is a 900 kg weight and circle divide 650 mm X 562 mm outer dimension (magnetic body) ion source. The injection magnetic field of the source is 1.28 T and the extraction magnetic field is 1.07 T. This source is designed to be running at 14.5 GHz. The high magnetic field inside the plasma chamber enables the source to give good performances at 14.5 GHz. LAPECR2 source is now under commissioning in IMP. In this article, the typical parameters of the source LAPECR2 are listed, and the typical results of the preliminary commissioning are presented.

Advanced superconducting electron cyclotron resonance ion source SECRAL: Design, construction, and the first test result

Superconducting electron cyclotron resonance (ECR) ion source with advanced design in Lanzhou (SECRAL) is a next generation ECR ion source and aims for developing a very compact superconducting ECR ion source with a structure and high performances for highly charged ion-beam production. The ion source was designed to be operated at 18 GHz at initial operation and finally will be extended to 28 GHz. 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. At full excitation, this magnet assembly can produce peak mirror fields on the axis of 3.6 T at injection, 2.2 T at extraction, and a radial sextupole field of 2.0 T at plasma chamber wall. What is different from the traditional design, such as LBNL VENUS and LNS SERSE, 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. SECRAL may open the way for building a compact and high-performance 18-28 GHz superconducting ECR ion source. Very preliminary commissioning results are promising. Detailed design, construction issues and very preliminary test results of the ion source at 18 GHz are presented.

Experimental study on the electric-sweep scanner and ion beam emittance of electron cyclotron resonance ion source

With a latest developed electric-sweep scanner system, we have done a lot of experiments for studying this scanner system and ion beam emittance of electron cyclotron resonance (ECR) ion source. The electric-sweep scanner system was installed on the beam line of Lanzhou electron resonance ion source No. 3 experimental platform of Institute of Modem Physics. The repetition experiments have proven that the system is a relatively dependable and reliable emittance scanner, and its experiment error is about 10%. We have studied the influences of the major parameters of ECR ion source on the extracted ion beam emittance. The typical results of the experiments and the conclusions are presented in this article.

The electron emission yield induced by the interaction of highly charged argon ions with silicon surface

The electron emission yield of the interaction of highly charged argon ions with silicon surface is reported. The experiment was done at the Atomic Physics Research Platform on the Electron Cyclotron Resonance (ECR) Ion Source of the National Laboratory HIRFL (Heavy Ion Research Facility in Lanzhou). In the experiment, the potential energy and kinetic energy was selected by varying the projectile charge states and extracting voltage, thus the contributions of the projectile potential energy deposition and electronic energy loss in the solid are extensively investigated. The results show that, the two main factors leading to surface electron emission, namely the potential energy deposition and the electronic energy loss, are both approximately proportional to the electron emission yield per ion.

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, 810e mu A of O7+, 505e mu A of Xe20+, 306e mu A of Xe27+, 21e mu A of Xe34+, 2.4e mu A of Xe38+ 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.

Structure analysis of the SECRAL superconducting magnet system

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.

Commissioning test of LAPECR2 source on the 320kV HV platform

The high charge state all permanent Electron Cyclotron Resonance Ion Source (ECRIS) LAPECR2 (Lanzhou All Permanent magnet ECR ion source No.2) has been successfully put on the 320kV HV platform at IMP and also has been connected with the successive LEBT system. This source is the largest and heaviest all permanent magnet ECRIS in the world. The maximum mirror field is 1.28T (without iron plug) and the effective plasma chamber volume is as large as circle divide 67mm x 255mm. It was designed to be operated at 14.5GHz and aimed to produce medium charge state and high charge state gaseous and also metallic ion beams. The source has already successfully delivered some intense gaseous ion beams to successive experimental terminals. This paper will give a brief overview of the basic features of this permanent magnet ECRIS. Then commissioning results of this source on the platform, the design of the extraction system together with the successive LEBT system will be presented.