The Progress of ECR ion source

Withitsmanyadvantagessuchashighefficiency,longlifeandgoodbeamquality,ECRionsourcehasbeenextensivelyadoptedasthemajorionsourceofhighcurrentprotonlinacworld-widelyinrecentyears.SignificantprogressonCIAEECRionsourcehasbeenmadethisyear.TheECRionsourceincludsa…     

用于质子直线加速器的强流ECR离子源

介绍了正在研制的一台强流ECR离子源。它的目标是用于加速器驱动的次临界系统(ADS)。两种结构的离子源均获得了较好的结果。在30 keV能量下,氢离子最大束流达到100 mA,质子比好于85％,引出束流密度最高可达340 mA/cm2。初步测定的发射度约为0.11πmm·mrad。已通过了100 h的连续运行考验。     

Identification of the ECR zone in the SWISSCASE ECR ion source

The magnetic field of the permanent magnet electron cyclotron resonance (ECR) ion source SWISSCASE located at the University of Bern has been numerically simulated and experimentally investigated. For the first time the magnetized volume qualified for electron cyclotron resonance at 10.88 GHz and 388.6 mT has been analyzed in highly detailed 3D simulations with unprecedented resolution. The observed pattern of carbon coatings on the source correlates strongly with the electron and ion distribution in the ECR plasma of SWISSCASE. Under certain plasma conditions the ion distribution is tightly bound to the electron distribution and can considerably simplify the numerical calculations in ECR related applications such as ECR ion engines and ECR ion implanters.     

The ECR ion source and associated equipment at the KVI

The performance of the ECR source at the KVI is discussed; beam properties at the three target stations for atomic and surface physics are given. The source is also in operation as an external source to the K = 160 AVF cyclotron.     

Numerical simulation program of multicomponent ion beam transport from ECR ion source

In order to research multi-component ion beam transport process and improve transport efficiency, a special simulating program for ECR beam is becoming more and more necessary. We have developed a program written by Visual Basic to be dedicated to numerical simulation of the highly charged ion beam and to optimization of beam dynamics in transport line. In the program the exchange of electrons between highly charged ions and low charged ions or neutral atoms (residual gas in transport line) is taken into account, adopting classical molecular over-barrier model and Monte Carlo method, so the code can easily give the change of charge state distribution along the transmission line. The main advantage of the code is the ability to simultaneously simulate a large quantity of ions with different masses and charge states, and particularly, to simulate the loss of highly charged ions and the increase of low charged ions due to electron exchange in the whole transport process. Some simulations have been done to study the transmission line of LECR3 which is an ECR ion source for highly charged ion beam at IMP. Compared with experimental results, the simulations are considered to be successful.     

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 ECRion 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.     

电子回旋共振离子源永磁体的优化设计

对永磁电子回旋共振(Electron cyclotron resonance,ECR)离子源磁场运用Poisson程序进行了模拟计算,将模拟计算结果和测量结果进行了比较.依据计算结果,设计加工了NdFeB(钕铁硼)永磁体,得到了比较好的磁场场形,并在ECR离子源调试中获得了较强的束流.     

Effect of magnetic field distribution on ECR ion source discharge

An electron cyclotron resonance ion source model that uses a coaxial antenna to inject the RF power was simulated, and the corresponding hydrogen plasma densities of the ion source were calculated at different magnetic field distributions via a fluid model. The results show that most of the microwave power is absorbed around the resonance surface near the antenna when the plasma density is below the cutoff density of 7.4 × 10~(16) m~(-3) for 2.45 GHz microwaves, and the simulation results also show that the plasma density is strongly influenced by the position and shape of the resonance surface, where a larger resonance surface would improve the plasma density.     

2.45GHz单电荷态电子回旋共振离子源

描述了一台2．45GHz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600W,引出高压22kV,引出孔径为φ6mm时,该离子源的总束流I（H1^ H2^ H3^ )可达90mA。     

Analysis of X-ray spectra in 14.5-GHz ECR ion source for optimizing operation conditions

An electron cyclotron resonance (ECR) ion source operating at 14.5 GHz was developed for the generation of charged ions at the Korea Atomic Energy Research Institute (KAERI). Experiments were carried out to study the plasma inside the ECR ion source by analyzing the X-ray spectra generated by it. The X-ray energy distribution and electron energy inside the plasma chamber are influenced by the status of the heated plasma. That status depends on various operation parameters such as microwave power, injected gas-pressure, and solenoid and trim coil currents. X-ray spectra were recorded to find the correlation between the plasma and the X-rays for variations in the operation parameters. A standard NaI(Tl) detector was used for that purpose. The X-ray energy distribution was studied in the range of 100–500 W for radiofrequency power. The influence of the injected gas pressure and the mirror ratio in the emission of X-rays were analyzed.     

ECR源控制用的网络模型

在研究ECR源智能控制的理论模型时，对几种模型进行理论探讨，编程并做仿真实验，对其结果进行了分析。着重对模糊modular神经网络(即组合网络)进行描述，分析该模型的优缺点，并在实验中对仿真计算结果随学习次数、规则条数和学习率之间的变化关系进行了深入研究。     

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320kV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14．5GHz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14．5GHz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。     

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柬流的LAPECRl-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.     

Bended probe diagnostics of the plasma characteristics within an ECR ion source with a rectangular waveguide

To reveal the argon plasma characteristics within the entire region of an electron cyclotron resonance(ECR) ion source, the plasma parameters were diagnosed using a bended Langmuir probe with the filament axis perpendicular to the diagnosing plane. Experiments indicate that,with a gas volume flow rate and incident microwave power of 4 sccm and 8.8 W, respectively,the gas was ionized to form plasma with a luminous ring. When the incident microwave power was above 27 W, the luminous ring was converted to a bright column, the dark area near its axis was narrowed, and the microwave power absorbing efficiency was increased. This indicates that there was a mode transition phenomenon in this ECR ion source when the microwave power increased. The diagnosis shows that, at an incident microwave power of 17.4 W, the diagnosed electron temperature and ion density were below 8 eV and 3?×?10~(17) m~(-3), respectively, while at incident microwave power levels of 30 W and 40 W, the maximum electron temperature and ion density were above 11 eV and 6.8?×?10~(17) m~(-3), respectively. Confined by magnetic mirrors, the higher density plasma region had a bow shape, which coincided with the magnetic field lines but deviated from the ECR layer.     

Study of a new cusp field for an 18 GHz ECR ion source

A feasibility study was performed to generate new sufficient mirror cusp magnetic field (CMF) by using the coils of the existing room temperature traditional 18 GHz electron cyclotron resonance ion source (ECRIS) at RIKEN. The CMF configuration was chosen because it contains plasma superbly and no multipole magnet is needed to make the contained plasma quiescent with no magneto-hydrodynamic (MHD) instability and to make the system cost-effective. The least magnetic field, 13 kG is achieved at the interior wall of the plasma chamber including the point cusps (PC) on the central axis and the ring cusp (RC) on the mid-plane. The mirror ratio calculation and electron simulation were done in the computed CMF. It was found to contain the electrons for longer time than in traditional field. It is proposed that a powerful CMF ECRIS can be constructed, which is capable of producing intense highly charged ion (HCI) beam for light and heavy elements.     

The relaxation of strong electron excitations in solids induced by multicharged ion bombardment

The relaxation of electron excitations arising from irradiation by multicharged ions of metals and insulators is considered. The excitation processes in solids are described. In metals, the relaxation is determined by the electron thermal conductivity, and electron energy transfer to the lattice is small. In insulators, the electron excitation relaxation is dependent on the low temperature ionization wave, the electron heat is localized, and lattice atoms receive enough energy for melting. The electron-phonon interaction at high electron temperatures and lattice relaxation is considered.     

Experimental results from an ECR source using an octupole

The large superconducting ECR source, ECREVIS (Louvain-la-Neuve) has shown better charge state distribution (CSD) than smaller sources like MINIMAFIOS or the Berkeley source. Computer simulation indicates that the reason could be a lower average electron energy in the smaller sources. It has been suggested by Jongen that the size of the magnetic gradients in the source could be the energy limiting factor, and that the average electron energy could be increased by replacing the usual sextupole by an octupole. After an extensive series of tests, the sextupole of the Berkeley source was replaced by an octupole. After modification, the CSD have been substantially improved in the direction of higher charge states, with a substantial reduction of low charge state intensity. The intensity of higher charge states like argon 14+ or krypton 18+ increased by one order of magnitude. The new CSD are now very similar to those of the large ECREVIS source, indicating a probable gain in average electron energy.     

A high charge state all-permanent magnet ECR ion source for the IMP 320 kV HV platform

A 320 kV high voltage (HV) platform has been constructed at Institute of Modern Physics (IMP) to satisfy the increasing requirements of experimental studies in some heavy ion associated directions. A high charge state all-permanent magnet ECRIS-LAPECR2 has been designed and fabricated to provide intense multiple charge state ion beams (such as 1000 eμA O⁶⁺, 16.7 eμA Ar¹⁴⁺, 24 eμA Xe²⁷⁺, etc.) for the HV platform. LAPECR2 has a dimension of ∅ 650 mm × 560 mm. The powerful 3D magnetic confinement to the ECR plasma and the optimum designed magnetic field for the operation at 14.5 GHz makes it possible to obtain very good performances from this source. After a brief introduction of the ECRIS and accelerator development at IMP, the conceptual design of LAPECR2 source is presented. The first test results of this all-permanent magnet ECRIS are given in this paper.     

Polarized ion source

A polarized ion source giving a current of about 0.1A has been constructed. The background from nonpolarized deuterons is 1–2%, and that from protons is 10–15%. The degree of alignment of the deuterons has been checked; this is revealed in the anisotropy of the angular distribution of partides in the reaction T(d,n)He⁴.The degree of alignment equals P₂ = –0.32₆ ± 0.01, which agrees closely with the theoretical value P₂ = –0.328 for an orienting field of 10 Oe. This latter leads to the conclusion that the polarization of the protons is about 50% and that of the deuterons about 33%. Cooling the water dissociator with liquid nitrogen increases the intensity approximately by a factor of two.Translated from Atomnaya Énergiya, Vol. 17, No. 1, pp. 17–22, July, 1964     

The negative ion source test facility ELISE

The ITER neutral beam system is using inductively coupled radio frequency (RF) ion sources, that have demonstrated the required ITER parameters on (small) sources with extraction areas up to 200 cm². As a next step towards the full size ITER source IPP is presently constructing the test facility ELISE (“Extraction from a Large Ion Source Experiment”) operating with a “half-size” source which has approximately the width but only half the height of the ITER source. The modular driver concept is expected to allow a further extrapolation to the full size in one direction to be made. The main aim of this experiment is to demonstrate the production of a large uniform negative ion beam with ITER relevant parameters in stable conditions up to one hour.Plasma operation of the source is foreseen to be performed continuously for 1 h; extraction and acceleration of negative ions up to 60 kV is only possible in pulsed mode (10 s every 180 s) due to limitations of the existing IPP HV system. The design of the source and extraction system implements a high experimental flexibility and a good diagnostic access while still staying as close as possible to the ITER design. The main differences are the source operating in air and the use of a large gate valve between the source and the target chamber.ELISE is expected to start operation at the end of 2011 and is an important step for the development of the ITER NBI system; the experience gained early will support the design as well as the commissioning and operating phases of the PRIMA NBI test facilities and the ITER neutral beam system.