强流ECR离子源引出系统研究

为了提高强流ECR 离子源的引出束流品质,分别设计了1# 和2# 引出系统,利用束流引出模拟软件PBGUNS 对1# 和2# 引出系统进行了质子束流引出与传输的模拟计算,结合实际测得的发射度数据分析引出系统,发现2# 引出系统比1# 引出系统引出束流品质高。对ECR 离子源引出系统的电势等位线分布等参数引起的球差进行了简单数学推导及MATLAB 绘图,并结合1# 和2# 引出系统束流相图模拟结果证明了球差会使引出束流品质有效发射度增长,通过适当加大电极孔径可改善束流聚焦情况,得到了束流光学聚焦较好的束流引出系统设计。To improve the quality of extracted ion beam from a high current ECR ion source, 1# and 2# extraction systems were designed and tested. The PBGUNS code was used to simulate the 1# and 2# extraction systems of proton ion beam. The emittance measurement results with the two different extraction systems were compared and analyzed with the simulation, the conclusion that more high quality beam extracted from 2# system than 1# system was got. The formula derivation of ECR ion source extraction system spherical aberration and MATLAB drawing was done by the analyzing on the distribution of extraction field equipotentials, effective emittance increasing caused by spherical berration was proved by 1# and 2# extraction systems beam phase space simulation result, beam focusing would be improved if electrode hole size increasing appropriately and a general concept on good optics focusing of ion beam extraction system was proposed finally.     

Arc Power Limit and Distribution on the Large Negative Ion Source Based on JT-60 NNBI

The target of the large negative ion source based on neutral beam injection (N-NBI) is to produce neutral beam current of 22 A and beam power of 10 MW at 500 keV with duration time of 10 s. Since it was successfully operated in 1996, the 5.3 MW neutral beam power at 380 keV with duration time of 3 s has been achieved. In recent years improving and enhancing the beam power are going on. Several reasons such as plasma non-uniformity, higher beam density at the upper region in the beam profile,     

Measurement of the Intensity Distribution of a Hard X-Ray Radiation Source

Physics of Atomic Nuclei - The procedure of measurement of the brightness distribution of the hard X-ray source of the MIB-7.5 betatron with a penumbral aperture is detailed (i.e., a measurement...     

Ion Beam Generation in a Vacuum Arc Ion Source with a Multicomponent Cathode

Russian Physics Journal - Vacuum arc ion sources are widely used for modifying the properties of various surfaces using ion implantation. The use of cathodes consisting of multicomponent compounds...     

Energetic Ion Effects on the Ion Saturation Current

The ion saturation current is very important in probe theory, which can be used to measure the electron temperature and the floating potential. In this work, the effects of energetic ions on the ion saturation current are studied via particle-in-cell simulations. It is found that the energetic ions and background ions can be treated separately as different species, and they satisfy their individual Bohm criterion at the sheath edge. It is shown that the energetic ions can significantly affect the ion saturation current if their concentration is greater than T_e/(γi2 T_(i2))~(1/2), where Te is the electron temperature, and γ_(i2) and T_(i2) represent the polytropic coefficient and temperature of energetic ions, respectively. As a result, the floating potential and the I V characteristic profile are strongly influenced by the energetic ions. When the energetic ion current dominates the ion saturation current, an analysis of the ion saturation current will yield the energetic ion temperature rather than the electron temperature.     

A Unidirectional Ion Source Discharge

An asymmetric axial plasma potential gradient would be useful for creating an efficient unidirectional ion source. A weak inhomogeneous axial magnetic field has been employed to enforce such plasma density and potential gradients. An alternative technique has been studied by computational methods and involves a differential vacuum pumping which introduces a strong axial dependence into the electron-gas ionization rate.     

High-Power Ion Beam Characteristics of a Magnetic Multi-Pole Line-Cusp Ion Source for the HL-2A Tokomak

A circular magnetic multi-pole line-cusp ion source with a nominal 45 keV 25 A hydrogen ion beam is developed for the neutraJ beam injector of the HL-2A tokomak. At present, this bucket ion source can produce a 40 keV 20 A hydrogen ion beam for less than lOOms on a test bed, and a 35 ke V 13A ion beam for 300ms on the injector of the HL-2A tokomak. The 1/e half-width of the ion beam power profile is about 6.0 ± 0.2 em at the positionof 3.26m downstream from ion source, and the corresponding divergence degree is nearly 1.1. The optimum perveance matched conditions were obtained experimentally, and were in good agreement with the values from experiential equation of Uhlemann et al. The maximum of optimum perveance reached 2.2 × 10^-6 A/V^1.5 for 38 keV beam energy. An ion beam with above 60% H^＋ species fraction can be achieved, which was measured by Ha light Doppler shift spectroscopy. According to research results, a neutral beam with a total power of more than 0.6 MW was successfully injected into the plasma of the HL-2A Tokomak in 2008.     

Direction Finding of a Source in an Acoustic Waveguide and the Angular Resolution Limit

Acoustical Physics - A reduced-rank adaptive algorithm is constructed, which makes it possible to find sound sources directions using a horizontal array operating in a waveguide with inaccurately...     

Laser Ion Source Project at IGISOL

The application of laser ionisation is being developed for the IGISOL mass separator facility in Jyväskylä, Finland. The conceived laser ion source will have two independent pulsed laser systems based on all solid-state lasers and dye lasers for maximal coverage of ionisation schemes throughout the periodic table. A laser ion source trap, LIST, method will be pursued for optimal selectivity.     

Development Towards a Laser Ion Source Trap for the Production of Exotic Species

A new type of resonance ionization laser ion source (RILIS) is presently being developed and tested at the off-line mass separator at Mainz University for future use at on-line exotic rare isotopes production facilities. For highest isobaric selectivity, this RILIS approach decouples the evaporation and ionization process. A further advantage is the generation of full temporal control of the resulting high quality ion beam. These facts are realized by a combination of atomizer – ion repeller – ion cooler and trap, which is operated together with a state-of-the-art, all solid state laser system. The principle and performance of this laser ion source trap (LIST) system are discussed applying simulation studies for the repeller-trap combination and first measurements for characterization.     

高电荷态ECR离子源

介绍了目前ECR离子源的发展状况和国际上几台典型的ECR离子源.Electron cyclotron resonance (ECR) ion source is the most efficient facility for producing highly charged ions. So far more than 1 emA of O 6+ and 0.02 eμA of U 55+ have been delivered by ECR ion source. In this paper the latest development of ECR ion source is presented and several typical ECR ion sources in the world is introduced.     

Simple Approach to the Solution of a Trapped and Radiated Cold Ion Beyond the Lamb—Dicke Limit

Trapping ions outside the Lamb-Dicke limit have been proven to be useful for the laser-cooling and quantum computing.Under the supposition of the Radi frequency much smaller than the Lamb-Dicke parameter,we can use a simple method to analytically solve the system with a single cold ion trapped and radiated beyond the Lamb-Dicke limit,in the absence of the rotating-wave approximation(RWA).Discussion has been made for the limitation of our approach and the comparison of our results with the solutions under the RWA.     

阴极真空弧离子源的研制

为发展金属离子束材料表面改性技术的工业应用，北师大低能核物理所研制成阴极真空弧离子源和离子注入装置．简要介绍该设备的结构、原理和性能． The cathode vacuum arc ion source and ion implantation facility have been developed in our institute for industrial application of surface modification of materials. In this paper the principle structure and performance of these facilities were described.     

On the Limit Lognormal and Other Limit Log-Infinitely Divisible Laws

The limit log-infinitely divisible multifractals of Muzy and Bacry (Phys. Rev. E 66:056121, 2002) are reviewed and shown to possess novel invariance relations that translate into functional Feynman-Kac equations for the corresponding probability distributions. In the special case of the limit lognormal process of Mandelbrot (in Statistical Models and Turbulence, M. Rosenblatt, C. Van Atta (Eds.), Springer, New York, 1972), the limit distribution is represented exactly in an operator form using the technique of intermittency expansions. A novel representation for the Mellin transform of the limit distribution is derived and related to the Hurwitz zeta function. For application, the cumulants of the logarithm of the limit lognormal distribution are computed explicitly.     

超声波空化作用对ICP光源辐射强度的影响

为了增大电感耦合等离子体辐射强度,降低分析检出限,实验研究了水样品经过超声波空化处理以后样品表面张力和粘度的变化,并探索了空化效应对光谱强度和信背比的影响。实验结果证明,样品溶液的表面张力和黏度随着超声波功率和空化时间的增加均呈现出先减小后增大的变化规律,在功率为50 W、时间为15min时水样品的表面张力和粘度最低。经此条件处理的水样品引入ICP以后,元素Al,Cd,Mn,Ni,Pb和Zn的谱线强度比无空化处理时分别提高了56.73%,57.23%,44.57%,43.20%,39.04%和40.19%,光谱信背比分别提高了61.54%,64.86%,44.95%,52.27%,40.84%和40.85%。可见,空化处理水溶液能够改善ICP发射光谱质量。