Concepts for the magnetic design of the MITICA neutral beam test facility ion accelerator

The megavolt ITER injector concept advancement neutral injector test facility will be constituted by a RF-driven negative ion source and by an electrostatic Accelerator, designed to produce a negative Ion with a specific energy up to 1 MeV. The beam is then neutralized in order to obtain a focused 17 MW neutral beam. The magnetic configuration inside the accelerator is of crucial importance for the achievement of a good beam efficiency, with the early deflection of the co-extracted and stripped electrons, and also of the required beam optic quality, with the correction of undesired ion beamlet deflections. Several alternative magnetic design concepts have been considered, comparing in detail the magnetic and beam optics simulation results, evidencing the advantages and drawbacks of each solution both from the physics and engineering point of view.     

Atomic hydrogen beam source: a convenient, extended cavity, microwave discharge design

An extended cavity design of a microwave discharge source for production of intense beams of atomic, radical, and metastable species in vacuo is described. The extended cavity enables the discharge to be run at the beam source nozzle while the power connection and tuning elements remain conveniently outside the apparatus. This design minimizes wall recombination losses to produce intense atomic hydrogen beams with considerably less engineering than previous discharge sources.     

Low-energy beam transport studies supporting the spallation neutron source 1-MW beam operation

The H(-) injector consisting of a cesium enhanced RF-driven ion source and a 2-lens electrostatic low-energy beam transport (LEBT) system supports the spallation neutron source 1 MW beam operation with ～38 mA beam current in the linac at 60 Hz with a pulse length of up to ～1.0 ms. In this work, two important issues associated with the low-energy beam transport are discussed: (1) inconsistent dependence of the post-radio frequency quadrupole accelerator beam current on the ion source tilt angle and (2) high power beam losses on the LEBT electrodes under some off-nominal conditions compromising their reliability.     

High-flux beam source of fast neutral helium

A high-flux beam source of fast neutral helium has been constructed by extending the designs of previous authors. The source is a dc or pulsed electric discharge in an expanding gas nozzle. The beam produced has a flux on the order of 10(15) atoms/s sr and a mean velocity on the order of 10(7) cm/s. The composition of the beam has been determined by the use of particle detectors and by the observation of the excitation of certain target gases. An upper bound of 3.7 x 10(-5) has been estimated for the He(2(3)S(1))/He((1)S(0))beam density ratio and a value of 0.2 found for the He(+)/He(1(1)S(0)) beam density ratio.     

Generation of an ion beam in a glow-discharge source

A mechanism of ion extraction from a glow-discharge ion source based on a hollow cathode and used for elemental analysis of solids, is considered Experiments have shown that two oppositely directed ion flows are formed from ions produced in the region of negative glow-discharge fluorescence. One flow has an ion energy ≥ 100 eV, is directed to the cathode, and bombards and sputters the analyzed sample. The sputtered atoms diffuse into the negative-glow region and are ionized. The second flow (low-energy ions) is extracted from the same negative-glow region and transported from the cathode to the surface of the anode chamber owing to an ambipolar diffusion. These ions are extracted from a hole in the anode chamber of a standard ion source by an electric field and are used for mass-spectrum analysis. The energy-distribution width for these ions is ∼5 eV. The intensity of the ion beam extracted from the anode hole is an order of magnitude higher than the intensity of the ion beam extracted from the cathode region. Original Russian Text ? G.G. Sikharulidze, 2009, published in Pribory i Tekhnika Eksperimenta, 2009, No. 2, pp. 105–109.     

Laser ion source with solenoid for Brookhaven National Laboratory-electron beam ion source

The electron beam ion source (EBIS) preinjector at Brookhaven National Laboratory (BNL) is a new heavy ion-preinjector for relativistic heavy ion collider (RHIC) and NASA Space Radiation Laboratory (NSRL). Laser ion source (LIS) is a primary ion source provider for the BNL-EBIS. LIS with solenoid at the plasma drift section can realize the low peak current (～100 μA) with high charge (～10 nC) which is the BNL-EBIS requirement. The gap between two solenoids does not cause serious plasma current decay, which helps us to make up the BNL-EBIS beamline.     

X-ray beam induced current method at the laboratory x-ray source

The x-ray beam induced current method (XBIC) is realized on the laboratory x-ray source using the polycapillary x-ray optics. It is shown that rather good images of grain boundaries in Si can be obtained by this method. The parameters of x-ray beam are estimated by the simulation of Schottky diode image. A good correlation between the experimental and calculated grain boundary XBIC contrast is obtained. The possibilities of laboratory source based XBIC method are estimated.     

架体梁的结构优化设计

针对第一重型机械集团公司设计的3500t三辊弯板机工作辊的架体梁进行有限元分析，给出了最终结构，进行了结构优化设计，对今后的设计提出了有益的建议。     

A high power density submicron electron beam source

An electron-optical system (with a thermal field electron source-cathode) is introduced. The system is designed to form on the target surface submicron microprobes of a power density exceeding the ablation threshold ( approximately 10(8)W/cm(2)) of condensed media. The numerical modeling of electron paths carried out using a software package (TAU) developed by the authors has shown that the proposed electron-optical system is capable of forming microprobes of a power density comparable with that of modern high-power pulsed laser sources (up to approximately 10(11)W/cm(2)).     

Ion optics of RHIC electron beam ion source

RHIC electron beam ion source has been commissioned to operate as a versatile ion source on RHIC injection facility supplying ion species from He to Au for Booster. Except for light gaseous elements RHIC EBIS employs ion injection from several external primary ion sources. With electrostatic optics fast switching from one ion species to another can be done on a pulse to pulse mode. The design of an ion optical structure and the results of simulations for different ion species are presented. In the choice of optical elements special attention was paid to spherical aberrations for high-current space charge dominated ion beams. The combination of a gridded lens and a magnet lens in LEBT provides flexibility of optical control for a wide range of ion species to satisfy acceptance parameters of RFQ. The results of ion transmission measurements are presented.     

高斯光束整形系统的光学设计

研究了真实光线追迹优化光学系统的方法以简化高斯光束整形系统的光学设计.理论分析了高斯光束整形原理,并选择超洛伦兹函数作为平顶光分布函数;根据能量守恒原理,推导了高斯光束整形系统中任意光线在入射面与出射面的坐标变换关系.针对该系统的特点,使用Zemax编程语言(ZPL)编写计算坐标变换的ZPL宏指令,并优化设计了高斯光束...     

基于满应力的桁架梁轻置化设计

桁架梁结构受外载荷作用时各杆件的受力情况不同,应力也不完全一样。以圆管带式输送机桁架梁结构为例,应用满应力设计法,使其在满足多种约束的条件下,各杆件都能均衡地承受载荷,具有合理的结构承载能力,达到减轻结构质量的目的。     

Ion source with longitudinal ionization of a molecular beam by an electron beam in a magnetic field

A high-efficiency ion source for a mass-spectrometer’s detector of molecular beams and their scattering products is described. The ion source is designed according to a scheme of impact ionization of a beam particle by a longitudinal electron beam in a magnetic field with a strength of up to 130 mT. The design of the source developed is very flexible and has no limitations for use in any experiments with molecular beams. An ionization efficiency of particles of an atomic helium beam of 10^?3 ions/atom has been achieved. The useful signal-to-background ratio in the detector’s chamber is 3 × 10⁴ during detection of ions with mass-to-charge ratio m/q = 4 amu.     

16厘米低能强流宽束离子源

介绍了一个新型16厘米束径多会切磁场低能强流宽束离子源(MCLB-16)。由于采用新型多会切磁场和优化的低能引出系统,所以该源在薄膜辅助沉积的能量(200eV～800eV)范围内,具有较好的低能特性。源的最大引出束流可达650mA。可用反应气体或惰性气体工作。源在使用氧气时,可连续工作数十小时。该源可用于各种高性能薄膜制备的辅助沉积,也可用于制备大面积类金钢石膜(DLC)。叙述了该源的结构及性能。     

Shunting arc plasma source for pure carbon ion beam

A plasma source is developed using a coaxial shunting arc plasma gun to extract a pure carbon ion beam. The pure carbon ion beam is a new type of deposition system for diamond and other carbon materials. Our plasma device generates pure carbon plasma from solid-state carbon material without using a hydrocarbon gas such as methane gas, and the plasma does not contain any hydrogen. The ion saturation current of the discharge measured by a double probe is about 0.2 mA∕mm(2) at the peak of the pulse.     

New ion source for KSTAR neutral beam injection system

The neutral beam injection system (NBI-1) of the KSTAR tokamak can accommodate three ion sources; however, it is currently equipped with only one prototype ion source. In the 2010 and 2011 KSTAR campaigns, this ion source supplied deuterium neutral beam power of 0.7-1.6 MW to the KSTAR plasma with a beam energy of 70-100 keV. A new ion source will be prepared for the 2012 KSTAR campaign with a much advanced performance compared with the previous one. The newly designed ion source has a very large transparency (～56%) without deteriorating the beam optics, which is designed to deliver a 2 MW injection power of deuterium beams at 100 keV. The plasma generator of the ion source is of a horizontally cusped bucket type, and the whole inner wall, except the cathode filaments and plasma grid side, functions as an anode. The accelerator assembly consists of four multi-circular aperture grids made of copper and four electrode flanges made of aluminum alloy. The electrodes are insulated using PEEK. The ion source will be completed and tested in 2011.     

Inverse determination of the loading source of the infinite beam on elastic foundation

The primary aim of the paper is to identify the loading source of infinite beams on an elastic foundation from given information of vertical deflection of infinite beams. An integral equation is obtained for the relationship between loading distribution and vertical deflection. It is shown that the inverse identification of a loading source is one-to-one but ill-posed. Because of ill-posedness, the usual numerical schemes produce arbitrarily large errors. A method for the solution is proposed by using Tikhonov’s regularization. L-curve criterion is introduced for the determination of optimal regularization parameter. Numerical experiments show that the present methodology is accurate and robust in the inverse determination of loading source. This paper was recommended for publication in revised form by Associate Editor Joo Ho Choi T. S. Jang, the corresponding author of the paper, is by birth a Korean, with Naval Architecture and Ocean Engineering Ph.D degrees from Seoul National University, who worked at the department of Naval Architecture and Ocean Engineering in Pusan National University from 2003 until now. His main field of research has been the optimization theory, water wave motion and inverse problem with special focus on ocean-related fields     

多波长激光扩束器的光学设计

在激光雷达以及光谱仪定标时常常需要较宽以及高准直性的激光光束。设计了一出射光束为16mm,扩束比为20倍的激光扩束器光学系统。通过移动激光扩束器的物镜与目镜间隔,可以实现光谱范围在543.5~850nm的激光扩束;比较了使用该激光扩束器发射的准直激光束与理想的单色平行光充满成像光谱仪的入瞳孔径后成像光谱仪传递函数的变化,说明该光学系统可行。     

Low background cold cathode ion source for molecular beam detection

An extractor gauge type electron bombardment ion source using carbon fiber bundles as field electron emitters is described. The cold cathode permits operation of the ionizer within a liquid He cooled cryopump. The high pumping speed for all molecules (except helium) together with its low background pressure make this ion source a very promising detector for crossed molecular beam scattering experiments.