微型溅射离子泵极小抽速精确测量的意义和难点

抽速小于10~(-4)m~3/s量级的微型溅射离子泵在航天载荷产品、电子器件、科学仪器领域应用广泛,现有的抽速测量方法都大于10~(-2)m~3/s量级,无法解决极小抽速精确测量的急需。制约抽速测量的主要原因是测量用电离真空计本身的抽速在10~(-5)～10~(-4)m~3/s量级,与被测微型真空泵抽速在同一数量级,以及现有测量方法无法适用于极小抽速的测量。在论述微型溅射离子泵极小抽速测量的重要意义及分析其难点的基础上,调研了极小抽速测量研究的最新进展,提出了极小抽速测量的构想,期望能为实现微型溅射离子泵极小抽速的精确测量提供帮助。     

溅射离子泵对N2和CO抽速的理论计算

根据潘宁放电机理，导出溅射离子泵抽速的理论公式。讨论了抽速对各种放电参数的依赖关系。计算了离子泵对Ｎ２和ＣＯ的抽速。计算结果和实验测试以及经验公式的结果有较好的符合。     

提高溅射离子泵抽速的研究

按抽气过程推出了溅射离子泵的抽速公式。实验研究了阳极结构、阴极材料对提高抽速的作用。通过离子泵抽氩清洗后抽速提高现象的分析研究.证实了阴极材料表层成分对离子泵抽速有几倍的影响;钛阴极的泵在抽氮气达到稳定值后,阴极表层即盖满 TiN,而泵的正常抽速是离子溅射 TiN 生成的钛原子在阳极表面抽气提供的。研究表明,理想的离子泵阴极材料不仅应当溅射率高,溅射膜有高的吸气性能,而且应对入射的被抽气体原子有足够高的扩散能力。     

微型复合溅射离子泵的设计研究

本文介绍了一种非蒸散型吸气剂（NEG）与微型溅射离子泵（SIP）集成构成的微型复合溅射离子泵。测试结果表明，当吸气剂激活后，复合泵的抽速达到0．45L／8，比未加吸气剂的同型溅射离子泵抽速提高了28％。该复合泵使真空器件的真空维持效果良好，可广泛应用于中小型的密闭真空器件中。     

溅射离子泵阳极筒-阴极板间距对抽气特性影响的数值研究

建立了描述溅射离子泵抽气单元抽气特性的计算模型。采用商业软件COMOL Multiphysics,将等离子体模块、磁场模块、带电粒子追踪模块进行耦合,计算得到了阳极筒内潘宁放电特性参数、气体离子入射阴极板能量和角度。引入非垂直入射溅射产额公式,计算得到阳极筒内壁溅射产额及抽气单元抽速。模拟计算结果与实验数据的对比表明,两者具有较好的一致性,验证了所建模型的适用性。基于所建计算模型,开展了溅射离子泵阳极筒-阴极板间距对抽气性能影响的数值研究。计算结果表明,阳极筒与阴极板间距对抽气单元的有效抽速有显著影响,并存在最优间距,该间距下抽气单元的抽速最大,同时最优间距随阳极筒半径增加而增大。基于模拟结果,提出了非等径、非等高阳极筒抽气单元阵列结构离子泵设计方案,为溅射离子泵的结构改进和性能优化提供了新的设计思路和可行路径。     

一种计算二极型溅射离子泵特性的新方法

本文通过各种实验结果相结合的理论考虑得出了计算溅射离子泵特性的一般方法,这种方法成功地应用于高能加速器中分配溅射离子泵的最佳设计。计算抽速和测量抽速的偏差小于30%。 绪言 尽管几乎所有的真空领域中广泛地使用溅射离子泵,但是,我们有关不同泵的参数对于抽速的影响的知识,经验的多于理论。这大概是由于溅射离子泵复杂的抽气机理,这种抽气机理,依赖于潘宁室的不同放电模型,高能离子轰击阴极的溅射率,以及气体分子和二个电极表面之间发生的物理化学现象。 除了阴极材料外,影响溅射离子泵抽速的主要参数是:磁场强度,施加电压和阳极室…     

溅射离子泵的再生处理

标志溅射离子泵性能的主要技术指标是泵的抽速和泵所能达到的极限真空度。这两项指标密切地依赖于泵的工作状态和泵的历史。因此,为了能正确地评价溅射离子泵的性能,除了规定一个统一而合理的工作条件以外,还必须使泵处于大致相同的初始条件下。 溅射离子泵抽气特点是内部储存与自身消耗。它不是把被抽气体经过前级泵排往大气中。而是借助于予抽泵把被抽空间的压强抽降到一定的压强下(低于10-2乇),然后溅射离子泵通过潘宁放电使气体电离。气体离子在电场作用下轰击钛或钽阴极。使气体离子与钛或钽的原子发生化学反应,或者被溅射出来的金属原…     

极高真空溅射离子泵的研制

研制出了获得极高真空的溅射离子泵，该溅射离子泵４小时烘共烤后温度降至１００℃，装磁钢，妄动离子泵进行敢，３４小时后压力达５．８×１０＾－１０Ｐａ。从抽速实验结果来看，该泵在１０＾１０Ｐａ时仍有１００Ｌ／ｓ的抽速。说明此泵在较 压力下仍有较强的潘宁放电。     

上海光源溅射离子泵性能测试

本文详细介绍了上海光源常用溅射离子泵性能测试的方法和原理,并对极限真空度,有效抽速,洁净度进行了测试.结果表明,溅射离子泵的极限真空度测量值都满足≤5.0×10-8Pa的指标要求.SIP200和SIP400的氮气再生抽速最大值均超过了各自的名义抽速,对惰性气体(氩气)的饱和抽速最大值也超过了名义抽速的60％.通过四极质...     

微型溅射离子泵性能测试

本文介绍了小抽速微型溅射离子泵的性能测试系统和参考机械行业标准确定的测试方法,探讨了测量结果误差来源.实验测试了微型溅射离子泵的各项性能指标,为进一步研制提供了依据.     

溅射与沉积过程的计算机模拟

应用TRIM和TRIDYN程序模拟氮化硼材料的溅射率与Ar 入射角的关系，Ar 辅助沉积氮化础薄膜与硅基片的界面结构，铜基片溅射率与入射能量的关系，以及Ar 以垂直于表面方向轰击非晶硅产生的溅射速率。铜基片溅射率的计算结果与已有的实验数据相比较表明，两者吻合得很好。硅片的溅射速率与应用38－cm宽束离子源设备的实验结果之间也吻合比较好。     

Experimental Study of Oil‐Free Claw Vacuum Pump Characteristics

Experimental study of pumping characteristics of a pilot model of a claw single‐stage vacuum pump with identical rotors was carried out. The curves of pumping speed vs. pressure at different rotary speed and the ultimate pressure at different rotors speed were determined on a test unit. Indicator pressure diagrams in working chambers of claw vacuum pump were obtained with the help of special sensors. Thus, an experimental data bank concerning the pumping characteristics of claw vacuum pump was created. It may be used for estimation of mathematical model adequacy and further development of the pump design.     

A new generation of getter‐coated sputter ion pumps for XHV applications

A new concept of sputtered ion getter pump is presented. The body of this pump is internally coated by a getter thin film constituted by a layer of TiZrV together with a protective covering of palladium, according to a technology that CERN (European Center for Nuclear Research) licensed us. TiZrV is a well‐known alloy able to pump getterable gases such as hydrogen, oxygen, nitrogen, carbon monoxide and dioxide. With the exception of H², the sorption of these gases is not reversible and it causes a progressive contamination of the bulk of the material. With the addition of the palladium overlayer, the pumping action is limited to hydrogen and carbon monoxide, but the lifetime of the film is strongly enhanced, thanks to the possibility of an unlimited number of thermal activations, which restore the initial performances of the film. An innovative sputter ion pump design, optimized for both pumping speed in ultra high vacuum and getter film sputtering, will be introduced. Moreover, pumping speed measurements and ultimate pressure data, obtained after a relatively short bake‐out at temperature lower than standard procedures, will be reported.     

Theoretical and experimental study of dry scroll vacuum pump

The rarefied gas flows through suction port, scroll clearance and discharge port are treated as leakage of dry scroll vacuum pump (DSVP). The models for predicting the above-mentioned leakage rate were derived in this paper. The model for predicting the heat transfer rate between rarefied gas and working chamber wall was also developed. Then, a general model for describing the working process of DSVP was set up according to the energy and mass conservation principle. This model can be applied to predict the performance of DSVP. The pumping speed for different suction pressures was obtained. Furthermore, the ultimate pressure and power consumption for different speeds were gotten. A good agreement between the theoretical results and experimental data was obtained. Finally, the volume ratio of prototype was changed and its influence on the performance was studied by experiment.     

The working process of an oil‐free claw vacuum pump

Mathematical model of oil free claw vacuum pump is presented. The model is based on energy balance differential equations of thermodynamic system of variable mass working body. Using the equations of coordinates transformation and contact line of rotors continuity condition, equations for geometry of claw pump working chamber on condition of rotors point connection are obtained. To evaluate the leakage through the rotor mechanism channels, their existence graphs are plotted and geometric parameters of the channels depending on rotors position are determined. As a result of modeling, dependence of pressure and temperature in suction and compression‐discharge chambers on rotation angle at different rotary speeds and on different inlet pressures and relationship between pumping speed and inlet pressure are obtained. The comparison between calculated values and experimental data obtained for one‐stage claw pump with identical rotors is carried out. The maximal difference between the calculated and experimental values does not exceed 15 %. The developed mathematical model is recommended for analysis of influence of rotors geometry on the working process parameters and pumping characteristics of an oil free claw pump.     

Bestimmung des Saugvermögens von Ionengetterpumpen

The pumping speed of ion getter pumps – Comparison of measurement methods Pumping speed measurements of sputtering ion pumps are typically carried out according to DIN 28429 or ISO/DIS 3556-1.2. In this article, we take a look at the differences between these two measurement methods. Based on experimental data, the impact of pressure holding times on reproducibility and absolute values of the extracted pumping speeds are discussed. Pumping speed measurements according to the now withdrawn ISO/DIN 3556-1.2 may yield up to 30 % higher values than values based on the validated DIN28429. The definition of sampling times according to DIN 28429 enables reproducible measurements.     

High-speed ion pump with a multipactor cathode—The multipactor ion pump

A new type of high-speed ion pump using a multipactor cathode is proposed and the experimental results, obtained with the first trial pump, are described. The multipactor cathode has excellent characteristics as an electron source in order to obtain increased pumping speed of an ion pump, namely: (1) since it is a cold cathode made of pure metal, such as Al, it does not contaminate the vacuum condition, (2) the electron emission density is high, (3) the supply of electrons can be greatly increased in comparison with that of any other supply method, (4) the electrons can be supplied easily into a very wide area.This proposal is to make a high-speed ion pump by combining such an attractive cathode with a normal ion pump. The experimental results showed that the maximum pump current per unit pump volume reached up to 30 times that of a normal ion pump in vacuum conditions of less than 10^?4 Pa.     

The use of perfluoropolyether fluids in vapour stream pumps

The performance of a 5 in. diameter diffusion pump (Edwards EO4) has been studied using a distillation cut of the perfluoropolyether fluid with an average mass of 3000 amu. A pumping speed for air of 700 l/s was measured which is similar to the speed obtained when the pump is charged with Silicone 704 fluid. A higher critical backing pressure was obtained, however, for the new fluid viz 1.2 torr compared with 0.8 torr for the conventional fluid. Fragmentation spectra of the vapour molecule obtained by direct injection into the ion source and from backstreaming fluid showed prominent peaks at mass to charge ratios 31 and 69 corresponding to the fragments CF and CF₃. The similarity of the spectra obtained by the two methods suggests that the fragmentation takes place in the ion source and that the fluis is not degraded by use in the pump. An analysis of the pumping mechanism in vapour stream pumps is given.