高分辨四极质谱计在HL-2A装置上的应用

将具有分辨氦(He)和氘(D2)能力的高分辨四极质谱计安装到HL-2A托卡马克装置上,同时送入氦气和氘气,得到了质谱计可分辨的最小He+/D2+峰值比.分别对真空室在辉光放电清洗前后、不同等离子体放电次数的氢同位素和氦进行测量,观察到四种工况下质谱峰m/q=4的主要成分为D2+,He+只在辉光放电清洗中作为工作气体引入.向真空室送入氘气后,比较了由分子泵和低温泵抽气的质谱情况.分压强的测量结果表明低温泵对氘气的抽速大于分子泵约18％.实验结果初步验证了高分辨四极质谱计应用于托卡马克装置可靠真空检漏和残余气体成分精确分析的可行性,并为托卡马克装置抽气泵的选型提供了依据.     

采用流量计测量复合分子泵抽速装置研制

本工作研制了一台采用流量计测量复合分子泵抽速的装置.本装置由测试台车、机柜、计算机自动控制和数据采集处理系统三部分组成.选用3个高精度流量计,满量程分别为1000 sccm、100 sccm和10 sccm,并联组成流量计组件用于测量输入气体的流量,选用高精度的复合真空计测量真空测试罩内气压.抽速测试结果显示,一台1200 L/s的复合分子泵N2抽速重复测量5次,14个气压测试点对应的抽速的最大相对标准偏差小于2％,重复性好.抽速测量的误差主要由流量计和真空计的系统误差决定.采用流量计测量一台分子泵在气压2.00×10-3 Pa～2.00 Pa范围的抽速,测量时间20 min以内.     

一种基于CF400接口分子泵抽速测试装置北大核心CSCD

针对国产化大抽速分子泵测试需求,研制出基于CF400接口分子泵抽速测试装置。采用量程为10~10-9 Pam3/s的复合型标准气体流量计提供可变的标准流量,仅用流量法实现了测试罩内气体压力处于10-1~10-7 Pa范围的抽速测试,而传统测试方法采用标准流导法和流量法相结合实现该范围的测试;装置集成了在线真空校准功能,用磁悬浮转子真空计作为参考标准,实现在10-1~10-4 Pa范围内对测试罩内气体压力的直接测量及副参考标准电离真空计的在线校准。研制的装置与原有测试方法相比较优点主要为:采用一种方法实现了分子泵抽速测试;在线校准技术解决了原有测量过程电离真空计灵敏度系数发生变化引起测量结果出现的较大偏差;实现对不同气体抽速的直接测量,避免原方法只能给出等效氮气测试结果的不足。实验结果证明,装置对分子泵抽速的测试范围为3000~5000 L/s,测量结果的合成标准不确定度为2.2%~4.4%。     

HT—7托卡马克氘丸注入实验研究

简要介绍了用于国家中型超导托卡马克装置HT-7弹丸注入系统;详细阐述了在HT-7装置首次用于加料实验的氘（D2）丸的成冰工艺、氘丸注入实验以及氘丸注入对等离子体产生的影响;研究了等离子体的密度、温度的分布变化。     

HT-7托卡马克氘丸注入实验研究

简要介绍了用于国家中型超导托卡马克装置HT-7弹丸注入系统;详细阐述了在HT-7装置首次用于加料实验的氘(D2)丸的成冰工艺、氘丸注入实验以及氘丸注入对等离子体产生的影响;研究了等离子体的密度、温度的分布变化。     

一种基于CF400接口分子泵抽速测试装置

针对国产化大抽速分子泵测试需求,研制出基于CF400接口分子泵抽速测试装置。采用量程为10～10~(-9) Pam~3/s的复合型标准气体流量计提供可变的标准流量,仅用流量法实现了测试罩内气体压力处于10~(-1)～10~(-7) Pa范围的抽速测试,而传统测试方法采用标准流导法和流量法相结合实现该范围的测试;装置集成了在线真空校准功能,用磁悬浮转子真空计作为参考标准,实现在10~(-1)～10~(-4) Pa范围内对测试罩内气体压力的直接测量及副参考标准电离真空计的在线校准。研制的装置与原有测试方法相比较优点主要为:采用一种方法实现了分子泵抽速测试;在线校准技术解决了原有测量过程电离真空计灵敏度系数发生变化引起测量结果出现的较大偏差;实现对不同气体抽速的直接测量,避免原方法只能给出等效氮气测试结果的不足。实验结果证明,装置对分子泵抽速的测试范围为3000～5000 L/s,测量结果的合成标准不确定度为2.2%～4.4%。     

液态锂中氘脱附特性分析

锂化壁处理/液态锂第一壁可为托卡马克装置提供良好壁条件，但存在燃料滞留问题，为解决这一问题，需进一步研究氢同位素在液态锂中的脱附特性。本文设计了液态锂中气体吸附/脱附系统，开展了氘气在液态锂中的吸附实验，并分析了其脱附过程，通过采用微调阀调整进气速率的方式标定不同氘气分压下的系统抽速，计算了热脱附过程中气体的抽除量。结果表明，氘气在液态锂中的脱附峰温度在481℃附近，脱附的氘气仅有约36%被抽气系统抽除，剩余部分被壁面冷凝的锂重新吸附。该研究可为深入分析氘在液态锂中的脱附行为奠定良好基础，为未来解决液态锂中的燃料回收问题提供技术支持。     

真空计量的需求与发展

综述了对真空计量的需求与发展,其中包括对全压力、分压力、气体微流量、真空泵抽速、空间真空测量和特殊条件下对真空测量的需求,还包括对真空计量标准和测试设备的需求.     

基于M-C方法模拟分析NBI真空压力分布的影响因素

中性束注入装置(Neutral Beam Injector,NBI)是产生高能中性粒子束用以加热托卡马克等离子体的装置.NBI真空压力分布是影响中性束传输效率特别是再电离损失的关键因素之一.本文研究分析了HT-7托卡马克NBI实验装置的工作原理和结构特点,利用Monte-Carlo方法建立NBI实验装置主真空室及飘移管道内分子运动及碰撞的相关模型,并进行编程实现对NBI实验装置真空压力分布模拟计算.模拟计算和实验结果表明:主真空室低温冷凝泵抽速为4×105L/s时,主真空室压力在脉冲充气过程中维持在10-3Pa量级;飘移管道低温冷凝泵抽速为4×104 L/s时,飘移管道压力维持在10-4Pa量级.文章的结论为中性束传输过程中再电离损失的研究提供了理论依据.     

新型吸气剂泵真空测试系统的搭建与实验研究北大核心CSCD

烧结型非蒸散吸气剂泵HV800(意大利SAES公司生产)具有抽速大、抽气容量高、安装维护简单等优点,可能适用于EAST托卡马克偏滤器抽气,提高该区域粒子排出能力。本文搭建了一套极限真空5. 1×10-7Pa、具备抽速定量标定的真空测试系统,对HV800开展了对氘气抽速的标定实验。研究结果表明在偏滤器工作气压下,平均抽速可达240 L/s。经评估HV800应用于EAST的初步方案,偏滤器区域会增加5×104L/s抽速,并可连续运行20 h以上,是有效提高EAST偏滤器粒子排出能力的可行选择。     

Residual gas analysis in the TOF vacuum system

The residual gas composition in the time-of-flight (TOF) spectrometer vacuum system has been measured with a quadrupole mass spectrometer. All residual gases except hydrogen and helium are condensed and freezed on the windows of the liquid hydrogen target. As a result it increases the background during the reaction between the cooler synchrotron (COSY) beam and the target. These condensates have to be cleaned from the target windows by fast heating the target cell from 16 K up to room temperature. The partial pressure spectrums of the condensed gases on the liquid hydrogen target are also measured. The residual gas analysis shows that the majority of the condensates on the target windows are nitrogen, oxygen and water vapor. The target area has to be in a high vacuum <1×10⁻⁶ mbar in order to minimize the condensate. The target windows have to be cleaned with the fast heating cycle every 48 h.     

Measuring volume ratios of vacuum vessels using non-evaporable getters

Several methods have been used in vacuum metrology for volume determination. Volume ratios can be determined by different gas expansion methods, which were primarily developed for the precise determination of expansion ratios in static expansion systems. Measurements of the volume ratios using the gas expansion methods below 10⁻² Pa are influenced by outgassing from chamber walls. To reduce outgassing in the expansion chambers during measurements at low pressures, we have installed non-evaporable getter (NEG) pumps, which pump hydrogen and other active gases but have a negligible pumping speed for inert gases. The volume ratio of two chambers of an experimental static expansion system has thus been measured using the inert gases argon, helium and krypton. The obtained results were compared with the measurements without the use of an NEG pump. Measurements of the pressure ratios were performed with a spinning rotor gauge (SRG).     

An experimental study of hydrogen solubility in liquid aluminium

Hydrogen solubility in molten aluminium at different temperatures from 973–1123 K, has been measured using Sieverts' method. Inert gas (helium or argon) was used as a reference gas to calibrate the measurement system of the Sieverts' apparatus. The measured hydrogen solubility was found to vary with the reference gases. Helium was detected to be soluble in liquid aluminium. When helium is used as the reference gas, its solubility resulted in lower measured hydrogen solubility than that when argon was used to calibrate the measurement system of the apparatus. Argon gas was therefore considered as an appropriate reference gas when Sieverts' method is used to measure the hydrogen solubility in liquid aluminium. The hydrogen solubility, S, in liquid aluminium as a function of melt temperature, T, determined in the present investigation is expressed as log S = (−2980/T) + 3.07.     

One-step synthesis of MoO3 and MoO3-x nanostructures by condensation in gas: effect of the carrier gas

MoO3 and MoO3-x nanostructures were grown in a simple one-step process by direct evaporation of MoO3 pellets from a tungsten resistive source in presence of helium or hydrogen at pressures from 100 to 1200 Pa. This method uses no templates, catalysts or oxidizing agents. It leads to one dimensional (1-D) crystalline nanostructures mixed with amorphous material in variable ratios. Amorphous structures grew preferentially when hydrogen was used as carrier gas while crystalline material predominated when helium was used. In fact, only crystalline structures were found when the evaporation was carried out under a helium pressure of 600 Pa with source temperatures between 763 and 910 degrees C. Hydrated MoO3 phases with different water concentrations were preferentially formed using hydrogen. X-ray photoelectron spectroscopy detected only molybdenum in its +6 oxidation state in the samples grown under helium, exhibiting the same chemical composition of the source material. Molybdenum in its +6 as well as its +5 oxidation states was detected in the samples obtained under hydrogen at 600 Pa. Hydroxyl groups were identified in samples grown using both gases. The effect of the helium pressure on the growth kinetics and crystallinity of the samples is discussed according to the kinetics conditions (supersaturation, evaporation, cooling and convection rates) driving to the formation of nanostructures in the inert-gas condensation. Finally, the effect of hydrogen on the growth of MoO3 is discussed.     

不同种类破空气体对高真空多层绝热低温容器真空丧失后传热的影响

通过实验,分别利用氮气、空气、氧气和氦气作为破空气体,对高真空多层绝热低温容器在真空完全丧失后的漏热进行了研究。结果表明,多层绝热结构对于绝热真空完全丧失后的低温容器能够起到一定的保护作用,初始和最终漏热和渗入到绝热真空夹层中气体的性质密切相关。     

高真空多层绝热低温容器完全真空丧失后传热及绝热夹层内温度分布规律实验

在搭建了高真空多层绝热低温容器完全真空丧失传热研究实验台的基础上,分别利用干燥氮气、二氧化碳、氧气、氦气及空气为破空介质,进行了高真空多层绝热低温容器发生完全真空丧失事故后的传热实验研究.实验中通过流量计和温度采集系统测得了高真空多层绝热低温容器在发生完全真空丧失事故后的排放率和绝热夹层内的温度分布规律.实验结果表明,...     

Glass-type hydrogen and deuterium absorption cells developed for D/H ratio measurements in the Martian atmosphere

Hydrogen and deuterium absorption cells of a new glass type have been developed for the D/H ratio measurements on the Japanese Mars mission PLANET-B. The H/D cells work as narrow-band rejection filters for the H/D Lyman-alpha line, respectively, when the H or D atoms are produced at a heated filament inside the cells. The absorption profiles of the cells were successfully measured with a high-resolution vacuum ultraviolet spectrometer with a wavelength resolution of 6.6 x 10(-4) nm. The derived optical thickness was found to be ~7 and ~14 for the hydrogen and deuterium cells, respectively. It was also found that the derived temperature of atomic gas ranges between the temperature of the cell wall and that of the heated filament, and it increases with increasing filament temperature. The measured profiles showed that the absorption efficiencies of the developed absorption cells are sufficient to observe the D/H ratios of the Martian atmosphere.     

HT-7中性束注入装置真空监控系统的设计

超导托卡马克装置HT-7中性束注入系统运行期间,实验环境中存在强磁场而要求封闭,因而对系统运行状况只能进行远距离监控,真空实时远程监控系统是整个监控系统的重要组成部分.本文介绍了真空实时远程监控系统的设计要求,讨论了该系统的硬件设计、软件设计及其工作原理,给出了部分实验结果.     

甲基硅橡胶膜的透气特性

甲基硅橡胶是气体透过量较大的一种，曾和于呼吸困难患者使用的医和富氧器或以节能为目的的燃烧系统，我们研究了甲基硅橡胶均质膜在不同温度下的透气性能，用压力法测定了它们的渗透系数、溶解度系数和扩散系数，比较和讨论了它们的透过机理。     

A novel route to compact,high performance pumping in UHV–XHV vacuum systems

The need to miniaturize and reduce the footprint of vacuum systems is increasing in industrial and research devices, such as portable analyzers, electron microscopes, surface science systems, semiconductor tools or particle accelerators. This poses serious challenges to the pumping groups in term of design, space constraints and weight. In this paper a novel type of combination pump is introduced, which integrates into a single device a Non Evaporable Getter (NEG) element with a small sputter ion pump (SIP). In this design, the NEG element acts as the main vacuum pump to remove hydrogen and the active gases, leaving to the SIP the ancillary task of pumping inert gases, which are not sorbed by the NEG. This approach, which develops large pumping speeds in a compact package, is helpful to achieve appropriate vacuum conditions in laboratory equipment. It can also improve and simplify the design of complex vacuum systems and apparatuses.