大发射电流密度Ir－Ce合金阴极的研究

制作了一种发射电流密度较大的铱－铈两相合金阴极。在１７７３Ｋ时，阴极零场发射电流密度为６７５Ａ／ｃｍ２，有效逸出功为２．７３ｅＶ；在１８２３Ｋ时，观察到最大发射电流密度超过２１．２Ａ／ｃｍ２。同时简介了阴极制作工艺和抗中毒情况以及未来的改进发展方向。     

大发射电流密度Ir—Ce合金阴极的研究

制作了一种发民流密度较大的铱－铈两相合金阴极。在１７７３Ｋ时，阴极零场发射电流密度为６．７５Ａ／ｃｍ＾２，有效逸出功为２．７３ｅＶ；在１８２３Ｋ时，观察到最大发射电流密度超过２１．２Ａ／ｃｍ＾２。同时简介了阴极制作工艺和抗中毒情况以及未来的改进发展方向。     

电沉积法制备碲靶

采用电沉积法将Ｔｅ电沉积在以Ｎｉ为底衬的Ｃｕ靶托上，制备出了质子回旋加速器ＣＹＣＬＯＮＥ－３０用碲靶，用以生产放射性医用同位素＾１２３Ｉ。研究了电流密度、电沉积时间、温度、电沉积溶液中碲的质量浓度（以ＴｅＯ２计）、碱度等工艺条件对碲靶质量的影响。推荐最佳工艺条件为：电沉积液介质浓度ｃ（ＫＯＨ）＝１ｍｏｌ／ｌ；ρ（ＴｅＯ２）＝５５－６５ｍｇ／ｍｌ；电流密度Ｊ＝１０－１２ｍＡ／ｃｍ＾２；温度Ｔ＝１８－     

间热式大面积六硼化镧中空阴极

介绍了适用于强流离子源的间热式大面积六硼化镧中空阴极。在１５ｃｍ双潘宁离子湖泊 上放电特性研究表明，该阴极性能良好，能可靠工作，使用过程中多次暴露于大气中，发射性能并未变坏，加热功率为１．４５ｋＷ，ＬａＢ６发射电流密度为２０Ａ／ｃｍ＾２，放电电流４００Ａ，脉冲宽度３０ｍｓ，放电波形重复性很好。使用１００ｈ后，发射体尺寸无明显变化。     

5.0MeV和9.5MeV快中子辐照在GaAs中产生的辐射损伤的正电子湮没研究

采用正电子湮没寿命测量方法研究了５．０ＭｅＶ和９．５ＭｅＶ快中子辐照在ＧａＡｓ中产生的辐射损伤，实验结果表明１０＾１１－１０＾１２ｎ／ｃｍ＾２注量的中子辐照只产生单空位缺陷１０＾１３ｎ／ｃｍ＾３注量的中子辐照产生单空位和双空位缺陷，１０＾１２ｎ／ｃｍ＾２注量的９．５ＭｅＶ中子辐照的ＧａＡｓ经４５０－６２０℃退火产生三空位缺陷，产生的缺陷浓度随中子能量和注量的增大而增大，但缺陷产生率对中子注量更灵敏     

^239Pu,^241Am,^99Tc和^137Cs在高压实缓冲材料中的扩散系数

本文从物质的一维非稳态扩散规律出发，在常温，纯氮条件下，测定了＾２３９Ｐｕ，＾２４１Ａｍ，＾９９Ｔｃ和＾１３７Ｃｓ在作为高放废物深地质处置库缓冲材料的高压实钠质膨润土中的扩散系数，９０ｄ的实验测定结果表明，在膨润土的干密度为１．９ｇ／ｃｍ＾３时，＾２３９Ｐｕ，＾２４１Ａｍ扩散系数为在１０＾－１５ｍ＾２／ｓ，＾９９Ｔｃ约为１０＾－１３ｍ＾２／ｓ，而＾１３７Ｃｓ约为１０＾－１２ｍ＾２／ｓ，都随缓冲材料     

折流板环形脉冲柱用作Purex工艺1A接触器研究

该研究跟踪国际先进水平，首次在我国进行折流板环形脉冲柱应用研究。采用５ｃｍ柱径，板间距２ｃｍ，开孔率２５％，正弦脉冲波。水力学性能研究结果表明，液泛通量高达２．７ｃｍ／ｓ，可采用Ｖ＿ｃ（１－Ｘ）＋Ｖ＿ｄ／ｘ＝Ｖ＿０（１－ｘ＿ｅ）￣（ＫＸ）关联分散相存留分数。其Ｋ值为４．５一６，大于零，为Ⅱ型柱；Ｕ传质结果表明，理论级当量高度为７０ｃｍ，当在振幅ａ＝２ｃｍ，频率ｆ＝１．５ｓ￣（－１）的脉冲条件下操作时，其理论级当量高度将降至５０ｃｍ。同脉冲筛板柱的对比试验结果表明，其传质性能优于脉冲筛板柱。与相同工艺条件下的串级结果对比，在ａ＝２ｃｍ，ｆ＝１．５ｓ￣（－１）条件下，２００ｃｍ的萃取柱可达４个理论级。     

大射野,大深度^60Coγ射线照射条件下组织—空气比的公式计算

本文利用＾６０Ｃｏγ放射源和７２ｃｍ×７２ｃｍ×９０ｃｍ（长×宽×高）体模，在大射野（１０．０ｃｍ×１０．０ｃｍ～５０．ｃｍ×５０．０ｃｍ）和大深度ｄ（１０．０～７０．０ｃｍ）照射条件下实测的组织－空气比数据，按Ｍｅｌｓｋｉ计算＾６０Ｃｏγ射线组织－空气比深度函数公式，Ａｅ＾Ｂｄ＋Ｃｅ＾Ｄｄ，利用高斯－牛顿逐次逼近的计算方法，拟合出该公式参数Ａ，Ｂ，Ｃ和Ｄ的最佳估计值，５组数据的残差平方和小于１．     

高能（MeV级）氧离子注入本征型GaAs的电性能及注入损伤退火行为的研究

在本征型ＧａＡｓ中注入２．０ＭｅＶ（剂量１．０×１０＾１５／ｃｍ＾２）＋２．９ＭｅＶ（剂量１．１×１０＾１５／ｃｍ＾２）的＾１６Ｏ，使氧在约１．５－２．５μｍ之间形成均匀分布。注入样品分别经４００－８００℃、１５ｍｉｎ热退火后的电阻率测量表明，经５００℃和６００℃退火后的样品具有高的电阻率（～１０＾８Ω·ｃｍ）；而当退火温度进一步升高时，其电阻率逐渐下降，并具有ｐ型导电行为。沟道ＲＢＳ分析表明，当     

X,γ系列标准源的研制

本文主要介绍用于Ｘ、γ谱仪能量及效率刻度的一套系列标准源的研制方法和检验结果。它是发射射线能量范围为５．９－１８３６．１ｋｅＶ的￣（５５）Ｆｅ、￣（１０９）Ｃｄ、￣（２４１）Ａｍ、￣（５７）Ｃｏ、￣（１３３）Ｂａ、￣（１３７）Ｃｓ、￣（５４）Ｍｎ、￣（６０）Ｃｏ、￣（２２）Ｎａ和￣（８８）Ｙ１０种核素标准源。采用的高纯放射性核素标准溶液，杂质的相对强度小于０．１％；由４π（ＬＳ）和４π（ＰＣ）β－γ符合方法确定的放射性浓度均在总不确定度范围（＜２．０％，置信水平为９９．７％）内相符。放射性核素密封于质量厚度为１５ｍｇ／ｃｍ￣２（除￣（５５）Ｆｅ源用７ｍｇ／ｃｍ￣２）的圆形聚脂膜中，活性区直径≤３ｍｍ。对６个￣（５７）Ｃｏ源活度用ＮｐＧｅ谱仪测定检验，偏差在０．５１％－１．０２％之间。经擦试检验表明，未见表面污染和泄漏。     

Oxide Coated Cathode Plasma Source of Linear Magnetized Plasma Device

Plasma source is the most important part of the laboratory plasma platform for fundamental plasma experimental research. Barium oxide coated cathode plasma source is well recognized as an effective technique due to its high electron emission current. An indirectly heated oxide coated cathode plasma source has been constructed on a linear magnetized plasma device. The electron emission current density can reach 2 A/cm 2 to 6 A/cm ² in pulsed mode within pulse length 5–20 ms. A 10 cm diameter, 2 m long plasma column with density 10 ¹⁸ m ⁻³ to 10 ¹⁹ m ³ and electron temperature T_e ≈ 3–7 eV is produced. The spatial uniformity of the emission ability is less than 4% and the discharge reproducibility is better than 97%. With a wide range of the plasma parameters, this kind of plasma source provides great flexibility for many basic plasma investigations. The detail of construction and initial characterization of oxide coated cathode are described in this paper.     

Characteristics of Single Cathode Cascaded Bias Voltage Arc Plasma

A single cathode with a cascaded bias voltage arc plasma source has been developed with a new quartz cathode chamber,instead of the previous copper chambers,to provide better diagnostic observation and access to the plasma optical emission.The cathode chamber cooling scheme is also modified to be naturally cooled only by light emission without cooling water to improve the optical thin performance in the optical path.A single-parameter physical model has been developed to describe the power dissipated in the cascaded bias voltage arc discharge argon plasmas,which have been investigated by utilizing optical emission spectroscopy(OES) and Langmuir probe.In the experiments,discharge currents from 50 A to 100 A,argon flow rates from 800 sccm to 2000 sccm and magnetic fields of 0.1 T and 0.2 T were chosen.The results show:(a) the relationship between the averaged resistivity and the averaged current density exhibits an empirical scaling law as η∝ j~(-0.63369) and the power dissipated in the arc has a strong relation with the filling factor;(b) through the quartz,the argon ions optical emission lines have been easily observed and are dominating with wavelengths between 340 nm and 520 nm,which are the emissions of Ar~+-434.81 nm and Ar~+-442.60 nm line,and theintensities are increasing with the arc current and decreasing with the inlet argon flow rate;and(c) the electron density and temperature can reach 2.0 × 10~(19) m~(-3) and 0.48 eV,respectively,under the conditions of an arc current of 90 A and a magnetic field of 0.2 T.The half-width of the n_e radial profile is approximatively equal to a few Larmor radii of electrons and can be regarded as the diameter of the plasma jet in the experiments.     

Influence of heating on the discharge characteristics of a hollow cathode

Hollow cathodes are widely used as electron sources and neutralizers in ion and Hall electric propulsion. Special applications such as commercial aerospace and gravitational wave detection require hollow cathodes with a very wide discharge current range. In this paper, a heater is used to compensate for the temperature drop of the emitter at low current. The self-sustained current can be extended from 0.6 to 0.1 A with a small discharge oscillation and ion energy when the flow rate is constant. This is also beneficial for long-life operation. However, when the discharge current is high(1 A), heating can cause discharge oscillation, discharge voltage and ion energy to increase. Further, combined with a rapid decline of pressure inside the cathode and an increase in the temperature in the cathode orifice plate, electron emission in the orifice and outside the orifice increases and the plasma density in the orifice decreases. This leads to a change in the cathode discharge mode.     

An experimental study on the degradation of the C12A7 hollow cathode

Emitter overheating is by far the greatest problem limiting the performance of novel C12A7 hollow cathodes. To explore the failure operating point and degradation mechanism of the C12A7 hollow cathode, microscopic analyses of a degraded electride emitter after 10 h of thermal electron emission are presented in this paper. The morphology and composition variation of overheated electride emitters by scanning electron microscopy, energy-dispersive spectroscopy and X-ray diffraction indicate the melting and decomposition of electride of the surface layer. The monitored temperature of the electride emitter during the C12A7 hollow cathode operation shows that to avoid overheating the electride emitter, the average current density allowed should be about 64 mA mm−2 for the C12A7 hollow cathode in its current configuration. Experimental results of the heaterless C12A7 hollow cathode demonstrate that xenon (Xe) ion bombardment can remove the insulating layer and restore the thermionic emission capability for less degraded emitters. Based on experimental results and microscopic characterization, the depletion and degradation mechanisms of electride emitters during the hollow cathode operation are discussed.     

Plasma characteristics in the discharge region of a 20A emission current hollow cathode

Numerical calculation and fluid simulation methods were used to obtain the plasma characteristics in the discharge region of the LIPS-300 ion thruster’s 20 A emission current hollow cathode and to verify the structural design of the emitter.The results of the two methods indicated that the highest plasma density and electron temperature,which improved significantly in the orifice region,were located in the discharge region of the hollow cathode.The magnitude of plasma density was about 10~(21)m~(-3)in the emitter and orifice regions,as obtained by numerical calculations,but decreased exponentially in the plume region with the distance from the orifice exit.Meanwhile,compared to the emitter region,the electron temperature and current improved by about 36%in the orifice region.The hollow cathode performance test results were in good agreement with the numerical calculation results,which proved that that the structural design of the emitter and the orifice met the requirements of a 20 A emission current.The numerical calculation method can be used to estimate plasma characteristics in the preliminary design stage of hollow cathodes.     

动态膜电解制备四价铀Ⅰ.装置建立及性能测试

以钛涂钌铱网为阳极、钛网为阴极,建立了动态膜电解制备四价铀装置,测试了该装置的性能,比较了使用国产膜和进口膜时的电解性能,同时还探讨了制备过程中各参数的变化。研究结果表明:该装置能在电流密度高达120mA/cm2的情况下稳定运行;隔膜采用贝斯特Nepem-417膜或旭化成Aciplex-F4112膜,对电解结果无显著差异;对于500mL铀质量浓度为199g/L的料液,仅采用72cm2的钛涂钌铱网为阳极、钛网作为阴极,电解180min,四价铀产率可达到93.1%;电解前后阴极料液中肼浓度从0.52mol/L下降为0.30mol/L,酸浓度从2.20mol/L下降为0.70mol/L,槽压在3～3.6V内变动,阴极电解液温度低于45℃(室温28℃)。     

Surface Charging Controlling of the Chinese Space Station with Hollow Cathode Plasma Contactor

A highly charged manned spacecraft threatens the life of an astronaut and extravehicular activity, which can be effectively reduced by controlling the spacecraft surface charging.In this article, the controlling of surface charging on Chinese Space Station(CSS) is investigated,and a method to reduce the negative potential to the CSS is the emission electron with a hollow cathode plasma contactor. The analysis is obtained that the high voltage(HV) solar array of the CSS collecting electron current can reach 4.5 A, which can be eliminated by emitting an adequate electron current on the CSS. The theoretical analysis and experimental results are addressed,when the minimum xenon flow rate of the hollow cathode is 4.0 sccm, the emission electron current can neutralize the collected electron current, which ensures that the potential of the CSS can be controlled in a range of less than 21 V, satisfied with safety voltage. The results can provide a significant reference value to define a flow rate to the potential controlling programme for CSS.     

低能高束流氩离子源的结构及性能

离子源技术是等离子体研究中的一项重要内容,而低能大束流源则是离子源技术研究中的一个重要方向,因为这样的源在离子束刻蚀、离子束溅射镀膜以及荷能粒子与物质相互作用方面都有广泛的应用;本文采用空心阴极空心阳极结构,用热阴极电子发射弧放电驱动并用磁场约束产生等离子体,用曲面发射引出离子束,研制成了氩气放电溅射离子源;研究了灯丝加热电流、弧压对弧流的影响和弧流与工作气体压力对离子束引出的影响规律.离子源的引出电压在0-4.0 kV之间连续可调,最大引出束流为100 mA,束斑面积为φ6.0 cm,以Ti为溅射靶时的最大溅射沉积率为0.45 nm/s,离子源可连续工作160 h.