Determining the Spatial Structure of a High-Power Electron Beam Using Optical Radiation Emitted by a Beam Collector

A method for determining the spatial structure of a high-power relativistic electron beam is described. Using an absolutely calibrated CCD collector, the thermal-radiation brightness distribution of the beam-collector surface is registered in the visible and near-IR spectral regions and then converted into a spatial distribution of the beam energy deposition in a target. This method is applied at a high specific beam-energy flux (1 kJ/cm²), one which causes noticeable erosion of the beam collector.     

离子束溅射生成气敏膜的研究

本文对离子束溅射生成气敏膜作了研究。与烧结陶瓷气敏传感器比较，溅射生成气敏膜对乙醇气体具有灵敏度高，长期稳定，对其它气体选择性好，而且响应恢复时间快。采用Ｘ光衍射等手段分析了离子束溅射膜的品质，表明材料组织结构相同，与基片附着性好，组织致密。     

光学平面镜面离子束修形中速度模式的实现

针对光学平面镜面离子束修形工艺中,目前采用的位置加工模式额外加工时间长、精度不高的缺点,提出离子束修形工艺中的速度加工模式,并给出速度加工模式中如何根据驻留时间计算加工中进给速度的方法。使用速度模式在自研的离子束加工机床KDIFS-500上进行了验证试验,对一块直径98 mm的微晶玻璃平面样镜进行修形,加工时间为17.5 min,样镜经过一次加工后,其面形误差的方均根值由初始的33.2 nm提高到了3.1 nm,面形收敛比高达10.7。试验结果表明,速度模式加工比位置模式加工可以缩短加工时间,提高加工精度,获得更大的面形收敛比。     

Radiation Hardness of a Fast Neutron Scintillation Spectrometer with a Stilbene Crystal

Neutron detectors with organic oscillators such as stilbene crystals are suggested for use in measuring the characteristics of neutron radiation in the International Thermonuclear Experimental Reactor (ITER). These detectors will be used as neutron-flux monitors in a multichannel neutron collimator for obtaining the spatial characteristics of a plasma source of thermonuclear neutrons with a 1-ms temporal resolution. In addition, operation in the spectrometric mode will ensure the measurement of the thermonuclear-neutron energy spectrum, which yields data on the fusion-plasma temperature and the ratio of the deuterium and tritium concentrations. During the operation of the facility, the detectors will be exposed to irradiation with a large fluence of fast neutrons. The first results obtained in studies of the characteristics of a stilbene crystal irradiated by fast neutrons with a fluence of up to 10¹⁴ neutrons/cm² are presented.     

Si3 N4浸渍处理提高硬度的研究

用硅粉冷等静压成型和反应烧结氮化工艺制造的氮化硅样品不规则气孔且多大，硬度偏低。浸渍处理可以填充气孔，显著提高硬度和抗弯强度。     

离子辅助制备碳化硅改性用硅膜的研究

本文介绍了一种利用霍尔型离子源辅助电子束蒸发，在碳化硅（Silicon Carbide: SiC）材料上制备硅改性薄膜的方法，研究了不同沉积速率下改性后的抛光效果。对样品进行了表面散射及反射的测量。通过样品的显微照片可知硅膜层在沉积速率增大条件下结构趋于疏松。通过精细抛光改性的反应烧结碳化硅（Reaction Bonded Silicon Carbide: RB-SiC）样品表面散射系数减小到1.46%，反射率接近抛光良好的微晶玻璃。温度冲击实验和表面拉力实验表明硅膜无龟裂和脱落，性质稳定，与碳化硅基底可以良好的结合。     

Determination of the Spectrum of a Pulsed Ion Beam from Current and Voltage Oscillograms

Instruments and Experimental Techniques - An algorithm for calculating the energy spectrum of a pulsed ion beam generated by a direct-acting accelerator is presented. The ion spectrum is calculated...     

Using a Laser Interferometer in Monitoring Characteristics of Seismic Acoustic Detectors

The paper reports on a technique using a laser interferometer for calibrating seismic acoustic detectors. Experimental results and recommendations for improvements in the apparatus design are given.     

碳离子束注入辅助蒸发低温沉积DLC薄膜研究

采用碳离子束注入辅助蒸发技术低温沉积了DLC薄膜,对薄膜沉积的工艺参数进行了优化,并对该薄膜的摩擦学行为进行了探讨。研究发现:碳离子束注入辅助蒸发技术沉积的DLC薄膜在离子量为3.0×1017ions/cm2,沉积率为0.1nm/s时具有最小的摩擦因数(<0.1);电流为2.0mA比3.0mA条件下所沉积的DLC薄膜表面光滑;磨损试验后,DLC薄膜的表面只有轻微磨损的痕迹。     

Unlubricated wear of Si/SiC and its composite with nickel Si/SiC-Ni

Using a pin-on-disk tribometer, dry friction and wear properties at different temperatures were investigated for reaction-sintered silicon carbide Si/SiC and its composites with nickel Si/SiC-Ni. The friction and wear properties of the composites are improved by the addition of nickel. The analysis on the worn surfaces and sub-surfaces by SEM suggest that shallow grooves are the main wear feature at 15°C. At 600°C, surface cracking and fracture is the predominating wear mechanism for Si/SiC, and the formation of flake pits on the surface due to crack propagation at subsurface is the main wear mechanism for Si/SiC-Ni. Finally the relationships between wear resistance and mechanical properties are discussed.     

A photoreactor on the basis of a Xe2 excilamp

A photoreactor developed on the basis of a Xe₂ excilamp with a power of ～10 W (with a power density of 15 mW/cm² emitted from a surface of ～700 cm²), which can operate in liquids and gases at a pressure of up to 40 atm, and a multifunctional cell with an active volume of ～760 cm³ is described. Data on water photolysis in a natural gas exposed to VUV radiation with λ=172 nm are presented.     

Increase in the Charge State of the Uranium Ion Beam Generated by the MEVVA Ion Source

The Metal Vapor Vacuum Arc (MEVVA) ion source and its modifications are investigated at the Institute of Theoretical and Experimental Physics (ITEP). In a series of the experiments, the possibility of increasing the charge state of the generated uranium ion beam was revealed. The charge state increases as a result of developing a high-current vapor vacuum arc discharge from the source cathode to an auxiliary anode located in an increasing axial magnetic field. The uranium ion beam with a total current of 150 mA was obtained, U⁷⁺ uranium ions being 10% of the current.     

Radiation Loads of the Detectors for the Central Region of the LHCb Experiment at LHC

The formation of the secondary-radiation field in the central region of the future LHCb experiment at LHC (CERN) was numerically simulated. The specific features of the field characteristics were revealed for different configurations of detectors in the experiment. The radiation loads governing the detector operation in a given radiation environment were evaluated. Methods for optimizing the design of the detectors and the accelerator vacuum chamber were proposed.     

双束聚焦离子束工作原理及微电子领域的应用

聚焦离子束系统以其超强的微加工及微分析能力在微电子领域的地位越来越重要。随着聚焦离子束系统的发展,离子束和电子束结合的双束聚焦离子束系统已经普遍被使用。双束聚焦离子束系统结合了高能离子束和电子束的优点,采用液态镓离子源通过高压引出,并经偏转会聚为离子束实现样品加工,利用高能电子束扫描样品成像,可以做到边加工边观察。本文介绍了双束聚焦离子束系统的组成,主要部件的工作原理及在微电子领域的主要应用,并详述了主要应用的操作方法。     

Dry sliding wear behavior of nano-sized SiC pins against SiC and Si3N4 discs

Micro- and nano-sized hot-pressed silicon carbide pins have been characterized by room-temperature unlubricated disk-on-pin tribological tests on hot-pressed silicon carbide and silicon nitride discs. The mean grain size was shown not to influence the steady state friction coefficient. The mean grain size clearly affected the disc wear rate: the finer was the grain size the lower was the disc wear rate. No impact of the grain size was observed on the pin wear rate. The basic wear mechanisms were grain fracture and fine abrasion. By depth-sensing indentation, it was shown that a possible explanation of the different wear behaviour between micro- and nano-sized silicon carbide are the values of mechanical properties, especially hardness, when they are measured on volumes scaling with the material microstructure.     

电子束选区熔化成形TC4合金的显微组织及硬度

采用电子束选区熔化成形技术制备不同尺寸(?8 mm×25 mm,?25 mm×8 mm)TC4合金试样,研究了2种试样在粉末堆积方向的显微组织及硬度变化.结果表明:尺寸?8 mm×25 mm试样的显微组织主要由原始β柱状晶界处的针状α集束组织和晶内针状α相互相交错形成的网篮状魏氏组织组成,原始β柱状晶主轴平行于堆积方向...     

用于线、面阵探测器上的多通道集成窄带滤光片的研制

利用自行设计的挡板机构,采用真空镀膜技术.在有效范围为25.4×2.5mm和6×6mm的条状基片上.分别制作了用于线阵探测器上的和用于面阵探测器上的多通道集成窄带滤光片,并详细研究了该滤光片的形成原理、膜系的设计分析、制备工艺以及应用等,给出了实验所得的结果。最后较系统地介绍了制备特定膜系的真空镀膜平面挡板的设计方法,并给出了适用于各类光学薄膜制备的平面挡板设计结果。     

45钢电子束扫描相变硬化组织和硬度的研究

电子束表面处理可以提高钢铁材料的表面硬度和力学性能。研究电子束扫描对45钢硬化层组织和性能的影响,探讨电子束功率、扫描速度等工艺参数对硬化层组织和性能的影响。采用扫描电镜分析45钢电子束表面强化层的显微组织,用显微硬度计进行硬度测试。结果表明,45钢经电子束扫描处理后,硬化层的组织为针状和板条状马氏体,组织比常规调质处理更加均匀、细小,试样表面的平均硬度达58 HRC,比淬火加低温回火处理的硬度高3～5 HRC,是调质处理的两倍,从处理表面往下沿深度方向硬度逐渐减小。电子束工艺参数对硬化层组织和性能有较大影响,硬化层宽度和深度随着电子束功率的增加而增加,随着扫描速度的增加而减小;硬化层的最高硬度随着电子束功率密度的增加而增加,随着扫描速度的增加而减小。     

两种陶瓷材料仪器化压入硬度与维氏硬度的比较分析

使用高精度压入仪分别测试氮化硅陶瓷、氧化锆陶瓷的仪器化压入硬度,并通过测量压痕对角线长度计算两种陶瓷材料的维氏硬度。结果表明:氮化硅陶瓷、氧化锆陶瓷的仪器化压入硬度均高于维氏硬度,两种硬度比值分别为1.225、1.130,基本符合文献所提比值1.195倍的关系,据此,陶瓷材料的维氏硬度可由仪器化压入测试获得,解决了小载荷硬度测试情况下因压痕不够清晰导致的压痕对角线测量困难问题。