同步辐射X射线源的剂量增强效应实验研究

设计了多层平板铝电离室,利用北京同步辐射装置BSRF产生的30—100keV同步辐射硬X射线,测量了不同材料界面Kovar/Au/Al,Pb/Al,Ta/Al的辐射剂量梯度分布,给出了不同材料界面剂量增强因子DEF.在该装置上同时开展了硬X射线辐照引起的CMOS器件4069的剂量增强效应RDEF研究.采用双层膜结构,通过实验给出辐照敏感参数随总剂量的变化关系,从而给出器件损伤增强因子.这些方法为器件抗硬X射线辐射加固技术研究提供了实验技术手段.     

浮栅ROM器件x射线剂量增强效应实验研究

给出了浮栅ROM器件在钴源和北京同步辐射装置(BSRF)3W1白光束线辐照的实验结果;比较了两种辐照的实验结果及其损伤异同性.通过实验在线测得位错误数随总剂量的变化,给出相同累积剂量时x射线辐照和γ射线辐照的总剂量效应损伤等效关系.获得了浮栅ROM器件x射线剂量增强因子.这些结果对器件抗x射线辐射加固技术研究有重要价值 关键词： EEPROM x射线 剂量增强剂量效应 同步辐射     

存储器硬X射线损伤效应实验

文章给出了大规模集成电路浮栅ROM,SRAM器件在钴源和北京同步辐射装置BSRF(Beijing Synchrotron Radiation Facility)3W1白光束线辐照的实验结果;比较了其两种辐照源的实验结果及其损伤异同性.通过实验在线测得位错误数随总剂量的变,给出基相同累积剂量时X射线辐照和γ射线辐照的总剂量效应损伤等关系.获得了浮栅ROM器件X射线剂量增强因子,给出不同集成度SRAM器件的X射线辐射加固技术研究有重要价值.     

55 nm硅-氧化硅-氮化硅-氧化硅-硅闪存单元的γ射线和X射线电离总剂量效应研究

基于~(60)Co-γ射线和10 keV X射线辐射源,系统地研究了55 nm硅-氧化硅-氮化硅-氧化硅-硅闪存单元的电离总剂量效应,并特别关注其电学特性退化的规律与物理机制.总剂量辐照引起闪存单元I-V特性曲线漂移、存储窗口变小和静态电流增大等电学特性的退化现象,并对其数据保持能力产生影响.编程态闪存单元的I_d-V_g曲线在辐照后显著负向漂移,而擦除态负向漂移幅度较小.对比两种射线辐照,擦除态的I_d-V_g曲线漂移方向不同.相比于擦除态,富含存储电子的编程态对总剂量辐照更为敏感;且相比于~(60)Co-γ射线,本文观测到了显著的X射线剂量增强效应.利用TCAD和Geant 4工具,从能带理论详细讨论了55 nm硅-氧化硅-氮化硅-氧化硅-硅闪存单元电离总剂量效应和损伤的物理机制,并模拟和深入分析了X射线的剂量增强效应.     

10位CMOS数模转换器在中子和γ混合环境下的综合辐射效应

研究了在反应堆中子和γ射线综合辐照环境下CMOS工艺10位数模转换器(DAC)的辐射效应。通过对DAC在γ辐射环境、中子辐射环境、中子和γ混合辐射环境以及中子预辐照后进行γ射线辐照下的效应对比发现,在中子和γ混合辐射环境下会产生电离总剂量效应加剧现象,即一定混合程度的中子和γ同时辐照会增强CMOS器件的辐射效应。     

不同集成度SRAM硬X射线剂量增强效应研究

给出了不同集成度16K—4Mb随机静态存储器SRAM在钴源和北京同步辐射装置BSRF3W1白光束线辐照的实验结果;通过实验在线测得SRAM位错误数随总剂量的变化,给出相同辐照剂量时20—100keVX光辐照和Co⁶⁰γ射线辐照的剂量损伤效应的比例因子;给出集成度不同的SRAM器件抗γ射线总剂量损伤能力与集成度的关系;给出不同集成度SRAM器件的X射线损伤阈值.这些结果对器件抗X射线辐射加固技术研究有重要价值.     

电离总剂量对纳米SRAM器件单粒子翻转敏感性的影响

电离总剂量（TID）与单粒子效应（SEE）是纳米SRAM器件在航天应用中的主要威胁。随着CMOS工艺的进步，两种辐射效应在纳米SRAM器件中的协同效应出现了一些新现象，有必要进一步开展深入研究。利用γ射线以及不同种类重离子对两款纳米SRAM器件开展了辐照实验，研究了不同辐照参数、测试模式以及数据图形条件下，电离总剂量对单粒子翻转（SEU）敏感性的影响。研究结果表明，γ射线辐照过后，存储单元中反相器开关阈值减小，漏电流增大，导致SRAM存储单元抗翻转能力降低，SEU截面有明显增大；未观察到"印记效应"，数据图形对测试结果没有明显影响；多位翻转（MBU）比例无明显变化。     

氮化镓基高电子迁移率晶体管单粒子和总剂量效应的实验研究

利用重离子加速器和~(60)Co γ射线实验装置,开展了p型栅和共栅共源级联结构增强型氮化镓基高电子迁移率晶体管的单粒子效应和总剂量效应实验研究,给出了氮化镓器件单粒子效应安全工作区域、总剂量效应敏感参数以及辐射响应规律.实验发现, p型栅结构氮化镓器件具有较好的抗单粒子和总剂量辐射能力,其单粒子烧毁阈值大于37 MeV·cm~2/mg,抗总剂量效应水平高于1 Mrad (Si),而共栅共源级联结构氮化镓器件则对单粒子和总剂量辐照均很敏感,在线性能量传输值为22 MeV·cm~2/mg的重离子和累积总剂量为200 krad (Si)辐照时,器件的性能和功能出现异常.利用金相显微镜成像技术和聚焦离子束扫描技术分析氮化镓器件内部电路结构,揭示了共栅共源级联结构氮化镓器件发生单粒子烧毁现象和对总剂量效应敏感的原因.结果表明,单粒子效应诱发内部耗尽型氮化镓器件的栅肖特基势垒发生电子隧穿可能是共栅共源级联结构氮化镓器件发生源漏大电流的内在机制.同时发现,金属氧化物半导体场效应晶体管是导致共栅共源级联结构氮化镓器件对总剂量效应敏感的可能原因.     

同步动态随机存储器辐射效应测试系统研制

在分析同步动态随机存储器(SDRAM)辐射效应主要失效现象的基础上,研制了具备了读写功能测试、刷新周期测试及功耗电流测试三种功能的SDRAM辐射效应在线测试系统,并开展了SDRAM的总剂量效应实验研究。结果表明,总剂量效应会导致SDRAM器件的数据保持时间不断减小,功耗电流不断增大以及读写功能失效。实验样品MT48LC8M32B2的功能失效主要由外围控制电路造成,而非存储单元翻转。数据保持时间虽然随着辐照剂量的累积不断减小,但不是造成该器件功能失效的直接原因。     

总剂量辐照下沟道长度对部分耗尽绝缘体上硅p型场效应晶体管电特性的影响

本文通过实验研究了0.8μm PD(Partially Depleted)SOI(Silicon-On-Insulator)p型Metal-oxidesemiconductor-feld-efect-Transistor(MOSFET)经过剂量率为50 rad(Si)/s的60Coγ射线辐照后的总剂量效应,分析了沟道长度对器件辐照效应的影响.研究结果表明:辐照总剂量相同时,短沟道器件的阈值电压负向漂移量比长沟道器件大,最大跨导退化的更加明显.通过亚阈值分离技术分析得到,氧化物陷阱电荷是引起阈值电压漂移的主要因素.与长沟道器件相比,短沟道器件辐照感生的界面陷阱电荷更多.     

High X-ray conversion efficiency with target irradiation by a frequency tripled Nd : Glass laser

High conversion efficiency of laser energy into X-rays from a laser irradiated target is of great interest for a variety of dynamical (pulsed) studies, e.g.: radiography of laser-imploded targets, structure determination by diffraction and absorption fine-structure, and X-ray laser pumping. We report here on a frequency tripled Nd : glass laser used to irradiate targets of various materials at ～5 x 10¹⁴W/cm². We find conversion efficiencies of between 1% and 0.1% (with respect to the incident laser energy) for individual X-ray lines between 1.8 and 7.8 keV. These efficiencies are more than an order of magnitude higher than whose achieved with 1.06 μm lasers.     

X-Rays emission by high-intensity pulsed lasers irradiating thin foils at PALS laboratory

X-rays and forward ion emission from laser-generated plasma in the Target Normal Sheath Acceleration regime of different targets with 10-μm thickness, irradiated at Prague Asterix Laser System (PALS) laboratory at about 10¹⁶ W/cm² intensity, employing a 1,315 nm-wavelength laser with a 300-ps pulse duration, are investigated. The photon and ion emissions were mainly measured using Silicon Carbide (SiC) detectors in time-of-flight configuration and X-ray streak camera imaging. The results show that the maximum proton acceleration value and the X-ray emission yield growth are proportional to the atomic number of the irradiated targets. The X-ray emission is not isotropic, with energies increasing from 1 keV for light atomic targets to about 2.5 keV for heavy atomic targets. The laser focal position significantly influences the X-ray emission from light and heavy irradiated targets, indicating the possible induction of self-focusing effects when the laser beam is focalized in front of the light target surface and of electron density enhancement for focalization inside the target.     

Surface roughness-aided hard X-ray emission from carbon nanotubes

Efficient low debris hard X-ray source based on multiwalled carbon nanotubes (MWNT) irradiated by intense, femtosecond laser over an intensity range of 10¹⁵–10¹⁷ W cm⁻² μm² is reported. The MWNT targets yield two orders of magnitude higher X-rays (indicating significant enhancement of laser coupling) and three orders of magnitude lower debris compared to conventional metallic targets under identical experimental conditions. The simple analytical model explains the basic experimental observations and also serves as a guide to design efficient targets to achieve low-debris laser plasma-based hard X-ray sources at low laser intensities suitable for multi-kHz operation.     

双极线性稳压器电离辐射剂量率效应及其损伤分析

为了对双极线性稳压器在电离辐射环境下损伤变化特征及其剂量率效应进行研究,选择一组器件进行⁶⁰Co γ高低剂量率的辐照和退火试验. 结果表明线性稳压器的输出电压、最大负载电流、线性调整率、压降电压等多个关键参数都有不同程度的蜕变. 且各器件在高低剂量率下的辐照响应略有不同,表现出不同的剂量率效应. 文中通过多种形式的测试结果分析,系统地讨论了各参数变化的原因及其内部各模块对稳压器功能的影响. 结合电离损伤退火特性,探讨了各剂量率效应形成的原因. 这不但对工程应用考核提供了参考,而且为设 关键词： 双极线性稳压器 总剂量效应 剂量率效应 辐射损伤     

Laser effects on graphene oxide irradiated in high vacuum

Graphene oxide (GO) foils were irradiated by using different fluences of an infrared nanosecond pulsed laser and characterized before and after the laser irradiation. The produced laser ablation was investigated as well as the generated plasma. Optical and AFM microscopies, mass quadrupole spectrometry, Rutherford backscattering analysis and X-ray photoelectron spectroscopy were used to analyze the irradiated GO foils. Results demonstrated that the GO loses oxygen with the laser irradiation becoming richer in sp²-hybridized carbon content.     

Nanostructuring of FePt thin films by plasma focus device: pulsed ion irradiation dependent phase transition and magnetic properties

The effects of the different number (1, 2 and 3) of H⁺ ion irradiation shots on pulsed laser deposited FePt thin films, using pulsed plasma focus device, are investigated. The FePt thin films were exposed to energetic H⁺ ions in a plasma focus device at a fixed distance of 4 cm from the top of central electrode. It was deduced that single shot ion irradiation based transient thermal treatment induces an effect similar to the conventional annealing at 400°C. Well-separated nanoparticles are formed, and the significant enhancement of the coercivity, by about two orders of magnitude, at a lower annealing temperature of 400°C has been observed in the single shot ion irradiated samples. The increase of plasma focus ion irradiation shots lead to the amorphorization in irradiated FePt samples due to excessive energy transfer causing more defects and lattice distortion, and a decreasing coercivity trend in irradiated and annealed samples are observed due to reduction in the texture coefficient of magnetic easy axis (001) orientation fct phase.     

Pulsed cathodoluminescence of irradiated LiF-O and LiF(U)-O crystals

The spectral kinetic characteristics of the luminescence excited in previously irradiated (≤10⁶ Gy) LiF-O and LiF(U)-O crystals have been investigated in the spectral range 4–1.8 eV by pulsed spectrometry with nanosecond time resolution. The luminescence of the crystals was excited by nanosecond nitrogen-laser or electron-beam pulses at 300 K. The inertial character of uranium luminescence enhancement and the dependence of the number of enhancement stages on the excitation technique are revealed. A difference in the character of the dependences of the intensities of the pulse photo-and cathodoluminescence of uranium on the irradiation dose is found.     

X射线探测器的脉冲标定技术

利用强流电子束技术产生通量密度为10¹⁸—10¹⁹X-ray photon/sr·s的脉冲CuKX射线源,标定PIN型硅二极管半导体探测器对X光子的脉冲灵敏度。用绝对X射线监测器——P10气体脉冲电离室作为脉冲X射线通量密度的标准。脉冲电荷自动测量仪由微处理机进行程序控制,并予以实时校准。该电离室测量通量密度的精度为±5％,适用的能通量率范围可达4×10^-9—2×10²W/cm²,适用的光子能量范围为1.5—10keV,标定探测器的精度为±7.0％,并发现PIN型硅二极管的脉冲灵敏度比稳态X射线束标定的灵敏度高30％左右。 关键词：