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1.
高博  余学峰  任迪远  崔江维  兰博  李明  王义元 《物理学报》2011,60(6):68702-068702
对一种非加固4007电路中p型金属氧化物半导体场效应晶体管(PMOSFET)在不同剂量率条件下的电离辐射损伤效应及高剂量率辐照后的退火效应进行了研究. 通过测量不同剂量率条件下PMOSFET的亚阈I-V特性曲线,得到阈值电压漂移量随累积剂量、退火时间的变化关系. 实验发现,此种型号的PMOSFET具有低剂量率辐射损伤增强效应. 通过描述H+在氧化层中的输运过程,解释了界面态的形成原因,初步探讨了非加固4007电路中PMOSFET低剂量率辐射损伤增强效应模型. 关键词: p型金属氧化物半导体场效应晶体管 60Co γ射线')" href="#">60Co γ射线 电离辐射损伤 低剂量率辐射损伤增强效应  相似文献   

2.
林丽艳  杜磊  包军林  何亮 《物理学报》2011,60(4):47202-047202
在研究光电耦合器电离辐射损伤机理基础上,分别建立光电耦合器电离辐射损伤电流传输比(CTR)表征模型和1/f噪声表征模型.结果表明CTR退化和噪声增加都归因于辐射后光敏三极管集电结和发射结处SiO2/Si界面缺陷增多.根据CTR退化和噪声变化分别与辐射剂量的关系,建立起噪声变化与CTR退化之间的关系,辐照实验对表征模型正确性进行了验证.运用噪声变化与辐射剂量的关系,通过低剂量辐照实验可以预测高剂量辐射后光电耦合器退化程度,故可用于评价光电耦合器抗辐射能力. 关键词: f噪声')" href="#">1/f噪声 光电耦合器 缺陷 模型  相似文献   

3.
本文采用60 MeV Br离子、5 MeV质子和1 MeV电子等三种辐射源, 针对CC4013型互补金属氧化物半导体器件(complementary metal oxide semiconductor, CMOS)进行辐射损伤研究. 通过Geant4程序计算了该器件电离辐射吸收剂量与芯片厚度的关系, 经过计算, 在相同注量下, 60 MeV Br离子的电离吸收剂量最大, 1 MeV电子产生的电离吸收剂量最小. 应用Keithley4200-SCS半导体特性分析仪在原位条件下研究了CC4013器件电性能参数随辐射吸收剂量的变化关系. 测试结果表明, 相同电离辐射吸收剂量下, 1 MeV电子对CC4013器件的阈值电压参数影响最大, 5 MeV质子其次, 60 MeV Br离子的影响最弱. 关键词: CMOS器件 高能带电粒子 电离辐射 辐射损伤  相似文献   

4.
CMOS器件60Coγ射线、电子和质子电离辐射损伤比较   总被引:1,自引:0,他引:1       下载免费PDF全文
利用TRIM95蒙特卡罗软件计算了质子在二氧化硅中的质量阻止本领和能量沉积,比较了质子在二氧化硅中的电离阻止本领与核阻止本领,分析了质子在材料的表面吸收剂量与灵敏区实际吸收剂量的关系.利用60Coγ射线、1MeV电子和2-9 MeV质子对CC4007RH和CC4011器件进行辐照实验,比较60Coγ射线和带电粒子的电离辐射损伤情况.实验结果表明,60Coγ射线、1MeV电子和2-7MeV质子辐照损伤效应中,在0V栅压下可以相互等效;在5V栅压下,以60Coγ射线损伤最为严重,1MeV电子的辐射损伤与60Coγ射线差别不大,9MeV以下质子辐射损伤总是小于60Coγ射线,能量越低,损伤越小.  相似文献   

5.
本文研究了Cu、Au薄膜镜面的激光辐射损伤,得到了反射率随激光及样品有关参数变化关系的实验结果,并对激光辐射损伤的机制进行了初步的讨论。  相似文献   

6.
本文研究了Cu、Au薄膜镜面的激光辐射损伤,得到了反射率随激光及样品有关参数变化关系的实验结果,并对激光辐射损伤的机制进行了初步的讨论。  相似文献   

7.
CMOS器件60Co γ射线、电子和质子电离辐射损伤比较   总被引:1,自引:0,他引:1       下载免费PDF全文
何宝平  陈伟  王桂珍 《物理学报》2006,55(7):3546-3551
利用TRIM95蒙特卡罗软件计算了质子在二氧化硅中的质量阻止本领和能量沉积,比较了质子在二氧化硅中的电离阻止本领与核阻止本领,分析了质子在材料的表面吸收剂量与灵敏区实际吸收剂量的关系.利用60Co γ射线、1MeV电子和2—9 MeV质子对CC4007RH和CC4011器件进行辐照实验,比较60Co γ射线和带电粒子的电离辐射损伤情况.实验结果表明,60Co γ射线、1MeV 电子和2—7MeV质子辐照损伤效应中,在0V栅压下可以相互等效; 关键词: γ射线 电子 质子 辐射损伤  相似文献   

8.
应用经典径迹蒙特卡罗方法研究Si2+离子与氢原子碰撞电离反应过程.计算了随入射离子能量变化的总截面、出射电子随角度和能量变化的一阶、二阶微分截面,及出射电子随入射离子能量变化的平均能量.根据计算结果,讨论展示了软碰撞、电子转移到入射离子连续态、两体相遇碰撞等电离机理,阐明了它们对碰撞总截面、微分截面、电离电子能量的影响.通过计算出射电子到入射离子和靶的距离比的电离电子数分布研究了不同入射离子能量"鞍点"电离机理的可能性.  相似文献   

9.
杨剑群  董磊  刘超铭  李兴冀  徐鹏飞 《物理学报》2018,67(16):168501-168501
航天器中电子器件在轨服役期间,会遭受到空间带电粒子及各种射线的辐射环境的显著影响,易于造成电离辐射损伤.本文采用60Coγ射线辐照源,针对有/无Si_3N_4钝化层结构的横向PNP型(LPNP)双极晶体管,开展了电离辐射损伤效应及机理研究.利用KEITHLEY 4200-SCS半导体参数测试仪测试了LPNP晶体管电性能参数(包括Gummel特性曲线和电流增益等).采用深能级瞬态谱分析仪(DLTS),对辐照前后有/无Si_3N_4钝化层结构的LPNP晶体管的电离缺陷进行测试.研究结果表明,在相同吸收剂量条件下,与无Si_3N_4钝化层的晶体管相比,具有Si_3N_4钝化层的LPNP晶体管基极电流退化程度大,并且随吸收剂量的增加,电流增益退化更为显著.通过DLTS分析表明,与无Si_3N_4钝化层的晶体管相比,有Si_3N_4钝化层的晶体管辐射诱导的界面态能级位置更接近于禁带中心.这是由于制备Si_3N_4钝化层时引入了大量的氢所导致,而氢的存在会促使辐射诱导的界面态能级位置更接近于禁带中心,复合率增大,从而加剧了晶体管性能的退化.  相似文献   

10.
丁丁  何斌  屈世显  王建国 《物理学报》2013,62(3):33401-033401
应用经典径迹蒙特卡罗方法详细研究了强磁场环境下He2++H (1s)的重粒子碰撞电离过程. 首先得到了在不同强度的纵向和横向磁场下电离电子的一阶能量微分截面, 发现它们不仅在数值上比未加磁场下的结果有明显的增加, 而且随电离电子的能量变化不再是单调下降, 而是呈现一定的峰值结构. 通过对电离事例的分析, 解释了这些变化形成的原因. 其次由于强磁场会导致碰撞电离的物理机理有很大变化, 因此也分析并解释了磁场强度、方向及入射粒子能量等因素对电离机理的影响行为.  相似文献   

11.
《Radiation measurements》2007,42(6-7):1063-1074
A nuclear incident or major release of radioactive materials likely would result in vast numbers of patients, many of whom would require novel therapy. Fortunately, the numbers of radiation victims in the United States (USA) have been limited to date. If a mass-casualty situation occurs, there will be a need to perform rapid, accurate dose estimates and to provide appropriate medications and other treatment to ameliorate radiation injury.The medical management of radiation injury is complex. Radiation injury may include acute radiation sickness (ARS) from external and/or internal radiation exposure, internal organ damage from incorporated radioactive isotopes, and cutaneous injury. Human and animal data have shown that optimal medical care may nearly double the survivable dose of ionizing radiation. Current treatment strategies for radiation injuries are discussed with concentration on the medical management of the hematopoietic syndrome.In addition, priority areas for continuing and future research into both acute deterministic injuries and also long-term stochastic sequelae of radiation exposure have been identified. There are several near-term novel therapies that appear to offer excellent prognosis for radiation casualties, and these are also described.  相似文献   

12.
Lysosomes have an important role in radiation injury of cells and tissues. Activation of autophagy is frequently observed in different types of pathological tissue degeneration. In radiation response it increases in some cases, and lysosomes are responsible for regulated degradation of the autophagic vacuoles. Lysosomes are also involved in ionizing radiation induced cell death. In apoptosis lysosomes degrade content of the phagocytotic vacuoles derived from engulfed apoptotic blebs. On the other hand lysosomal enzymes discharged from disintegrated cells have a key role in induction of necrotic changes. In this work we investigate autophagy and lysosomal protein degradation in the relatively radiation insensitive exocrine pancreatic acini in vivo and in vitro. Type of cell death induced by X-ray was also examined in relation to the changes of the lysosomal processes. In 5h after 16 Gy in vivo whole body irradiation we observed significant increase in the cytoplasmic volume fraction of autophagic vacuoles and in the number of apoptotic cells in vivo. But in the acini isolated from irradiated rats we could not detect a change in the lysosomal degradation of intracellular proteins. Therefore irradiation probably influences the autophagy in an earlier step than lysosomal degradation. Extended necrotic lesions were not observed in vivo as long as 48 h. Isolated pancreatic acini usually contain more autophagic vacuoles than in vivo, but we could not observe additional increase in autophagy after 8 Gy, in vitro irradiation. Lysosomal degradation of intracellular proteins was also unaltered after 8 Gy, in vitro irradiation. Other biochemical functional parameters of the isolated pancreatic acini, like protein synthesis and amylase secretion were not changed either after 8 Gy, in vitro X-ray treatment. These results indicate that pancreatic acinar cells in vitro have a high tolerance to irradiation. The observed in vivo radiation induced changes of the exocrine pancreas are possibly indirectly induced by injuries of more sensitive mechanisms.  相似文献   

13.
The paper is devoted to nuclear reactor accidents, radiation injuries during accidents, and the so-called “human factor”. The balance equation of dose characteristics in the human body and environment is presented. It is attempted to quantitatively estimate the relative variability of the human ability to ignore radiation risk.  相似文献   

14.
A method of analysis is presented that allows for the separation of specific radiation‐induced changes into distinct components in real space. The method relies on independent component analysis (ICA) and can be effectively applied to electron density maps and other types of maps, provided that they can be represented as sets of numbers on a grid. Here, for glucose isomerase crystals, ICA was used in a proof‐of‐concept analysis to separate temperature‐dependent and temperature‐independent components of specific radiation‐induced changes for data sets acquired from multiple crystals across multiple temperatures. ICA identified two components, with the temperature‐independent component being responsible for the majority of specific radiation‐induced changes at temperatures below 130 K. The patterns of specific temperature‐independent radiation‐induced changes suggest a contribution from the tunnelling of electron holes as a possible explanation. In the second case, where a group of 22 data sets was collected on a single thaumatin crystal, ICA was used in another type of analysis to separate specific radiation‐induced effects happening on different exposure‐level scales. Here, ICA identified two components of specific radiation‐induced changes that likely result from radiation‐induced chemical reactions progressing with different rates at different locations in the structure. In addition, ICA unexpectedly identified the radiation‐damage state corresponding to reduced disulfide bridges rather than the zero‐dose extrapolated state as the highest contrast structure. The application of ICA to the analysis of specific radiation‐induced changes in real space and the data pre‐processing for ICA that relies on singular value decomposition, which was used previously in data space to validate a two‐component physical model of X‐ray radiation‐induced changes, are discussed in detail. This work lays a foundation for a better understanding of protein‐specific radiation chemistries and provides a framework for analysing effects of specific radiation damage in crystallographic and cryo‐EM experiments.  相似文献   

15.
电介质材料辐射感应电导率的模型研究   总被引:5,自引:0,他引:5       下载免费PDF全文
全荣辉  韩建伟  黄建国  张振龙 《物理学报》2007,56(11):6642-6647
在传统的Rose-Fowler-Vaisberg(RFV)模型基础上引入辐射激发项,解释了辐射感应电导率与辐射剂量率的指数关系及范围.利用改进后的模型分析了不同辐射条件下材料感应电导率的变化情况,其结果表明,辐射剂量率主要影响感应电导率的大小,对感应电导率的整体变化趋势无显著影响,决定感应电导率长时间衰减的是材料载流子复合率.  相似文献   

16.
Radiation damage is one of the major impediments in obtaining high‐resolution structural information utilizing ionizing radiation. From electron microscopy it is known that electron irradiation of biological samples results in the formation of molecular hydrogen. In the present work radiation‐induced structural changes of the polypeptide cyclosporine A were observed at a temperature of 100 K. Bond length changes are thought to be due to radiation‐induced hydrogen abstraction which chemically modifies the molecules in an irreversible way. The resulting formation of molecular hydrogen might explain the observed increase of the crystal mosaicity, which has also been reported in many previous radiation damage studies.  相似文献   

17.
A numerical model is developed to describe the leakage characteristics in ferroelectric thin films under ionizing radiation. The trap-controlled space-charge-limited conduction mechanism is modified by considering radiation-induced charge carriers and changes in the relative dielectric constant. The effect of dose rate is related to the changes in the carrier mobility. Numerical simulation using this model reveals a radiation hardness of 10 Mrad(Si) for barium strontium titanate (BST) thin films at a constant dose rate of 10 Krad(Si)/s. Differences in the leakage behavior under radiation for different conduction regions are also discussed. This model provides a useful tool in predicting the leakage behavior under ionizing radiation and estimating the radiation hardness for ferroelectric materials.  相似文献   

18.
Specific features of the radiation inheritance of metals and alloys are analyzed. A conclusion on the irreversible changes in the structure of materials after irradiation is drawn. Mechanisms of inheriting the radiation effects in the process of high-temperature transformation of materials are suggested. The concentration microinhomogeneities initiated in the preliminary irradiated defect structure of the material are shown to be the genetic factor of the radiation inheritance.  相似文献   

19.
New phenomena of dynamic changes of the radiation mode in a rectangular cavity during its accelerated motion are detected. Eigenvalues of the three-dimensional problem for a homogeneous equation of phase change are determined. Allowed radiation directions in the non-uniformly moving cavity are discussed.  相似文献   

20.
Radiation response of cell organelles   总被引:2,自引:0,他引:2  
The cellular responses to various form of radiation, including ionizing- and UV-irradiation or exposure to electromagnetic fields is manifested as irreversible and reversible structural and functional changes to cells and cell organelles. Moreover, beside the morphological signs related to cell death, there are several reversible alterations in the structure of different cell organelles. The radiation-induced changes in the supramolecular organization of the membranes, including plasma membrane, and different cell organelle membranes, play a significant role in the development of acute radiation injury. These signs of radiation-induced reversible perturbation biological membranes reflect changes in the organization and/or composition of the glycocalix, modified activity and/or distribution of different membrane domains, including enzymes and binding sites. The observed changes of the cell surface micromorphology and the alteration of intercellular connections are closely related to the reorganization of the cytoskeletal elements in the irradiated cells. The mitochondria, endoplasmic reticulum, Golgi-complex, the lysosomal system have long been considered to be direct intracellular targets of irradiation. The listed morphological alterations of nuclear chromatin (e.g. changes of fine structure, altered number of nucleolar organizing regions and micronuclei, development of chromosome aberrations) may originate from the radiation-induced damage to the supramolecular organization of DNA and/or nucleus specific proteins. These endpoints of radiation effects resulted as direct consequence(s) of absorbed radiation energy, and indirectly altered intra-, intercellular communication or modified signal transduction. Some complementary data suggest that all these effects are not strictly specific to radiation and may be best considered as general stress responses, similar to those observed after application of various injurious agents and treatments to cells. Moreover, they may be equally responsible for direct degradation of supramolecular component of cells, altered signal transduction, or changes in the amount or ratio of any extracellular mediators upon irradiation. Nevertheless, qualitative and/or quantitative evaluation of any changes of chromosomes by different techniques (morphological analysis of metaphase chromosomes, fluorescent in situ hybridization, development of micronuclei etc.) are useful biological indicators as well as "biological dosimeters" of radiation injury. It is suggested, that some modern methods such as immunohistochemical detection of different proteins, specific markers of cell organelles and cytoskeleton, inspection of distribution of cell surface charged sites and different membrane domains and application of tracer substances may all be included into protocols for evaluation of cell alterations induced by different types and intensities of radiation.  相似文献   

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