VDMOS电离辐射效应快速评估方法

高压垂直双扩散金属-氧化物半导体场效应晶体管(Vertical Double-diffused MOSFET,VDMOS)是空间广泛应用的半导体器件,由于空间环境存在电离辐射,需要开展其抗辐射能力的评估。通常采用国军标规定的常温辐照至考核剂量,再追加50%辐照剂量和168 h的高温退火评估方法,实验周期较长。为缩短实验周期,开展了VDMOS电离辐射效应快速评估方法研究,通过国军标实验方法与高温100℃辐照结果对比发现,在较大的剂量范围内,高温辐照可以缩短测试评估时间,并较好地评估高压VDMOS器件的抗辐射能力。通过典型数字电路在高温100℃下辐照与国军标方法对比,证明了高温辐照方法具有国军标方法的等效性,且可以节省168 h的退火时间,极大的缩短了评估周期。本方法可用于高压VDMOS器件的抗电离辐射能力的快速评估。     

萃取色层法测定90Sr时消除210Bi干扰的修正方法

²¹⁰Bi是环境样品分析⁹⁰Sr过程中最重要的干扰核素之一。在二（2-乙基己基）磷酸酯(Bis（2-ethylhexyl）phosphate,HDEHP)萃取色层法分析⁹⁰Sr过程中,通过对淋洗液分段收集、测量并绘制淋洗曲线,发现铋、钇完全被吸附在色层柱上且二者无法完全分离,导致⁹⁰Sr测量结果偏高。对于部分环境样品（如土壤、气溶胶等）,²¹⁰Pb-²¹⁰Bi的含量远高于⁹⁰Sr-⁹⁰Y,必须采取进一步的除铋措施。过柱分离后残留的²¹⁰Bi可以通过Bi₂S₃沉淀的方法去除;未进行Bi₂S₃沉淀除铋或除铋不完全时²¹⁰Bi仍有残留。因此推荐一种利用衰变规律通过对样品源重复测量、运用公式修正的方法消除²¹⁰Bi干扰。试验结果表明：²¹⁰Bi与<...     

聚合物的基本辐射效应辐射向聚合物的能量转移

聚合物的辐射交联、降解和接枝改性都是由辐射向聚合物的能量转移引发的.任何一种辐射源的辐射,都可以引发聚合物分子的活化或电离,生成发生化学反应所需的活性粒子.能量转移的主要形式是射线通过电离与聚合物分子发生作用,而碰撞的贡献比较小.X射线或γ射线等电磁波的辐射会产生高能二次电子,高能二次电子可以使聚合物分子发生电离.电子束、γ射线和离子束作为辐射源,其穿透聚合物材料过程中能量损失方式的宏观机理大相径庭.本文从宏观和微观两方面的机理分别对由电子、γ射线、离子和中子引发的单一辐射效应事件进行描述.     

同步辐射双晶单色器平行度测量方法研究

针对上海光源(SSRF)光束线建设和晶体单色器须进行双晶晶体表面(晶面)平行度离线测量的需求,探讨了利用十字位相板改进后光笔干涉仪法测量双晶晶体表面平行度的可行性,并开展原理性实验.该方法克服了自准直仪法不能测量晶面绝对平行度的缺陷,并实现了同时测量双晶单色器的二维平行度.在本实验装置下,投角和滚角的理论测量精度可达0...     

Approach to reducing the effect of bone—coal power station on radiation environment

The effect of two bone-coal power stations(6MWe) on environment was investigated within the scope of the dose contribution caused by various radionucildes in different ways.It is found that the best measures to reduce the effect of bone-coal power station on radiation environment include to select a fine boiler system and a comprehensive utilization of the bone-coal cinder(BCC),soot and ash in the catchers.     

长期低剂量电离辐射对工作人员心电图影响的Meta分析

通过搜索有关文献,按照预先设定的纳入排除标准严格筛选后,以放射组和对照组心电图检查总人数、心电图异常人数为基本数据,研究其异质性检验,用OR(OR即比值比,表示暴露者的疾病危险性与非暴露者疾病危险性的比值)作为效应值,然后使用固定效应模型或随机效应模型进行Meta分析。结果显示,符合纳入标准的文献共计15篇;放射组与对照组之间异常率有统计学意义[OR=1.63,95%CI(1.32,2.02),p0.000 01]。结果提示,长期暴露于低剂量电离辐射环境下会对工作人员心电图异常有显著影响。     

耐温屏蔽复合材料的研制及性能研究

为满足核电站、乏燃料存储设施等对防护材料的耐温性、热稳定性、耐辐照性能等要求,研制四官能环氧树脂基(AGA型)耐温屏蔽复合材料。首先对基体材料的热稳定性进行分析,由热重分析(thermogravimetric analysis,TG)曲线得到其起始分解温度为353.5℃,200℃恒温储存170 h后,基体材料失重1.22%。动态热机械性能分析(dynamic thermomechanical analysis,DMA)表明,随着钨(W)含量的增加,AGA型耐温屏蔽复合材料的玻璃化温度向高温区移动并且峰型变宽。用⁶⁰Co放射源辐照50 kGy剂量,当AGA型耐温屏蔽复合材料的W含量10.5 wt%,B₄C含量3 wt%时,其辐照前后冲击强度均为最优。用²⁵²Cf中子源测试2 cm厚AGA型耐温屏蔽复合材料的屏蔽性能,当加入3 wt%的B₄C时,AGA-4耐温屏蔽复合材料的快中子透射率为50.00%。实验结果表明,AGA型耐温屏蔽复合材料具有一定的耐温性和耐辐照性能,并且密度较小。     

Ionizing radiation effect on 10-bit bipolar A/D converter

<正>In this article,radiation effects and annealing characteristics of a bipolar analog-to-digital converter(ADC) are investigated in different biases and dose rates.The results show that ADC is sensitive to both the bias and dose rate. Under high-dose-rate irradiation,the ADC functions well,while under low-dose-rate irradiation,the parameters of ADC change obviously at low dose level,and the damage is significant at zero bias.Combining the fringing field with the space charge model,the underlying mechanism for this response is discussed.     

A three-dimensional numerical study on the effect of geometric asymmetry on arcjet thruster performance

In an arcjet thruster, the cathode and constrictor degrade with time, and the electrical arc discharge may become unsymmetrical. In this work, a three-dimensional numerical model of a hydrogen plasma arcjet is developed and validated to study the effect of unsymmetrical electric arc discharge on thruster performance. The unsymmetrical arc discharge is realized by introducing a radial shift of the cathode so that the cathode tip offset is 80 μm(25% of the constrictor radius). Simulations are cond...     

The effect of dose rate on the response of austenitic stainless steels to neutron radiation

Depending on reactor design and component location, austenitic stainless steels may experience significantly different irradiation dose rates in the same reactor. Understanding the effect of dose rate on radiation performance is important to predicting component lifetime. This study examined the effect of dose rate on swelling, grain boundary segregation, and tensile properties in austenitic stainless steels through the examination of components retrieved from the Experimental Breeder Reactor-II (EBR-II) following its shutdown. Annealed 304 stainless steel, stress-relieved 304 stainless steel, 12% cold-worked 316 stainless steel, and 20% cold-worked 316 stainless steel were irradiated over a dose range of 1–56 dpa at temperatures from 371 to 440 °C and dose rates from 0.5 to 5.8 × 10⁻⁷ dpa/s. Density and tensile properties were measured for 304 and 316 stainless steel. Changes in grain boundary composition were examined for 304 stainless steel. Swelling appears to increase at lower dose rates in both 304 and 316 stainless steel, although the effect was not always statistically significant. Grain boundary segregation also appears to increase at lower dose rate in 304 stainless steel. For the range of dose rates examined, no measurable dose rate effect on tensile properties was noted for any of the steels.     

甘氨酸辐射效应的谱学研究

用固体高分辨核磁共振~(13)C谱、电子自旋共振谱以及X衍射光谱研究了多晶甘氨酸的γ辐射稳定性。结果表明甘氨酸在0—140kGy辐照剂量范围内是稳定的,而~(13)C共振谱线则随着辐照剂量的增加而线性地增宽。     

纸张的电子束辐照效应研究

为确证电子束辐照邮件的可行性,寻找辐照纸张时可保证品种等级的剂量范围,用不同剂量电子束照射新闻纸、复印纸、牛皮纸、书写纸、照片等几种常用的纸张,测定了纸张的定量、白度、撕裂度、抗张强度、耐折度、色差等物理性能发生的变化,并对辐照效应的机理进行了研究.结果分析表明,20-30 kGy的邮件辐照灭菌剂量对上述性能影响小于25%.     

原位X射线荧光测井井液的影响与校正

本文研究原位X射线荧光测井探测中探测装置与井壁间井液厚度变化对测量结果的影响,通过对测量谱线特征参数的获取提出了一种新的井液校正方法.实验结果表明,这是一种对高含量样品有效、快速、实用的校正方法,校正后目标元素特征X射线峰峰面积与实测没有井液干扰时的峰面积的偏差小于5%.     

Effect of the composition of radiation on the radiation damage to graphite

A statistical analysis is performed of the results on the determination of the critical neutron fluence in MR, SM-2, and BOR-60 with different irradiation temperature. It is shown that the critical neutron fluence depends not only on the irradiation temperature but also, and to an even greater extent, on the radiation composition factor (ratio of the neutron and γ-ray flux densities). Thus the critical neutron fluence for irradiation at 600°C in MR (radiation composition factor 0.13) is 17·10²¹ cm⁻² and in SM-2 (radiation composition factor 0.1) 11·10²¹ cm⁻² at the same temperature. When the same graphite is irradiated in the region of the outer corner of a working block of RBMK, where the radiation composition factor is 0.55, it is expected that the critical neutron fluence will be 31.7·10²¹ cm⁻². In summary, taking account of the effect of γ-radiation introduces substantial corrections: the experimental results obtained in research reactors are found to be at least a factor of 2 too low. This gives hope of substantiating the substantial increase in the service life of the RBMK graphite masonry. 3 figures, 8 references. Scientific-Research and Design Power-Engineering Institute. State Science Center—Scientific-Research Institute of Nuclear Reactors. Translated from Atomnaya énergiya, Vol. 87, No. 1, pp. 24–28, July, 1999.     

The effect of radiation on the properties of silicone rubber

As a result of -radiation, silicone rubber undergoes a series of changes due to radiation cross-linking. The modulus of elasticity increases linearily with a dose up to 150–200 megarads. The vitrification temperature (– 120 to- 125 ° C) hardly changes up to 100 megarads and at 270 megarads it is –110 to –115 ° C. With cross-linking, the rate of crystallization and degree of crystallinity decrease. The melting point falls from – 35 ° C for the initial material to – 55 ° C for rubber Irradiated with a dose of 40 megarads. A dose of 100 megarads practically completely eliminates crystallization. This dose produces rigid rubbers with a modulus of 200– 250 kg/cm² and a high degree of frost resistance, (Tg –125 ° C), but with a very small breaking stretch (15–20%) with a strength of 30–40 kg/cm².     

The effect of radiation on the anaerobic corrosion of steel

To ensure the safe encapsulation of spent nuclear fuel elements for geological disposal, SKB of Sweden are considering using a canister, which consists of an outer copper canister and a cast iron insert. Previous work has investigated the rate of gas generation due to the anaerobic corrosion of ferrous materials over a range of conditions. This paper examines the effect of radiation on the corrosion of steel in repository environments. Tests were carried out at two temperatures (30 °C and 50 °C), two dose rates (11 Gray h⁻¹ and 300 Gray h⁻¹) and in two different artificial groundwaters, for exposure periods of several months. Radiation was found to enhance the corrosion rate at both dose rates but the greatest enhancement occurred at the higher dose rate. The corrosion products were predominantly magnetite, with some indications of unidentified higher oxidation state corrosion products being formed at the higher dose rates.     

A superposition method to calculate the interaction effect between bodies in diffusion theory

We introduce a method for calculating the neutron flux around a finite number of spheres arranged in-line. The method uses the concept of superposition in which the solution for a group of spheres is composed of a sum of solutions for the individual spheres. We illustrate the method by a simple example based on a chain of highly absorbing spheres in a non-absorbing moderator and show that it converges rapidly to the exact solution.