Synergistic effects of neutron and gamma ray irradiation of commercial CHMOS microcontroller

This paper presents the experimental results of a combined irradiation environment of neutron and gamma rays on 80C196KC20, which is a 16-bit high performance member of the MCS96 microcontroller family. The electrical and functional tests were made in three irradiation environments: neutron, gamma rays, combined irradiation of neutron and gamma rays. The experimental results show that the neutron irradiation can affect the total ionizing dose behaviour. Compared with the single radiation environment, the microcontroller exhibits considerably more severe degradation in neutron and gamma ray synergistic irradiation. This phenomenon may cause a significant hardness assurance problem.     

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。     

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。     

Modeling the Behavior of a MOS Transistor under Fast Neutron and Gamma Irradiation

A numerical model of trapping of the radiation-induced charge in the bulk and on the surface of the oxide layer of a MOS transistor has been developed. The model takes into account the generation of point defects under fast neutron irradiation. The volume and surface charges obtained by the numerical modeling have been used to calculate the drain—gate characteristic of the MOS transistor exposed to neutron irradiation in different doses and accompanying high-energy gamma-ray irradiation. To model the effect of neutron irradiation, different methods for estimating the rate of point defect generation in a two-component material (SiO2) have been developed. The simulated drain—gate characteristic is shown to agree well with the experimental data obtained at the concentration of hole traps and their capture cross sections lying within the published data for an unirradiated device after exposure to gamma rays from a 60Co gamma source and after irradiation with fast neutrons with an average energy of ∼1 MeV and accompanying gamma rays using a pool-type reactor.     

Fast neutron detection under intense gamma-ray fields with novel nuclear emulsion technique

In order to measure neutron flux and energy in the presence of high-intensity background gamma rays, a new nuclear emulsion based on a non-sensitized OPERA film was synthesized, which had small AgBr grain sizes of 60, 90 and 160 nm. The sensitivity of this new emulsion, which is described in terms of the stopping power and grain density, was estimated experimentally by neutron irradiation at several energies. The response of the emulsion to gamma-ray-induced electrons was also simulated and the results were compared with experimental data obtained using a ⁶⁰Co gamma source. The results indicated that each AgBr grain has a threshold energy that must be deposited before the AgBr can develop into metallic Ag. Based on these results, the efficiency of the new emulsion in detecting gamma rays and neutrons was evaluated.     

The behavior of HfB2 at neutron irradiation: a simulation study

The behavior of Hafnium di-boride (HfB₂) under neutron irradiation has been simulated in a wide range of energy from 0.025?eV up to 14?MeV. The simulation and the analysis have been carried out using Geant4 and its related database. From the radiation shielding perspective, it was observed that, under thermal neutron irradiation, HfB₂ scatters neutrons with a marginally higher energy than the incident neutrons and also produces prompt gamma rays up to 11?MeV. These results would indicate that, for high-energy neutron 14?MeV, not only is HfB₂ unacceptable as a reasonable neutron absorber but also produces 20?MeV prompt gamma rays.     

High-resolution gamma-ray spectroscopy

To obtain the highest possible resolution in a measurement has always been one of the major challenges for experimental physicists because increased resolution generally results in progress. At the Institut Laue-Langevin, gamma rays emitted after neutron capture can be recorded with parts-permillion resolution. This is achieved by diffracting the gamma rays on highly perfect Sior Ge crystals. Precise measurement of the Bragg angles and the crystal lattice spacings permits the determination of wavelengths or energies. This outstanding resolving power allows the measurement of extremely small Doppler effects caused by the emission of primary gamma rays. These so-called gamma-ray-induced Doppler broadening measurements have given rise to applications in both nuclear and condensed matter physics.     

Features of Radiation Changes in Electrical Properties of InAlN/GaN Hemts

Russian Physics Journal - The effect of the proton, electron, gamma - rays, and fast neutron irradiation on the parameters of InAlN/GaN HEMT structures is analyzed. The features of initial...     

Radiation attenuation and nuclear properties of high density concrete made with steel aggregates

Abstract

The fast neutron and gamma ray spectra measured behind different thickness of steel scrap concrete with density of 4 g/cm³ have been studied. The mix proportions by weight of this type of concrete were 1 cement: 6.89 steel scrap: 2.9 sand and 0.5 Water. Comparison with a standard ordinary concrete of density 2.3 g/cm³ have been carried out. The measurements were made using a collimated beam of both gamma rays and neutrons emitted from one of the horizontal channel of the Egyptian Research Reactor-1. A fast neutron and gamma ray spectrometer with a stilbene crystal was used to measure the spectra of fast neutrons and gamma rays. Pulse shape discrimination using the zero cross over technique was used to separate the photon pulses from the electron pulses. The equation due to Schmidt has been modified and applied for determining the neutron effective removal cross sections (～_R) for steel scrap, ordinary, hematite–serpentine, ilmenite–limonite and ilmenite concretes. This equation gives results which are in good agreement with the measured values. The derived empirical equation in a previous work to calculate the neutron integral flux behind different thicknesses of different types of concretes, gives good results for steel scrap concrete under investigation comparing with the corresponding experimental data. Total neutron macroscopic cross sections, linear attenuation coefficients for gamma rays and the half-value layers for both radiations at different energies have been obtained for steel scrap concrete and comparing with the corresponding values of ordinary concrete. The results show that steel scrap concrete is better than ordinary, hematite–serpentine, ilmenite–limonite and ilmenite concretes from the radiation shielding point of view.     

Messung einiger (n, γ)-Spektren mit einem Paarspektrometer hoher Empfindlichkeit

A pairspectrometer of the 180°-focussing type with high efficiency and good resolution is described. The efficiency has been determined in function of the energy, both theoretically and experimentally and it is possible, therefore, to use this spectrometer for absolute calibration of gamma rays above 2·5 MeV. The evaluation methods of the pair spectra allow the single line to be determined with an error as little as ±8 keV (from 2·5 to 9 MeV). We have measured the neutron capture gamma spectrum of J¹²⁷, Cs¹³³, Ir^191,193, Bi²⁰⁰ and given the energy and intensity of the resolved gamma rays. From these results it is possible to compute the binding energy of the last neutron and also some unknown levels. The experiments, which have been performed in connection with the pairspectrometer, have shown an interesting possibility for research work with reactors. With an appropriate experimental arrangement and some special neutron capture gamma spectra, monochromatic gamma rays in the energy range between 3 and 11 MeV are obtained, which are better and much more intense as corresponding gamma rays from (p, γ) reactions.     

D-T中子与平板型聚乙烯材料作用的次级中子角度谱实验研究

基于反冲质子法建立了一种测量D-T中子与平板型宏观样品作用的次级中子角度谱的实验方法.为保证探测器的能量线性并在较低的中子有效测量下阈(0.5 MeV)情况下获得好的中子-伽马射线甄别性能,采用高、低能段分别测量的方法.采用事件记录法,同时记录了次级中子和伴随伽马射线的脉冲形状甄别和脉冲幅度二维信息,利用基于ROOT数据分析平台编写的离线数据分析程序,完成了伴随伽马射线的挑选和扣除,以及高、低两能段反冲质子谱的拼接,并成功的将神经网络技术应用于中子能谱的解谱,获得了D-T中子与9和18 cm厚平板型聚乙烯材料作用的0.5-15 MeV的次级中子角度谱实验结果.实验模型的MC模拟由MCNP5完成,数据库采用ENDF-VI,实验结果和MC计算结果在实验不确定度范围内一致. 关键词： D-T中子 积分中子学 反冲质子法 次级中子能谱     

γ射线对含氢正比计数管中子能谱测量的影响

通过蒙特卡罗模拟和实验测量相结合的方法,获得从50 keV～10 MeV区间射线在直径为30 mm内充1.013 25 MPa氢气的球形含氢正比计数管上的能量响应,结果显示,射线在该计数管中的能量沉积主要集中在100 keV附近及以下。Am-Be中子源和137Cs源的实验测量结果显示,强137Cs源的射线会严重影响含氢正比计数管对Am-Be中子源100 keV以下能谱的测量,这表明,裂变材料介质内的强射线同样会影响到介质内100 keV以下中子能谱的测量。根据计数管对反冲质子和电子电离信号的收集特性,采用上升时间法甄别掉本底射线是可行的。     

γ射线对含氢正比计数管中子能谱测量的影响

通过蒙特卡罗模拟和实验测量相结合的方法,获得从50keV~10MeV区间γ射线在直径为30mm内充1.013 25MPa氢气的球形含氢正比计数管上的能量响应,结果显示,γ射线在该计数管中的能量沉积主要集中在100keV附近及以下。Am-Be中子源和137 Cs源的实验测量结果显示,强137 Cs源的γ射线会严重影响含氢正比计数管对Am-Be中子源100keV以下能谱的测量,这表明,裂变材料介质内的强γ射线同样会影响到介质内100keV以下中子能谱的测量。根据计数管对反冲质子和电子电离信号的收集特性,采用上升时间法甄别掉本底γ射线是可行的。     

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The physical model of the neutron camera Monte-Carlo partical transport (MCNP) for HL-2A was established by using Monte-Carlo simulation code. The shielding of D-D fusion neutrons and gamma rays was simulated. The shielding effects were compared for four common shielding materials, including mixture of paraffin lithium carbonate, polyethylene, lead, 316L stainless steel. Calculation results show that mixture of paraffin lithium carbonate and lead are the best shielding materials for neutron camera, among them the mixture of paraffin lithium carbonate is used for slowing-down and absorpting neutrons, while lead is used for blocking neutrons and gamma rays. In addition, both the required thickness of shielding material for neutron and gamma ray and the neutron scattering rate of collimator tube have been obtained by using MCNP simulation.     

HL-2A中子相机屏蔽系统模拟

利用蒙特卡罗模拟程序,建立了HL-2A中子相机蒙特卡罗粒子输运(MCNP)物理模型,对D-D聚变中子和γ射线的屏蔽进行了模拟计算。对石蜡碳酸锂混合物、聚乙烯、铅和316L不锈钢4种常用中子慢化吸,收剂组成的屏蔽层材料的屏蔽效果进行了对比。计算结果表明,石蜡碳酸锂混合物和铅组合是中子相机的最佳屏蔽层材料,其中石蜡碳酸锂混合物用于慢化吸收中子,铅用于屏蔽中子和γ射线。此外,利用MCNP模拟计算得到了屏蔽中子和γ射线所需的屏蔽厚度,以及准直管的中子散射率。     

用于n,γ混合场的新型脉冲中子探测器研究

新型脉冲中子探测器采用特殊工艺将两个PIN半导体组合而成.利用脉冲γ辐射研究了探测器对γ的响应；利用脉冲中子源研究了探测器对DT中了的响应，并与闪烁探测器进行了比较 .结果表明：脉冲中子探测器对脉冲γ辐射基本不灵敏，对脉冲中子辐射的灵敏程度依赖于中子辐射体，是一种用于n，γ混合脉冲辐射场中子测量的新型探测器. 关键词： 硅半导体 差分补偿 脉冲中子探测器 n γ混合场     

不同顺序中子/γ辐照对双极器件电流增益的影响

利用CFBR-Ⅱ快中子反应堆（中国第二座快中子脉冲堆）和⁶⁰Co装置开展不同顺序的中子/γ辐照双极晶体管的实验。在集电极-发射极电压恒定条件下,测量了双极晶体管电流增益随集电极电流的变化曲线,研究不同顺序中子/γ辐照对双极晶体管电流增益的影响。分析实验结果发现,集电极-发射极电压一定时,集电极电流极低情况下电流增益退化比较大,随集电极电流增加电流增益逐渐减小;就实验选中的两类晶体管而言,先中子后γ辐照造成双极晶体管电流增益的退化程度大于先γ后中子辐照,而且PNP型晶体管比NPN型晶体管差异更明显。本文进行了双极晶体管电离/位移协同辐照效应相关机理的初步探讨。     

A comparison of ionizing radiation damage in CMOS devices from 60Co gamma rays, electrons and protons

Radiation hardened CC4007RH and non-radiation hardened CC4011 devices were irradiated using 80Co gamma rays, 1 MeV electrons and 1--9 MeV protons to compare the ionizing radiation damage of the gamma rays with the charged particles. For all devices examined, with experimental uncertainty, the radiation induced threshold voltage shifts (△Vth) generated by 60Co gamma rays are equal to that of 1 MeV electron and 1-7 MeV proton radiation under 0 gate bias condition. Under 5 V gate bias condition, the distinction of threshold voltage shifts (△Vth) generated by 60Co gamma rays and 1 MeV electrons irradiation are not large, and the radiation damage for protons below 9 MeV is always less than that of 60Co gamma rays. The lower energy the proton has, the less serious the radiation damage becomes.     

Angular momentum misalignment in deep inelastic processes and angular distribution of sequentially emitted particles and gamma rays

The angular momentum misalignment for fragments produced in deep inelastic scattering is discussed in terms of the thermal excitation of angular-momentum-bearing modes in the intermediate complex. Analytical expressions for the in- and out-of-plane angular distributions are obtained for sequentially emitted particles and fission fragments. The angular momentum dependence of the ratio between particle and neutron decay widths is explicitly treated and found to be quite important. Similarly angular distributions are obtained both for dipole and quadrupole gamma decay. The theoretical results are compared with experimental angular distributions of sequential fission fragments, sequential alphas and gamma rays, and a good agreement is found.     

Vector analysis vs. regions of integration ratio method for determination of gamma and neutron contributions in a mixed field

The different ratios of the dosimetry peaks and the high temperature peaks after gamma and neutron irradiation can be employed for mixed field dosimetry, after performing proper analysis. In the present work the results obtained by the vector analysis method were compared to those obtained by the regions of integration (ROI) method for TLD600 chips irradiated by different combinations of gamma rays and thermal neutron doses. When applying the ROI method, the calculated neutron to gamma dose ratios (D_n/D_γ) were in good agreement (differences up to about 20%) with the actual experimental values in the D_n/D_γ range from 0.033 to 20. When applying the vector analysis method, the range of the D_n/D_γ ratio with differences up to about 20% is reduced to 0.033–4, and the uncertainties are generally higher. Thus, no advantage is expected when using the vector analysis method compared to the ROI method for evaluation of the dose ratio D_n/D_γ in a mixed field.