裂变快中子辐照在GaAs中产生缺陷的正电子湮没研究

采用正电子湮没寿命测量方法研究了注量为６５×１０１５／ｃｍ２和１．４×１０１４／ｃｍ２、Ｅｎ≥１ＭｅＶ的裂变快中子辐照在掺Ｓｉ、Ｎ型单晶ＧａＡｓ中产生的缺陷。此辐照在ＧａＡｓ中产生单空位和双空位缺陷。缺陷浓度正比于辐照注量,高温退火产生王空位缺陷及小空位团。单空位、双空位和三空位缺陷的退火温度分别为２５０．４５０．６５０℃     

5.0MeV和9.5MeV快中子辐照在GaAs中产生的辐射损伤的正电子湮没研究

采用正电子湮没寿命测量方法研究了５．０ＭｅＶ和９．５ＭｅＶ快中子辐照在ＧａＡｓ中产生的辐射损伤,实验结果表明１０１１－１０１２ｎ／ｃｍ２注量的中子辐照只产生单空位缺陷,而１０１３ｎ／ｃｍ２注量的中子辐照产生单空位和双空位缺陷;１０１８ｎ／ｃｍ２注量的９．５ＭｅＶ中子辐照的ＧａＡｓ经４５０－６２０℃退火产生三空位缺陷。产生的缺陷浓度随中子能量和注量的增大而增大,但缺陷产生率对中子注量更灵敏     

铝外壳Si（Au）面垒探测器受快中子辐照后性能恢复的研究

本文研究了探测器经注量＜10^15n/cm^2的快中子辐照后，在重新加偏压过程中它们的反向电流猛增而使性能变坏的原因，然后采用慢加偏压的方式恢复了探测器的性能，延长了使用寿命。     

纳米晶Al的快中子辐照效应研究

采用真空热压技术将自悬浮定向流法制得的纳米Al粉压制成平均晶粒尺寸约为120nm的块体,并对其进行了注量为1.9×1012~7.2×1014 cm-2的快中子(E1 MeV)辐照。通过X射线衍射(XRD)分析、扫描电子显微镜与能谱(SEM-EDS)分析和显微硬度测试研究了快中子辐照对纳米晶Al的微观结构和显微硬度的影响。研究结果表明:快中子辐照同时造成了纳米晶Al的平均晶粒尺寸增大和显微硬度提高。随快中子辐照注量的增大,纳米晶Al的平均晶粒尺寸和显微硬度分别增大了2.09%~9.09%和3.54%~4.37%。纳米晶Al的平均晶粒尺寸的增长率随快中子注量的增加而增大。     

快中子辐照链霉菌和黑曲霉的诱变效应

本文叙述了快中子辐照弗氏链霉菌、灰色链霉菌、埃维链霉菌和黑曲霉在不同的辐照剂量条件下,对菌种的死亡率、产酸率、遗传性状和变异类型等进行了测定和分析,获得了较满意的结果。灰色链霉菌产生的五种不同的变株、很有深入研究意义。     

隐藏爆炸物检测装置快中子辐照安全分析

为推广隐藏爆炸物检测装置在反恐领域的应用,对快中子辐照炸药、食品及药品的安全性进行了分析。通过蒙特卡罗方法建立了装置的快中子辐照炸药安全性评估模型。通过能量沉积计算及炸药起爆机理分析可知,快中子辐照炸药不会产生爆炸的危险。采用剂量分析法对快中子辐照食品及药品的安全性进行了分析,结果表明,在隐藏爆炸物检测装置的快中子辐照条件下,食品及药品的辐照剂量在国家和国际限定的标准内,快中子辐照食品及药品的安全性是可接受的。     

Si(Au)探测器的快中子辐射损伤

在核实验中,半导体硅探测器常用来对带电粒子和中子进行探测。其能量响应和时间响应特性均十分良好,但是耐辐射性能却较差,尤其在伴有γ和中子本底的环境中,由于辐照引起探测器晶格损伤,导致半导体探测器性能退化,如探测器漏电流增大、能量分辨本领变差、能量亏损增加、时间响应增长等,严重影响探测器的使用和寿命。     

SR-XRD和EXAFS研究Mn掺杂ZnO薄膜的微观结构

用射频磁控溅射技术在蓝宝石衬底上制备了一组不同衬底温度的Mn掺杂ZnO薄膜。质子激发X射线荧光（PIXE）测量表明,薄膜中仅有含量为5 at.%的Mn,未见其它磁性杂质元素（如Fe、Co、Ni等）。同步辐射X射线衍射（SR-XRD）表明,这些Mn掺杂ZnO薄膜具有纤锌矿ZnO结构。SR-XRD和扩展X射线吸收精细结构谱（EXAFS）分析显示,薄膜中未发现Mn团簇或MnO、MnO2、Mn2O3、Mn3O4等二次相,Mn原子是通过替代Zn原子而进入了ZnO晶格。     

^60Co 线照射对皮张质量影响的研究

has already proved that radiation with ⁶⁰Co γ rays wita dose less than 20 kGy possesses a good effect of pesticide and disinfectant. Tensile strength, rate of elongation, strength of break-up, tearing strength and number of folding break-off ect have been taken asthe targets for inspecting the quality of hides after being radiated. The inspection proves that within a certain limit of dosage, radiation would not influence obviously the quality of the hides. Besides, it proves that in case a dosage of disinfectant or pesticide is used, the radiation would be able to kill reddish fur vermin.     

一个同轴Ge(Li)探测器的快中子辐射损伤

实验结果表明:本文给出的探测器对快中子辐射损伤的灵敏度相当高。当累积中子通量为6.22×10~8cm~(-2)时,探测器对~(60)Co 1.33MeV γ射线的能量分辨(FWHM)大幅度变坏,为辐射损伤前的三倍;观察到了损伤后的能量分辨的瞬态变化现象;用~(137)C662keV的γ射线扫描技术从实验上再次证明了快中子辐射在探测器中产生空穴陷阱,导致能量分辨变坏。采用简单的净化漂移方法,能恢复损伤过的探测器的性能。     

平面型硅快中子剂量探测器初步研究

介绍了平面型硅快中子剂量探测器,初步探索了探测器的中子剂量响应与PN结长和结宽的关系。基于239Pu-Be中子辐射实验结果,可以得出探测器电压随中子剂量线性变化的结论。对探测器等效电阻进行了计算,给出了测试电流为1~10 mA时平面型硅快中子剂量探测器的电流、电压和中子剂量的关系式。     

Production of defects in hexagonal boron nitride monolayer under ion irradiation

Atomistic computer simulations based on analytical potentials are employed to investigate the response of a hexagonal boron nitride monolayer to irradiation with noble gas ions having energies from 35 eV up to 10 MeV. Probabilities for creating different types of defects are calculated as functions of ion energy and incidence angle, along with sputtering yields of boron and nitrogen atoms. The presented results can be used for the optimization of ion processing of single-layer and bulk hexagonal boron nitride samples and for predicting the evolution of the material in radiation hostile environments.     

Effect of 80-MeV nitrogen ion irradiation on ZnO nanoparticles: Mechanism of selective defect related radiative emission features

We report on the 80-MeV nitrogen ion irradiation on spherical ZnO nanoparticles fabricated by way of solid state mixing. The structural and compositional analyses of the as-synthesized ZnO nanoparticles were done by X-ray diffraction, electron microscopy and energy dispersive spectroscopy studies. As evident from the optical absorption spectra, the energetic ion irradiation, on the nanoparticle system, is governed by evolution of new characteristic absorption features owing to modification in the electronic states. Again, in the luminescence spectra, though the near band-edge emission was not observable for pristine ZnO, it was recovered (at ∼385 nm) upon irradiation. As far as the defect related emission is concerned, a competition between the formation and annihilation of different defects (especially, zinc vacancies and interstitials) at different ion fluences was realized. Correlating the luminescence spectra and the theoretical investigation, it can be understood that during irradiation the formation of zinc related defects are energetically favorable than the oxygen related counterparts. Exploration of defect related radiative features corresponding to definite structural organization/modification would help in making next generation light emitting and display devices, where a select emission response is desired.     

隐藏爆炸物的快中子活化检测

用２种不同产额中子源，检测有无炸药时行李箱不同位置氮、氧元素的０．５１１、６．１３ＭｅＶγ能谱及其比值，确定检测灵敏度和检速，给出不同氮、氧含量的炸药与非炸药材料的平面分布，讨论检测方法的安全性及快中子活化分析（ＦＮＡＡ）系统的整体设计。     

Ag离子注入ZnO薄膜对其发光性质的影响

采用磁控溅射技术在蓝宝石基底上制备了ZnO薄膜,并对样品在氧气氛下进行了热处理,然后采用不同能量、剂量的Ag离子注入ZnO薄膜中,形成Ag纳米颗粒。利用X射线衍射、光致发光、紫外可见吸收等技术详细地研究了样品的结构与发光性质。结果表明,未注入的ZnO薄膜在380 nm和610 nm处出现发光峰,分别对应ZnO激子峰与深能级缺陷峰。Ag离子注入ZnO样品的激子发光峰增强,并在400 nm和430 nm左右处出现新发光峰,同时深能级缺陷引起的发光峰减弱。在N2气氛下退火处理后,Ag离子注入ZnO样品在400 nm处的发光峰消失,430 nm左右发光峰减弱。Ag离子注入ZnO薄膜中合成了Ag纳米颗粒,观察到了Ag纳米颗粒的等离子共振效应。对Ag纳米颗粒和离子注入产生的缺陷、ZnO发光性质的影响给出了解释。     

Raman investigation of incident N-, Xe-ions induced effects in ZnO thin films

Highly c-axis orientation ZnO thin films with hundreds nanometers in thickness have been deposited on (1 0 0) Si substrate by RF magnetron sputtering. These films are implanted at room temperature by 80 keV N-ions with fluences from 5.0 × 10¹⁴ to 1.0 × 10¹⁷ ions/cm², implanted by 400 keV Xe-ions with 2.0 × 10¹⁴ to 2.0 × 10¹⁶ ions/cm², irradiated by 3.64 MeV Xe-ions with 1.0 × 10¹² to 1.0 × 10¹⁵ ions/cm², or irradiated by 308 MeV Xe-ions with 1.0 × 10¹² to 5.0 × 10¹⁴ ions/cm², respectively. Then the ZnO films are investigated using a Raman spectroscopy. The obtained Raman spectra show that a new Raman peak located at about 578 cm⁻¹ relating to simple defects or disorder phase appears in all ZnO films after ion implantation/irradiation, a new Raman peak at about 275 cm^-1 owing to N-activated zinc-like vibrations is observed in the N-implanted samples. Moreover, a new Raman peak at about 475 cm⁻¹ is only seen in the samples after 400 keV and 3.64 MeV Xe-ions bombardment. The area intensity of these peaks increases with increasing ion fluence. The effects of ion fluence, element chemical activity, atom displacements induced by nuclear collisions as well as energy deposition on the damage process of ZnO films under ion implantation/irradiation are discussed briefly.     

Irradiation effects with 100 MeV Xe ions on optical properties of Al-doped ZnO films

Al-doped ZnO (AZO) films are known as n-type transparent semiconductors. We have investigated the effects of 100 MeV Xe ion irradiation on the optical and structural properties of AZO films, which were prepared on SiO₂ glass at 400 °C by using a RF-magnetron sputtering deposition method. We discuss relationships between these property modifications and the recent observations of the conductivity increase by ion irradiation. It is suggested that the band-gap modification has more close relation with the conductivity increase than the structural modification.     

Enhancement of ZnO thin film transistor performance by high-dose proton irradiation

The object of this study was to improve the performance of ZnO thin film transistors (TFTs) by exposing them to high-dose proton irradiation. A rapid thermal annealing (RTA) process was necessary to improve the interface characteristics between the source-drain electrodes and the channel layer for the high performance of ZnO-TFTs. However, this affected the resistivity of the ZnO channel layer; it was dramatically decreased during the RTA process. As a result, the RTA-treated ZnO-TFTs did not show the proper off-state characteristics. In order to control the electrical properties of the channel layer, we exposed the RTA-treated ZnO-TFTs to 6.1 MeV of proton irradiation beam energy at fluences from 6.7 × 10¹² cm⁻² to 6.5 × 10¹⁴ protons-cm⁻². The resulting resistivity of the ZnO thin film increased after the high-dose proton irradiation. In addition, we studied the structural and electrical properties and the variations in the native defects of ZnO thin films. The field effective mobility of ZnO-TFTs increased from 1.65 to 4.12 cm²/V s after both the RTA and the high-dose proton irradiation. We obtained an enhancement of ZnO-TFT performance using high-dose proton irradiation.     

Orientation dependence of near-threshold damage production by electron irradiation of 4H SiC and diamond and outward migration of defects

Low temperature photoluminescence measurements have been made on samples of 4H SiC and diamond irradiated in different crystallographic directions with electrons having energies close to the atomic displacement thresholds. The defects produced in the 4H SiC are found to show some differences from those predicted by molecular dynamics calculations and possible reasons for the differences are discussed. The discussion refers to results from earlier as well as new experiments on the outward migration of defects during irradiation. The results for the energy dependence of the damage introduced into <1 0 0>, <1 1 0> and <1 1 1> oriented diamond are evaluated and shown to be consistent with theory.