Ar离子辐照非晶态合金引起的尺寸变化

利用兰州重离子加速器(HIRFL)提供的2.79MeV/u Ar离子,在50K以下的低温辐照了Fe₄₇Ni₂₉V₂Si₆B₁₆等4种非晶态合金样品,室温下使用光学显微镜对辐照前、后的同一样品拍照,对比测量了样品的宏观尺寸. 结果表明:在辐照剂量为1.5×10¹⁴离子/cm²时,非晶态合金形变不明显,测量到的样品宽度相对增长Δb/b₀均小于1.0%;当辐照剂量增加到1.6×10¹⁵离子/cm²时,所有非晶态合金样品都发生了显著的形变,其宽度相对增长分布在4.3%—12.0%之间,对此结果进行了定性的分析.     

18 MeV质子辐照对TiNi形状记忆合金R相变的影响

 研究了用HZ-B串列加速器的18MeV质子辐照对TiNi形状记忆合金R相变的影响，辐照在奥氏体母相状态下进行。示差扫描量热法（DSC）表明，辐照后R相变开始温度T^s_R和逆马氏体相变结束温度T^f_A随辐照注量的增加而降低。当注量为1.53×10¹⁴/cm²时，T^sR和T^f_A分别下降6K和13K，辐照未引起R相变结束温度T^s_R和逆马氏体相变开始温度T^f_A的变化。表明辐照后母相(奥氏体相)稳定。透射电镜（TEM）分析表明辐照后没有引起合金可观察的微观组织变化。辐照对R相变开始温度T^s_{R和逆马氏体相变结束温度Af的影响可能是由于质子辐照后产生了孤立的缺陷团，形成了局部应力场，引起晶格有序度的下降所造成的。}     

用于质子和伽马射线探测的金刚石薄膜探测器的辐照性能

 研制出CVD金刚石薄膜探测器,在国家串列加速器和⁶⁰Co稳态辐射源上分别完成了该探测器对9 MeV质子束流和1.25 MeV γ射线的辐照性能研究。结果表明:该探测器在9 MeV质子照射累积强度达到10¹³ cm^-2时,探测器信号电荷收集效率减小量低于3.5%,辐照前后探测器暗电流没有明显变化。计算得到9 MeV质子对该探测器的损伤系数为1.3×10^-16 μm^-1·cm²。由于γ射线与金刚石作用产生的电子起到了填补缺陷的作用,探测器信号电荷收集效率随γ射线照射剂量的增加略有增加,在γ射线累积照射量达到10.32 C/kg时,其增幅小于0.7%。说明金刚石薄膜探测器具有较高耐辐照强度,适用于高强度辐射测量领域。     

FTIR研究快中子辐照直拉硅中的VO2

快中子辐照直拉硅(CZ-Si)经400—450℃热处理后，空位_双氧复合体(VO₂)是其 主要 的缺陷.在300—500℃热处理快中子辐照的CZ_Si后，IR光谱中有919．6cm^-1和 1006cm^-1两个吸收峰伴随VO₂(889cm^-1)出现，这两个IR吸收 峰是VO₂的一种亚稳态缺陷(O-V-O)引起的，此缺陷态是由一个VO(A中心)与次临近的一个 间隙氧原子(O_i)相互作用所形成的.在300℃延长退火时间或升高退火温度，都 会使(O -V-O)转变为稳态VO₂.辐照剂量在10¹⁹数量级，经400—450℃热处 理所形成的缺陷主要为多空位型，而VO₂被抑制.     

110keV质子辐照温控涂层性能变化的XPS分析

实验研究了注量在1.0×10¹¹—1.0×10¹⁶p/cm²范围依次变化时110keV质子辐照引起的温控涂层热光性能的变化,并使用XPS谱仪分析了辐照样品化学态的变化. 实验结果表明,质子注量不高于1.0×10¹⁴p/cm²时,同种材料的温控涂层样品的相对光反射率变化很小,同时同种材料样品的表面化学结构如化学位移和元素的比例变化很小.当注量高于1.0×10¹⁴p/cm²时, 样品的相对光反射率变化明显,样品表面的原子化学结构变化大, 化学位移明显增加, 元素比例变化显著,所有样品表面的C元素比例明显增大而O元素比例明显减小.一定注量的低能质子辐照能够使某些低太阳吸收率α_s的温控涂层的太阳吸收率变得更低, 具有改善热光性能的效果.质子辐照之后温控涂层样品表面化学结构的变化与样品的物理性能的变化存在直接的关联.     

3 MeV质子辐照对AlGaN/GaN高电子迁移率晶体管的影响

研究了AlGaN/GaN 高电子迁移率晶体管(HEMT)的质子辐照效应. 在3 MeV质子辐照下, 当辐照剂量达到1× 10¹⁵ protons/cm²时, 漏极饱和电流下降了20%, 最大跨导降低了5%. 随着剂量增加, 阈值电压向正向漂移, 栅泄露电流增加. 在相同辐照剂量下, 1.8 MeV质子辐照要比3 MeV质子辐照退化严重. 从SRIM软件仿真中得到不同能量质子在AlGaN/GaN异质结中的辐射损伤区, 以及在一定深度形成的空位密度. 结合变频C-V测试结果进行分析, 表明了质子辐照引入空位缺陷可能是AlGaN/GaN HEMT器件电学特性退化的主要原因.     

含氮类金刚石薄膜的紫外辐照研究

 用射频等离子体方法在玻璃基底上制备的类金刚石（DLC）薄膜，采用离子注入法掺氮，并对掺氮DLC薄膜紫外（UV）辐照前后的性能变化进行了研究。研究结果表明：随氮离子注入剂量及UV辐照时间的增加，位于2 930cm^-1附近的SP ³C-H吸收峰明显变小，而位于1 580cm^-1附近的SP2C-H吸收峰则明显增强，薄膜的电阻率明显呈下降趋势；随UV辐照时间的增加，位于1 078cm^-1附近的Si-O-Si键数量及位于786cm^-1附近的Si-C键数量明显增加。即氮离子注入和UV辐照明显改变了DLC薄膜的结构与特性。     

电子束在VO2薄膜中引起的价态、相结构和光学性能的改变

 利用能量为1.7MeV, 注量分别为1.25×10¹³/cm², 1.25×10¹⁴/cm², 1.25×10¹⁵/cm²的电子束辐照VO₂薄膜,采用XPS, XRD等测试手段对电子辐照前后的样品进行分析,并研究了电子辐照对样品相变过程中光透射特性的影响。结果表明电子辐照引起VO₂薄膜中V离子出现价态变化现象,并使薄膜的X射线衍射峰发生变化。电子辐照在样品中产生的这些变化显著改变了VO₂薄膜的热致相变光学特性。     

锆离子注入锆-4合金缺陷的慢正电子研究

采用慢正电子束多普勒展宽谱研究了Zr离子注入Zr-4合金产生的缺陷及其退火回复行为，发现经过大于离子注入剂量为1×10¹⁶cm^-2的样品所产生的缺陷在注入过程中已经回复，而对剂量为1×10¹⁵cm^-2样品做300℃退火处理，其缺陷基本回复，得出合金缺陷回复能较低的结论. 考虑到材料的缺陷含量越高，其抗腐蚀性能越差，在辐照环境下通过给材料保持一定温度，即可使其缺陷得到较好回复，从而提高材料的抗腐蚀性能.     

keV 质子辐照对Kapton/Al光学性能的影响

 采用空间综合辐照设备对Kapton/Al薄膜进行了质子辐照地面模拟试验，选取质子能量90 keV,辐照通量5.0×10¹¹ cm¹²·s^-1。通过辐照前后光谱反射系数的变化考察了实验样品的光学性能退化特征。借助于反射光谱和紫外-可见吸收光谱和傅里叶转换红外光谱分析技术分析了辐照后Kapton/Al光学性能的退化机理。研究结果表明：辐照过程中样品表面发生了复杂的化学反应，随着辐照剂量的增加光能隙逐渐减小，Kapton吸收曲线的末端边缘发生红移并且在可见光区吸收强度增加。     

质子辐照对MQ硅树脂增强的加成型硅橡胶质损及热性能的影响

 采用空间综合辐照模拟设备研究了100 keV和150 keV能量的质子辐照对MQ硅树脂增强的加成型硅橡胶的损伤及其对硅橡胶热性能的影响。试验结果表明：质子辐照后，硅橡胶表面出现损伤裂纹，随辐照能量和剂量的增加，裂纹的数量增多，裂纹增大；质子辐照后，硅橡胶的质量有所损失，其质损率随辐照能量和剂量的增加而增加；质子辐照后硅橡胶的耐热性随辐照剂量的增加先略有增加而后下降，经辐照后的硅橡胶在玻璃态和玻璃转变区的温度区间内收缩率降低，而在高弹态的温度区间内膨胀率增加。     

Study on irradiation-induced defects in GaAs/AlGaAs core–shell nanowires via photoluminescence technique

To gain a physical insight into the radiation effect on nanowires(NWs), the time resolved photoluminescence(TRPL)technique is used to investigate the carrier dynamic behaviors in GaAs/AlGaAs core–shell NWs before and after 1-MeV proton irradiation with fluences ranging from 1.0 × 10~(12) cm~(-2) to 3.0 × 10~(13) cm~(-2). It is found that the degradations of spectral peak intensity and minority carrier lifetime show similar trends against irradiation fluence, which is closely related to the displacement defects induced by irradiation. We also find that the proton irradiation-induced defects behave as Shockley–Read–Hall(SRH) recombination center trapping free carriers. Finally, the defect concentration could be estimated through measuring the minority carrier lifetime.     

Polydimethylsiloxane rubber gamma radiation effect studies by positron annihilation lifetime spectroscopy

Polydimethylsiloxane rubber was irradiated at various radiation doses up to 800 kGy in air. The lifetime and intensity of the long component τ₃ were obtained by positron annihilation lifetime spectroscopy (PALS). The crystallization property and the molecular flexibility were estimated using the differential scanning calorimetry and dynamic thermomechanic analysis. Thermal volatile property was determined by thermogravimetry analysis. It was proved that the cross-linking reaction made the chain flexibility of the rubber to reduce gradually during gamma radiation, which resulted in the reduction of the o-Ps intensity observed by PALS. Although the degradation effect existed during gamma radiation, it was still less significant than the cross-linking effect when the radiation dose was up to 800 kGy.     

Low-energy(40 keV) proton irradiation of YBa_2Cu_3O_(7-x) thin films:Micro-Raman characterization and electrical transport properties

To investigate the damage profiles of high-fluence low-energy proton irradiation on superconducting materials and related devices, Raman characterization and electrical transport measurement of 40-keV-proton irradiated YBa_2Cu_3O_(7-x)(YBCO) thin films are carried out. From micro-Raman spectroscopy and x-ray diffraction studies, the main component of proton-radiation-induced defects is found to be the partial transition of superconducting orthorhombic phase to the semiconducting tetragonal phase and non-superconducting secondary phase. The results indicate that the defects induced in the conducting CuO_2 planes, such as increased oxygen vacancies and interstitials, can result in an increase in the resistivity but a decrease in the transition temperature TCwith the increase in the fluence of proton irradiation, which is confirmed in the electrical transport measurements. Especially, zero-resistance temperature TC_0 is not observed at a fluence of 10~(15)p/cm~2.Furthermore, the variation of activation energy U_0 can be explained by the plastic-flux creep theory, which indicates that the plastic deformation and entanglement of vortices in a weakly pinned vortex liquid are caused by disorders of point-like defects. Point-like disorders are demonstrated to be the main contribution to the low-energy proton radiation damage in YBCO thin films. These disorders are likely to cause flux creep by thermally assisted flux flow, which may increase noise and reduce the precision of superconducting devices.     

Mo/Si多层膜在质子辐照下反射率的变化

为了检验应用在极紫外波段空间太阳望远镜上Mo/Si多层膜反射镜在空间辐射环境下反射率的变化情况, 模拟了部分空间太阳望远镜运行轨道的辐射环境, 利用不同能量和剂量的质子对Mo/Si多层膜反射镜进行辐照实验.辐照前后反射率测量结果显示,由于带电粒子的辐照损伤,质子辐照会使Mo/Si多层膜反射镜的反射率降低,且质子能量越低、剂量越大,对多层膜的反射率影响越明显. 当质子能量E=160keV,剂量＝6×10¹¹/mm²时,反射率降低4.1%;能量E=100keV,剂量=6×10¹¹/mm²时, 反射率降低5.7%;能量E=50keV,剂量=8×10¹²/mm²时,反射率降低10.4%. 用原子力显微镜测量辐照后Mo/Si多层膜反射镜的表面粗糙度比辐照前明显增加,致使散射光线能量逐渐增大并最终导致反射率的降低. 关键词： 质子辐照 Mo/Si多层膜反射镜 辐照损伤     

Evidence of the Zn vacancy acting as the dominant acceptor in n-type ZnO

We have used positron annihilation spectroscopy to determine the nature and the concentrations of the open volume defects in as-grown and electron irradiated (E(el)=2 MeV, fluence 6 x 10(17) cm(-2)) ZnO samples. The Zn vacancies are identified at concentrations of [V(Zn)] approximately 2 x 10(15) cm(-3) in the as-grown material and [V(Zn)] approximately 2 x 10(16) cm(-3) in the irradiated ZnO. These concentrations are in very good agreement with the total acceptor density determined by temperature dependent Hall experiments. Thus, the Zn vacancies are dominant acceptors in both as-grown and irradiated ZnO.     

Penetrating flavors

Hadrons made of heavy flavor quarks are expected to have small cross sections and perhaps reduced energy loss in collisions, leading to their being more “penetrating” than ordinary hadrons. Some effects of this in cosmic ray phenomena are considered. If the heavy particle lives long enough it can become the dominant hadron component in the atmosphere. With particles of short lifetime there is a threshold effect in energy where the penetrating hadron travels far enough to become important. Some of the anomalous effects in 10² – 10³ TeV phenomena could be caused via this mechanism by a particle with lifetime ～ 10^?11 s. An ～ 150 cm thick iron absorber would provide a substantial enhancement in the charm/proton ratio in the 10–100 TeV range. If free quarks are produced and have the same cross section as bound quarks, they act as highly penetrating hadrons.     

Effects of hyperthermal proton bombardment on alkanethiol self-assembled monolayer on Au(1 1 1)

The effects of hyperthermal proton bombardment on alkanethiol self-assembled monolayer (SAM) on Au(1 1 1) are studied with scanning tunneling microscopy (STM) and X-ray photoemission spectroscopy (XPS). The STM and XPS results show that proton bombardment with proton energy as low as 2 eV can induce cross-linking of the adsorbed alkanethiols and transform the original ordered SAM lattice to an array of nanoclusters of the cross-linked alkanethiols. For a bombardment at 3 eV with a fluence of 3×10¹⁵ cm⁻², the typical cluster size is about 5 nm. In addition, the cluster size distribution is narrow, with no cluster larger than 8 nm. The cluster growth can be promoted by increasing the fluence at a fixed bombardment energy or increasing the energy at a fixed fluence. This indicates that surface diffusion of alkanethiols and cluster growth can be harnessed by the control of the bombardment energy and fluence.     

Imaging of small distortions in A15 “lattice” by electron microscopy

One effect of high energy nuclear radiation on A15 compounds has been postulated earlier to be a loss of translational symmetry of the lattice. We report direct evidence of such distortions in Nb₃Sn irradiated with high energy neutrons, using moiré fringes. The distortion is found to increase with increasing fluence, up to a fluence of 2 × 10¹⁹ cm^-2.