低能粒子辐照对铝膜反射镜光学性能的影响

地面模拟研究了低能质子和电子对铝膜反射镜光学性能的影响。结果表明,低能质子辐照后,在200~800nm波长范围内铝膜反射镜反射率随辐照剂量增加而下降。质子辐照能量越低射程越短,则反射镜表面膜层中质子浓度越大损伤也更为明显。电子辐照射程较深,辐照作用对铝膜反射镜光学性能影响很小。     

纳米二氧化钛对质子辐照下MQ增强硅橡胶力学性能的影响

采用空间综合辐照模拟设备研究了纳米二氧化钛对100 keV和150 keV能量质子辐照下MQ增强加成型硅橡胶力学性能的影响。试验结果表明,质子辐照后,未添加纳米粒子的硅橡胶表面颜色明显加深,同时出现不同程度的老化龟裂裂纹,裂纹数量和深度随辐照能量和剂量的增加而增加;硅橡胶的硬度和拉伸强度随辐照剂量的增加先增加而后降低。添加纳米二氧化钛的硅橡胶与未改性硅橡胶相比,经过相同能量、剂量的质子辐照后,表面颜色加深和表面裂纹损伤的程度均减小,硬度和力学性能的损伤程度下降,表现出明显的抗质子辐照性能。     

在空间质子辐照下甲基硅橡胶的破坏模型

利用空间辐照环境地面模拟设备研究了质子辐照对甲基硅橡胶的破坏,建立了甲基硅橡胶的破坏模型.结果表明,在辐照能量为180 keV,辐照剂量为1016cm-2的条件下,被质子辐照后,硅橡胶生成CH3SiOCH3气体产物;量子化学计算表明,在H 直接进攻硅橡胶高分子链中的O导致高分子链断裂的过程中要放热655.34 kJ/mol,是唯一的放热反应通道.这一过程不会形成稳定的过渡态和中间体,而是直接形成断键产物.计算结果与质子辐照生成的气体产物CH3SiOCH3一致.     

纳米二氧化钛对质子辐照下MQ增强硅橡胶热性能的影响

采用空间综合辐照模拟设备研究了纳米二氧化钛对100keV和150keV能量质子辐照下MQ增强加成型硅橡胶损伤及热性能的影响.试验结果表明,质子辐照后,未添加纳米粒子的硅橡胶表面颜色明显加深,同时出现不同程度的老化裂纹,裂纹数量随辐照能量和剂量的增加而增加;辐照后硅橡胶的质损率增加,耐热性能下降;辐照后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.添加纳米二氧化钛的硅橡胶与未改性硅橡胶相比,经过相同能量、剂量的质子辐照后,表面颜色加深和表面裂纹损伤的程度减小;质损率增加、耐热性能下降以及收缩膨胀率变化的程度均降低,表现出明显的抗辐照性能.     

铝膜反射镜空间环境适应性研究

铝膜反射镜是反射式空间聚光太阳电池阵的重要组成部分。通过对铝膜反射镜电子、质子、紫外、原子氧环境等一系列辐照及环境试验,研究和考察了铝膜反射镜反射率的变化和空间环境适应性。研究结果表明,铝膜反射镜适应地球同步轨道环境条件下,反射镜平均反射率在15年寿命末期大于75%;在低地球轨道环境中有必要对铝膜反射镜进行抗原子氧侵蚀防护。     

质子辐照甲基硅橡胶的热释光和热释电研究

用空间辐照环境模拟设备对甲基硅橡胶进行了质子辐照.辐照能量为200keV,辐照剂量范围为1014～1016cm-2.用热发光和热激电流分析方法,研究了硅橡胶质子辐照前后载流子陷阱能级△E及载流子类型的变化规律结果表明:当辐照剂量小于1015cm-2时,△E下降;当辐照剂量超过1015cm-2后,△E上升硅橡胶原始样品中主要载流子类型是电子型.当质子辐照剂量超过5×1014cm-2后,主要载流子类型转变为空穴型.辐照剂量继续增加,载流子类型又有向电子型转变的趋势.     

模拟空间辐照环境对卫星用第二表面镜性能的影响

介绍了模拟空间辐照环境对卫星用掺铈玻璃型第二表面镜光(热)学性能的影响。对导电型和非导电型两类掺铈玻璃第二表面镜进行了模拟空间辐照试验。试验项目包括真空中的紫外辐照、真空中两种能量的电子和两种能量的质子辐照。经过相当子同步轨道卫星南北极处7年剂量总和的紫外、电子、质子辐照后,导电型掺铈玻璃第二表面镜的太阳吸收率从0.081上升到0.105;法向发射率从0.84下降到0.80,非导电型掺铈玻璃第二表面镜的太阳吸收率从0.085上升到0.092;法向发射率从0.85下降到0.82。     

ZnO白漆的质子辐照损伤与光学性能退化机理

为进一步阐明ZnO白漆的辐照损伤与光学性能退化机理,在模拟的空间环境下对S781白漆进行了150keV质子辐照实验。质子辐照后,在原位条件下测试了光谱反射系数和太阳吸收比的退化规律,并利用模拟仿真和光致荧光光谱研究了ZnO白漆与质子间的微观交互作用和辐照诱发缺陷。结果表明,质子辐照下ZnO颜料发生电离生成-1价锌空位,是S781白漆出现b带吸收和光学性能退化的主要原因。此外,本工作支持了ZnO绿带荧光源于锌空位的第一原理计算结果。     

质子辐照引起的质量损失模型及实验验证

聚合物材料在质子辐照环境中因发生出气逸出行为可造成分子污染。根据质子辐照聚合物材料过程中的假设条件,基于扩散理论建立质子辐照质量损失数学模型。借助分离变量法,获得质量损失与各影响因素的函数关系式。在高能质子模拟环境中进行了聚酰亚胺薄膜辐照实验,测试了辐照后聚酰亚胺材料的质量损失。对比研究了模拟值与实验值间的误差,最终得到了质子辐照聚酰亚胺引起的质量损失与辐照时间的函数关系式。研究结果表明,建立的质量损失数学模型与实验数据间的最大误差为-5.8%,数学模型可满足一般工程设计的需要,并可为筛选空间材料提供理论依据。     

质子、电子综合辐照作用下Teflon FEP/Al辐照损伤效应研究

在地面模拟研究了能量为30keV的质子与电子辐照对Teflon FEP/Al的光学性能退化的综合影响。结果表明,质子辐照引起Teflon FEP/Al在可见光区反射性能退化,而电子引起其在可见光与近红外区反射性能的全面下降。电子辐照更多的是使材料的大分子形成激发态进而轰击出主链上的F原子,形成自由基以及游离态的C。质子辐照时,除产生上述的辐照缺陷外,H~*的离子注入还使材料中形成各种新的官能团。质子与电子辐照的顺序不同,Teflon FEP/Al的C_(1s)谱也明显不同。     

Influence of argon neutral beam energy on the structural properties of amorphous carbon thin films grown by neutral particle beam assisted sputtering

The effects of argon neutral beam (NB) energy on amorphous carbon (a-C) films were investigated, the a-C films were deposited by a neutral particle beam assisted sputtering (NBAS) system. The energy of the neutral particle beam can be directly controlled by a reflector bias voltage as a unique operating parameter of the system. The results from the analysis by Raman spectra, Fourier transform infrared (FT-IR), UV-visible spectroscopy and electrical conductivity indicate the properties of the amorphous carbon films can be manipulated by simply adjusting the NB energy (or reflector bias voltage) without changing any other process parameters. By increasing the reflector bias voltage, the amount of cross-linked sp² clusters as well as the sp³ bonding in the a-C film coating from the NBAS system can be increased effectively and the composition of carbon thin films can be changed from a nano-crystalline graphite phase to an amorphous carbon phase. In addition, the deposition rate increases with reflector bias voltage due to additional sputtering at the carbon reflector without any variation of physical and electrical properties of the a-C film.     

近紫外冷反射镜的镀制研究

为充分利用紫外光源系统中所需要的有用的紫外光,同时减少红外光照射,根据常用紫外光源的发光特性、能量曲线分析,通过真空镀膜技术,在玻璃基片表面镀制多层硬质光学薄膜,制备出了对中紫外光谱区域的反射率高于90%,同时可见及红外区域的平均透过率在85%以上的近紫外冷反射镜。     

Helium ion bombardment of thin aluminium films

A study is presented of the effect of 5 keV helium ion bombardment on thin (about 2000 Å) aluminium films using proton backscattering, scanning and transmission electron microscopy and α particle energy loss spectroscopy. Measurements of helium content after irradiation using proton backscattering indicate low below-saturation retention for both room temperature and low temperature implantations (19% and 24% respectively). Electron microscopy examination of the films reveals a severe deformation in the form of coarse and fine-scale wrinkling whose amplitude increases with increasing helium dose. This deformation does not appear to be the result of bubble swelling. An attempt has been made to quantify the wrinkling by measuring the energy loss spectrum of α particles transmitted through irradiated films and the combination of these measurements with a simple sinusoidal deformation model indicates an increase in film area of up to 20%.     

Coloring effects of optical antireflective film irradiated by 60 keV protons

In this study, the irradiation coloring effects by 60 keV protons on space applied lens coated with a MgF₂/ZrO₂/Al₂O₃ optical multilayer antireflection film were investigated by ground experiment and computer simulation methods. The energy loss within each layer of the antireflection film caused by proton irradiation was calculated using SRIM program based on the Monte Carlo simulation approach. It was shown that the lower energy proton irradiation led to a smaller range, but induced larger energy loss, resulting in worse damage in the antireflection film. Degradation in spectrum transmission of the lens irradiated by 60 keV protons using a synthesized space irradiation simulation facility was examined. Evolutions of the color centers in the irradiated films were also evaluated by absorption spectrometry techniques. It was found that the F₂ color centers in the MgF₂ film, and the V_ōH and F₂+ color centers in the Al₂O₃ film are responsible for the absorption bands at 370 nm, 400 nm and 440-450 nm, respectively. The absorption band at 490 nm was caused by F+ color centers in the ZrO₂ film, and the absorption band at 580-660 nm was induced by some impurity color centers.     

Pseudo-orthogonal frequency coded wireless SAW RFID temperature sensor tags

SAW sensors are ideal for various wireless, passive multi-sensor applications because they are small, rugged, radiation hard, and offer a wide range of material choices for operation over broad temperature ranges. The readable distance of a tag in a multi-sensor environment is dependent on the insertion loss of the device and the processing gain of the system. Single-frequency code division multiple access (CDMA) tags that are used in high-volume commercial applications must have universal coding schemes and large numbers of codes. The use of a large number of bits at the common center frequency to achieve sufficient code diversity in CDMA tags necessitates reflector banks with >30 dB loss. Orthogonal frequency coding is a spread-spectrum approach that employs frequency and time diversity to achieve enhanced tag properties. The use of orthogonal frequency coded (OFC) SAW tags reduces adjacent reflector interactions for low insertion loss, increased range, complex coding, and system processing gain. This work describes a SAW tag-sensor platform that reduces device loss by implementing long reflector banks with optimized spectral coding. This new pseudo-OFC (POFC) coding is defined and contrasted with the previously defined OFC coding scheme. Auto- and cross-correlation properties of the chips and their relation to reflectivity per strip and reflector length are discussed. Results at 250 MHz of 8-chip OFC and POFC SAW tags will be compared. The key parameters of insertion loss, cross-correlation, and autocorrelation of the two types of frequency-coded tags will be analyzed, contrasted, and discussed. It is shown that coded reflector banks can be achieved with near-zero loss and still maintain good coding properties. Experimental results and results predicted by the coupling of modes model are presented for varying reflector designs and codes. A prototype 915-MHz POFC sensor tag is used as a wireless temperature sensor and the results are shown.     

蒙特卡洛法计算G型辐冷器抛物面屏耦合因子的研究

抛物面屏是G型辐冷器的主要制冷部件之一，蒙持卡洛法计算其与各辐射表面之间耦合因子的关键是正确模拟计算随机辐射能束的发射位置与发射方向。对于抛物面屏这种立体曲面截面，提出新的算法正确模拟计算随机辐射能束的发射位置与发射方向。通过扩展抛物面屏曲面，删除抛物面屏外的辐射能束，筛选初次模拟辐射能束，解决了发射位置的模拟计算。通过切平面坐标与原辐冷器坐标变换，将切平面辐射能束的发射方向变换坐标系，解决了发射方向的模拟计算。以上述算法为基础，蒙特卡洛法淮确计算了G型辐冷器抛物面屏对各表面的耦合因子，并对计算结果进行了误差分析。     

Reactive particle beam based deposition process of nano-crystalline silicon thin film at low temperature for the flexible AM-OLED backplane

A novel deposition process for depositing nano-crystalline silicon (nc-Si) thin films at low temperature was developed using reactive particle beam assisted chemical vapor deposition (RPB-CVD) for applications to the thin film transistor (TFT) backplane of flexible active matrix-OLEDs with plastic substrates. During the formation of nc-Si thin films by the RPB-CVD process with a silicon reflector electrode at low temperatures or room temperature, energetic particles could induce the formation of a crystalline phase in polymorphous Si thin films without additional substrate heating. The effects of the incident RPB energy controlled by the reflector bias were confirmed by Raman spectroscopy. The dark conductivity of polymorphous Si thin films increased with increasing reflector bias, whereas the ratio of photo and dark conductivity decreased monotonically. The optical band gap of the Si thin films also could be changed from amorphous to nano-crystalline by controlling the reflector bias. The first results of a primitive nc-Si TFT by RPB-CVD at room temperature demonstrate the technical potential of RPB-based processes as flexible TFT backplanes.     

High roughness Ag back reflector on a metal underlayer for thin film solar cell applications

The roughness development of Ag film was investigated for potential as a back reflector material in thin film solar cells on flexible stainless steel (STS) substrates. The influence of metal underlayers was evaluated in order to obtain a rough Ag film at a low deposition temperature (≤400 °C). By depositing Ag on a 100 nm Al underlayer to induce Ag–Al alloying, the film roughness was increased three times more than that of Ag films on bare STS at 400 °C. The Ag film deposited on an Al underlayer at 350 °C exhibited 75 nm roughness and uniformly distributed crystallites, which was effective for visible light scattering. The Ag–Al alloy phase was also controlled using the thickness ratio of Ag and Al. The present work clearly demonstrated that an Ag back reflector film with a higher roughness could be fabricated through inserting a metal underlayer at a deposition temperature much lower than the 500 °C that has been reported in earlier works.