共查询到18条相似文献,搜索用时 171 毫秒
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月球表面环境对Mo/Si多层膜光学特性的影响 总被引:1,自引:0,他引:1
研究了月球表面高温、强辐射的空间环境下Mo/Si多层膜的热稳定性和辐照稳定性。Mo/Si多层膜采用磁控溅射法镀制,将制备好的多层膜在100℃和200℃高温下加热,利用激光等离子体反射率计和X射线衍射仪(XRD)对加热前后的多层膜进行了测量。结果显示在200℃以内,多层膜反射率和中心波长没有显著变化,表现出良好的热稳定性。利用Monte Carlo方法模拟了质子在多层膜内造成的缺陷的分布和浓度分布。模拟显示,能量大的质子沉积在多层膜内部,造成的缺陷也集中在多层膜内部。用能量为60keV,剂量分别为3×1012 cm-2和3×1014 cm-2的质子对Mo/Si多层膜进行辐照实验。发现多层膜内部出现了烧蚀损伤缺陷及节瘤缺陷。结果表明能量相同时,辐照剂量越大对多层膜反射率影响越大。 相似文献
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利用透射电子显微镜对质子辐照前后空间太阳望远镜Mo/Si多层膜的微观结构进行了表征, 并对其辐照前后反射率的变化进行了测量.研究表明, Mo/Si多层膜经质子辐照后形成了一些缺陷结构,局部区域Mo/Si的周期性遭到破坏, Mo层与Si层的宽度发生了变化,多层膜层与层之间的界面也比辐照前更为粗糙,部分层状结构由于质子辐照发生了明显的扭曲和折断等现象;此外,质子辐照导致了Mo/Si多层膜反射率的下降,这些微观缺陷的形成是光学性能降低的直接诱因.
关键词:
空间太阳望远镜
Mo/Si多层膜
微观结构
反射率 相似文献
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采用分光光度计测定了60keV质子辐照后铝膜反射镜反射光谱的变化规律.用慢正电子湮没等分析技术研究了辐照损伤的微观机制.结果表明,当质子辐照主要作用于反射镜铝膜层中时反射镜在200—800nm波长范围内反射率随辐照剂量增加而下降.入射质子可对铝膜中的缺陷产生填充作用,减小铝膜中电子密度,增加弱束缚电子带间跃迁.紫外至可见光能量较高的波段可引起带间激发跃迁,使相应的谱段反射率下降,导致反射镜光学性能的退化.
关键词:
反射镜
光学性能
质子辐照
慢正电子湮没 相似文献
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用磁控溅射技术制备不同调幅波长 (L) 的W(Mo)/Cu纳米多层膜,所制膜系在60 keV氦离子 (He+) 辐照条件下注入不同剂量: 0, 1×1017 He+/cm2, 5×1017 He+/cm2. 用X射线衍射仪 (XRD) 和高分辨透射电子显微镜(TEM)表征W(Mo)/Cu纳米多层膜辐照前后微观结构. 研究结果表明: 1) He+离子轰击引起温升效应是导致沉积态亚稳相β-W 转变成稳态 α-W相的主因, 而与调幅波长无明确关联; 2) 纳米多层结构中W(Mo) 和Cu膜显现出的辐照耐受性与调幅波长相关, 调幅波长越小, 抗He+的辐照性能越强; 3) 在5×1017 He+/cm2注入条件下, 观察到He团簇/泡在纳米结构W(Mo) 和Cu膜中的积聚行为存在明显差异: 在W (Mo) 膜中He团簇/泡的分布与晶粒取向相关, He团簇/泡倾向于沿W (211) 晶面分布; 而Cu膜非晶化且He团簇/泡在其体内呈均匀分布.
关键词:
W(Mo)/Cu纳米多层膜
+辐照')" href="#">He+辐照
He团簇/泡
相转变 相似文献
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利用CTMC方法计算Cq+,Nq+,Oq+与H原子的碰撞过程的截面.入射粒子的能量范围为10~250keV/amu,离子为部分电离和完全电离的离子.给出了十二个耦合的Hamilton运动方程.用六个伪随机数确定粒子的轨道. Aq+离子和作用电子的势为模型势,其他两个势为纯库仑势。在计算中,需要2000个以上的轨道.引入约化变量σtr=σtr/q,E=E/q1/2,得到了q标度的俘获截面,这些截面数据都集中在一条曲线附近.计算结果与其他理论计算结果作了比较,它们符合得很好. 相似文献
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为了检验应用在极紫外波段空间太阳望远镜上Al滤光片在空间辐照环境下透过率的变化情况,用能量100 keV,剂量为6×1011/mm2的质子束对其进行辐照,利用透射电子显微镜分析了质子辐照前后滤光片的微观结构。实验结果表明:由于质子辐照使滤光片受质子侵蚀后,Al原子被击出发生质量损失,表面形态发生了变化,造成滤光片变薄,从而导致透过率由辐照前的12.1%增大到15.0%,且滤光片的薄厚分布不均匀使透过率曲线出现了次级峰,造成其光学性能的退化。 相似文献
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Samples from sheets of the polymeric material Makrofol DE 7-2 have been exposed to 1 MeV protons of fluences in the range 2.5×1013–5×1015 p/cm2. The resultant effect of proton irradiation on the thermal properties of Makrofol has been investigated using thermogravimetric analysis and differential thermal analysis (DTA). The onset temperature of decomposition T o and the activation energy of thermal decomposition E a were calculated, and the results indicated that the Makrofol detector decomposes in one weight loss stage. Also, the proton irradiation in the fluence range 7.5×1013–5×1015 p/cm2 led to a more compact structure of Makrofol polymer, which resulted in an improvement in its thermal stability with an increase in the activation energy of thermal decomposition. The variation of transition temperatures with proton fluence has been determined using DTA. The Makrofol thermograms were characterized by the appearance of an endothermic peak due to the melting of the crystalline phase. The melting temperature of the polymer, T m, was investigated to probe the crystalline domains of the polymer. At a fluence range of 7.5×1013–5×1015 p/cm2, the defect generated destroys the crystalline structure, thus reducing the melting temperature. In addition, the V–I characteristics of the polymer samples were investigated. The electrical conductivity was decreased with the increasing proton fluence up to 5×1015 p/cm2. Further, the refractive index, transmission of the samples and any color changes were studied. The color intensity Δ E was greatly increased with the increasing proton fluence and was accompanied by a significant increase in the red and yellow color components. 相似文献
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Samples from polycarbonate/poly (butylene terephthalate) (PC/PBT) blends film have been irradiated using different fluences (1?×?1015– 5?×?1017 H+/cm2) of 1?MeV protons at the University of Surrey Ion Beam Center, UK. The structural modi?cations in the proton irradiated samples have been studied as a function of fluence using different characterization techniques such as X-ray diffraction and UV spectroscopy. The results indicate that the proton irradiation reduces the optical energy gap that could be attributed to the increase in structural disorder of the irradiated samples due to crosslinking. Furthermore, the color intensity ΔE, which is the color difference between the non-irradiated sample and those irradiated with different proton fluences, increased with increasing the proton fluence up to 5?×?1017 H+/cm2, convoyed by an increase in the red and yellow color components. In addition, the resultant effect of proton irradiation on the thermal properties of the PC/PBT samples has been investigated using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). It is found that the PC/PBT decomposes in one weight loss stage. Also, the variation of transition temperatures with proton fluence has been determined using DSC. The PC/PBT thermograms were characterized by the appearance of two endothermic peaks due to the glass transition and melting temperatures. The melting temperature of the polymer, Tm, was investigated to probe the crystalline domains of the polymer, since the proton irradiation destroys the crystalline structure so reducing the melting temperature. 相似文献
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Low-temperature (40 K) photoluminescence (PL) measurements were used to follow the defect formation induced in the 4H-SiC epitaxial layer by irradiation with 200 keV H+ and 800 keV C+ in the fluence range of 5×109–3.5×1012 ions/cm2. After irradiation, the PL spectra show the formation of some sharp lines, called “alphabet lines”, located in the wavelength range of 425–443 nm, due to the recombination of excitons at structural defects induced by ion beams. The analysis of luminescence line intensity versus ion fluence allows us to mark two different groups of peaks, namely the P1 group (e, f and g lines) and the P2 group (a, b, c and d lines). The normalised yield of P1 group lines increases with ion fluence and reaches a maximum value, while the normalised yield of P2 group lines exhibits a threshold fluence and then increases until a saturation value is reached. These different trends indicate that, while the P1 group lines are related to the primary defects created by ion beams (interstitial defects, vacancies), the P2 group lines can be associated with some complex defects (divacancy, antisites). The trends are similar for irradiation with H+ and C+ ions; however, the defect formation occurs in the fluence range of 5×109–1011 ions/cm2 for C+ irradiation and 1011–4×1012 ions/cm2 for H+ irradiation. Taking into account the different values of energy deposited in elastic collision, a dependence on the ion type was found: the C+ ion results in being less effective in defect production as a higher defect recombination occurs inside its dense cascade. 相似文献
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J. P. Allain M. Nieto-Perez M. R. Hendricks P. Zink C. Metzmacher K. Bergmann 《Applied Physics A: Materials Science & Processing》2010,100(1):231-237
Sn+ irradiations of Ru single-layer mirrors (SLM) simulate conditions of fast-Sn ion exposure in high-intensity 13.5 nm lithography
lamps. Ultra-shallow implantation of Sn is measured down to 1–1.5 nm depth for energies between 1–1.3 keV at near-normal incident
angles on Ru mirror surfaces. The Sn surface concentration reaches an equilibrium of 55–58% Sn/Ru for near-normal incidence
and 36–38% for grazing incidence at approximately 63 degrees with respect to the mirror surface normal. The relative reflectivity
at 13.5 nm at 15-degree incidence was measured in-situ during Sn+ irradiation. For near-normal Sn+ exposures the reflectivity is measured to decrease between 4–7% for a total Sn fluence of 1016 cm−2. Theoretical Fresnel reflectivity modeling shows for the same fluence assuming all Sn atoms form a layer on the Ru mirror
surface, that the reflectivity loss should be between 15–18% for this dose. Ex-situ absolute 13.5 nm reflectivity data corroborate
these results, indicating that implanted energetic Sn atoms mixed with Ru reflect 13.5-nm light differently than theoretically
predicted by Fresnel reflectivity models. 相似文献
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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. 相似文献
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A dedicated small‐angle X‐ray scattering beamline with a superconducting wiggler source at the NSRRC
Din‐Goa Liu Chien‐Hung Chang Chin‐Yen Liu Shih‐Hung Chang Jwei‐Ming Juang Yen‐Fang Song Kuan‐Li Yu Kuei‐Fen Liao Ching‐Shiang Hwang Hok‐Sum Fung Ping‐Chung Tseng Chi‐Yi Huang Liang‐Jen Huang Shih‐Chun Chung Mau‐Tsu Tang King‐Long Tsang Yu‐Shan Huang Chien‐Kuang Kuan Yi‐Chih Liu Keng S. Liang U‐Ser Jeng 《Journal of synchrotron radiation》2009,16(1):97-104
At the National Synchrotron Radiation Research Center (NSRRC), which operates a 1.5 GeV storage ring, a dedicated small‐angle X‐ray scattering (SAXS) beamline has been installed with an in‐achromat superconducting wiggler insertion device of peak magnetic field 3.1 T. The vertical beam divergence from the X‐ray source is reduced significantly by a collimating mirror. Subsequently the beam is selectively monochromated by a double Si(111) crystal monochromator with high energy resolution (ΔE/E? 2 × 10?4) in the energy range 5–23 keV, or by a double Mo/B4C multilayer monochromator for 10–30 times higher flux (~1011 photons s?1) in the 6–15 keV range. These two monochromators are incorporated into one rotating cradle for fast exchange. The monochromated beam is focused by a toroidal mirror with 1:1 focusing for a small beam divergence and a beam size of ~0.9 mm × 0.3 mm (horizontal × vertical) at the focus point located 26.5 m from the radiation source. A plane mirror installed after the toroidal mirror is selectively used to deflect the beam downwards for grazing‐incidence SAXS (GISAXS) from liquid surfaces. Two online beam‐position monitors separated by 8 m provide an efficient feedback control for an overall beam‐position stability in the 10 µm range. The beam features measured, including the flux density, energy resolution, size and divergence, are consistent with those calculated using the ray‐tracing program SHADOW. With the deflectable beam of relatively high energy resolution and high flux, the new beamline meets the requirements for a wide range of SAXS applications, including anomalous SAXS for multiphase nanoparticles (e.g. semiconductor core‐shell quantum dots) and GISAXS from liquid surfaces. 相似文献
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Large dimensional expansion has been observed at room temperature in erbium metal films implanted at room temperature with high fluences of helium. The interferometrically measured film thickness increases linearly with fluence up to a critical dose of 3 × 1017 He+/cm2 (E = 160 keV) and is superlinear at higher fluences. Annealing at 400°C causes a reduction of the induced expansion for fluences below the critical dose without apparent release of helium. Annealing of samples implanted to fluences greater than 3.5 × 1017 He+/cm2 causes accentuated expansion which is accompanied by formation and rupture of bubbles at the film surface. 相似文献