扫描电子显微镜测量靶丸表面形貌

介绍了用扫描电子显微镜监测靶丸４π表面形貌的方法。为此研制了对惯性约束聚变靶丸４π搓动的扫描电子显微镜样品台,对靶丸的旋转精度为２ μｍ 。它提供了观察靶丸缺陷的最佳方法,可为惯性约束聚变实验精选靶丸。     

扫描电子显微像测量靶丸表面形貌

介绍了用扫描电子显微镜监测靶丸４π表面形貌的方法,为此研制了对惯性约束聚变靶丸４π搓动的扫描电子显微镜样品台,对靶丸的旋转精度为２μｍ,它提供了观察靶丸缺陷的最佳方法,可为惯性约束束聚变实验精选靶丸。     

激光核聚变靶的X射线相衬显微成像研究

激光核聚变在置有聚合物靶丸的金属靶室内进行,靶丸通常由碳、氢等低Z元素组成,传统的X射线成像很难诊断靶丸在靶室内的位置.X射线相衬成像在低z元素样品成像中具有独特的优越性,但很少用于强吸收介质包裹的低Z样品结构成像.针对激光核聚变靶丸位置无损检测这一难点,建立了相应的X射线相衬显微成像物理模型.数字模拟和微聚焦源X射线相衬成像初步实验研究的结果表明,通过选择合适的成像参数,如光子能量、成像距离等,可以获得靶丸位置的清晰成像.因此,可以认为X射线相衬成像技术用于激光核聚变靶室诊断是可行的.该技术还可以扩展到其他高Z介质内部低Z样品结构成像,如石油勘探中包裹体的研究等.     

激光靶丸全表面检测与功率谱特征评价

本工作基于靶丸全球面测量的经纬迹线法,应用由原子力显微镜、精密回转气浮轴系及辅助转位轴系等组成的靶丸表面形貌测量系统,对直径0.34mm的空心塑料靶丸表面进行了测量实验。实验选择了圆周9条经圆(间隔20°),每个经圆方向上纬圆间隔10μm,最大偏移20μm的方案,获取了靶丸全球面的经纬测量迹线,并对测量结果进行了模数-功率谱特征曲线和表面均方根粗糙度的分析。     

激光驱动靶丸超高速发射研究

本文通过理论模拟和实验相结合的方法,对激光驱动靶丸超高速发射以及超高速靶丸撞击防护材料进行研究。首先利用辐射流体程序HYADES对靶的飞行速度进行了理论模拟预估,其次在中国工程物理研究院神光Ⅲ原型装置上开展实验验证,得到了将直径200 μm的铝球加速至44 km/s的实验结果,完成了高速铝球与防护材料撞击测试,并通过撞击形态验证了该材料的防护效果。本研究在模拟在轨航天器空间碎片撞击与防护方面具有十分重要意义。     

辐射条件下冷冻靶靶丸表面及充气管温度特性数值研究

在惯性约束核聚变冰层均化实验阶段,观测到充气管内冰晶无法保持,从而不能堵管,靶丸直接与高温氘气源连接,无法继续实验。为解决难以堵管的问题,本文建立了三维冷冻靶系统计算模型,研究了辐射条件下屏蔽罩温度、封口膜透射率及铝套筒表面发射率等因素对冷冻靶靶丸表面及充气管沿程温度特性的影响规律。结果表明：改变封口膜透射率能有效降低靶丸与充气管连接处的温度,在本文讨论的边界条件下,封口膜透射率大于0.025时靶丸与充气管连接处温度相对较低,晶核可维持,充气管能被堵管;而改变屏蔽罩温度及铝套筒表面发射率等做法对靶丸与充气管连接处的温度降低作用不明显,充气管无法被堵管。     

辐射条件下球腔冷冻靶温度场分布数值研究

惯性约束聚变冷冻靶系统中,为成功实现靶丸点火,冰层厚度均匀性需达到99%,表面粗糙度的均方根要小于1 μm。控制靶丸表面最大温差小于0.1 mK能满足以上点火要求。为研究辐射对惯性约束聚变间接驱动靶丸的温度场影响,建立了三维对称球腔冷冻靶系统的计算模型。考虑球腔内部激光入射口封口膜吸收率以及外部辐射温度对球腔内部温度场分布的影响,利用FLUENT软件对球腔冷冻靶温度场进行了数值模拟计算。研究表明：球腔由于自身具有的球对称几何结构,其内部的温度场分布更加均匀;受外界辐射影响,有窗侧靶丸表面温度较无窗侧温度高;辐射温度越高,靶丸表面的绝对温度越高,虽然靶丸表面的温差变化基本可忽略,但要防止由于外界辐射温度过高而导致的DT冰层均匀性恶化,应选用多层屏蔽罩结构降低辐射的影响;激光入射口封口膜吸收率大于0.2时,靶丸表面温差显著增大。     

冷冻靶的环境热辐射屏蔽技术研究

通过建立三维柱腔冷冻靶计算模型,研究了外界环境辐射对间接驱动冷冻靶靶丸及燃料冰层温度场的影响。考虑柱腔内部激光入射孔（LEH）膜透光率对柱腔内靶丸和冰层温度场分布的影响,利用COMSOL软件对柱腔冷冻靶温度场进行了数值模拟计算。研究结果表明：受外界辐射影响,靶丸表面温度场呈两极热、赤道冷分布;LEH膜透光率越大,靶丸外表面温差和冰层内表面温差越大。当LEH膜透光率小于1%时,冰层内表面最大温差低于0.1 mK,可满足冰层均化和保持的要求。实验中,通过在LEH膜上镀不同厚度的铝层调控其透光率,并选择LEH膜镀铝层厚度为35 nm的冷冻靶开展了氘氘冷冻均化实验。结果表明：当LEH膜上的镀铝层厚度为35 nm时,冰层的保持能力得到大幅提升。从X射线相衬图像可知,冰层的厚度均匀性约为80.2%,粗糙度约为1.65 μm,平均厚度约为50.5 μm。     

ITER的靶丸加料计算(英文)

运用考虑动力效应的Kuteev2-D透镜模型,数值计算了靶丸在国际热核实验堆(ITER)中的消融率,讨论了目前现有的加料工艺的技术困难和可能的解决办法。数值积分结果发现目前已有的靶丸加料技术很难满足堆级等离子体ITER中心加料的要求,计算表明对一个2m长的单级气动枪要加速一个半径0.5cm的靶丸达到速度24.27km/s才能渗透ITER等离子体100cm。用两种典型的消融理论计算了渗透深度与靶丸速度和半径的依赖关系并作了比较。新近的研究从高场侧(HFS)注入靶丸来改善芯部加料效率可能给芯部加料困难贡献一种解决办法,对相关的问题作了讨论。     

X射线法ICF靶丸几何参数批处理及壁厚分布计算

分析了靶丸微焦X射线成像的基本原理,采用改进Hough变换对靶丸X射线数字图像进行自动圆参数检测,结合最小二乘圆拟合算法获得了精确的多层靶丸几何参数,给出了靶丸图像批处理的整个分析流程,并开发了一套完整的靶丸X射线图像批处理计算软件。在此基础上讨论了靶丸壁厚分布的批处理计算问题,给出了多层靶丸壁厚分布状态及单层靶丸全表面壁厚分布情况的计算示例。     

Degradation of polyimide induced by nitrogen laser irradiation

The degradation behavior of polyimide (PMDA-ODA) induced by nitrogen laser irradiation was studied. The changes in the surface morphology and the composition of the irradiated polyimide films were examined by scanning electron microscopy, X-ray photoelectron spectroscopy and FT-IR spectroscopy. The initial reaction was achieved by photochemical degradation of polyimide in the highly electronic excited state by the absorption of a second 337 nm photon. Atmospheric oxygen sequentially reacted with the produced radicals to form a highly oxidized layer. The formation of carbonyl group was enhanced by the heat remaining on the irradiated polyimide film surfaces.     

堆用热管的热特性计算分析

热管已广泛地用于许多领域。为把热管技术用于材料试验堆内的辐照罐温度控制,近年来日本原子力研究所 JMTR 堆上的研究人员对热管作了大量的研究工作,并进行了堆外热特性试验和部分堆内试验。作者在 JMTR 堆上工作期间,主要对几种堆用垂直重力协助式热管的热特性进行了计算分析。研究结果表明,轴向槽道式热管和无吸液热管不仅结构简单,而且具有良好的热特性,可工作在500K 左右的温度范围内,适用于考验压水堆材料的辐照罐。均匀吸液芯热管在较高温度下沸腾极限较低,因此更适合于较低温度下的使用。本文简介热管在辐照技术上的应用并讨论几种堆用重力热管的传热极限。     

Polyimide-based scintillating thin films

The production procedure and the scintillation characteristics of thin polyimide films containing rhodamine B are reported. Fluorinated polyimide has been chosen as host matrix for its well known radiation hardness, in order to improve the lifetime of detector systems based on plastic thin film scintillators, 6FDA (4,4'-hertafluoroisopropylidene diphthalic anhydride) and DAB (diaminobenzophenone) have been used as polyimide precursor monomers. The samples have been cured in air at temperatures ranging from 80°C up to 250°C. The scintillation spectra have been collected by irradiating the samples with a 5.478 MeV alpha particle source and their shape and intensity have been investigated as a function of dopant concentration and curing temperature     

Ablation and carbon deposition induced by UV laser irradiation of polyimide: Application to the metallization of VIAs in high density printed circuit boards

Polyimides are known to exhibit large ablation rates upon irradiation with excimer laser due to their high absorbance in the UV and low fluorescence yield. We have studied different regimes of laser ablation according to the fluence and studied the structures resulting from carbon products deposition. For fluences larger than the polyimide ablation threshold, but lower than the carbon one, the development of one structure is the dominant process, whereas large ablation rates lead to polyimide etching above the carbon ablation threshold. The deposition of a carbon layer on the walls of ablated slits has in particular been investigated using an original experimental technique. Optical microscopy and MEB have shown that this carbon layer covered the main height of the ablated holes whereas a threshold (bare polyimide) for carbon condensation was evidenced at the bottom of the ablated hole. Raman spectroscopy and conductivity measurements have shown that the carbon phase is mainly graphitic. A dependence of the carbon condensation threshold on the slit width has been evidenced and discussed in relation with the angle of ejection of ablation debris. A procedure has been developed to render the bare polyimide of the threshold region conductive. At last the conductive properties of the walls of the ablated holes have been exploited to perform an electrolytic metallization. Implications for the production of interconnection vertical interconnections (VIAs) in high density printed circuits are addressed.     

废放射源整备用封装管的设计与检测

研制废放射源整备封装管,使整备后废放射源满足处置或者长期贮存要求,是废放射源管理的重要组成部分。本文针对不同活度、不同核素的废放射源,设计制造了不同的封装管,并对其中的螺纹封装管进行了跌落性、抗冲击性、耐热性等一系列检测。检测结果表明,本研究设计的封装管,满足封装废放射源的要求。     

Radiation-assisted phosphorous diffused polyimide as low thermal emissivity material

Radiation enhanced diffusion of phosphorous into the surface layer of polyimide is shown to be effective in lowering its thermal emissivity in the range of wavelengths between 8 and 14 μm. The effect of the fluence of irradiation on the value of emittance has been studied and lowest emissivity was associated with the formation of nanoclusters on the surface. The variation in the dielectric constant of the irradiated polyimide has been monitored as a function of irradiation. Increase in the value of dielectric constant is correlated to the corresponding value of the thermal emittance. Semiempirical calculations, using Fresnel’s relation, are used to validate the measurements. Elemental concentration of phosphorous in the surface region of the film and its morphology has been studied by energy dispersive X-ray analysis using scanning electron microscope.     

Wetting response of KrF laser ablated polyimide surfaces

The wettability of polyimide surfaces microstructured using KrF laser radiation at fluences above the material ablation threshold was studied by static contact angle measurements. The laser-treated surfaces present a morphology consisting of conical features whose dimensions and areal density depend on the fluence. The effect of these parameters on the surface apparent contact angle depends on the wetting regime. When wetting occurs in the homogeneous regime, the apparent contact angle of the treated surfaces increases with the radiation fluence because the cone dimensions increase. In contrast, when wetting occurs in the heterogeneous regime, the apparent contact angle increases with the radiation fluence because the average distance between cones increases. The apparent water contact angle of the laser-treated surfaces can reach values as high as 162°, as compared to 75° for virgin polyimide.     

新型充Ar靶丸设计

从惯性约束聚变实验物理诊断需求出发,提出并分析了利用聚碳硅烷空心微球作为DT燃料容器实现扩散法充氩的可行性。初步实验研究表明,聚碳硅烷微球有望替代玻璃微球作为DT燃料容器用于内爆物理研究。     

Observations of a steady state effect limiting radiation damage in reactor vessel steels

Reactor vessel material surveillance capsules which contain specimens of actual material used in the construction of a vessel are contained in nearly all operating reactors. These specimens monitor the changes in properties of the reactor vessel and assure that predicted changes based on trend curves which are used to set operating limits for the plant are conservative. Recently, data has been obtained from the Point Beach Unit No. 1 and Connecticut Yankee reactor vessel surveillance capsules exposed to neutron radiation for much longer periods of time, than those irradiated in test reactors and surveillance capsules which were removed at the first refueling and other early refueling outages. The data from these long time surveillance capsule exposures when compared to data from capsules removed from the same reactors earlier in life indicated that a limiting or steady state condition has resulted rather than a continuous embrittlement as predicted by trend curves. It is believed that the limited embrittlement or steady state condition which occurred from the surveillance capsule tests is due to a combination of relatively low neutron flux compared to that existing in test reactors which were the primary source of data used to establish trend curves and the longer exposure periods in the capsules that led to significant “annealing” during irradiation.     

内表面掺硫聚苯乙烯空心微球初步研制

以聚苯乙烯磺酸钠（PSS）为掺杂源,采用乳液微封装法制备内表面掺S的聚苯乙烯（PS）空心微球。XPS测量表明,微球内表面存在明显的S元素。利用低能X射线照相技术研究了不同掺杂源浓度下干燥时重力和表面张力对掺杂均匀性的影响,当掺杂源浓度降为0.2%时,得到了内表面掺杂S均匀的PS微球,微球直径为200～800μm,直径300μm的微球中掺杂层S原子面密度为8.57×10⁶μm^－2。