D+离子束轰击时间对氘钛靶特性的影响

利用ZF-300keV中子发生器,采用伴随粒子法研究了氘钛靶的中子产额随D⁺离子束轰击时间的变化特性;利用慢正电子湮没技术和扫描电镜分别研究了D⁺离子束轰击前后靶辐射损伤特性和表面形貌特征.结果表明,束流轰击引起氘钛靶缺陷结构和表面形貌的改变 ,但轰击时间的不同并未引起氘钛靶的中子产额、缺陷结构和表面形貌有明显差异;数值模拟了D⁺离子束在氘钛靶的辐射损伤特性和能量损失规律并与实验结果进行了比照分析和讨论. 关键词： 中子发生器 氘钛靶 伴随粒子法 慢正电子湮没技术     

强流脉冲离子束辐照对电弧离子镀TiNbN硬质薄膜摩擦磨损性能的影响

 利用分离靶电弧离子镀工艺在高速钢基体上制备TiNbN多元硬质薄膜,利用TEMP-6型强流脉冲离子束（HIPIB）设备,采用含C/H离子、加速电压300 kV、脉冲宽度70 ns、束流密度60 A/cm2的强流脉冲离子束对所制备的薄膜进行辐照处理,研究辐照前后膜层的摩擦磨损性能的变化。实验结果表明：HIPIB辐照以后,薄膜的表面熔化,摩擦系数降低,晶粒细化,膜层的硬度由HK3444提高到HK3820,膜基结合力由59 N提高到65 N。在测试载荷300 N和600 N条件下,薄膜的摩擦磨损性能均有较大改善。     

磁控溅射制备的W,WSi2,Si单层膜和W/Si,WSi2/Si多层膜应力

采用直流磁控溅射技术制备了厚度约100 nm的W,WSi2,Si单层膜和周期约为20 nm,Si膜层厚度与周期的比值为0.5的W/Si,WSi2/Si周期多层膜.利用台阶仪对镀膜前后基底表面的面形进行了测试,计算并比较了不同膜系的应力值.结果表明:W单层膜表现出较大的压应力,而W/Si周期膜则表现为张应力.WSi2单层...     

用于超薄反射镜热成形的Pt、Pt/Cr分离膜

针对热弯玻璃成形法制备高精度超薄反射镜时Pt分离膜造成的镜片污染问题,研究了Pt/Cr分离膜中不同Cr层厚度对热成形超薄反射镜玻璃基底表面粗糙度的影响.采用厚度为0.3 mm的Schott D263玻璃作为超薄反射镜基底材料,选取Pt、Pt/Cr作为模具和D263镜片之间的分离层材料进行实验.Pt薄膜的厚度为50nm,Cr层厚度分别为5nm、3.5nm、2.5nm、1.5nm,热成形实验采用"直接"复制方式.实验结果表明:Cr层厚度为1.5nm时,成形后模具表面分离膜未发生脱落,镜片表面粗糙度约为0.5nm,与D263镜片初始值接近,能够满足高能X射线望远镜对反射镜基底表面粗糙度的要求.     

流脉冲离子束辐照对DZ4合金性能的影响

 用含Cⁿ⁺和H⁺、加速电压250 kV、脉冲宽度70 ns、束流密度160 A/cm²的强流脉冲离子束辐照DZ4合金，辐照次数分别为2，5，10，15。实验结果表明：辐照后样品的表面出现了熔坑，多次脉冲辐照后样品的表面熔坑边缘模糊甚至消失。近表面存在厚1~2 mm的重熔层，晶粒较细，晶界模糊；熔坑周围富集Cr和Mo等元素;强流脉冲离子束辐照处理后DZ4合金的耐腐蚀性能明显提高，腐蚀速率下降,这是由于辐照减弱了由于晶界和晶粒本体的成分差异而引起的晶界腐蚀；同时离子束辐照后的DZ4合金在高温氧化时更容易形成一层连续的保护性氧化物，其主要成分是致密的Al₂O₃，使得DZ4合金的耐高温氧化性能也有所改善。     

用高能H+束辐照类金刚石碳膜的研究

用能量(112,89keV)和剂量(1×10¹⁷,5×10¹⁶个/cm²)配比不同的H⁺束对双离子束溅射淀积的类金刚石碳(DLC)膜进行辐照,用Raman光谱、红外透射光谱和膜层电阻率测量、粘着力测定等多种手段对辐照前后的DLC膜进行,表征和分析,结果表明,高能H⁺束辐照效应跟高能重离子辐照效应是不同的,H⁺束辐照使膜层sp³C—H键相对减少,sp关键词：     

氘在碳钨共沉积层中的滞留行为研究

运用射频磁控溅射方法, 在氘氩混合气氛中制备了含氘碳钨共沉积薄膜. 利用离子束分析方法[卢瑟福背散射(RBS)和弹性反冲(ERD)]对薄膜样品的厚度、成分、 氘含量等进行了分析; 利用拉曼光谱和扫描电子显微镜(SEM), 分别分析了薄膜的结构和表面形态. 离子束分析发现, 氘原子更易被碳原子俘获位俘获, 并且氘含量会随着沉积温度的升高而降低; 其他镀膜条件固定的情况下, 不同混合气体压强下薄膜样品中的氘浓度在5.0 Pa处有一个峰值; 拉曼光谱分析显示, 沉积温度从室温升高到725 K时, 碳钨共沉积层中的类石墨化成分增加, 同时, 非晶化的程度也加剧; 扫描电子显微镜图像表明, 随着温度的升高薄膜表面被腐蚀的痕迹消失, 但是由于应力的改变表面出现了多处的凸起. 关键词： 氘滞留 碳钨共沉积 射频磁控溅射     

强流脉冲离子束辐照混合双层靶的Monte Carlo模拟

采用Monte Carlo方法模拟强流脉冲离子束与铝基钛膜双层靶的相互作用.强流脉冲离子束与双层靶材相互作用过程中,随着离子的注入,高能离子束引起涂层原子与基体材料原子之间相互渗透和混合,同时离子能量沉积到靶材内一定深度,并呈规律性的空间分布.这种能量分布影响靶内两种材料的熔化或气化过程,并导致界面物质结合强度发生变化.利用建立的束流模型,计算束流在靶材内的能量沉积和分布状况及界面处级联碰撞对双层靶界面混合区的影响,得出强流脉冲离子束混合双层靶时级联碰撞不起主要作用的结论,离子流密度在100A·cm^-2~150A·cm^-2时对离子束混合最为有利.     

长脉冲激光辐照下单层HfO2薄膜的温度场分析

激光系统中的光学薄膜极易受到高能激光的辐照而产生热损伤,因此研究长脉冲激光作用下光学薄膜的温度场非常重要。建立了二维轴对称杂质模型,使用有限元方法计算了单层HfO2薄膜材料的瞬态温度分布,进一步分析了铂金杂质粒子的吸收系数、填满深度对膜层及其基底最大温升的影响。结果表明：相比于纯净HfO2薄膜,当薄膜中杂质粒子深度为100 nm时,其表面最大温度增加1倍左右;当粒子深度大于750 nm时,基底温度高于薄膜表面温度,从而可以使热损伤从薄膜基底开始。研究结果对于长脉冲激光系统中的光学薄膜的制备和预处理,具有一定的指导意义。     

桑色素修饰金纳米粒子自组装膜的制备及其性能研究

采用水相硅烷化方法,将γ-氨基丙基三乙氧基硅烷[H₂N(CH₂)₃Si(OC₂H₅)₃](APES)组装在石英表面,在基底表面修饰上氨基为末端的单层膜,并进一步在这种功能化的单层膜基底上组装金纳米粒子得到金纳米粒子/APES/石英的纳米复合结构。以制备的金纳米粒子自组装膜修饰石英为基底及DL-半胱胺酸为中介,利用桑色素(Morin)和DL-半胱胺酸的化学吸附作用,将桑色素间接组装在金纳米粒子自组装膜修饰石英基底表面,所构建的桑色素修饰金纳米粒子自组装膜对三苯基锡有灵敏的荧光识别作用。文章着重研究了桑色素修饰金纳米粒子自组装膜的制备以及组装条件对其荧光行为的影响,探讨了膜的响应特性及响应机理。     

电子束辐照下的注氘铝的结构变化

利用离子加速器在室温下对纯铝注入氘离子或氢离子,然后在透射电镜中对注氘铝或注氢铝中的气泡进行电子束辐照,发现在电子束辐照下气泡会长大、破裂.随着气泡的变化,选区电子衍射花样中出现了表示多晶存在的衍射环.这表明电子束辐照气泡时,发生某种放热现象,从而使附近的铝先熔化后再凝固,由单晶变为多晶.     

高压氘氚靶球的制备与拉曼光谱研究

氢同位素的定量分析与监测在能源与环境领域都有着重要的意义。激光拉曼光谱由于其可以无损分析氢同位素分子,已经成为一种重要的方法,在国际热核聚变实验反应堆(ITER)和美国萨凡纳河工厂得到了广泛应用。利用高压充气装置得到了惯性约束聚变(ICF)高压靶丸,并对靶丸内气体进行原位拉曼光谱测量,通过对高压下氘氚混合气体的拉曼光谱进行分析得到了靶丸内气体的成分比例,验证了靶丸充气工艺参数。实验表明,在CCD的积分时间延长到1 min时,氘(DD),氘氚(DT)和氚(TT)的测量精度可以达到1%,同时对不同时刻靶丸内气体组分的拉曼光谱进行测量,实验结果表明在氘氚渗透和氚衰变两者共同作用下,靶丸内总气体压力随时间不断下降,但是气体组成基本不发生变化。     

Hydrogen isotope replacement reactions on rhenium

The existence of a mobile equilibrium at room temperature between part of the hydrogen adsorbed on rhenium and gaseous hydrogen is demonstrated by the easy exchange of isotopes between the adsorbed layer and the gas phase. The adsorbed gas is desorbed as a mixture of homonuclear molecules (of H₂ or D₂)and of the isotopically mixed species (HD). However, the replacement reactions are not symmetrical; there is a greater proportion of HD in the desorbed gas when deuterium is replaced by hydrogen than in the converse reaction. This kinetic isotope effect is attributed to differences between the zero-point energies of the various hydrogen containing species.Quantatitive agreement between the shapes of the experimentally observed desorption curves and calculated curves is obtained if the zero-point energy of the bond between a surface rhenium atom and deuterium is assigned the value 2.6 kcal mole^?1.     

超声喷流氩氢混合团簇特性研究

利用瑞利散射方法研究了超声喷流Ar-CH4混合团簇和超声喷流Ar-H2混合团簇的特性.通过测量不同混合比例和不同背压下所形成混合团簇的散射信号发现,当用Ar气和CH4的混合气体进行超声喷流时很容易形成Ar-CH4混合团簇,当Ar气含量为50%时混合团簇尺度最大且大于相同气压下纯Ar团簇尺度和纯CH4团簇尺度.实验发现,与纯H2团簇只能在低温条件下获得不同,常温下即可形成Ar-H2混合团簇,实现了常温下含氢团簇的获取,从而有效降低了制备成本.在H2含量大于40%时混合团簇开始形成并在60%时达到最大尺度.含氢(氘)混合团簇在氢(氘)团簇的基础上引入了更重的异核Ar元素,在激光氘团簇聚变实验中它将进一步加速氘离子从而获得更高的能量,并具有更高的中子产额和聚变效率.     

Doppler spectroscopy of hydrogen and deuterium Balmer alpha line in an abnormal glow discharge

The results of hydrogen and deuterium Balmer alpha line shapes and line intensities study in an abnormal glow discharge are reported and analyzed. The Doppler shifts along line wings are used to determine energies of excited hydrogen and deuterium atoms. For 12 different cathodes, intensity and shape of line wings are examined and dependence upon cathode material is determined. Tentative explanation of line wings intensity dependence is related to the sputtering of cathode material and back-scattering coefficients of incident hydrogen or deuterium ions and atoms from cathode surface. The influence of the light reflected on a cathode surface to the line shape measurements along discharge axis is considered. In hydrogen, deuterium, and Ar+3%H/sub 2/ discharges, basic mechanisms of fast hydrogen generation and excitation are studied. The shape and intensities of the H/sub /spl alpha// line profiles in pure hydrogen and in argon-hydrogen mixture may be correlated with hydrogen atom-carrier gas collision excitation cross sections. In order to assess the importance of reflected fast hydrogen atoms back scattered from the cathode surface, for the Balmer line shape formation, a simulation program is used. The results are in a qualitative agreement with Balmer line shapes observations.     

高温高密度氢（氘）的物态方程——离解效应研究

 高温高压下流体氢将发生离解化学反应，形成具有相互作用的氢分子和氢原子混合体系，此时粒子间的相互作用复杂。利用单组分流体近似的范德瓦尔斯混合模型，将混合物粒子间的相互作用等效为单组分粒子间相互作用，从而简化了对体系的统计热力学处理；并由自由能函数极小化确定化学平衡时各组分含量、体系的内能、压强。研究了温度在10 000 K以下、密度在0.6 g/cm³以下（相应摩尔体积大于3.3 cm³/mol）区间的热致离解和压致离解现象对流体氢（氘）状态方程的影响。所得结果与双组分流体变分理论计算以及第一原理的分子动力学模拟、蒙特卡罗模拟结果以及二级轻气炮实验数据进行了比较，它们之间的一致性表明：用单组分流体近似的范德瓦尔斯混合模型处理氢（氘）分子的离解区域的物态方程是成功的。     

Regularities and mechanisms of hydrogen trapping in graphitized carbon composite upon irradiation by atoms with thermal velocities

Experiments are performed to study particle trapping in a graphitized carbon composite upon its exposure to a flux of deuterium atoms. It is shown that irradiation by deuterium atoms with thermal velocities ensures trapping according to a potential mechanism: atoms of the irradiating flux and hydrogen atoms from a layer of water molecules sorbed on the surface are both trapped. Mechanisms of trapping are discussed. Based on the experimental results, the contribution to deuterium-atom trapping in CFC irradiated in deuterium plasma is determined for each component-ions, electrons, and atoms.     

The effect of a nitrogen-rich surface layer on the sub-surface deuterium (hydrogen) concentration distribution in titanium

Deuterium and nitrogen depth profiles in Ti with modified surfaces have been measured with Auger electron spectroscopy, secondary ion mass spectroscopy, and D(³He,p)⁴He nuclear reaction analysis. Nitrogen-rich surfaces layers of varying thicknesses were created on Ti by exposure to N₂ gas at 650°C. Deuterium loading was performed by exposure to 1 Torr of D₂ gas at 500°C. The deuterium distribution was influenced by nitrogen in the near-surface regions of all samples. Specifically, deuterium solubility was suppressed in surface regions of high (greater than 1%) nitrogen concentration. The deuterium solubility also remained low within the first few microns, well beyond the region of high nitrogen concentration. This effect is attributed to internal elastic stresses imposed by the non-deuterium absorbing nitrogen-rich layer on the Ti. These stresses prohibit the volume expansion associated with deuterium absorption. We estimate stresses on the order of 3–4 GPa are required to suppress the deuterium solubility to the values observed. The deuterium absorption kinetics were observed to depend systematically on the thickness of the nitrogen-rich layer. This is consistent with limited solubility near the surface or a surface poisoning effect influencing the overall deuterium diffusion from the gas phase into the Ti bulk.     

Blackbody spectra for sonoluminescing hydrogen bubbles

The dynamical motion of sonoluminescing bubbles formed from a mixture of water and hydrogen gas indicates that these bubbles contain hydrogen. Their spectrum is well matched by an ideal 6000 K blackbody radiating from a surface with a radius less than 1/4 microm. According to this model, the state of matter inside the collapsed bubble is so stressed that the photon mean free path is much smaller than 1 microm. Implications for various theories of the light-emitting mechanism and the role of chemical reactions are discussed.     

Analysis of a tungsten surface irradiated by fast ions and deuterium plasma

The effects occurring on the surface of tungsten under irradiation with fast ions with an energy in the megaelectrolvolt range and with high fluxes of hydrogen (deuterium) plasma are considered. These effects are radiation damage of the surface layer of the material, its erosion and deuterium retention in it. Irradiation with helium ⁴He²⁺ (3.2–4.0 MeV) and carbon ¹²C³⁺ (10 MeV) ions is performed using a cyclotron at the National Research Center Kurchatov Institute. The thickness of the damaged layer is 3.5–6 μm. The irradiated samples are exposed to steady-state deuterium plasma using a LENTA linear plasma facility to reach a plasma ion fluence of 10²¹–10²² cm^?2. Tungsten erosion and modification of the structure of the damaged layer are analyzed at a plasma-ion energy of 250 eV. Deuterium retention in the damaged layer is studied by elastic recoil detection analysis. The deuterium concentration and its penetration depth into the material are measured. The data obtained for different kinds of fast ions used in the work are compared.