圆柱面和圆锥面弯晶谱仪的理论计算及设计

用光线追迹的方法对圆柱面和圆锥面弯晶谱仪进行了理论计算,得到了谱仪的空间与色散坐标、线色散率、角色散率、光谱分辨力、空间和光谱放大率以及谱仪亮度等参数的解析计算公式,并对两类谱仪进行了具体的参数设计及性能比较.结果表明,圆锥面弯晶谱仪比同类型的传统圆柱面弯晶谱仪有着更为良好的聚焦性能,能够进一步改善谱仪的光子收集效率、谱仪亮度以及空间分辨力.这项工作为谱仪研制提供了理论基础和设计依据.     

线状等离子体测量中的晶体谱仪及其在X射线激光实验中的应用

本文讨论了两种适用于Ｘ射线激光实验的聚焦型弯晶谱仪和针孔晶体谱仪。给出了弯晶谱仪的设计参数，以及针孔晶体谱仪在实验中摄得的线状Ｍｇ和ＣａＦ２等离子体空间分辨谱；分析了晶体谱仪在Ｘ射线激光实验中的应用。     

多道时间谱仪测量光速

介绍了多道时间谱仪的时间幅度变换原理，描述了谱仪的调试和主要指标的测定，并应用多道时间谱仪测量了光速．     

透射晶体谱仪及其理论计算

为了测量更广能量范围的等离子体辐射的硬X射线轫致辐射光谱,以获得激光等离子体超热电子能谱的特性,基于柱面弯曲晶体的分光原理,提出了透射晶体谱仪。为满足实验中光源到谱仪距离不同的需要,设计了Johann型可调节透射晶体谱仪。谱仪中的会聚狭缝设计成可移动的,位置随着光源到谱仪距离的变化而改变。通过理论计算获得了会聚狭缝位置变量与光源距离变化之间的关系,得出小角度(小于0.2 rad)入射时能够保证入射光线经过晶体后近似会聚于一点,并对谱仪具体设计时遇到的一些问题,给出了初步的理论分析和看法。该谱仪中会聚狭缝的可调节解除了谱仪到光源距离固定的限制;前端晶体的可更换,也增加了谱仪测量的灵活性。     

透射式柱面弯晶谱仪的单滤片能量刻度方法

根据布拉格衍射定律和晶层模型,推导了透射式柱面弯晶谱仪的三维衍射光路的理论公式,并利用该理论研究了谱仪测量光谱的能量刻度问题。在考虑了实验中谱仪与光源的准直度和记录介质放置姿态带来的误差后,发现利用多种滤片的K吸收边进行公式拟合得到弯晶谱仪能量刻度曲线的方法对低能X射线谱线的误差较大,进而提出了用单滤片通过理论公式模拟计算进行谱仪能量刻度的方法。通过对透射式柱面弯晶谱仪测量到的Ag靶X光机的实验光谱进行能量刻度,实现了用单滤片在线定标弯晶谱仪,验证了理论公式和能量刻度方法的正确性。     

时空分辨透射光栅谱仪及其应用

本文介绍了时间分辨透射光栅谱仪和空间分辨透射光栅谱仪的结构、原理和实验技术。给出了利用这两种谱仪在惯性约束聚变实验研究中获得的典型结果。     

带有磁分析器的半导体探测器带电粒子谱仪

本文报导了一个新型的带电粒子谱仪。它将小型磁分析器分析粒子动量和半导体探测器有较高能量分辨率的特点结合起来,达到了分辨粒子和分析能谱的目的。本文叙述了谱仪的设计、结构和用于核反应研究的一些实验结果,讨论了该谱仪的应用范围和特点。这种谱仪简单灵活,且有较好的性能。     

高反射效率高定向性的热解石墨晶体X射线谱仪

基于高定向热解石墨晶体(highly oriented pyrolitic graphite,HOPG)研制了一种新型反射式X射线谱仪.该谱仪具有高反射效率、较高能谱分辨率及相对较宽的能谱测量范围.根据计算,在相同的入射条件下,该谱仪的效率比一般X射线弯晶谱仪高3个量级;谱仪能谱分辨率理论值最高达350;理论探测范围是6.891keV至9.193 keV.我们将该谱仪应用在高功率密度激光与固体靶相互作用的实验中,发现在普通弯晶谱仪无法采到信号的实验条件下,HOPG谱仪依然采集到清晰的Cu K谱线.分析发现在8.048 keV(Cu的Kα光子能量)附近的能谱分辨能力最高达到40 eV,分辨率大于200.     

高分辨椭圆弯晶谱仪在激光等离子体实验中的应用

 描述了用于激光等离子体X射线光谱研究的椭圆弯曲晶体谱仪系统。在“神光Ⅱ”第九路激光上对该谱仪进行标定实验,利用CCD相机成功地获得了激光等离子体铝和钛离子的K壳层和金离子M壳层谱;通过研究和辨认谱线,得到了X射线光谱,同时还给出了实验测定的谱仪分辨率。椭圆弯曲晶体谱仪除有高的收集光子效率外,还有更好的谱分辨和空间分辨率。分析了椭圆弯曲晶体谱仪在前沿科学技术和高技术实验中的应用。     

用三坐标测量机调整掠入射光栅谱仪

用三坐标测量机调整掠入射光栅谱仪是我们在研制掠入射光栅谱仪中采用的新方法．我们用这种方法研制了一台曲率半径为１ｍ的光栅谱仪，在２—３２ｎｍ波段范围内，谱线分辨达０．００５ｎｍ，与通常采用的用光源摄谱调整光栅谱仪的方法相比，节省了人力、物力，缩短了研制周期．     

多光谱融合的海洋沉积物碳含量检测

海洋沉积物中碳的变化是衔接海洋生态系统的过去与未来的信息桥梁,揭示了海洋生态过程变化规律。因此开展海洋沉积物碳含量的研究,对掌握海洋生态系统碳循环规律,研究全球碳循环,研究对气候变化的响应和反馈有着重要的作用。光谱技术是一种快速、无损的测量方法,在定量分析中已有很成熟的应用。多光谱融合通过将多个光谱数据结合一起,获得比单一光谱更丰富的信息,有利于物质的分析研究。将多光谱融合应用于海洋沉积物碳含量的研究,以青岛海洋潮间161份沉积物为样品,分别采用海洋光学QE65000光谱仪（光谱仪1）和AVANTES光纤光谱仪AvaSpec-ULS2048（光谱仪2）采集沉积物可见-近红外光谱。将两种光谱仪的光谱进行多光谱融合,分别采用偏最小二乘回归算法（PLSR）和BP神经网络算法（BPNN）建立沉积物碳含量模型。在PLSR沉积物碳含量建模结果中,多融合光谱结果优于光谱仪2,略低于光谱仪1,RPD值为1.968;在BPNN沉积物碳含量建模结果中,多融合光谱结果优于两个单光谱仪,RPD值为2.235。将多光谱融合后的光谱划分多个波段,分别建立沉积物碳含量模型,寻找沉积物碳的特征波段。通过分析多光谱融合各波段模型结果,560～790 nm的建模效果最好,R2_c为0.949,RMSEC为0.550,R2_p为0.874,RMSEP为0.733,RPD值为2.823。预测效果相较于光谱仪1、光谱仪2、多光谱融合全波段都有了显著的提高。因此采用多融合光谱特征波段建立海洋沉积物碳含量模型,能够提高海洋沉积物碳含量的预测结果,建立准确度更高的沉积物碳模型,为沉积物碳的快速测定打下基础。     

Preparation of a Pd/ZnO (0001) model catalyst and its characterization by AES,LEED and UHV reaction studies

Supported Pd catalysts are prepared in UHV on ZnO (000$\text{1}$) (oxygen face). By repeated cycles consisting of Pd deposition and an annealing step total amounts from 0.3 to 130 monolayers (ML) are reached. The growth mode of Pd is deduced indirectly from an analysis of Auger peak heights as a function of deposition amount and annealing temperature. At 300 K substrate temperature Pd, deposited with a rate of 1.2 ML/min, weakens the zinc and oxygen Auger yields in such a way that up to a deposit of 10 ML a constant ratio is maintained. This is ascribed to an agglomeration of the Pd deposit into clusters much higher than the escape depth. A critical inititial height of the clusters is derived as 6 ML (14.6 Å). The height increases linearly with Pd deposit. Above a deposit of 10 ML the oxygen Auger yield decreases much faster than the zinc yield. The data can be fitted using the assumption of a homogeneous Pd film on the free areas between the clusters. Annealing of faces with up to 130 ML Pd deposit at temperatures up to 970 K reestablishes free substrate area between the clusters. No evidence is found for zinc or oxygen atoms on top of the clusters. Pd does not desorb but at constant substrate Auger signals the Pd signal is significantly reduced upon annealing above room temperature. Therefore, it is concluded that appreciable amounts of Pd diffuse into the bulk or react with the substrate. After Pd deposition at room temperature only a faint (1 × 1) LEED pattern appears but on annealed faces with less than 35 ML Pd deposit intense (1 × 1) LEED spots of the ZnO lattice prevail indicating epitaxial growth. At higher coverages additional spots with hexagonal symmetry show up, arising from a Pd (111) structure aligned parallel to the ZnO lattice. In addition, TDS results of ethanol decomposition are discussed: The presence of 5.2 ML Pd deposit on ZnO (000$\text{1}$) increases at low temperatures the rates of the products already known from the uncovered face. This implies that a part of the ZnO surface is still accessible for desorption. Above 10 ML Pd deposit also CO from a total oxidation appears     

Improving electroless Cu via filling with optimized Pd activation

To improve the via fill capability of electroless (EL) Cu, we explored the influence of the Pd activation process prior to EL Cu deposition. We found that EL Cu roughness is closely related to the Pd nuclei size range and density, which are functions of Pd activation time. With activation time, Pd deposition goes through the sequential stages of growth, secondary nucleation, and ripening. The smoothest EL Cu film can be achieved with a Pd nucleation time that corresponds to the beginning of the ripening stage. A Pd activation process that leads to the smoothest EL Cu deposit also yields the most conformal via filling.     

Pd deposits on Ni(111): a theoretical study

The ASED-MO method has been used to gather electronic and energetic information on Pd deposits on Ni(111) and Pd atom inclusion in the first Ni layer since these model catalysts exhibit a striking catalytic efficiency towards butadiene hydrogenation. The electronic structure of Pd atoms is strongly altered compared with pure Pd. A Pd(4d)→Pd(5s) electronic transfer occurs in the case of the deposit when a slight similar transfer and a charge transfer from Pd to surrounding Ni takes place in the case of the inclusion. Those results are consistent with XPS experimental data. A low density of states, near the Fermi level, is also observed. The optimal geometrical situation for Pd deposits is found to be 2D-aggregates (in pseudoepitaxy or pseudomorphy with the underlying Ni surface, depending on the aggregate size). Small aggregates (part of the first Ni layer) are found to be the most stable in the case of a Pd inclusion in the Ni with a Pd---Pd distance of 2.64 Å, in agreement with available EXAFS experimental data.     

Development of a portable x‐ray fluorescence spectrometer equipped with two monochromatic x‐ray sources and silicon drift detector and field analysis of Islamic glasses at an excavation site in Egypt

A portable x‐ray fluorescence spectrometer equipped with a silicon drift detector (SDD) and a digital signal processor (DSP) was developed for in‐field analysis of archeological samples at an excavation site. This spectrometer allows us to carry out highly sensitive analyses of various elements with atomic numbers down to Na in air by using two monochromatic x‐ray sources obtained by doubly bent toroidal monochromators of graphite (0002) (Pd Kα for medium–heavy elements) and PET (200) (Pd Lα for light elements) and white x‐rays with a Zr filter excited at 40 kV for heavy elements. The detection limit was 0.31% for Al and 4 ppm for Sr in a standard cement sample. The spectrometer was set in a room of the excavation laboratory at al‐Tūr Sinai in the Sinai Peninsula in Egypt in the summer of 2001. The Middle Eastern Culture Center has been conducting an excavation of the sites in al‐Tūr al‐Kilani and Rāya, which were important port cities of Red Sea trade from early Islamic periods: al‐Tūr (A.D. 14–20) and Rāya (A.D. 8–12). The instrument was operated without any problems and 222 glass objects, 26 pottery sherds, seven pigments and 88 metallic objects were analyzed non‐destructively during a 1 month stay. Since this was the first chemical analysis done at the sites, many important archaeological findings were obtained in the present study. Glass objects were successfully classified based on their chemical compositions. Characterization of stained (luster) glasses was conducted. Copyright © 2004 John Wiley & Sons, Ltd.     

Search for double beta decay of 106Cd

A search for the β⁺β⁺, β⁺/EC, and EC/EC decays of ¹⁰⁶Cd was performed at the Modane Underground Laboratory (France) located at a depth of 4800 m w.e. using a TGV-2 multidetector germanium spectrometer. A preliminary evaluation is performed of the experimental data accumulated during the measurements (12 900 h) of ～13.6 g of ¹⁰⁶Cd (with an enrichment of 75%) and the spectrometer background without samples and with samples of natural Cd. New limits (at a 90% confidence level) of half-lives are obtained: T _1/2 ? 1.7 × 10²⁰ yr and T _1/2 ? 1.6 × 10²⁰ yr for the 0νEC/EC resonant decay of ¹⁰⁶Cd to the 2741 keV and 2718 keV excited states of the daughter nucleus ¹⁰⁶Pd and T _1/2 ? 4.2 × 10²⁰ yr for the 2νEC/EC decay to the ground state of ¹⁰⁶Pd (0⁺ → 0⁺, g.s.). The limits for other branches of the double beta decay of ¹⁰⁶Cd with transitions to the ground and excited states of ¹⁰⁶Pd are improved.     

Calibration of NaI(TI) spectrometer for radiocesium volume-samples. Some results from Transylvania region

A four-channel NP-424 type gamma analyzer coupled with a large NaI(Tl) scintillator was calibrated using a¹³⁷Cs point source. The volume-samples were plexiglas cylindrical boxes (D=76mm, H=40mm) directly placed on the NaI(Tl) detector. Measurements for 64 indoor positions at full-662 keV-peak were made. Sample selfabsorbtion was determined considering a linear attenuation for gamma rays and measuring the absorption factor for maximum thickness of the volume sample (h0=40mm). The obtained results for two types of environmental samples (soil and milk-powder) are compared with the data acquired from other Romanian laboratories, in the frame of the Environmental Radioactivity Action (ERA) which standardized such types of measurements. The same samples were measured with a calibrated GeLi detector (INAN-Louvain la Neuve) and the results were in good agreement with our measurements. Using this NaI(Tl) calibrated spectrometer some radiocesium deposits (56 localities) from Transylvanian region were measured. The results show that a large deposit exists in the direction NE-SW in connection with the radioactive cloud passing. For Alba region were measured more than 40 kBq/m² of cesium deposit.     

A procedure for clean deposition of100Pd on surfaces

For a program of surface and interface experiments with the PAC isotope¹⁰⁰Pd, a procedure has been developed to chemically separate¹⁰⁰Pd from irradiated rhodium and deposit it on surfaces by evaporation under UHV conditions. First results have been obtained for¹⁰⁰Pd on an Ni(111) surface.     

Measurement of the mass of110Pd and114Pd using the (14C,16O) reaction

A measurement of the mass excess of¹¹⁰Pd and¹¹⁴Pd has been made by detecting emergent¹⁶O ions in aQ3D magnetic spectrometer using the¹¹²Cd(¹⁴C,¹⁶O)¹¹⁰Pd and¹¹⁶Cd(¹⁴C,¹⁶O)¹¹⁴Pd reactions at 60 MeV. The results are compared with theoretical predictions.     

福州盆地第四纪钻孔XRF连续扫描的元素特征及沉积相指示意义

对福州盆地河口地区一个39 m钻孔岩芯进行X-Ray Fluorescence(XRF)扫描,通过XRF元素连续扫描结果探讨福州盆地海陆交互地层在不同沉积单元中各元素的变化特征及其沉积相指示意义。钻孔岩芯从晚更新世晚期至全新世共经历了5个沉积阶段：湖泊相—河流冲积相—淤泥质滨海潮滩相—河口潮滩相—河流冲积相。XRF扫描结果表明：元素Co, Fe, Ti, Si及其与Rb的比值受到沉积物粒度影响较大,对陆相(河流相)和海相(潮滩相)中粒度特征相近的层位进行了元素均值统计显示,近岸河口湾海相沉积物中的Ca, Ti, Mn, Fe, Co等元素是陆相地层中的3～10倍,Si元素则在陆相层中相对富集。说明除了粒度因素,海-陆沉积环境的变化对元素的富集也起到了重要作用。Ca,Ti,Mn,Fe,Co等元素是较好的海相沉积指示元素,而Si则是较好的陆相沉积指示元素,K,Rb,Sr对陆相沉积具有一定的指示意义。研究结果表明XRF元素连续扫描可以识别沉积物的元素变化细节,并根据元素的强度变化进一步判断沉积相,可以作为沉积相划分的重要辅助手段。该研究为XRF连续扫描方法在海陆交互带的应用提供了实例。