软X光平面镜反射率标定实验

报道了掠入射软X光平面镜反射率标定实验。实验利用北京同步辐射装置 (BSRF) 3W 1B束线及反射率计靶室 ,在束流 35mA～ 110mA、贮存环电子能量 2GeV专用光运行模式下 ,在 5 0eV～ 85 0eV能区分四个能段 ,进行了 5°掠入射Ni平面镜反射率标定实验。标定过程中用高灵敏度无死层的硅光二极管代替X射线二极管作探测器 ,输出信号提高 2～ 3个量级 ,可标定能区从 15 0eV～ 2 70eV拓展到 5 0eV～ 85 0eV ,给出了完整的 5°Ni平面镜反射率标定曲线。最后把实验数据与理论计算作了比对并进行了分析。     

HT-6B托卡马克装置上的软X射线起伏测量

本文介绍HT-6B托卡马克装置上的高灵敏软X射线起伏测量系统及其第一期测量结果在平均电子温度T_e<100eV的条件下,观测到了各种典型软X射线起伏波形,破裂不稳定性,MHD扰动模式,以及一些有趣现象。 关键词：     

HL—1装置的硬X射线锯齿振荡

软X射线的锯齿振荡,在ST,Pulsator和TEXT等装置上已观测到;在Pulsator和PLT上已研究了硬X射线锯齿波。PLT和Pulsator观测结果为,产生的硬X射线锯齿振荡为反锯齿和内破裂的软X射线锯齿相对应。Pulsator的硬X射线锯齿和软X射线锯齿一样,这种趋势一直持继到放电结束,而硬X射线峰值发生在软X射线内破裂后大约200μs。PLT的硬X射线锯齿比软X射线锯齿延迟1至5ms。本工作目的是在内破裂后,从软、硬X射线锯齿波对比,观测硬X射线到达峰值这段延迟时间,并以此来量度逃逸电子约束时间。     

软X射线光导纤维传输特性

 为优化设计软X射线聚束透镜，使之与软X射线源配合能最大限度地获得高强度软X射线束，在北京同步辐射装置软X光站3W1B束线上，对不同能量软X射线（50～1 500 eV）在不同规格毛细管光导纤维中的传输特性进行研究。研究结果表明：玻璃毛细管对软X光有较高的传输效率，毛细管内径越小，曲率越小，光子能量越小，则传输效率越大；使用含硼（B）量高的DM308型号玻璃材料拉制成内直径为0.45 mm﹑外直径为0.6 mm的毛细管组成的软X光聚束透镜有较高的传输效率，该规格毛细管可以将能量为250 eV的X射线传播方向改变26°后，其出射能量是入射能量的12%；使用由该规格毛细管设计的软X射线聚束透镜同软X射线点光源组合，收光角可以达到30°，透镜焦点处的功率密度是不使用透镜时的104倍。     

俄歇效应泵浦的波长1089的激光增益实验

本文介绍了LF-11~#钕玻璃激光装置上进行的一次短波长激光增益实验。用波长1.06μm、能量20J、脉宽650ps左右的激光束辐照钽靶,形成的等离子体发射出能区在70到130eV之间的软X射线,然后用软X射线去泵浦压强为266.6Pa的Xe气激光工作介质,产生出1089A的激光。实验得出小信号激光增益系数a=2.38/cm。激光持续时间为700ps。     

丝阵靶箍缩等离子体软X射线辐射能谱研究

 在S—300装置上研究了丝阵靶Z箍缩等离子体的软X射线辐射的动态过程。利用多通道X射线谱仪在50～2 000 eV范围内测量了丝阵靶内爆等离子体X射线辐射谱,辐射主要位于60~220 eV谱段。辐射谱可用温度为40~50 eV的Planck黑体谱近似描述。在能量高于500 eV的谱段,辐射谱与Planck黑体谱有较大的偏离。这主要是因为等离子体热斑的出现、在1.5~2 keV范围内线谱的存在和加速电子轫致辐射的结果。     

通过软X射线信号研究芯部等离子体的结构

介绍了如何从软X射线原始信号上分析等离子体芯部磁场结构的方法. 在HT-7托卡马克上,通过分析一炮典型的放电数据,直接从软X射线原始信号上分析了磁岛的位置和旋转方向. 通过软X射线图像反演的结果和Mirnov信号上观察到的m=2模的走向验证了磁岛旋转的方向和位置. 关键词： 软X射线 MHD不稳定性 磁岛     

HL-1装置的X射线测量

本文叙述了HL-1装置的X射线测量。结果表明,电子温度随着等离子体电流通道的缩小而升高,其典型值为480eV。稳定放电的软X射线扰动幅度大约是总强度的15％,锯齿振荡周期约为2ms。与磁探针信号比较,明显看到了内、外模之间的耦合关系。多次放电清洗了真空空器壁,含水量下降;硬X射线测量表明,逃逸产生率减小。     

HL—1装置逃逸电子扰动及硬X射线发射

HL-1装置逃逸电子扰动,硬X射线锯齿振荡和软X射线锯齿振荡关联,内破裂后硬X射线发射强度到其峰值的延迟时间,被解释为逃逸电子从q=1面附近输运到等离子体边缘时间。当有电子回旋共振预电离时,硬X射线显著减少;相反,电子回旋共振加热时,硬X射线明显地增加。     

一种时间分辨三通道软X射线光谱仪

报道了时间分辨的三通道软X射线光谱仪研制工作，重点介绍了研制的三通道能谱仪的工作原理以及210 eV，420 eV和900 eV三个能区的设计参数，谱仪在上海神光Ⅱ高功率激光器三倍频实验中进行了多次实时考核，取得较好实验结果，将多道平面镜、滤光片成功配接于高时间分辨X射线条纹相机上，使该谱仪在亚千电子伏能区内，可同时进行三个波段软X射线的时间和空间分辨测量，提供的实验结果也表明：X射线平面镜结合滤光片的分光技术可应用于高时间分辨的X射线条纹相机上，从而获得高达10 ps的时间分辨. 关键词： 软X射线条纹相机 平面镜 滤光片 掠入射     

Identification of m=2 competent mode of complex magneto-hydro-dynamics activities during internal soft disruption based on singular value decomposition and tomography of soft-X-ray emission on the HT-7 tokamak

In this paper,the singular value decomposition(SVD) method as a filter is applied before the tomographic inversion of soft-X-ray emission.Series of ’filtered’ signals including specific chronos and topos are obtained.(Here,chronos and topos are the decomposed spatial vectors and the decomposed temporal vectors,respectively).Given specific magnetic flux function with coupling m = 1 and m = 2 modes,the line-integrated soft-X-ray signals at all chords have been obtained.Then m = 1 and m = 2 modes have been identified by tomography of simulated ’filtered’ signals extracted by the SVD method.Finaly,using the experimental line-integrated soft-X-ray signals,m = 2 competent mode of complex magnetohydrodynamics(MHD) activities during internal soft disruption is observed.This result demonstrates that m = 2 mode plays an important role in internal disruption(Here,m is the poloidal mode number).     

Penetration of ammonia molecule into ice film; activation energy analysis using Xe molecular beam irradiation

We have investigated the barrier energy for an ammonia molecule to penetrate into ice film by the use of infrared spectroscopy and Xe supersonic beam. After the ice film on a Pt(1 1 1) surface is exposed to ammonia molecules, an umbrella mode of ammonia molecules adsorbed on the ice film has been observed in infrared spectra. After the irradiation of accelerated Xe beam, we observed an energy shift of the mode of ammonia. The shifted mode is assigned to that of ammonia molecules at the interface between the ice film and the Pt(1 1 1) surface. This indicates that the collision with Xe beam induced the penetration of an ammonia molecule to the interface through the ice film. Using this feature, we estimate a barrier for penetration as 0.28 ± 0.03 eV which is much smaller than the one previously reported for bulk ice.     

Estimation of soft X‐ray and EUV transition radiation power emitted from the MIRRORCLE‐type tabletop synchrotron

The tabletop synchrotron light sources MIRRORCLE‐6X and MIRRORCLE‐20SX, operating at electron energies E_el = 6 MeV and E_el = 20 MeV, respectively, can emit powerful transition radiation (TR) in the extreme ultraviolet (EUV) and the soft X‐ray regions. To clarify the applicability of these soft X‐ray and EUV sources, the total TR power has been determined. A TR experiment was performed using a 385 nm‐thick Al foil target in MIRRORCLE‐6X. The angular distribution of the emitted power was measured using a detector assembly based on an NE102 scintillator, an optical bundle and a photomultiplier. The maximal measured total TR power for MIRRORCLE‐6X is P_max? 2.95 mW at full power operation. Introduction of an analytical expression for the lifetime of the electron beam allows calculation of the emitted TR power by a tabletop synchrotron light source. Using the above measurement result, and the theoretically determined ratio between the TR power for MIRRORCLE‐6X and MIRRORCLE‐20SX, the total TR power for MIRRORCLE‐20SX can be obtained. The one‐foil TR target thickness is optimized for the 20 MeV electron energy. P_max? 810 mW for MIRRORCLE‐20SX is obtained with a single foil of 240 nm‐thick Be target. The emitted bremsstrahlung is negligible with respect to the emitted TR for optimized TR targets. From a theoretically known TR spectrum it is concluded that MIRRORCLE‐20SX can emit 150 mW of photons with E > 500 eV, which makes it applicable as a source for performing X‐ray lithography. The average wavelength, = 13.6 nm, of the TR emission of MIRRORCLE‐20SX, with a 200 nm Al target, could provide of the order of 1 W EUV.     

Revisiting the sodium and calcium matrix effects in inductively coupled plasma optical emission spectrometry. Excitation mechanisms by inelastic collisions

Abstract

The dependence of calcium and sodium matrix effects on the total excitation energy of analyte emission signals was used as a tool for the study of excitation mechanisms in radial view mode inductively coupled plasma optical emission spectroscopy. A total of 95 atomic and 66 ionic emission signals of aluminum, cobalt, chromium, iron, magnesium, manganese, nickel, and silicon in the 3.0–17.59?eV energy range were measured at the non-robust plasma operating conditions to facilitate the matrix effect study. Different matrix effects versus total excitation energy relationships were observed regarding the energy interval. The change of sign from negative to positive of the both matrix effect versus total excitation energy relationship observed around 14?eV, in the 12.06–17.59?eV energy range, is interpreted as experimental evidence of the action of two non-thermic excitation mechanisms: Penning ionization from approximately 12 to 14?eV and charge transfer from 14 to 17?eV. Based on the energy resonance principle and total spin conservation Wigner’s Theorem, possible reactions between excited ionic argon and ground state analyte ions were proposed.     

Infrared modulated reflectance spectra of n and p type gallium antimonide and n type indium antimonide

We have observed the modulated reflectance spectra of n and p type GaSb at 300, 80, and 5 K from 0.56 to 2 eV. The modulated reflectance of intrinsic n type InSb was measured at 80 K from 0.2 to 2 eV. The “dry sandwich” vapor deposition technique was used to make the electroreflectance (ER) samples. The low-temperature spectrum of the undoped p type GaSb sample shows three peaks at the band edge that could be associated with transitions from the top of the valence band, the light (0.903 eV) and heavy (1.014eV) hole state Fermi levels to the conduction band. The energies of the observed peaks are in agreement with the Fermi level determination from Hall effect and Faraday rotation measurements. This modulation mechanism is based on band population effects. The ER signal of InSb under flatband condition at 80 K has five half oscillations at the direct band gap. The contribution of piezoelectric strain to ER is present since the dc bias required to achieve flatband condition is different at the band gap than at E₁. The ER signal corresponding to the direct gap energy E₀ and to the spin-orbit energy E₀ + Δ₀ was determined in the n and p type samples of GaSb at different temperatures. We have measured the intrinsic energy gap in GaSb at room temperature. E_g = 0.74 eV. The corresponding spin-orbit splitting was found to be Δ₀ = 0.733 ± 0.002 eV.     

Electron impact ionization of sodium Rydberg atoms below 2 eV

We have observed electron impact ionization of highly excited sodium Rydberg atoms in ns and nd states, n=35-51, below E=2 eV electron kinetic energy with energy resolution 0.25 eV. Measured absolute cross sections near 0 eV range from sigma(35d) approximately 7 x 10(-10) to sigma(50d) approximately 4 x 10(-9) cm(2). The energy dependence is consistent with that of widely used binary encounter approximation cross sections, and sigma(n) follows a power law in n. The measured cross sections are 14 to 24 times larger than theoretically predicted values. This enhancement may signal the effect of large polarizabilities of high Rydberg states not yet accounted for in ionization theories.     

Nature of the well screened state in hard X-ray Mn 2p core-level photoemission measurements of La1-xSrxMnO3 films

Using hard x-ray (HX; hnu=5.95 keV) synchrotron photoemission spectroscopy (PES), we study the intrinsic electronic structure of La(1-x)Sr(x)MnO(3) (LSMO) thin films. Comparison of Mn 2p core-levels with soft x-ray (SX; hnu approximately 1000 eV) PES shows a clear additional well-screened feature only in HX PES. Takeoff-angle dependent data indicate its bulk (> or =20 A) character. The doping and temperature dependence track the ferromagnetism and metallicity of the LSMO series. Cluster model calculations including charge transfer from doping-induced states show good agreement, confirming this picture of bulk properties reflected in Mn 2p core-levels using HX PES.     

The oxidation of GaAs(1 0 0) surfaces under atmospheric pressure conditions studied in real time using dynamic reflectance anisotropy spectroscopy at 2.6 and 4 eV

Using real-time, dynamic reflectance anisotropy spectroscopy (RAS) at both 2.6 eV and 4.0 eV, we demonstrate that an anisotropic oxide will form on As rich c(4 × 4)/d(4 × 4) GaAs surfaces when exposed to moisture- free air diluted in inert gases in a metal organic chemical vapour deposition (MOCVD) reactor, and that the initial c(4 × 4)/d(4 × 4) structure effects the resulting optical anisotropy of the oxide. This was achieved by investigating how the RA signals at 2.6 eV and 4 eV of annealed GaAs (1 0 0) surfaces evolve relative to the as-etched and as-annealed signals when exposed to oxygen. It is found that while the 2.6 eV response, which is known to be associated with the As dimers, degrades to pre-process levels indicating their destruction, the 4 eV signal, stabilizes at an intermediate, permanent level, suggesting the formation of an anisotropic oxide film whose structure is determined at least in part, by the initial c(4 × 4)/d(4 × 4) surface.