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高分辨(e,2e)谱仪采用二维位置灵敏探测器同时对能量和角度进行多道测量.二维位置灵敏探测器由级联使用的微通道板和电阻阳极板组成,由于电阻阳极板的边缘效应和制造工艺的缺陷,测量得到的位置图像与实际图像总会有一定的形变,存在一定的非线性.本文针对高分辨(e,2e)谱仪二维位置灵敏探测器输出图像的“桶形”畸变及位置非线性,采用一种简易的冷刻法(用脉冲信号来模拟真实电子束团),检验了二维位置灵敏探测器的Gear型电阻阳极板的线性好坏,并用分割成小三角形的方法找出测量得到的畸变图像与原始真实图像的映射关系,再用此关系对其它测量得到的畸变图像进行修正,并对修正的结果进行了评估.通过修正,由“桶形”畸变所造成的图像扭曲得到明显改善.修正后的x方向非线性由修正前的2.1%变为0.59%.这种检验和修正方法对其它领域类似探测器输出图像的修正也有一定的指导意义. 相似文献
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北京谱仪Ⅱ的μ探测器的位置分辨和击中效率与带电粒子的动量和入射位置有关, 利用选取的宇宙线样本和强子样本对μ,探测器逐层进行了标度, 并利用构造的效率比函数在物理分析中有效地识别μ和强子. 相似文献
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利用新研制的能量分辨为0.5 eV 的高分辨(e, 2e)谱仪测量了CF3I分子在9-15 eV能区的束缚能谱.新谱仪能较好地分辨该分子碘孤对轨道的自旋轨道劈裂组分5e3/2和5e1/2,并得到了它们各自的电子动量分布以及分支比随动量的变化关系.实验结果清楚地显示了5e3/2和5e1/2态波函数的相对论效应.这是第一个分子轨道波函数相对论效应的直接实验观测. 相似文献
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Seidl R Hasuko K Abe K Adachi I Aihara H Anipko D Asano Y Aushev T Bakich AM Balagura V Barberio E Bartel W Bay A Bitenc U Bizjak I Blyth S Bozek A Bracko M Browder TE Chang P Chen A Cheon BG Choi Y Choi YK Chuvikov A Dalseno J Danilov M Dash M Dragic J Eidelman S Fratina S Gabyshev N Gershon T Go A Gokhroo G Golob B Gorisek A Grosse Perdekamp M Ha HC Hayasaka K Hayashii H Hazumi M Hokuue T Hoshi Y Hou S Hou WS Iijima T Inami K Ishikawa A Itoh R Iwasaki M Iwasaki Y Kang JH Kapusta P Katayama N 《Physical review letters》2006,96(23):232002
The Collins effect connects transverse quark spin with a measurable azimuthal dependence in the yield of hadronic fragments around the quark's momentum vector. Using two different reconstruction methods, we find evidence of statistically significant azimuthal asymmetries for charged pion pairs in e(+)e(-) annihilation at a center-of-mass energy of 10.52 GeV, which can be attributed to a transverse polarization of the primordial quarks. The measurement was performed using a sample of 79 x 10(6) hadronic events collected with the Belle detector. 相似文献
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The angular variations of the five-fold differential cross section obtained by using different wave functions of helium are
compared with experimental data. It is found that in the coplanar geometry two kinematical arrangements, (i) equal energy
sharing between the two ejected electrons with one of them ejected along the momentum transfer direction and the other along
varying direction and (ii) the Bethe ridge condition with fixed sum of ejected electron energies and varying angle between
them, are very sensitive to e-e correlations contained in the target wave function. This comparison has been used to show
that open-shell class of wave functions better incorporate e-e correlations than the closed-shell class. 相似文献
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We study two examples of infrared-safe quantities in deep inelastic scattering: the flow of energy in a given angular range and the energy-energy angular pattern. We derive expressions for these quantities in perturbative QCD, to order αs, and show explicitly their infrared safety. Our formulas for the angular energy flow and the energy-energy angular pattern depend only on well-defined QCD factors and on the deep inelastic structure functions. To gauge whether or not these perturbative QCD results are applicable to present day data, we estimate in a simple model the effects of hadronization and primordial parton transverse momentum. In general these non-perturbative effects mask the resulting QCD pattern at present energies, but vanish more rapidly at higher energies than the QCD effects. However, we point out two examples where it may be possible to test the perturbative QCD predictions with available data. One of them involves studying the x-dependence of the azimuthal asymmetry of the energy flow. The other involves studying the angular width of the energy-energy correlation function. 相似文献
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We present a detailed treatment of the theoretical and experimental aspects of the symmetric (e, 2e) reaction in atoms, molecules and solids. Two experimental arrangements are described for measuring angular correlations and separation energy spectra. the one arrangement employing coplanar and the other noncoplanar symmetric kinematics. The latter arrangement is shown to be particularly suitable for extracting structure information. The basic approximation, the factorized distorted-wave off-shell impulse approximation with fully distorted waves, is shown to correctly describe the reaction in some test cases, as does the phase distortion approximation. At energies of the order of 1200 eV the simple eikonal and plane wave approximations adequately describe the valence shell cross sections for light atoms and molecules containing first row elements. Energy independent structure information is obtained on: (a) shapes and magnitudes of the square of the momentum space wave functions for individual electron orbitals; (b) separation energies for individual ion eigenstates; (c) the characteristic orbital of each state; and (d) spectroscopic factors describing the probability that an eigenstate contains the principal configuration of a hole in the characteristic orbital for each eigenstate. Comparison is made with photoelectron spectroscopy and Compton scattering, since they separately yield some of the information obtained by the (e, 2e) method. A brief summary is given of other electron-electron coincidence experiments. 相似文献
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在矢量衍射理论基础上给出了任意入射状态下二维平面光栅的光栅方 程,推导出二维平面光栅角色散公式的完整解析形式,确立了二维平面光栅衍射极角 角色散(第一类角色散)和衍射方位角角色散(第二类角色散)的概念. 通过二维平面光栅 衍射极角和衍射方位角角色散的理论分析和数值计算,阐明了当入射波矢偏离光栅法线时, 衍射光斑阵列发生畸变的机理,并明确指出了引起衍射方位角角色散的突变、导致衍射光斑 阵列剧烈变化的条件,因而具有理论上的意义. 在实际应用方面,以晶体和量子点 的x射线衍射、低能电子衍射和反射式高能电子衍射为
关键词:
二维平面光栅
衍射极角角色散
衍射方位角角色散
晶体电子衍射 相似文献
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Differential cross sections and angular distributions of protons from the 2H(e, p)e′n reaction have been measured at four incident electron energies. The proton angular distributions were measured with the neutron-proton relative energy approximately constant, and an 85° differential cross section was measured as a function of the incident electron energy. The electrodisintegration cross section was calculated using the Hulthén wave function for the ground state with a plane wave for the final state. Reasonable agreement between experiment and theory is found. 相似文献
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运用修正后的BBK理论计算了入射能为27.6 eV,29.6 eV和34.6 eV,非共面双对称几何条件下,电子入射离化氦原子的三重微分截面,计算结果与实验结果进行比较发现两者符合的较好,验证了低入射能时修正后的BBK模型同样适用于非共面双对称条件下的(e,2e)过程,从碰撞的微观机理上分析了影响出射电子角分布的原因. 相似文献
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An investigation of the energy distributions and angular correlations of outgoing electrons in the (e, 2e) reaction on thin aluminum films using the coincidence technique is presented. The excitations of plasmon satellites and a plasmaron have been observed. 相似文献
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Giovanni Montani 《General Relativity and Gravitation》2011,43(4):1121-1140
We present a discussion of two-dimensional magneto-hydrodynamics (MHD) configurations, concerning the equilibria of accretion
disks of a strongly magnetized astrophysical object. We set up a viscoresistive scenario which generalizes previous two-dimensional
analyses by reconciling the ideal MHD coupling of the vertical and the radial equilibria within the disk with the standard
mechanism of the angular momentum transport, relying on dissipative properties of the plasma configuration. The linear features
of the considered model are analytically developed and the non-linear configuration problem is addressed, by fixing the entire
disk profile at the same order of approximation. Indeed, the azimuthal and electron force balance equations are no longer
automatically satisfied when poloidal currents and matter fluxes are included in the problem. These additional components
of the equilibrium configuration induce a different morphology of the magnetic flux surface, with respect to the ideal and
simply rotating disk. 相似文献