共查询到18条相似文献,搜索用时 93 毫秒
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电子离子碰撞电离截面是模拟激光等离子体的超热电子的能谱和产额的主要过程之一.基于相对论性的电子离子碰撞的K壳层电离截面理论,计算了Nb、Ag的K壳层和L壳层电子碰撞电离截面,结果和最近的文献实验数值和其它理论数值进行了比较,计算结果比其它模型更加准确,与最近的实验结果也吻合较好,该结果可用来模拟激光等离子体的超热电子能谱和产额. 相似文献
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报道了电子引起的钛,锰原子的K壳层电离截面实验值。实验中,采用了薄靶厚衬底技术,并将衬底中反射的电子对测量值的影响进行了修正。实验结果与其他文献报道的测量结果相吻合。最后,还将实验结果与Casnati等人的经验公式进行了比较。 相似文献
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用Si(Li)探测器测量薄Ni靶在9-46keV的电子轰击下产生的K壳层特征X射线,以确定其K壳层电子的电离截面。测量结果与前人的实验和理论计算以及经验公式的计算结果作了比较。 相似文献
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使用5—27 keV能量范围内的单能电子束轰击薄碳衬底上的薄Al (Z=13),Ti (Z=22),Cu (Z=29),Ag (Z=47),Au(Z=79)靶,使用硅漂移型探测器(SDD)收集产生的特征X射线,测量了Al,Ti,Cu的K壳层电离截面以及Cu,Ag和Au的L壳层特征X射线的产生截面,并且使用蒙特卡罗PENELOPE程序对实验结果进行了修正.本文给出了Cu的L壳层特征X射线产生截面.与半相对论扭曲波玻恩近似(semi-relativistic distorted-wave Born approximation,DWBA)理论值相比,本文的大多数实验值在7%的范围内与理论值符合.研究表明,中重元素的L壳电离截面的理论计算以及相应的原子参数有待更精确的确定. 相似文献
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在David Botz分析模型的基础上,综合考虑正电子及电子碰撞电离的库仑效应和电子交换效应,引入离子效应和相对论效应修正因子,计算了Ag,In,Sn原子的L壳层电离截面.计算结果表明,引入了修正因子的计算结果明显优于平面波波恩近似和扭曲波波恩近似的计算结果,并和最近文献的实验值符合得较好.其计算结果可为激光等离子体模拟提供准确参数. 相似文献
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在David Botz分析模型的基础上,综合考虑正电子及电子碰撞电离的库仑效应和电子交换效应,引入离子效应和相对论效应修正因子,计算了Ag,In,Sn原子的L壳层电离截面.计算结果表明,引入了修正因子的计算结果明显优于平面波波恩近似和扭曲波波恩近似的计算结果,并和最近文献的实验值符合得较好.其计算结果可为激光等离子体模拟提供准确参数. 相似文献
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本文提出了一种计算多电荷离子与原子碰撞中K壳层电子俘获截面的新方法,称为模型势Oppenheimer-Brinkman-Krammer近似(MPOBK)。在该方法中我们用模型势来描述K电子所处的有效场,同时在波函数中考虑屏蔽效应。我们得到的K壳层总俘获截面是一个表解析达式。对H~ 、He~(2 )-Ne,H~ 、He~(2 )-C及O~(5 ,6 )-Ar体系的计算表明本文结果较好地与实验数据一致。 相似文献
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低能正电子碰撞原子内壳层电离截面的实验数据目前还很缺乏,从而影响了对近年来发展的各相关理论模型的检验,限制了慢正电子束流技术在诸多领域中的应用.本文采用慢正电子束流装置产生的8—9.5 keV正电子束碰撞纯厚Ti靶,利用硅漂移探测器(SDD)收集正电子碰撞Ti靶产生的X射线,同时采用高纯锗探测器在线获得与靶碰撞的入射正电子数,从而得到Ti的K壳层实验产额,并基于蒙特卡罗模拟程序PENELOPE获得模拟产额.将实验产额分别与内壳层电离截面数据库采用经典光学数据模型(ODM)和扭曲波玻恩近似理论模型(DWBA)的蒙特卡罗模拟产额进行对比,发现基于ODM理论模型的模拟产额与实验值有较大的偏差,基于DWBA理论模型的模拟产额与实验结果符合较好.根据实验产额和基于DWBA理论模型的模拟产额的比较结果,对蒙特卡罗模拟程序使用的DWBA理论模型数据库进行修正后再进行模拟和比较,从而得到可靠的8—9.5 keV正电子致Ti原子K壳层电离截面数据. 相似文献
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M. R. Talukder S. Bose M. A.R. Patoary A. K.F. Haque M. A. Uddin A. K. Basak M. Kando 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,46(2):281-287
A simple empirical formula is proposed for the rapid
calculation of electron impact total ionization cross sections both for the
open- and closed-shell neutral atoms considered in the range 1≤
Z≤92 and the incident electron energies from threshold to about
104 eV. The results of the present analysis are compared with the
available experimental and theoretical data. The proposed model provides a
fast method for calculating fairly accurate electron impact total ionization
cross sections of atoms. This model may be a prudent choice, for the
practitioners in the field of applied sciences e.g. in plasma modeling, due
to its simple inherent structure. 相似文献
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Kunihiro Shima 《Physics letters. A》1980,77(4):237-239
Near the threshold energy, electron induced Mn and Cu K-shell ionization cross sections have been measured. Except for energies very close to threshold, the results are in good agreement with the semi-empirical formula of Green and Cosslett. 相似文献
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Calculated cross sections for the single ionization of atoms (N, Cu, As, Se, Sn, Sb, Te, I, Pb) by electron impact
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By correcting some primary parameters in the semi-classical
Deutsch--M?rk (DM) formula, this paper calculates the absolute
single electron-impact ionization cross sections of atoms N, Cu, As,
Se, Sn, Sb, Te, I and Pb from threshold to 10000eV. The calculated
cross sections are compared with available experimental data and other theoretical results. An excellent agreement was achieved between the calculated and measured cross sections for
these atoms over a wide range of impact energies. 相似文献
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The dissociative ionization of CO2 induced by 5 keV electrons in two-body and three-body dissociative channels of CO2+2 and CO3+2 is identified by the ion-ion coincidence- method using a momentum imaging spectrometer. The partial ionization cross sections (PICSs) of different ionic fragments are measured and the results generally agree with the calculations made by a semi-empirical approach. Furthermore, the PICSs of the dissociative channels are also obtained by carefully considering the detection efficiency of the micro-channel plates and the total transmission efficiency of the time of flight system. 相似文献
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Triple differential cross sections for ionization of hydrogen atoms in the metastable 2s-state by the impact of electrons and positrons have been calculated for coplanar symmetric geometry. In this calculation
a multiple scattering theory due to Das [10] and Das and Seal [11] has been used. An analysis of the results reveals that
unlike scattering from the ground state, scattering from 2s-state is essentially a higher order process except for the binary collision direction. Moreover, here, the cross section
results for 2s-state are much larger compared to those for scattering from the ground state. It is also found that the ionization mechanism
at large scattering angles for ionization from the 2s-state is different from that for ionization from the ground state. 相似文献
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HU Wei WANG Yansen FANG Dufei LU Fuquan TANG Jiayong YANG Fujia 《Chinese Journal of Lasers》1994,3(3):223-230
ElectronimpactionizationcrosssectionsforLi-likeAlioningroundandexcitedstatesHUWei;WANGYansen;FANGDufei;LUFuquan;TANGJiayong;Y... 相似文献