Electron Impact Ionization Cross Section of Nitrogen Atoms

The direct ionization cross sections for electron scattering by nitrogen are calculated by applying an equivalentlocal optical model from 15eV to 1100eV. The present results are compared with the experimental data and other theoretical calculation results.     

Assessment of Hydrocarbon Electron‐Impact Ionization Cross Section Measurements for Magnetic Fusion

Partial ionization cross section experiments have been carried out recently at the University of Innsbruck for three types of hydrocarbons, i.e. acetylene, ethylene and propene. Cross section data fits are generated and compared to the compilation of earlier experimental data summarized in the online database HYDKIN [www.hydkin.de]. New data fits are brought into a suitable form to be incorporated into the database. In order to illuminate underlying dissociation mechanisms the energy dependence of branching ratios above energies of 20 –30 eV is reviewed in light of the present results (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

L-Shell X-Ray Production Cross Sections of Ta and Tm by Electron Impact near the Threshold Region

We present experimental measurements of L-shell production cross sections Lα, Lβ and Lγ for tantalum and thulium by electron impact at incident electron energies from about one to three times the threshold energy. From the experimental data, the total production cross section and mean ionization cross section are deduced. The influence of electrons reflected from the substrate is corrected by the electron transport bipartition model. Tile measured cross sections are compared with the theoretical predictions.     

Electron Impact Ionization Cross Section for Excited State of Ne like Ions in Detailed Configuration

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电子引起的钛和锰的K壳层电离截面测量

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。     

Calculation of Absolute Outer-Shell Electron Impact Ionization Cross Sections

The recently developed semiempirical DM-approach for the calculation of electron impact single ionization cross sections is applied here to the ionization of the rare gases (Ne, Ar, Kr and Xe) via ejection of an outer s-shell electron. The results obtained are compared with previous experimental and theoretical s-shell ionization cross section functions.     

Partial Cross Sections for Dissoziative Ionization of Fluorinated Compounds by Electron Impact

Ionization cross sections of fragment ions of CF₄, C₂F₆, C₃F₈, n-C₄F₁₀, C₂F₄, 1-C₄F₈, SiF₄, COF₂. CHF₃ were determined in dependence on electron energy up to 125 eV by means of a quadrupol mass spectrometer. Tails at the low energy part of the characteristics are interpreted as a result of kinetic energy depending on molecular weight of fragments. Parent ions are only detected for chemically unsaturated compounds showing characteristic curves of ionization efficiency. Total cross sections obey the additive rule.     

Measurement of Titanium and Manganese K -shell Ionization Cross Sections by Electron Impact

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。     

On Cross Sections for Electron Impact Ionization of Multicharged Ions

Electron impact ionization cross sections calculated by means of two semi-empirical expressions (Lotz, Seaton), a semiclassical model (Burgess: "ECIP"), and a simple quantum approximation (Seaton) are compared with results of more elaborate quantum (Coulomb-Born) calculations and measurements for several multicharged ions (N2+, Mg2+, C3+, O3+, C5+, O5+, Fe14+). While in some cases the comparisons are not definitive, the simple formula of Lotz appears to represent the C-B and experimental results more consistently than the other methods.     

电子碰撞引起的铜元素K壳层电离截面的测量与修正

 在电子碰撞的情形下,通过对铜靶的特征X射线测量,从而推算出它的K壳层电离截面。在实验中采用了薄靶厚衬底新方法。通过电子输运计算,由厚衬底产生的反射电子对计数的影响得以修正。用蒙特卡罗技术对质量厚度为23 mg∕cm²的铜靶的多次散射影响作了修正。     

电子碰撞Li~+(ls)电离的三重微分截面

利用修正的ＢＢＫ理论,考虑入射道的库仑相互作用及出射道电子的交换对称性,在共面－等能分享－垂直角度碰撞几何中,计算了能量分别为８５．６、１０５．６、２２７．６和３７５．６ｅＶ的入射电子碰撞Ｌｉ＋（ｌｓ）电离的三重微分截面．讨论了干涉效应、关联效应及入射道库仑场对截面的影响.Based on revised BBK theory, triple differential cross sections (TDCS) have been calculated for ionization of Li + (ls) by electron impact. A coplaner, equal energy, fixed re1ative angle kinematics are chosen and the particular case where the scattered and ionized electrons emerge perpendicular to each other is emphasized. The incoming electron state is considered by a Coulomb wave from the long range...     

Nightside Martian Ionosphere Produced by Electron Impact Ionization

Based on the Martian magnetic field model established by magnetohydrodynamics simulation, we determine the possible precipitation areas of the solar wind electron in the nightside Martian atmosphere, and analyze the electron impact ionization to estimate the height of the nightside Martian ionospheric peak and the electron density profile using the energy flux analysis method. The influences of the single electron energy, electron energy density and ionization efficiency on the altitude of the ionospheric peak and the electron density profile are also investigated. Our results show that the solar wind electron moves along the V-shaped solar wind magnetic field lines, to precipitate into the Martian atmosphere. Due to the crustal magnetic field, the precipitation regions on the nightside are quite narrow and unstable. The impact ionization happens at the altitude of 130-500km, and the height of the ionospheric peak is around 170km, with a peak electron density of 3.0×10^3 cm^-3. The simulation results are consistent with the results from Mars 4/5 and Viking occultation measurements.     

1.0 MeV电子碰撞引起Ta 和Au 内壳电离截面的测量

无论对深入理解电子-原子的作用机制,还是在材料等领域的实际应用,电子轰击原子的内壳电离截面都具有重要意义。当前电子碰撞引起原子内壳电离的实验数据多集中在几十keV 入射能量和中小Z 靶原子,其它数据相对比较缺乏。本工作以能量为1.0 MeV电子轰击Ta 和Au 靶,通过测量靶原子特征X射线的产额,获得其K壳电离截面分别为13.3 和10.1 b,L 壳电离截面分别为554 和338 b。并将实验结果和相应的理论进行了对比,结果显示,本实验测得的K壳电离截面与Casnati、Hombourger 理论值、L 壳电离截面与Scoeld和Born-Bethe 的理论值相符。Accurate experimental data for atomic inner-shell ionization cross-sections by electrons are of basic importance both in understanding inelastic electron-atom interaction and its application. Up to now, most of available data on this process were mainly concentrated on the low and medium Z atoms by the bombardment of low energy electrons. In present experiments K-shell and L-shell ionization cross-sections of Ta and Au in collisions with 1.0 MeV eleltron were determined by measuring the characteristic X-rays emitted from the target atoms. For the present collision systems the K-shell ionization cross-sections were found to be 13.3 and 10.1 b,and the L-shell ionization cross sections were 554 and 338 b, respectively. The measured K-shell ionization cross sections are in reasonable agreement with the theoretic predictions of Casnati and Hombourger, while L-shell ionization cross sections are consistent with the theoretical results of Soc eld and Born-Bethey.     

电子碰撞电离截面的全相对论扭曲波计算

在相对论框架下 ,给出了电子与高电荷态离子碰撞直接电离截面的扭曲波玻恩交换近似计算方法 .作为示例 ,计算了几个离子 (类氢、类锂和类氖离子 )的电离截面 ,计算结果与实验值和其它理论计算值有比较好的符合. A fully relativistic distorted-wave exchange approximation method is presented. It can be used to obtain electron impact ionization cross section of highly charged ions. The ionization cross sections of several H-, Li, and Ne-like ions have been calculated. Good agreement is obtained while the calculated values are compared with the experiments or other relativistic calculations.