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An Empirical Formula of Atomic K-Shell ionization Cross Sections by Electron Impact

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Chinese Physics Letters 2001年第8期18卷 1053-1055页

作者：唐昶环安竹范晓强罗正明 Laser Fusion Research Center CAEPMianyang 621900 Institute of Nuclear Science and Technology Sichuan UniversityKey Laboratory for Radiation Physics and Technology of Education Ministry of ChinaChengdu 610064 Institute of Nuclear Physics and Chemistry CAEPMianyang 621900

An empirical formula is proposed to describe the K-shell ionization cross sections by electron impact over a wide range of atomic numbers and overvoltages U(the ratio between the electron incident energy and the binding energy of the electrons in the K-shell).The study is based on the analysis of existing experimental data of K-shell ionization cross sections.The expression shows the results in good agreement with the data for Z<6 atoms as well as for 6≤Z≤79.

关键词： Electron ionization incident

Angle-resolved spectra of the direct above-threshold ionization of diatomic molecule in IR + XUV laser fields

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Chinese Physics B 2019年第2期28卷 185-191页

作者：石尚金发成王兵兵 Laboratory of Optical Physics Beijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese Academy of Sciences University of Chinese Academy of Sciences Faculty of Science Xi'an Aeronautical University

The direct above-threshold ionization(ATI) of diatomic molecules in linearly-polarized infrared and extreme ultraviolet(IR+XUV) laser fields is investigated by the frequency–domain theory based on the nonperturbative quantum electrodynamics. The destructive interference fringes on the angle-resolved ATI spectra, which are closely related to the molecular structure, can be well fitted by a simple predictive formula for any alignment of the molecular axis. By comparing the direct ATI spectra for monochromatic and two-color laser fields, we found that the XUV laser field can both raise the ionization probability and the kinetic energy of the ionized electron, while the infrared(IR) laser field can broaden the energy distribution of the ionized electron. Our results demonstrate that, by using IR+XUV two-color laser fields, the angle-resolved spectra of the direct ATI can image the structural information of molecules without considering the recollision process of the ionized electron.

关键词： above-threshold ionization IR+XUV laser fields molecular structure

Quantum Electrodynamic Perspective on Multiphoton ionization

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Chinese Physics Letters 1999年第12期16卷 888-890页

作者：陈京陈式刚刘杰 Institute of Applied Physics and Computational Mathematics Beijing 100088 Graduate School of China Academy of Engineering Physics P.O.Box 2101Beijing 100088

A fully quantum nonperturbative method is developed to describe multiphoton ionization in intense fields. It is shown that, treating the radiation field with quantum electrodynamic(QED) theory enables u s to obtain the above-threshold ionization energy distribution spectrum in analytical form firstly. Moreover, in addition to the well-known semiclassical theory, the framework presented here, derived from a QED perspective, provides a new picture of the multiphoton ionization.

关键词： dynamic quantum ionization

Femtosecond strong-field coherent control of nonresonant ionization with shaped pulses

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Chinese Physics B 2019年第3期28卷 153-160页

作者：佟秋男廉振中赵亮齐洪霞陈洲胡湛 Institute of Atomic and Molecular Physics Jilin UniversityChangchun 130012China Advanced Light Field and Modern Medical Treatment Science and Technology Innovation Center of Jilin Province Jilin UniversityChangchun 130012China

The strong-field coherent control of the nonresonant ionization of nitrous oxide using shaped pulses is investigated.We study the dependence of periodic coherent oscillation of the total ionization yield on the variation of laser phase parameters. The physical mechanism of the strong-field coherent control is investigated experimentally and theoretically by the nonresonant spectral phase interferences in the frequency domain. We show that the intense shaped pulses with broadband and off-resonance can be used as a robust strong-field coherent control method.

关键词： coherent control nonresonant ionization shaped pulse

ionization CONSTANTS OF d,1-2,3,5, 6-TETRAHYDRO-6-PHENYLIMIDAZO-[2,1-b] THIAZOLE AND STABILITY CONSTANTS OF ITS COMPLEXES WITH Zn(Ⅱ)

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Chinese Science Bulletin 1985年第1期30卷 71-74页

作者：章爱铀章健民 Xuzhou Rare and Noble Metal Institute Jiangsu Province Medical College of Neimonggal

In 1967, A. Holbrook and B. Scales reported the ionization constant of this compound pK_α=7.94(μ=0.01), but without the method of determination. We have investigated the ionization equilibrium of this compound by pH method anew, calculated the first and second ionization constants, and determined the stability constants of its complexes with zinc ions. At the same time, we have proposed an im-

关键词： constants ionization complexes tetrahydro reagent titration equilibria straight olein deter

Impact of atmospheric ionization by delayed radiation from highaltitude nuclear explosions on radio communication

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Nuclear Science and Techniques 2019年第12期30卷 58-64页

作者： Heng Xu Jian-Ming Ouyang Shang-Wu Wang Yun Liu Xu Sun College of Liberal Arts and Sciences National University of Defense TechnologyChangsha 410073China College of Physics and Micro Electronic Hunan UniversityChangsha 410006China College of Electronics Science National University of Defense TechnologyChangsha 410073China

In this study,we investigated the motion,shape,and delayed radiation intensity of a radioactive cloud by establishing a volume-source model of delayed radiation after high-altitude nuclear explosions.Then,the spatial distribution of electron number density at different moments on the north side of the explosion point generated by delayed γ-rays and delayed β-rays from the radioactive cloud under the influence of the geomagnetic field was calculated by solving chemical reaction kinetics equations.The impact of radio communication in the different frequency bands on the process of atmospheric ionization was also studied.The numerical results of the high-altitude nuclear explosion (120 km high and with a 1 megaton equivalent at 40°N latitude) indicated that the peak of electron number density ionized delayed γ-rays is located at a height of approximately 100 km and that of electron number density ionized delayed β-rays is about 90 km high.After 1 min of explosion,the radio communication in the medium frequency (MF) and high-frequency (HF)bands was completely interrupted,and the energy attenuation of the radio wave in the very high-frequency (VHF)band was extremely high.Five minutes later,the VHF radio communication was basically restored,but the energy attenuation in the HF band was still high.After 30 min,theVHF radio communication returned to normal,but its influence on the HF and MF radio communication continued.

关键词： High-altitude nuclear explosions Delayed radiation ionization effect Radio communication

Uniqueness Theorem for the Non-Local ionization Source in Glow Discharge and Hollow Cathode

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Journal of Modern Physics 2012年第10期3卷 1647-1662页

作者： Vladimir V. Gorin Kyiv National Taras Shevchenko University Kiev UkraineMoscow Institute of Physics and Technology Moscow Russia

The paper is devoted to the proof of the uniqueness theorem for solution of the equation for the non-local ionization source in a glow discharge and a hollow cathode in general 3D geometry. The theorem is applied to wide class of electric field configurations, and to the walls of discharge volume, which have a property of incomplete absorption of the electrons. Cathode is regarded as interior singular source, which is placed arbitrarily close to the wall. The existence of solution is considered also. During the proof of the theorem many of useful structure formulae are obtained. Elements of the proof structure, which have arisen, are found to have physical sense. It makes clear physical construction of non-local electron avalanche, which builds a source of ionization in glow discharge at low pressures. Last has decisive significance to understand the hollow cathode discharge configuration and the hollow cathode effect.

关键词： Integro-Differential Operator The Fredholm 2-nd Kind Equation Existence and Uniqueness Theorem Nil-potency Glow Discharge Hollow Cathode Non-Local ionization Non-Local Kinetics

RESONANCE AND ANTIRESONANCE IN THE AUTOionization SPECTRA INDUCED BY RYDBERG VIBRATIONAL STATES OF BENZENE MOLECULE——ULTRA SENSITIVE LASER MULTIPHOTON ionization SPECTROSCOPY

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Chinese Science Bulletin 1988年第8期33卷 690-695页

作者：范俊颖 Shanghai Institute of Optics and Fine Mechanics Academia Sinica

Ⅰ. INTRODUCTION In recent years laser multiphoton ionization spectroscopy is developed rapidly. The main reason is that it has many substantial advantages, such as high sensitivity, low background noise and easy detection. In fact, it is a very effective method for investigating the higher excited states of atoms and molecules as well as for

关键词： Rydberg excited ionization LASER vibrational insensitive struc stored processed mirror

LET Monitoring Using Liquid ionization Chambers

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International Journal of Medical Physics, Clinical Engineering and Radiation Oncology 2017年第2期6卷 197-207页

作者： Sara Tegami Stephen D. Bello Shuang Luan Andrea Mairani Katia Parodi Michael H. Holzscheiter Max Planck Institute for Nuclear Physics Heidelberg Germany Dept. of Physics & Astronomy University of New Mexico Albuquerque NM USA Dept. of Computer Science University of New Mexico Albuquerque NM USA Heidelberg Ion Beam Therapy Center Heidelberg University Hospital Heidelberg Germany Medical Physics Unit CNAO Foundation Pavia Italy Dept. of Medical Physics Ludwig-Maximilians-Universit&auml t München Munich Germany

Relative biological effectiveness (RBE) is an important quantity in planning particle beam cancer therapy. In general, the RBE describes the biological effectiveness of a given primary beam with respect to a reference photon irradiation. RBE varies not only for different primary beams but also with depth in the target for a given beam modality. It is not a quantity that easily lends itself to measurements or computation as it depends on many biological and physical quantities. Numerous experiments in vitro using various cell lines and irradiation modalities have shown that a general relationship between RBE and the physical quantity Linear Energy Transfer (LET) exists. Several groups have proposed including LET in the radiation therapy treatment planning instead of the more complicated and elusive RBE. It has been shown that LET is an important quantity to consider in treating radio-resistant tumors. The concept of LET painting has been proposed with the goal of improving tumor control probability (TCP) for hypoxic tumors by focusing high LET radiation on the hypoxic region of the tumor while restricting the surrounding normal tissue to low LET radiation. In order to properly incorporate LET in clinical treatment, it is important to be able to experimentally measure and verify LET distribution. We propose a novel method for measuring LET using a dual chamber methodology exploiting the difference in the observed recombination between air filled ionization chambers (IC) and liquid filled ionization chambers (LIC). The resulting difference in the measured signals will be used to directly extract the relative LET of an actual treatment beam in real time. This paper describes our initial studies of this method, presents preliminary results, and discusses further improvements toward a practical real-time LET measuring device.

关键词： Linear Energy Transfer Relative Biological Effectiveness Liquid ionization Chambers