共查询到20条相似文献,搜索用时 0 毫秒
1.
The goal of this work is to derive the angular distributions of electrons irradiated at the outer ionization of large atomic clusters from Xe atoms by relativistic laser pulses taking into account rescattering processes. Both the magnetic field of the laser pulse and the Coulomb field of the ionized cluster significantly influence the rescattering of ejected electrons. The multiply inner ionization of atoms occurs at the leading edge of the laser pulse. The atomic ions with charge multiplicities up to Z = 26 are subsequently produced (each atomic ion with the next charge multiplicity appears in 3–5 fs) when the laser intensity increases. The measurements of the angular distributions of electrons allow us to reproduce the imaging dynamics of outer ionization of the cluster at the leading edge of the relativistic femtosecond laser pulse. 相似文献
2.
A technique for measuring the angular distribution of electrons escaping from the center of the window of the IGUR-3 and ÉMIR-M powerful accelerators (designed at the All-Russia Institute of Technical Physics, Russian Federal Nuclear Center) into ambient air is presented, and measurement data are reported. The number of electrons is measured with cable detectors (the solid angle of the collimator of the detector is ≈0.01 sr). The measurements are made in three azimuthal directions in 120° intervals in the polar angle range 0–22°. The angular distributions of the electrons coming out of the accelerators are represented in the form of B splines. 相似文献
3.
The paper brings the survey of greater number of experimentally derived angular distributions of electrons emitted from sandwich cathodes at various leakage voltages and temperatures. Measured angular distributions consist of central maximum and the background in the form of side maximum. The magnitude and position of this second maximum is evaluated statistically in the dependence on cathode parameters.This paper is based on the RNDr thesis of the first author. 相似文献
4.
The angular distribution of electrons having an initial energy of 6.74 MeV has been studied after passage through C, Al, Cu, Sn, and Pb samples having thicknesses in the range in which multiple-scattering theory does not apply.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, Vol. 12, No. 7, pp. 51–54, July, 1969. 相似文献
5.
A study is reported of the angular distribution of monoenergetic electrons from a betatron which have traversed barriers of Al, Cu, and Pb with thicknesses reaching the extrapolated range. The initial electron energy is in the range 3–8 MeV. The experimental results agree well with Monte Carlo calculations carried out for identical calculations and with the results of earlier work for smaller barriers. The half-width of the electron angular distribution, increasing with increasing barrier thickness, reaches a nearly constant value, while the distribution itself corresponds to the laws of complete diffusion, i. e., converts into a distribution similar to cos2. As the thickness of the absorbers is increased further, the half-width decreases and the distribution becomes narrower, due to the penetration far into the absorbers of electrons which have been scattered predominantly in the forward direction.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 35–38, May, 1975. 相似文献
6.
M. Okada M. Saito M. Takatsu K. Kosemura T. Nagata H. Ishiwari N. Yokoyama 《Superlattices and Microstructures》1991,10(4)
This paper reports on the measurement of the angular distribution of electrons injected through a quantum point contact. We observed double peaks in the distribution with the point contact quantized in two modes. Our calculation of the distribution using an approximation of Fraunhofer diffraction through a quantized single slit agreed well with results. This paper also discusses the interference between the first and second modes, and shows how the terms of interference in the angular distribution are canceled. 相似文献
7.
Energy spectrum of ejected electrons in ionization of hydrogen atoms has been calculated following a multiple scattering theory
of Das and Seal [15]. The results show peaks around two to three Rydbergs of energies of the ejected electrons, for incident
electron energy of 250 eV and 500 eV, considered here, and for different combinations of the angular variables of the scattered
and the ejected electrons, for scattering in a plane. The peaks are very similar to those observed in relativistic K-shell
ionization of Ag atoms by electrons at 500 KeV energy [6]. The physical origin of these peaks may be traced to the second
order scatterings, scattering first by the atomic nucleus (or the atomic electron) and then a second time by the atomic electron.
These peaks are, however, absent in the first Born results. Experimental verification of the present results and theoretical
calculation by some other well-known methods will be interesting. 相似文献
8.
The asymmetry of the angular distributions of photoelectrons in the photoionisation of polarised alkali atoms is investigated. The general formulas for the amplitude of the multiphoton ionisation of np-states are given. In these formulas the dynamical and kinematical factors are explicitly separated. Our calculations within Fues model potential approach demonstrate that, under the experimental conditions essentially similar to those employed in [M. Schuricke, Ganjun Zhu, J. Steinmann, K. Simeonidis, I. Ivanov, A. Kheifets, A.N. Grum-Grzhimailo, K. Bartschat, A. Dorn, J. Ullrich, Phys. Rev. A 83 (2011) 023413(11)], the relative magnitude of the linear magnetic dichroism in three-photon ionisation of Li can be as large as 30%. 相似文献
9.
For neutrinoless double-beta decay caused by the exchange of light Majorana neutrinos, an expression for the differential width with respect to the angle between the final-electron momenta is obtained on the basis of a Lorentz-invariant effective Lagrangian of the general form. The shape of this angular distribution is analyzed within various extensions of the Standard Model that allow this process—in particular, within theories that involve Majorana super partners and (or) right-handed currents. The angular correlation coefficient for electrons as a function of the mass of the right-handed W boson and the effective Majorana neutrino mass in the decay of the 76Ge nucleus is considered within the model involving left—right symmetry. 相似文献
10.
Summary The elastic scattering of electrons from caesium and xenon atoms at collision energies below 40 eV is discussed. We study
the use of theX
α-potential with α=0.55 and compare our calculations using this potential with experimental cross-sections. Reasonable agreement
has been found with the measured angular distributions of Gehenn and Reichert and Kleweret al., respectively, in contrast to the existing calculations of Fink and Yates, Walker and McCarthyet al.
Riassunto Si discute lo scattering elastico di elettroni dagli atomi di cesio e xenon ad energie di collisione al di sotto dei 40 eV. Si studia l'uso del potenzialeX α con α=0.55 e si confrontano i nostri calcoli che usano questo potenziale con sezioni d'urto sperimentali. Si è trovato un ragionvole accordo con le distribuzioni angolari misurate di Gehenn e Reichert, Kleweret al., respettivamente, in contrasto con i calcoli esistenti di Fink e Yates, Walker e McCarthyet al.
Резюме Обсуждается упругое рассеяние электронов на атомах ксенона и цезия при энергиях ниже 40 эВ. Мы анализируем использованиеХ α-потеициала с α=0.55 и сравниваем наши вычисления, использующие этот потенциал, с экспериментальными поперечными сечениями. Получено разумное согласие с угловыми распределениями, измеренными Гехеном и Райхертом и Клевером и др., в иротивоположность существующим вычислениям Финка и Ятса, Уолкера и Маккарти и др.相似文献
11.
The angular distributions of the electrons undergoing inelastic scattering at He3 and H3 nuclei (accompanied by the two-particle splitting of the nuclei) are derived, with and without allowing for the interaction between the nucleon and deuteron so formed. Interaction in the final state has a major effect on the calculated relationships, and due allowance for this interaction improves agreement between theory and experiment in relation to the calculated cross sections. 相似文献
12.
Angular distributions of electrons ejected in thermal collisions of He(21 S, 23 S)-metastables with Ar, Kr, Xe, Hg, CO, N2 are measured with respect to the vector of relative velocity of the colliding particles. Except for preliminary results on the He(21S, 23 S)-/Ar-system, these are the first such distributions reported. They are found to be strongly anisotropic and asymmetric in some cases, and approximately isotropic in those cases where the interaction potential between the metastable- and the target particle is strong. For the cases of weak interaction potential, the connection between the “internal” angular distribution in the frame fixed to the internuclear axis and the laboratory angular distribution, has been derived. Calculations of laboratory angular distributions involving an assumed “internal” distribution and the kinematics of a hard core collision show good qualitative agreement with the experimental results. 相似文献
13.
Secondary electron spectra up to 3.5 keV electron energy arising from the passage of alpha particles and252Cf fission products through a 2μg/cm2 carbon foil are measured for a forward (42°) and a backward (138°) angle of emission. The forward spectra induced by alpha-particles are compared to binary encounter calculations and to a gas target spectrum. Systematic differences in the shapes of the alpha particle and the fission product induced spectra are discussed. Total yields and mean energies of the secondary electrons are derived from the spectra. 相似文献
14.
M.A. Kornberg J.E. Miraglia 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,12(1):45-51
We present numerical results for the photoelectron spectrum in double ionization by keV photons in the quasiequal-energy sharing
region. In this region of the spectrum, the relevant ionizing mechanism is due to a mutual sharing of the photon momentum
by both electrons, with small momentum transferred to the atomic nucleus. Calculations were performed for photon energies
of 25 and 50 keV, where retardation effects are fundamental, while final-state correlations are of minor importance. The spectra
present a two-peak structure, with maxima located at the photoelectron energies , with the photon energy in atomic units. We discuss the general features of the spectrum in terms of the picture of the photoionization
of two free electrons, and we propose a way of detecting the contribution by experiments.
Received 24 January 2000 相似文献
15.
Two-photon ionization of the hydrogen-like uranium ion by elliptically polarized radiation is investigated in the present
work. It is demonstrated that the fundamental effect of interference of the probability amplitudes arises in the angular photoelectron
distribution when the degree of ellipticity of ionizing radiation is varied.
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 39–41, December, 2008. 相似文献
16.
A. L. Galkin M. P. Kalashnikov V. A. Trofimov 《Bulletin of the Lebedev Physics Institute》2012,39(8):241-245
Based on the dynamics of the electron in the field of a laser pulse of relativistic intensity, the electron emission angles with respect to the laser pulse propagation axis are calculated. The angular distribution of accelerated electrons is analyzed together with their energy spectrum. It is shown that fast electrons forming the high-energy spectral region are emitted into a fixed angular cone. 相似文献
17.
Secondary electron spectra in the energy range below 3.5 keV arising from the passage of α-particles and fission products through thin carbon and gold foils are presented and compared to gas target spectra and theoretical calculations which include the slowing down and the angular scattering of the electrons in the foil. A good agreement between the calculation and the experimental results is found. The shape of fission product induced electron spectra differs systematically from that of light ion induced spectra. Total yields and mean energies of the secondary electrons are derived from the spectra. 相似文献
18.
19.
It is found that secondary electrons ejected (by incident 1 keV electrons) from an oxidized europium layer, which is at about 20 K in a magnetic field of 1.5 T, show longitudinal spin polarization. The maximum value observed in first experiments is 32 per cent. 相似文献
20.
用3TW超短超强激光器进行了激光与固体靶相互作用实验。采用电子角分布仪和LiF热释光探测器探测了超热电子的角分布。测量结果显示:能量较高的电子发射的定向性好于能量较低的电子;能量较低的电子呈溅射状发射;能量较高的电子发射出现两个尖锐的发射峰,其中,激光反射方向的超热电子发射峰则由反射激光、有质动力径向分量、侧向拉曼散射等加速机制共同作用的结果,靠近靶法线方向的超热电子发射峰是由其振吸收机制产生,且理论预言与实验结果相吻合。 相似文献