This paper describes the standardization of the proton-induced x-ray emission（PIXE） technique for finding the elemental composition of thick samples. For the standardization, three different samples of standard refe...This paper describes the standardization of the proton-induced x-ray emission（PIXE） technique for finding the elemental composition of thick samples. For the standardization, three different samples of standard reference materials（SRMs） were analyzed using this technique and the data were compared with the already known data of these certified SRMs. These samples were selected in order to cover the maximum range of elements in the periodic table. Each sample was irradiated for three different values of collected beam charges at three different times. A proton beam of 2.57 Me V obtained using 5UDH-II Pelletron accelerator was used for excitation of x-rays from the sample. The acquired experimental data were analyzed using the GUPIXWIN software. The results show that the SRM data and the data obtained using the PIXE technique are in good agreement.展开更多
The photodetachment of a hydrogen negative ion (H^(-)) near a hard spherical surface is investigated by using the theoretical imaging method.The surface is oriented in such a fashion that the laser polarization direct...The photodetachment of a hydrogen negative ion (H^(-)) near a hard spherical surface is investigated by using the theoretical imaging method.The surface is oriented in such a fashion that the laser polarization direction is perpendicular to the principal axis of the spherical surface.Analytical expressions are derived for the detachedelectron flux and photodetachment cross section.Strong interference patterns are observed in the detachedelectron flux,while no visible oscillations are found in the photodetachment cross section.展开更多
Photo-detached electron spectra from a hypothetical linear tetra-atomic negative ion is obtained.A plane polarized laser parallel to the axis of the molecular ion is used to knock off the loosely bound electron.The sp...Photo-detached electron spectra from a hypothetical linear tetra-atomic negative ion is obtained.A plane polarized laser parallel to the axis of the molecular ion is used to knock off the loosely bound electron.The spectrum of the detached-electron flux shows strong interference peaks,while the number of peaks increases with the increase in the photon energy.Strong oscillations are also observed in the total photodetachment cross section spectrum.The frequency of the oscillations increases with the increase in the distance between the successive atoms d in the linear chain.These quantum interference effects vanish for very large d or very high photon energy.展开更多
Photodetachment spectra from a linear tetra-atomic negative ion is investigated by treating the detached-electron wave function quantum mechanically.A plane polarized laser light,perpendicular to the axis of the ion,i...Photodetachment spectra from a linear tetra-atomic negative ion is investigated by treating the detached-electron wave function quantum mechanically.A plane polarized laser light,perpendicular to the axis of the ion,is used to detach the electron from the ion.Analytical expressions for the electron flux and total photodetachment cross section are derived.The electron flux on screen shows strong-energy-dependent oscillations with different frequencies.The total cross section of the tetra-atomic negative ion reduces the cross section of mono-atomic,diatomic and triatomic negative ions for high energy photons,while for low energy photons it becomes four times the cross section of mono-atomic negative ions.展开更多
文摘This paper describes the standardization of the proton-induced x-ray emission（PIXE） technique for finding the elemental composition of thick samples. For the standardization, three different samples of standard reference materials（SRMs） were analyzed using this technique and the data were compared with the already known data of these certified SRMs. These samples were selected in order to cover the maximum range of elements in the periodic table. Each sample was irradiated for three different values of collected beam charges at three different times. A proton beam of 2.57 Me V obtained using 5UDH-II Pelletron accelerator was used for excitation of x-rays from the sample. The acquired experimental data were analyzed using the GUPIXWIN software. The results show that the SRM data and the data obtained using the PIXE technique are in good agreement.
文摘The photodetachment of a hydrogen negative ion (H^(-)) near a hard spherical surface is investigated by using the theoretical imaging method.The surface is oriented in such a fashion that the laser polarization direction is perpendicular to the principal axis of the spherical surface.Analytical expressions are derived for the detachedelectron flux and photodetachment cross section.Strong interference patterns are observed in the detachedelectron flux,while no visible oscillations are found in the photodetachment cross section.
文摘Photo-detached electron spectra from a hypothetical linear tetra-atomic negative ion is obtained.A plane polarized laser parallel to the axis of the molecular ion is used to knock off the loosely bound electron.The spectrum of the detached-electron flux shows strong interference peaks,while the number of peaks increases with the increase in the photon energy.Strong oscillations are also observed in the total photodetachment cross section spectrum.The frequency of the oscillations increases with the increase in the distance between the successive atoms d in the linear chain.These quantum interference effects vanish for very large d or very high photon energy.
文摘Photodetachment spectra from a linear tetra-atomic negative ion is investigated by treating the detached-electron wave function quantum mechanically.A plane polarized laser light,perpendicular to the axis of the ion,is used to detach the electron from the ion.Analytical expressions for the electron flux and total photodetachment cross section are derived.The electron flux on screen shows strong-energy-dependent oscillations with different frequencies.The total cross section of the tetra-atomic negative ion reduces the cross section of mono-atomic,diatomic and triatomic negative ions for high energy photons,while for low energy photons it becomes four times the cross section of mono-atomic negative ions.
