Bound States of Fast Electrons in Planar Channeling

1976 ◽  
Vol 76 (2) ◽  
pp. 779-786 ◽  
Author(s):  
V. V. Kaplin ◽  
D. E. Popov ◽  
S. A. Vorobev
Keyword(s):  
Bound States ◽  
Planar Channeling ◽  
Fast Electrons

Investigation of Quantum States of Fast Electrons under Planar Channeling in Silicon Crystals

1987 ◽  
Vol 142 (1) ◽  
pp. 49-65 ◽  
Author(s):  
V. I. Gridnev ◽  
V. V. Kaplin ◽  
V. G. Khlabutin ◽  
E. I. Rozum ◽  
S. A. Vorobiev
Keyword(s):  
Quantum States ◽  
Planar Channeling ◽  
Fast Electrons ◽  
Silicon Crystals

Orientational Population of Quantum States for Fast Electrons in Planar Channeling

1981 ◽  
Vol 103 (1) ◽  
pp. 81-87 ◽  
Author(s):  
S. V. Plotnikov ◽  
D. E. Popov ◽  
E. I. Rozum ◽  
O. G. Kostareva ◽  
S. A. Vorobiev
Keyword(s):  
Quantum States ◽  
Planar Channeling ◽  
Fast Electrons

Angular Distributions of Fast Electrons at Planar Channeling in Silicon Crystals

1984 ◽  
Vol 126 (2) ◽  
pp. 565-574 ◽  
Author(s):  
V. V. Kaplin ◽  
S. B. Nurmagambetov ◽  
V. I. Gridnev ◽  
E. I. Rozum ◽  
S. Pak ◽  
...  
Keyword(s):  
Angular Distributions ◽  
Planar Channeling ◽  
Fast Electrons ◽  
Silicon Crystals

DECHANNELING OF POSITRONS BY DISLOCATIONS: EFFECTS OF ANHARMONIC INTERACTIONS

2010 ◽  
Vol 25 (supp01) ◽  
pp. 144-156
Author(s):  
JUBY GEORGE ◽  
A. P. PATHAK
Keyword(s):  
Bound States ◽  
Mechanical Treatment ◽  
Transition Probabilities ◽  
Dislocation Core ◽  
Quantum Mechanical ◽  
Planar Channeling ◽  
Quantum Mechanical Treatment ◽  
Anharmonic Interactions ◽  
Channeling Radiation ◽  
Perfect Channel

A quantum mechanical treatment of the effects of dislocations on planar channeling of positrons is presented. The effects of anharmonic terms on the positron planar potential are considered in these calculations. The wavefunction of channeled positron in the perfect channel and the two regions of dislocation affected channel are found and compared with harmonic case. The corresponding effects on bound states and the transitions among these states are calculated. The transition probabilities and the resulting dechanneling probabilities are found for initially channelled particles in states |0〉 and |1〉. The calculations are carried out with varying channel distance from the dislocation core. Applications of anharmonic interactions on channeling radiation are also investigated.

Recent Radiative and Collisional Atomic Data of Astrophysical Interest

1988 ◽  
Vol 102 ◽  
pp. 129-132
Author(s):  
K.L. Baluja ◽  
K. Butler ◽  
J. Le Bourlot ◽  
C.J. Zeippen
Keyword(s):  
Mass Production ◽  
Bound States ◽  
Physical Models ◽  
Impact Excitation ◽  
Electron Impact Excitation ◽  
Atomic Data ◽  
Isoelectronic Sequence ◽  
Astrophysical Interest ◽  
Radiative Transitions ◽  
Forbidden Transitions

SummaryUsing sophisticated computer programs and elaborate physical models, accurate radiative and collisional atomic data of astrophysical interest have been or are being calculated. The cases treated include radiative transitions between bound states in the 2p4and 2s2p5configurations of many ions in the oxygen isoelectronic sequence, the photoionisation of the ground state of neutral iron, the electron impact excitation of the fine-structure forbidden transitions within the 3p3ground configuration of CℓIII, Ar IV and K V, and the mass-production of radiative data for ions in the oxygen and fluorine isoelectronic sequences, as part of the international Opacity Project.

Design of Sensitive Photographic Materials for the High-Voltage Electron Microscope

1975 ◽  
Vol 33 ◽  
pp. 156-157
Author(s):  
Murray Vernon King ◽  
Donald F. Parsons
Keyword(s):  
Electron Microscope ◽  
Radiation Damage ◽  
High Voltage ◽  
Radiation Sensitivity ◽  
Fast Electrons ◽  
Voltage Electron ◽  
High Voltage Electron Microscope ◽  
High Voltage Electron ◽  
Biological Studies ◽  
Low Sensitivity

Effective application of the high-voltage electron microscope to a wide variety of biological studies has been restricted by the radiation sensitivity of biological systems. The problem of radiation damage has been recognized as a serious factor influencing the amount of information attainable from biological specimens in electron microscopy at conventional voltages around 100 kV. The problem proves to be even more severe at higher voltages around 1 MV. In this range, the problem is the relatively low sensitivity of the existing recording media, which entails inordinately long exposures that give rise to severe radiation damage. This low sensitivity arises from the small linear energy transfer for fast electrons. Few developable grains are created in the emulsion per electron, while most of the energy of the electrons is wasted in the film base.

High-angle electron scattering from amorphous silicon

1995 ◽  
Vol 53 ◽  
pp. 162-163
Author(s):  
M. Libera ◽  
J.A. Ott ◽  
K. Siangchaew ◽  
L. Tsung
Keyword(s):  
Electron Scattering ◽  
Amorphous Material ◽  
Structural Defects ◽  
Constant Thickness ◽  
High Angle ◽  
Fast Electrons ◽  
Angle Scattering ◽  
Stem Image ◽  
Amorphous Si ◽  
Thermal Vibrations

Channeling occurs when fast electrons follow atomic strings in a crystal where there is a minimum in the potential energy (1). Channeling has a strong effect on high-angle scattering. Deviations in atomic position along a channel due to structural defects or thermal vibrations increase the probability of scattering (2-5). Since there are no extended channels in an amorphous material the question arises: for a given material with constant thickness, will the high-angle scattering be higher from a crystal or a glass?Figure la shows a HAADF STEM image collected using a Philips CM20 FEG TEM/STEM with inner and outer collection angles of 35mrad and lOOmrad. The specimen (6) was a cross section of singlecrystal Si containing: amorphous Si (region A), defective Si containing many stacking faults (B), two coherent Ge layers (CI; C2), and a contamination layer (D). CBED patterns (fig. lb), PEELS spectra, and HAADF signals (fig. lc) were collected at 106K and 300K along the indicated line.

Sign in / Sign up

Export Citation Format

Share Document