Effects of Dipole Length on Dosimetric Probe Sensitivity

2006 ◽  
Author(s):  
Alain Tran ◽  
Mustapha Yagoub
Keyword(s):  
Dipole Length

The continuous absorption of light in alkali-metal vapours

1953 ◽  
Vol 219 (1136) ◽  
pp. 89-101 ◽  
Keyword(s):  
Cross Section ◽  
Alkali Metals ◽  
Theoretical Calculations ◽  
Wave Length ◽  
Energy Difference ◽  
Continuous Absorption ◽  
Absorption Of Light ◽  
Sodium Vapour ◽  
Good Agreement ◽  
Dipole Length

The first section of this paper is an account of some experiments on the absorption of light in sodium vapour from the series limit at 2412 Å to about 1600 Å (an energy difference of 2·6 eV). The absorption cross-section at the limit is 11·6 ± 1·2 x 10 -20 cm 2 . The cross-section decreases giving a minimum of 1·3 ± 0·6 x 10 -20 cm 2 at 1900 Å and then increases to 1600 Å. A theoretical calculation by Seaton based on the dipole-length formula gives good agreement with the experiments at the series limit and also correctly predicts the wave-length for the minimum, but it predicts a significantly lower absorption at the minimum. The experiments described in the first section of the paper conclude a series on the absorption of light in the alkali metals. The second section consists of a general discussion of the results of these experiments and of their relation to theoretical calculations. There is good agreement between theory and experiment except in regard to the magnitude of the absorption at the minimum.

A comparison of theory and experiment for photo-ionization cross-sections I. Neon and the elements from boron to neon

1951 ◽  
Vol 208 (1094) ◽  
pp. 408-418 ◽  
Keyword(s):  
Cross Sections ◽  
General Trend ◽  
Wave Functions ◽  
Ionization Cross ◽  
Hartree Fock ◽  
Quantal Theory ◽  
Ionization Cross Sections ◽  
Photo Ionization ◽  
Near Future ◽  
Dipole Length

The quantal theory of the continuous photo-electric absorption of radiation is briefly summarized, pàrticular attention being given to the alternative formulae available and to the accuracy to be expected in practical calculations. Detailed calculations are described for the photo-ionization cross-section of neon, a system for which it is understood that experimental data should be available in the near future. The calculation is made using Hartree-Fock wave functions and the two formulae of the dipole length and the dipole velocity. The corresponding cross-sections are found to be 5.8 and 4.4 x 10- 18 cm 2 . at the spectral head and to rise slowly with increasing frequency until a broad maximum is reached for an energy of the ejected electron of about 11 eV. A comparison is made with previous calculations on the elements from boron to neon ; the general trend of the results is discussed and improved estimates for boron and fluorine are given (10 x 10 -18 cm 2 . for boron and 4.3 x 10- 18 cm 2 . for fluorine at the spectral head).

scholarly journals Atomic X-ray Transition Probabilities: A Comparison of the Dipole Length, Velocity and Acceleration Forms

1984 ◽  
Vol 37 (1) ◽  
pp. 45 ◽  
Author(s):  
HM Quiney ◽  
FP Larkins
Keyword(s):  
Transition Probabilities ◽  
Nuclear Charge ◽  
Principal Quantum Number ◽  
Dipole Transition ◽  
Final States ◽  
X Ray ◽  
Hartree Fock ◽  
Isoelectronic Series ◽  
Rydberg Electron ◽  
Dipole Length

The length, velocity and acceleration forms of the dipole transition operator are examined in calculations of diagram and satellite X-ray emission probabilities in the Ne + to Ar 9 + isoelectronic series. All calculations are within the relaxed nonrelativistic Hartree-Fock framework, using separately optimized numerical wavefunctions for the initial and final electronic states. Divergence between the alternative forms of the transition moment, as the principal quantum 'number of the Rydberg electron and nuclear charge are increased, is discussed in the context of electron correlation differences between the initial and final states.

The photo-ionization cross-section of neon

1953 ◽  
Vol 220 (1140) ◽  
pp. 71-76 ◽  
Keyword(s):  
Cross Section ◽  
Ionization Cross Section ◽  
Wave Length ◽  
Grazing Incidence ◽  
Absorption Coefficients ◽  
Ionization Cross ◽  
Ionization Limit ◽  
Resonance Transitions ◽  
Photo Ionization ◽  
Dipole Length

The absorption of radiation of wave-length between 230 and 800 Å in neon was measured photometrically in a grazing incidence vacuum spectrograph. For wave-lengths longer than that corresponding to the first ionization limit the absorption coefficients were found to be zero except for photo-excitation of resonance transitions. Two sharp absorption edges were observed at 575 and 256 Å corresponding to the L 3 - and L 1 -edges respectively with a flat maximum between them. The photo-ionization cross-section at the first ionization limit was found to be 5⋅4 x 10 -18 cm 2 independent of the pressure between 50 and 500 μ ; this should be compared with the theoretical value of 5⋅8 x 10 -18 cm 2 obtained by Seaton using a dipole-length approximation. Between 575 and 400 Å the calculated and experimental curves agreed closely within the limits of measurement.

Ferrite Rod Aerials

1976 ◽  
Vol 13 (1) ◽  
pp. 35-40
Author(s):  
H. Sutcliffe
Keyword(s):  
Equivalent Circuit ◽  
Direct Approach ◽  
Dipole Length

The theoretical behaviour of ferrite rod aerials is discussed in relation to generalized aerial theory. It is shown that the concept of dipole length provides a direct approach to the derivation of a simple and useful equivalent circuit.

scholarly journals Corrigendum: Atomic X-ray Transition Probabilities: A Comparison of the Dipole Length, Velocity and Acceleration Forms

1984 ◽  
Vol 37 (6) ◽  
pp. 709
Author(s):  
HM Quiney ◽  
FP Larkins
Keyword(s):  
Matrix Element ◽  
Transition Probabilities ◽  
Typographical Error ◽  
X Ray ◽  
The Matrix ◽  
Dipole Length

All the expressions given in Table 1 (p. 47) must be multiplied by -}3/-}2 and the numerical values in Tables 2-4 by 3/2. Due to a typographical error, the coefficient of the matrix element for process C [ls]-[2p2(lS)]3p should be --}2/3 and not --}2/-}3 as printed.

scholarly journals 2D Geoelectric Imaging of the Uneme-Nekhua Fracture Zone

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Muslim B. Aminu ◽  
Tunde M. Akande ◽  
Olubukola A. Ishola
Keyword(s):  
Fracture Zone ◽  
Tectonic Activity ◽  
Recent Sediment ◽  
Stream Data ◽  
Southwestern Nigeria ◽  
Near Surface ◽  
Array Configuration ◽  
The North ◽  
Electrode Separation ◽  
Dipole Length

We have employed 2D geoelectric imaging to reveal the geometry and nature of a fracture zone in Uneme-Nekhua, southwestern Nigeria. The fracture zone is discernable from an outcropping rock scarp and appears to define the course of a seasonal stream. Data were acquired using the dipole-dipole survey array configuration with electrode separation of 6 m and a maximum dipole length of 60 m. Three traverses with lengths varying between 72 m and 120 m were laid orthogonal to the course of the seasonal stream. 2D geoelectric images of the subsurface along the profiles imaged a north-south trending fracture zone. This fracture zone appears to consist of two vertical fractures with more intense definition downstream. The eastern fracture is buried by recent sediment, while the western fracture appears to have experienced more recent tectonic activity as it appears to penetrate through the near surface. Perhaps at some point, deformation ceased on the eastern fracture and further strain was transferred to the western fracture. The fracture zone generally defines the course of the north-south seasonal stream with the exception of the downstream end where the fracture appears to have died out entirely. Two associated basement trenches lying parallel to and east of the fracture zone are also imaged.

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