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Craig F. Smith - One of the best experts on this subject based on the ideXlab platform.

  • A spectrometric approach in radiography for detection of materials by their effective Atomic Number
    Nuclear Instruments and Methods in Physics Research Section A: Accelerators Spectrometers Detectors and Associated Equipment, 2009
    Co-Authors: Vladimir D. Ryzhikov, S. V. Naydenov, G.m. Onyshchenko, P. Lecoq, Craig F. Smith
    Abstract:

    In this paper we report a spectrometric approach to dual-energy digital radiography that has been developed and applied to identify specific organic substances and discern small differences in their effective Atomic Number. An experimental setup has been designed, and a theoretical description proposed based on the experimental results obtained. The proposed method is based on the application of special reference samples made of materials with different effective Atomic Number and thickness parameters known to affect X-ray attenuation in the low-energy range. The results obtained can be used in the development of a new generation of multi-energy customs or medical X-ray scanners.

  • Direct reconstruction of the effective Atomic Number of materials by the method of multi-energy radiography
    Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2004
    Co-Authors: S. V. Naydenov, Vladimir D. Ryzhikov, Craig F. Smith
    Abstract:

    A direct method is proposed for reconstruction of the effective Atomic Number by means of multi-energy radiography of the material. The accuracy of the method is up to 95% . Advantages over conventional radiographic methods, which ensure accuracy of just about 50%, are discussed. A physical model has been constructed, and general expressions have been obtained for description of the effective Atomic Number in a two-energy monitoring scheme. A universal dependence has been predicted for the effective Atomic Number as a function of relative (two-energy) radiographic reflex. The established theoretical law is confirmed by the experimental data presented. The proposed development can find multiple applications in non-destructive testing and related fields, including those in the civil sphere as well as anti-terrorist activities.Comment: 15 pages LaTeX, 4 figures, the paper accepted in Nuclear Methods and Instruments in Physics Research, Section

  • Direct reconstruction of the effective Atomic Number of materials by the method of multi-energy radiography
    Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 2003
    Co-Authors: S. V. Naydenov, Vladimir D. Ryzhikov, Craig F. Smith
    Abstract:

    A direct method is proposed for reconstruction of the effective Atomic Number by means of multi-energy radiography of the material. The accuracy of the method is up to 95%. Advantages over conventional radiographic methods, which ensure accuracy of just about 50%, are discussed. A physical model has been constructed and general expressions have been obtained for description of the effective Atomic Number in a two-energy monitoring scheme. A universal dependence has been predicted for the effective Atomic Number as a function of relative (two-energy) radiographic reflex. The established theoretical law is confirmed by the experimental data presented. The proposed development can find multiple applications in non-destructive testing and related fields, including those in the civil sphere as well as anti-terrorist activities.

K Stierstorfer - One of the best experts on this subject based on the ideXlab platform.

  • density and Atomic Number measurements with spectral x ray attenuation method
    Journal of Applied Physics, 2003
    Co-Authors: Bjoern Heismann, J Leppert, K Stierstorfer
    Abstract:

    X-ray attenuation measurements are widely used in medical and industrial applications. The usual results are one- to three-dimensional representations of the attenuation coefficient μ(r). In this paper, we present the ρZ projection algorithm for obtaining the density ρ(r) and Atomic Number Z(r) with an energy-resolving x-ray method. As input data the algorithm uses at least two measurements μ1,μ2,… with different spectral weightings of the source spectrum S(E) and/or detector sensitivity D(E). Analytically, ρ is a function of μ1−cμ2, c=const, and Z is a function of μ1/μ2. The full numerical treatment yields ρ(μ1,μ2) and Z(μ1,μ2) with S(E) and D(E) as commutative parametric functions. We tested the method with dual-energy computed tomography measurements of an organic sample and a set of chemical solutions with predefined ρ and Z. The resulting images show ρ and Z as complementary information: The density ρ reflects the morphology of the objects, whereas the Atomic Number Z=Number of electrons/atom describ...

D. Colombant - One of the best experts on this subject based on the ideXlab platform.

  • Pinch spot formation in high Atomic Number z discharges.
    Physical review letters, 1992
    Co-Authors: D. Mosher, D. Colombant
    Abstract:

    A nonlinear, quasi-two-dimensional model for pinch spot formation in radiation-dominated, high Atomic Number {ital z} pinches is presented that reproduces the experimental electrical and radiation characteristics. The high line-radiation rates of such discharges produce localized, high-density pinch spots in contrast to the spindle pinches predicted for hydrogenic discharges.

A Boyde - One of the best experts on this subject based on the ideXlab platform.

  • mean Atomic Number and backscattered electron coefficient calculations for some materials with low mean Atomic Number
    Scanning, 2006
    Co-Authors: P G T Howell, K M W Davy, A Boyde
    Abstract:

    In modelling electron backscattering from solids using Monte Carlo simulations, knowledge of mean Atomic Number, mean Atomic weight, and density of the bulk material are required. We studied four different ways in common useforthe calculation of mean Atomic Number. An alternative and improved approach is to calculate the mean backscattered electron (BSE) coefficient, η, from a knowledge of the elemental composition and values of η for the elements. Again, we studied a Number of formulae suggested for this averaging process. As it is not possible to measure η directly for a Number of elements, the method used to interpolate between elements with known η was also examined. In addition, we obtained experimental backscattering relationships for topography-free samples of poly (methylmethacrylate) (PMMA), carbon, aluminium, and a series of novel halogenated resins, all solids with relatively low mean Atomic Numbers, and calcified tissues. None of the methods for determining mean Atomic Number placed the materials of interest in the correct sequence of their experimentally determined BSE peaks: the data differed widely between the individual methods. The averaged BSE coefficient calculated by the Castaing formula gave the best agreement with the experimentally derived data.

Bjoern Heismann - One of the best experts on this subject based on the ideXlab platform.

  • density and Atomic Number measurements with spectral x ray attenuation method
    Journal of Applied Physics, 2003
    Co-Authors: Bjoern Heismann, J Leppert, K Stierstorfer
    Abstract:

    X-ray attenuation measurements are widely used in medical and industrial applications. The usual results are one- to three-dimensional representations of the attenuation coefficient μ(r). In this paper, we present the ρZ projection algorithm for obtaining the density ρ(r) and Atomic Number Z(r) with an energy-resolving x-ray method. As input data the algorithm uses at least two measurements μ1,μ2,… with different spectral weightings of the source spectrum S(E) and/or detector sensitivity D(E). Analytically, ρ is a function of μ1−cμ2, c=const, and Z is a function of μ1/μ2. The full numerical treatment yields ρ(μ1,μ2) and Z(μ1,μ2) with S(E) and D(E) as commutative parametric functions. We tested the method with dual-energy computed tomography measurements of an organic sample and a set of chemical solutions with predefined ρ and Z. The resulting images show ρ and Z as complementary information: The density ρ reflects the morphology of the objects, whereas the Atomic Number Z=Number of electrons/atom describ...