Results 241 to 250 of about 799,637 (297)
Some of the next articles are maybe not open access.
X-ray energies for effective atomic number determination
Neuroradiology, 1976The measurement of the effective atomic number of a piece of material in vivo can be achieved using computed tomography. The precision of measurement of this parameter depends on the precision of measurement of the X-ray absorption coefficient at two energies and the separation of these energies.
R A, Rutherford +2 more
openaire +4 more sources
Effective Atomic Numbers of Heterogeneous Materials
Nature, 1965FOR a single element, the three γ-ray processes—photoelectric, Compton and pair production, can be expressed as a function of photon energy hν and the atomic number Z of the element. At a given photon energy, the interaction is proportional to Zn where n is between 4 and 5 for the photoelectric effect, 1 for the Compton effect, and 2 for pair ...
openaire +3 more sources
Effective atomic numbers for some calcium–strontium-borate glasses
Annals of Nuclear Energy, 2012Abstract Effective atomic number acts as a fundamental property of compounds and mixtures and it plays a vital role in the computation of various dosimetric parameters such as buildup factor, effective dose and heat generation. Effective atomic numbers have been computed in the energy range from 1 keV to 100 GeV for different chemical compositions of
Renu Sharma +3 more
openaire +3 more sources
Calculations of effective atomic number
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2007We will present and discuss effective atomic number (Zeff) obtained by different methods of calculations. There is no unique relation between computed values. This observation led us to the conclusion that any Zeff is valid only for given process. We will compare Zeff obtained by following methods: 1. Variational method (Slater), 2.
Kaliman, Zoran +2 more
openaire +4 more sources
The effective atomic number of mix D
The British Journal of Radiology, 1979It is well known that mix D, which was introduced by Jones and Raine (1949), has been widely used as a phantom material for photons and electrons in radiotherapy. By adding fillers of magnesium oxide and tianium dioxide to wax, they made an improvement for mix D compared with wax alone in terms of mechanical properties and the attenuation ...
T, Hiraoka, K, Kawashima
openaire +2 more sources
The effective atomic number of dosimetric gels
Australasian Physics & Engineering Sciences in Medicine, 2008Radiological properties of gel dosimeters and phantom materials are often compared against each other and against water or tissue by consideration parameters including their effective atomic number, Zeff. Effective atomic numbers have been calculated for a range of ferrous-sulphate and polymeric gel dosimeters using mass attenuation coefficient data ...
Taylor, M +3 more
openaire +3 more sources
Determination of atomic cross-sections and effective atomic numbers for some alloys
Annals of Nuclear Energy, 2000Abstract The transmission of gamma-rays at the energies, 81, 356, 511, 662, 835, 1274 and 1332 keV has been studied on the alloys brass, bronze, steel, aluminum–silicon and lead–antimony. The mass absorption coefficients have been measured. The total interaction cross-sections and effective atomic numbers have been determined on the basis of mixture ...
A.H. El-Kateb +2 more
openaire +1 more source
An Experimental Evaluation of the Atomic Number Effect
Advances in X-ray Analysis, 1973AbstractA method for measuring the atomic number effect is developed using a sandwich sample technique. The depth distributions of x-ray production, ϕ(ρz) curves, have been measured for a zinc tracer in aluminum, copper, silver and gold matrices at 30, 25, 20 and 15 keV. The ϕ(ρz) curves were measured using a Cambridge Microscan 5 in which the electron
L. Parobek, J. D. Brown
openaire +1 more source
Effective principal quantum numbers of valence atomic orbitals
Chemical Physics Letters, 1971Abstract Analysis of radial moments of Hartree-Fock atomic orbitals shows that their shape near the radial maximum implies an effective principal quantum number that remains small even for heavier elements.
L.C. Cusachs, H.S. Aldrich
openaire +1 more source