The relation between the back-scattering factor of �-radiation and �-particle yield from a thickllayer source and the atomic number of a substance

1963 ◽  
Vol 15 (6) ◽  
pp. 1297-1299
Author(s):  
F. K. Levochkin ◽  
Yu. Ya. Sokolov
Keyword(s):  
Atomic Number ◽  
Particle Yield ◽  
Back Scattering ◽  
Scattering Factor

BACK-SCATTERING AND SELF-ABSORPTION OF β−-PARTICLES

1963 ◽  
Vol 41 (9) ◽  
pp. 2283-2293 ◽  
Author(s):  
M. S. Lafleur ◽  
S. Kahana ◽  
T. F. Morris ◽  
L. Yaffe
Keyword(s):  
Atomic Number ◽  
Effective Atomic Number ◽  
The Self ◽  
Back Scattering

The self-absorption of the β−-radiation from S35 and P32 has been studied in various compounds. The function derived by Gora and Hickey has been shown to fit the data. The back-scattering of the β−-radiation from P32 by various elements and compounds has been examined and a semiempirical treatment used to suggest an effective atomic number for back-scattering by compounds.

scholarly journals Rutherford Back Scattering of Protons at Medium Energies

1972 ◽  
Vol 25 (1) ◽  
pp. 113
Author(s):  
ER Cawthron
Keyword(s):  
Energy Range ◽  
Cross Section ◽  
Atomic Number ◽  
Scattering Cross Section ◽  
Coulomb Scattering ◽  
Rutherford Back Scattering ◽  
Scattering Cross ◽  
Rutherford Scattering ◽  
Back Scattering ◽  
Light Ions

In the 3-20 keV energy range for light ions we are on the threshold of validity for the Lindhard-Scharff theory, but the screening is sufficiently small for the screened Coulomb scattering to be approximated by Rutherford scattering. Using the Rutherford scattering cross section, McCracken and Freeman (1969) showed that, for an incident ion of energy E0 and atomic number Z1 upon a target of atomic number Z2, where NE is the total number of back scattered ions with energy exceeding E, I(E/E0) is an integral which McCracken and Freeman plotted numerically in their paper, and the function f(z) is approximated by for Z1 << Z2 For heavy targets the screening is not negligible and the expression (1) is only qualitative. However, it does predict the observed changes in NE with E0 to considerable accuracy, for energies in the several keV range.

Determination of effective atomic number of biomedical samples using Gamma ray back-scattering

2018 ◽  
Author(s):  
Inderjeet Singh ◽  
Bhajan Singh ◽  
B. S. Sandhu ◽  
Arvind D. Sabharwal
Keyword(s):  
Atomic Number ◽  
Gamma Ray ◽  
Effective Atomic Number ◽  
Back Scattering

Dependence of the back-scattering coefficient for?-rays on the atomic number of the target

1969 ◽  
Vol 12 (5) ◽  
pp. 663-665
Author(s):  
L. M. Belyus ◽  
P. D. Korzh ◽  
M. V. Krylov ◽  
O. M. Ignatovskii ◽  
L. S. Dolzhenkova ◽  
...  
Keyword(s):  
Atomic Number ◽  
Scattering Coefficient ◽  
Back Scattering

Thickness and composition determinations from T.E.M. specimens using both x-ray and backscattered electron data

1984 ◽  
Vol 42 ◽  
pp. 576-577
Author(s):  
M.D. Ball ◽  
H. Lagace ◽  
M.C. Thornton
Keyword(s):  
Electron Microscope ◽  
Atomic Number ◽  
Transmission Electron Microscope ◽  
Convenient Method ◽  
Flow Chart ◽  
X Ray ◽  
Intensity Measurements ◽  
Transmission Electron ◽  
Electron Intensity ◽  
Backscattered Electron

The backscattered electron coefficient η for transmission electron microscope specimens depends on both the atomic number Z and the thickness t. Hence for specimens of known atomic number, the thickness can be determined from backscattered electron coefficient measurements. This work describes a simple and convenient method of estimating the thickness and the corrected composition of areas of uncertain atomic number by combining x-ray microanalysis and backscattered electron intensity measurements.The method is best described in terms of the flow chart shown In Figure 1. Having selected a feature of interest, x-ray microanalysis data is recorded and used to estimate the composition. At this stage thickness corrections for absorption and fluorescence are not performed.

Is there a “universal” MAC equation?

1990 ◽  
Vol 48 (2) ◽  
pp. 228-229
Author(s):  
Robert E. Ogilvie
Keyword(s):  
Absorption Coefficient ◽  
Atomic Absorption ◽  
Atomic Number ◽  
X Ray ◽  
Time Period ◽  
Image Position

The search for an empirical absorption equation begins with the work of Siegbahn (1) in 1914. At that time Siegbahn showed that the value of (μ/ρ) for a given element could be expressed as a function of the wavelength (λ) of the x-ray photon by the following equationwhere C is a constant for a given material, which will have sudden jumps in value at critial absorption limits. Siegbahn found that n varied from 2.66 to 2.71 for various solids, and from 2.66 to 2.94 for various gases.Bragg and Pierce (2) , at this same time period, showed that their results on materials ranging from Al(13) to Au(79) could be represented by the followingwhere μa is the atomic absorption coefficient, Z the atomic number. Today equation (2) is known as the “Bragg-Pierce” Law. The exponent of 5/2(n) was questioned by many investigators, and that n should be closer to 3. The work of Wingardh (3) showed that the exponent of Z should be much lower, p = 2.95, however, this is much lower than that found by most investigators.

Contribution of x-ray total reflection to the background intensity in EPMA

1990 ◽  
Vol 48 (2) ◽  
pp. 202-203
Author(s):  
Werner P. Rehbach ◽  
Peter Karduck
Keyword(s):  
Atomic Number ◽  
Target Material ◽  
Total Reflection ◽  
Background Intensity ◽  
X Rays ◽  
Characteristic Radiation ◽  
X Ray

In the EPMA of soft x rays anomalies in the background are found for several elements. In the literature extremely high backgrounds in the region of the OKα line are reported for C, Al, Si, Mo, and Zr. We found the same effect also for Boron (Fig. 1). For small glancing angles θ, the background measured using a LdSte crystal is significantly higher for B compared with BN and C, although the latter are of higher atomic number. It would be expected, that , characteristic radiation missing, the background IB (bremsstrahlung) is proportional Zn by variation of the atomic number of the target material. According to Kramers n has the value of unity, whereas Rao-Sahib and Wittry proposed values between 1.12 and 1.38 , depending on Z, E and Eo. In all cases IB should increase with increasing atomic number Z. The measured values are in discrepancy with the expected ones.

Material Identification in Presence of Metal for Baggage Screening

2020 ◽  
Vol 2020 (14) ◽  
pp. 294-1-294-8
Author(s):  
Sandamali Devadithya ◽  
David Castañón
Keyword(s):  
Atomic Number ◽  
Effective Atomic Number ◽  
Simulated Data ◽  
Dual Energy ◽  
Basis Functions ◽  
Total Variation Regularization ◽  
Ct Scanner ◽  
Edge Preserving ◽  
Baggage Screening ◽  
Dual Energy Imaging

Dual-energy imaging has emerged as a superior way to recognize materials in X-ray computed tomography. To estimate material properties such as effective atomic number and density, one often generates images in terms of basis functions. This requires decomposition of the dual-energy sinograms into basis sinograms, and subsequently reconstructing the basis images. However, the presence of metal can distort the reconstructed images. In this paper we investigate how photoelectric and Compton basis functions, and synthesized monochromatic basis (SMB) functions behave in the presence of metal and its effect on estimation of effective atomic number and density. Our results indicate that SMB functions, along with edge-preserving total variation regularization, show promise for improved material estimation in the presence of metal. The results are demonstrated using both simulated data as well as data collected from a dualenergy medical CT scanner.

A Spectrum-Adaptive Decomposition Method for Effective Atomic Number Estimation Using Dual Energy CT

2020 ◽  
Vol 2020 (14) ◽  
pp. 293-1-293-7
Author(s):  
Ankit Manerikar ◽  
Fangda Li ◽  
Avinash C. Kak
Keyword(s):  
Atomic Number ◽  
Decomposition Method ◽  
Traditional Approach ◽  
Effective Atomic Number ◽  
Dual Energy ◽  
Performance Comparison ◽  
Estimation Methods ◽  
Dual Energy Ct ◽  
Projection Data ◽  
X Ray

Dual Energy Computed Tomography (DECT) is expected to become a significant tool for voxel-based detection of hazardous materials in airport baggage screening. The traditional approach to DECT imaging involves collecting the projection data using two different X-ray spectra and then decomposing the data thus collected into line integrals of two independent characterizations of the material properties. Typically, one of these characterizations involves the effective atomic number (Zeff) of the materials. However, with the X-ray spectral energies typically used for DECT imaging, the current best-practice approaches for dualenergy decomposition yield Zeff values whose accuracy range is limited to only a subset of the periodic-table elements, more specifically to (Z < 30). Although this estimation can be improved by using a system-independent ρe — Ze (SIRZ) space, the SIRZ transformation does not efficiently model the polychromatic nature of the X-ray spectra typically used in physical CT scanners. In this paper, we present a new decomposition method, AdaSIRZ, that corrects this shortcoming by adapting the SIRZ decomposition to the entire spectrum of an X-ray source. The method reformulates the X-ray attenuation equations as direct functions of (ρe, Ze) and solves for the coefficients using bounded nonlinear least-squares optimization. Performance comparison of AdaSIRZ with other Zeff estimation methods on different sets of real DECT images shows that AdaSIRZ provides a higher output accuracy for Zeff image reconstructions for a wider range of object materials.

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