Angular distribution of ?-rays from a point source, scattered in shielding

1965 ◽  
Vol 19 (4) ◽  
pp. 1340-1341
Author(s):  
A. V. Larichev

A uniqueness theorem is presented for reflector mappings in the complex plane. These arise in geometrical optics, in the synthesis of a reflector surface to produce a ray beam with specified angular distribution of energy when illuminated by a non-isotropic point-source. The mappings may be represented as solutions of a nonlinear boundary-value problem involving the Monge-Ampère equation. When the equation is elliptic there are at most two solutions, provided that either the incident or far-field ray cone satisfies a convexity condition, which is always the case if one cone is circular. The result has practical application to the design of single and offset dual reflectors used for radar and communications purposes.


1970 ◽  
Vol 29 (2) ◽  
pp. 816-817
Author(s):  
V. F. Kokovikhin ◽  
N. A. Kondurushkin ◽  
V. Ya. Belovintsev ◽  
V. V. Barchugov

Author(s):  
Ryuichi Shimizu ◽  
Ze-Jun Ding

Monte Carlo simulation has been becoming most powerful tool to describe the electron scattering in solids, leading to more comprehensive understanding of the complicated mechanism of generation of various types of signals for microbeam analysis.The present paper proposes a practical model for the Monte Carlo simulation of scattering processes of a penetrating electron and the generation of the slow secondaries in solids. The model is based on the combined use of Gryzinski’s inner-shell electron excitation function and the dielectric function for taking into account the valence electron contribution in inelastic scattering processes, while the cross-sections derived by partial wave expansion method are used for describing elastic scattering processes. An improvement of the use of this elastic scattering cross-section can be seen in the success to describe the anisotropy of angular distribution of elastically backscattered electrons from Au in low energy region, shown in Fig.l. Fig.l(a) shows the elastic cross-sections of 600 eV electron for single Au-atom, clearly indicating that the angular distribution is no more smooth as expected from Rutherford scattering formula, but has the socalled lobes appearing at the large scattering angle.


Author(s):  
D. A. Carpenter ◽  
Ning Gao ◽  
G. J. Havrilla

A monolithic, polycapillary, x-ray optic was adapted to a laboratory-based x-ray microprobe to evaluate the potential of the optic for x-ray micro fluorescence analysis. The polycapillary was capable of collecting x-rays over a 6 degree angle from a point source and focusing them to a spot approximately 40 µm diameter. The high intensities expected from this capillary should be useful for determining and mapping minor to trace elements in materials. Fig. 1 shows a sketch of the capillary with important dimensions.The microprobe had previously been used with straight and with tapered monocapillaries. Alignment of the monocapillaries with the focal spot was accomplished by electromagnetically scanning the focal spot over the beveled anode. With the polycapillary it was also necessary to manually adjust the distance between the focal spot and the polycapillary.The focal distance and focal spot diameter of the polycapillary were determined from a series of edge scans.


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