The Induced EMF Method as an Alternative to the Iterative Method for the Approximation of the Reflection Coefficient on Thin Wires

Author(s):  
Felix Middelstaedt ◽  
Sergey V. Tkachenko ◽  
Ralf Vick
Author(s):  
G.D. Danilatos

The possibility of placing the specimen in a gaseous medium in the environmental SEM (ESEM) has created novel ways for detection of signals from the beam-specimen interactions. It was originally reported by Oanilatos that the ionization produced by certain signals inside the conditioning medium can be used to produce images. The aim of this report is to demonstrate some of the improvements on the system that have occurred thereafter.Two straight thin wires are aligned horizontally along a direction normal to the direction of the two scintillator backscattered electron (BSE) detectors reported elsewhere. The free end tips of the wires are about 5 mm apart halfway between the specimen and the pressure limiting aperture (specimen distance = 1.5 mm). The other end of each wire makes contact with the input of a separate preamplifier, two of which are built inside a shielding aluminum stub. With such a design, interference noise from the input cables is avoided.


2020 ◽  
pp. 59-63
Author(s):  
A.S. Bondarenko ◽  
A.S. Borovkov ◽  
I.M. Malay ◽  
V.A. Semyonov

The analysis of the current state of the reflection coefficient measurements in waveguides at millimeter waves is carried out. An approach for solving the problem of reproducing the reflection coefficient measurement scale is proposed. Mathematical equations, which are the basis of the reflection coefficient measurement equation are obtained. The method of determining the metrological performance of reflection coefficient unit’s reference standards is developed. The results of electrodynamic modeling and analytical calculations by the developed method are compared. It is shown that this method can be used for reproducing the reflection coefficient unit in the development of the State primary standard.


Author(s):  
M. S. Sudakova ◽  
M. L. Vladov ◽  
M. R. Sadurtdinov

Within the ground penetrating radar bandwidth the medium is considered to be an ideal dielectric, which is not always true. Electromagnetic waves reflection coefficient conductivity dependence showed a significant role of the difference in conductivity in reflection strength. It was confirmed by physical modeling. Conductivity of geological media should be taken into account when solving direct and inverse problems, survey design planning, etc. Ground penetrating radar can be used to solve the problem of mapping of halocline or determine water contamination.


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