Electromagnetic deflection system

The electron beam is moved on the surface of the specimen by an electromagnetic deflection system that is integrated in the objective lens moving the beam in a raster over the specimen as mentioned above. The deflection system consists of two sets of crossed... 

With the application of electronics, beam balances are replaced by scale balances (commonly just called scales) that do not directly compare masses. Instead, a scale uses the beam balance principle to quantify an unknown mass by comparing it with a calibrated scale against a known force. The amount of deflection of the scale applied by the unknown mass against the known force determines the quantity of the unknown mass. This tends to simplify the procedure by eliminating the requirement to maintain a set of known comparative masses (a set of standard weights) that are always subject to physical damage, chemical attack, and loss. However, it also requires that the functional force and electromagnetic feedback systems be routinely tested and calibrated. 

Electron-beam deflecting system (electrostatic or electromagnetic)... 

The PIMMS-elements can be divided in the fields of fluidic, plasma physics, electrostatic, and high frequency technology. The fluidic part covers the supply with plasma and sample gas, their distribution inside, and their evacuation out of the system. By means of plasma physics both the ionization of the plasma gas by the microwave field and the ionization of the sample gas by impact ionization are described. Electrostatic theory governs to design the elements for acceleration, focusing, and deflection of the plasma electrons and the sample gas ions. Electromagnetic wave theory describes the creation of a microwave-field inside the plasma chamber. 

The simplest method of beam microbalance operation is to measure the deflection of the ends of the beam by optical magnification. This method has the disadvantage that the maximum weight change that can be observed is limited and the vacuum system must usuaUy be opened to reset the zero point. However, a beam microbalance can be readily converted to a null point instrument by electromagnetic adjustment. A commercially available instrument which features electromagnetic compensation and automatic recording is shown schematicaUy in Fig. 10. 

In the relationship (5) C is the speed of propagation of electromagnetic radiation in a vacuum. At the harmonic approximation, the dependency Ar is sinusoidal. But in the case of molecules, the potential energy is dependent on the momentary deflection Ar of the system in a manner more complicated, so the approximation describes successfully the harmonic oscillations limited to a diatomic molecules. As a result of difficulties with mathematical order but the description of molecular oscillations, especially in the case poliatomice molecules, it accepts harmonic approximation."... 

The total angular momentum is conserved as in Equation 12.41 therefore, locally, the particle currents should be deflected in a finite system. This is numerically demonstrated as the complex eigenvalue of the electronic dielectric constant l(r). The complex eigenvalues of e(r), magnetic permeability p(r), effective charge Z(r), and electric conductance o(r) mean rotational deflected response of electron toward applied electromagnetic field. ... 

Scanning with an SEM is accomplished by the two pairs of electromagnetic coils located within the objective lens (see Figure 21-18) one pair deflects the beam in the. r direction across the sample, and the other pair deflects it in the v direction. Scanning is controlled by applying an electrical signal to one pair of scan coils, such that the electron beam strikes the sample to one side of the center axis of the lens system. By varying... 

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