Radio frequency ion traps which consist of periodical sequence of circular orifices are considered. It is shown that by changing the phase shift for the radio frequency voltages applied to neighboring electrodes from its classical value 180° to a new value 90°, the parasitic local pseudopotential minima and corresponding charge particle trapping regions can be eliminated. The latter can significantly improve the effectiveness of conveying of charged particles by the radio frequency ion traps with ring electrodes used as the ion guides and ion storage devices.

Radio frequency ion guiding traps with periodical electrodes without spurious trapping regions

We investigated the charged micron-sized particle separation by the alternating electric field in a linear quadrupole electrodynamic trap in open air under standard atmospheric temperature and pressure conditions (STP). In experiments we varied the amplitude of the alternating voltage supplying the electrodynamic trap and used a mixture of charged glassy carbon and alumina particles. The carried out numerical simulations and experimental results showed the mutual influence of the amplitude and frequency of the supplied to the trap electrode voltage on the separation of the different sizes particles. The typical particle charges in simulations were approximately equal to experimentally measured values obtained in a corona discharge.

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Microparticle separation in a linear Paul trap

The influence of pulse recurrence frequency on the accuracy of electrochemical machining of steel 08KP, nickel H1, and copper M1 is shown. Variation of the pulse recurrence frequency leads to similar changes in the tool electrode copying accuracy. This allows us to extend the scope of application of the pulsed mode of electrochemical machining. The correlation between the surface passivity and the effects of the pulse mode is demonstrated. A possible explanation of the observed effects using the existing theoretical background regarding the motion of charged particles in nonstationary inhomogeneous electric fields is discussed.

Influence of pulse recurrence frequency on the accuracy of electrochemical machining of nickel, copper, and steel

We consider radio-frequency ion guides formed by electrodes, which are periodic sequences of circular apertures. With the help of pulse voltages arranged as trains of a special type, a relay-switched sequence of axial distributions of the pseudopotential can be organized along the axis of the system in the form of space waves with alternating maxima and minima, which convey charged particles along the conveying channel. The disadvantage of the proposed conveying technology is the obligatory presence of neutral gas in moderate amounts, which dampens the excess kinetic energy acquired by charged particles in the jump-like switching of the radio-frequency electric field. An advantage of the proposed conveying technology is the simplified form of radio-frequency voltages applied to the electrodes of the device and the flexible control of the guiding velocity in Gas Chromatography–Mass Spectrometry interfaces, for example.

Radio-Frequency Ion Guides with Periodical Electrodes and Pulse Voltages

In previous years, a lot of experimental work was done on the factors that affect the breakdown voltage of transformer oil but recently software techniques for optimization gained so much attention. The basic purpose is to analyze the behavior of the properties that affect the breakdown voltage, to optimize the results according to the requirement and to enable the researcher to predict results before the experimental work. As we know, if the applied electric field is provided above a certain limit even for few nano-seconds it could lead to the breakdown of transformer oil. There are certain factors and dielectric properties that affect the breakdown strength of transformer oil and compromising the throughput of the electrical system. The optimization technique used for this purpose is Genetic Algorithm because of its good results, simplicity, and ease of use. It can deal with multiple variables at a time. The considered factors that affect the breakdown voltages are temperature, permittivity, tan δ, viscosity, velocity of the particles. The gap length is considered as 10mm and the factors are optimized around breakdown voltage of 50KV. Generally, oil having breakdown less than 50KV requires oil reconditioning. Considering these factors are leads to analyze many other factor affecting the breakdown voltage.

Optimization of the factors affecting the breakdown voltage of the transformer oil using genetic algorithm

The equations of motion for a charged particle in an electric field featuring a stationary and an oscillating component are considered for the case where the force of friction is linear in the particle velocity. The averaging of these equations over the period of field oscillations is legitimate under some specific conditions. The most general expression for an additional stationary force acting on the particle under these conditions is derived, and the limiting values of this force are found. Applications of the results obtained in the present study are considered. Such applications include the use of pulsed currents in the electrochemical dimensional treatment of materials.

M. A. Solunin

Papers

On the motion of charged particles in an alternating nonuniform electric field