Over-optimistic computing: concept and approbation in the problem of modeling an electrostatic lens

The subject of research is the possibility of parallelizing loops with dependent iterations and a body, in which the order of execution of operators is strictly defined. Such loops are quite often encountered, for example, in problems of numerical simulation by the method of particles in cells, where at the first stage of the cycle body execution the particles are processed and a certain field determined by them is calculated, and at the second stage a partial differential equation dependent on this field is solved. The possibility of parallelizing the bodies of such cycles is currently insufficiently covered in the literature, this topic is relevant. The ideas of applying predictive (autoregressive point) channels in the programmed transactional memory are used. The implementation is built using object-oriented programming. For the first time, the concept of super-optimistic computing was formulated, that is, working with predictive channels in conditions of partially transactional memory. Mechanisms for the implementation of partially transactional memory, adapted to the use of channels, are proposed. A scheme for parallelizing linearly executed cycle bodies (with dependent loops) on the basis of super-optimistic calculations is proposed, its justification is shown on the example of solving the problem of modeling a beam of charged particles in an electrostatic lens.

Properties of electrostatic correcting systems with annular apertures

Image formation in electron microscopes with circular hole and annular apertures is studied theoretically. The apertures—the circular hole aperture being negative with respect to the annular aperture—produce an additional electrostatic field that exerts a force on the electrons directed toward the optical axis. The resulting deflection angle decreases with increasing distance from the optical axis. This electrostatic field results in a correcting effect of the unavoidable spherical aberration of round electron lenses; the deflection toward the optical axis increases stronger than linearly with increasing distance from the optical axis. Analytical formulae are given for the correcting effect of circular hole and annular apertures. The expressions are based on the Davisson–Calbick formula, which is used to calculate focal length of a simple electrostatic lens.

Plasma Activated Bonding for an Enhanced Alignment Electrostatic Lens

This article presents the design and fabrication of an electrostatic lens unit for the focusing of an electrospray beam. In our design, the post fabrication assembly is eliminated when silicon electrodes and glass spacers are permanently bonded using plasma activated wafer bonding. Minimizing fabrication errors and electrodes misalignment are essential in order to minimize geometrical aberration sources such as astigmatism. Our fabrication process allows etching each electrode in a separate step and eliminates aperture size mismatch. The glass standoffs in the lens unit provide a breakdown voltage of up to 22kV for focusing in vacuum.