Parallel processing software shortens simulation run-times

Based on the sequential processing version of Opera's space charge solver SCALA, the module uses code which is optimised for the shared memory architecture of standard PCs and workstations with multi-core processors. Cobham Technical Services claims that by paralleling the solve process, including the existing efficient particle tracking algorithms, the parallel processing version of the space charge solver can shorten simulation run-times significantly.

Access to Opera’s full range of model creation and results analysis tools is provided by the module, which fully integrates with Opera-3d’s Modeller and Post-Processor. Models of complex geometry emitters can be constructed easily and accurately within the 3D Modeller, or imported from CAD systems via industry-standard interfaces such as STEP and IGES, and proprietary formats such as SAT (Standard ACIS Text) and Pro/Engineer. Mesh generation, using tetrahedral, prismatic or hexahedral elements, or a user-defined mix of two or more element types, is performed by the Modeller in preparation for FE analysis. 

A comprehensive set of surface and volume emission models are incorporated by the 3D Space Charge module. These include a range of formulations for thermionic and field effect surface emission, secondary emission from surfaces and from within volumes, and magnetised plasma emission. The latter is a specialised plasma emission module designed for the efficient analysis of magnetron sputter coating systems. User-defined emission models are also supported, allowing, for example, measured emission data to be used. A single model can accommodate multiple emission models and particle species, allowing systems of essentially arbitrary complexity to be simulated.

Emission and the subsequent trajectories of particles in the presence of electric and applied magnetic fields are calculated by the module. The charged particles themselves contribute to the space charge, and so affect the electric field; this is accounted for self-consistently by iterating the trajectory and field solutions until convergence is reached. Dielectric materials, if present in the model, can become charged by particle incidence and produce leakage current flow, further influencing the particle trajectories. Although the effect of the modified space charge is often the dominant factor in determining particle trajectories, in high intensity beams the self-magnetic field generated by the beam current can also be important, and can optionally be included in the simulation. 

The 3D Space Charge module features comprehensive post processing facilities, enabling the designer to extract the maximum information from an analysis. 3D visualisation, together with full colour field overlays and contour maps, allow models and the analysis results to be viewed from any perspective. Particle trajectories may be displayed and colour-coded by metrics such as energy, current or time-of-flight. Intersections of the trajectories with model surfaces may be determined and processed to give, for example, the distributions of beam and deposited current and power density.

Compatible with Opera-3d’s powerful multi-physics capabilities, the module supports simulations that involve more than one physical effect. For example, the temperature rise caused by particles bombarding a surface can be computed, together with the resultant deformation and stress induced by thermal expansion. The deformed structure can subsequently be analysed to determine the effect on the electromagnetic solution – the cycle continuing until a converged solution is reached. 

The 3D Space Charge module is suitable for use in applications such as  X-ray machines, electron microscopes, field emission displays, mass spectrometers, electron beam lithography equipment, ion-beam sources and magnetron sputter coaters.