Coplanar-grid electrode design of HgI2 detector by finite elements simulation

Polycrystalline mercuric iodide films are being developed as a new detector technology for X-ray imaging at room temperature. In this paper, different electrode patterns were designed by varying the widths of grid and gap. The finite elements analysis was used to simulate the potential distribution of the coplanar-grid detectors. The electrode design of pattern A (the width of grid was 150 μm and the width of gap was 500 μm) was the best. In addition, the influence of edge effects resulting from the asymmetrical electrodes on the potential distribution was discussed. In this way, the geometry of electrodes for coplanar-grid detectors was optimized by widening the second grids near the edges as shown in pattern N.