SPATIAL-RESOLUTION OF A DIFFUSION-BASED SILICON NUCLEAR RADIATION DETECTOR

The spatial resolution of a diffusion-based silicon nuclear radiation detector is investigated by analyzing the diffusion process in both vertical and lateral directions. A theoretical model is derived, which is verified by illuminating the detector from the backside with a small light bundle. The model and the measurements show good agreement and it is demonstrated that the spatial resolution mainly depends on the nuclear radiation type. For ionizing particles the spatial resolution is below 1-mu-m and is independent of the detector thickness. For high-energy photons the resolution depends on the absorption depth and was 310-mu-m for the experimental device. Although the spatial resolution for X- and gamma-radiation is rather low, the diffusion-based nuclear radiation detector has an excellent position resolution for nuclear particle radiation.