Analysis of background events in Silicon Drift Detectors

Measurements of the energy resolution and the peak-to-background ratio of a Silicon Drift Detector at several positions and biasing voltages are performed. The origins of events with partial charge collection, which contribute to the background, are identified. A model describing the different mechanisms and the spatial distribution of partial events is developed. By optimizing the biasing voltages, an improvement of the peak-to-background ratio of up to 20% is obtained.